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• Calling All Agile Customers-Share Your Stories at the Upcoming PLM Summit

  - by Terri Hiskey

  Now that we've closed the door on another Oracle OpenWorld, planning is in full swing for the next PLM Summit, taking place February 4-6, 2013 in San Francisco, in conjunction with the Oracle Value Chain Summit. This event is a must-attend for all Agile PLM customers. We will be holding five tracks with over forty Agile PLM-focused sessions covering a range of topics and industries. If you'd like to be notified once registration is live for this event, be sure to sign up at www.oracle.com/goto/vcs. CALL FOR PRESENTATIONS: We are looking for some fresh, new customer stories to share with attendees. Read below for descriptions of the five tracks, and the suggested topics that we'd like to hear from customers. If you are interested in presenting at the PLM Summit (and getting a FREE pass to attend if your presentation is accepted!) send me an email at terri.hiskey-AT-oracle.com with: Your proposed session title and the track your session fits into 3-5 bullets of takeaways that attendees will get from your presentation Your complete contact information including name, title, company, telephone number and email The deadline for this call for presentations is Thursday, November 15, so get your submission in soon! PLM Track #1:  Product Insights and Best Practices This track will provide executive attendees and line of business managers with an overview of how Agile PLM has been deployed and used at customers to enable and manage critical product-related business processes including enterprise quality and supplier management, compliance, product cost management, portfolio management, commercialization and software lifecycle management. These sessions will also provide details around how to manage the development and rollout of the solutions and how to achieve and track value. Possible session topics: Software Lifecycle Management Enterprise Quality Management New Product Development Integrated Business Planning ECO effectivity planning Rapid Commercialization             Manage the Design to Release Process for Complex Configured Products PLM for Life Sciences Companies I (Compliant Data Set) PLM for Life Sciences Companies II (eMDR, UDI) Discrete CPG – Private Label Mgmt Cost Management and Strategic Sourcing IP Mgmt in the Semiconductor Industry Implementing the Enterprise Training Record using Agile PLM PLM Track #2: Product Deep Dives & Demos This track is aimed at line of business  and IT managers who would like to understand the benefits of expanding their PLM footprint. The sessions in this track will provide attendees with an up-close and in-depth look Agile PLM’s newer and exciting applications, including analytics and innovation management, and will detail features and functionality that are available in the latest version of Agile PLM Possible session topics: Oracle Product Lifecycle Analytics Integrating PLM with Engineering and Supply Chain Systems Streamline PLM Design to Manufacturing Processes with AutoVue Visualization Solutions         Achieve Environmental Compliance (REACH and ROHS) with Agile Product Governance & Compliance PIM Deep Dive Achieving Integrated Change Control with Agile PLM and E-Business Suite Deploying PLM at Small and Midsize Enterprises Enhancing Oracle PQM w/APQP and 8D functionality Advanced Roles and Privileges – Enabling ITAR Model Unit Effectivity Implementing REACH with 9.3.2 Deploying Job Functions, Functional Teams in 9.3.2 to Improve Your Approval Matrix PLM Track #3: Administration & Integrations This track will provide sessions for Agile administrators, managers and daily Agile PLM users who are preparing to upgrade or looking to extend the use of their current PLM implementation through AIA and process extensions. It will include deeper conversation about Agile PLM features and best practices on managing an Agile PLM infrastructure. Possible session topics: Expand the Value of your Agile Investment with Innovative Process Extension Ideas Ensuring Implementation & Upgrade Success Ensure the Integrity and Accuracy of Product Data Across the Enterprise              Maximize the Benefits of an Integrated Architecture with AIA Integrating your PLM Implementation with ERP               Infrastructure Optimization Expanding Your PLM Implementation PLM Administrator Open Forum Q&A/Discussion FDA Validation Best Practices Best Practices for Managing a large Agile Deployment: Clustering, Load Balancing and Firewalls PLM Track #4: Agile PLM for Process This track is aimed at attendees interested in or currently using Agile PLM for Process. The sessions in this track will go over new features and functionality available in the newest version of PLM for Process and will give attendees an overview on how PLM for Process is being used to manage critical business processes such as formulation, recipe and specification management Possible session topics: PLM for Process Strategy, Roadmap and Update New Product Development and Introduction Effective Product Supplier Collaboration             Leverage Agile Formulation and Compliance to Manage Cost, Compliance, Quality, Labeling and Nutrition Menu Management Innovation Data Management Food Safety/ Introduction of P4P Quality Mgmt PLM Track #5: Agile PLM and Innovation Management This track consists of five sessions, and is for attendees interested in learning more about Oracle’s Agile Innovation Management, an exciting new addition to the Agile PLM application family that redefines the industry’s scope of product lifecycle management. Oracle’s innovation solutions enable companies to collaborate in a focused way among various functional groups (marketing, sales, operations, engineering/R&D and sourcing), combining insights of customer needs/requirements, competition, available technologies, alternate design scenarios and portfolio constraints to deliver what customers truly value. The results are better products, higher margins, greater efficiencies, more satisfied customers and the increased ability to continuously innovate. Possible session topics: Product Innovation Management Solution Overview Product Requirements & Ideation Management Concept Design Management Product Lifecycle Portfolio Management Innovation as a Competitive Differentiator

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• An issue with tessellation a model with DirectX11

  - by Paul Ske

  I took the hardware tessellation tutorial from Rastertek and implemended texturing instead of color. This is great, so I wanted to implemended the same techique to a model inside my game editor and I noticed it doesn't draw anything. I compared the detailed tessellation from DirectX SDK sample. Inside the shader file - if I replace the HullInputType with PixelInputType it draws. So, I think because when I compiled the shaders inside the program it compiles VertexShader, PixelShader, HullShader then DomainShader. Isn't it suppose to be VertexShader, HullSHader, DomainShader then PixelShader or does it really not matter? I am just curious why wouldn't the model even be drawn when HullInputType but renders fine with PixelInputType. Shader Code: [code] cbuffer ConstantBuffer { float4x4 WVP; float4x4 World; // the rotation matrix float3 lightvec; // the light's vector float4 lightcol; // the light's color float4 ambientcol; // the ambient light's color bool isSelected; } cbuffer cameraBuffer { float3 cameraDirection; float padding; } cbuffer TessellationBuffer { float tessellationAmount; float3 padding2; } struct ConstantOutputType { float edges[3] : SV_TessFactor; float inside : SV_InsideTessFactor; }; Texture2D Texture; Texture2D NormalTexture; SamplerState ss { MinLOD = 5.0f; MipLODBias = 0.0f; }; struct HullOutputType { float3 position : POSITION; float2 texcoord : TEXCOORD0; float3 normal : NORMAL; float3 tangent : TANGENT; }; struct HullInputType { float4 position : POSITION; float2 texcoord : TEXCOORD0; float3 normal : NORMAL; float3 tangent : TANGENT; }; struct VertexInputType { float4 position : POSITION; float2 texcoord : TEXCOORD; float3 normal : NORMAL; float3 tangent : TANGENT; uint uVertexID : SV_VERTEXID; }; struct PixelInputType { float4 position : SV_POSITION; float2 texcoord : TEXCOORD0; // texture coordinates float3 normal : NORMAL; float3 tangent : TANGENT; float4 color : COLOR; float3 viewDirection : TEXCOORD1; float4 depthBuffer : TEXTURE0; }; HullInputType VShader(VertexInputType input) { HullInputType output; output.position.w = 1.0f; output.position = mul(input.position,WVP); output.texcoord = input.texcoord; output.normal = input.normal; output.tangent = input.tangent; //output.normal = mul(normal,World); //output.tangent = mul(tangent,World); //output.color = output.color; //output.texcoord = texcoord; // set the texture coordinates, unmodified return output; } ConstantOutputType TexturePatchConstantFunction(InputPatch inputPatch,uint patchID : SV_PrimitiveID) { ConstantOutputType output; output.edges[0] = tessellationAmount; output.edges[1] = tessellationAmount; output.edges[2] = tessellationAmount; output.inside = tessellationAmount; return output; } [domain("tri")] [partitioning("integer")] [outputtopology("triangle_cw")] [outputcontrolpoints(3)] [patchconstantfunc("TexturePatchConstantFunction")] HullOutputType HShader(InputPatch patch, uint pointId : SV_OutputControlPointID, uint patchId : SV_PrimitiveID) { HullOutputType output; // Set the position for this control point as the output position. output.position = patch[pointId].position; // Set the input color as the output color. output.texcoord = patch[pointId].texcoord; output.normal = patch[pointId].normal; output.tangent = patch[pointId].tangent; return output; } [domain("tri")] PixelInputType DShader(ConstantOutputType input, float3 uvwCoord : SV_DomainLocation, const OutputPatch patch) { float3 vertexPosition; float2 uvPosition; float4 worldposition; PixelInputType output; // Interpolate world space position with barycentric coordinates float3 vWorldPos = uvwCoord.x * patch[0].position + uvwCoord.y * patch[1].position + uvwCoord.z * patch[2].position; // Determine the position of the new vertex. vertexPosition = vWorldPos; // Calculate the position of the new vertex against the world, view, and projection matrices. output.position = mul(float4(vertexPosition, 1.0f),WVP); // Send the input color into the pixel shader. output.texcoord = uvwCoord.x * patch[0].position + uvwCoord.y * patch[1].position + uvwCoord.z * patch[2].position; output.normal = uvwCoord.x * patch[0].position + uvwCoord.y * patch[1].position + uvwCoord.z * patch[2].position; output.tangent = uvwCoord.x * patch[0].position + uvwCoord.y * patch[1].position + uvwCoord.z * patch[2].position; //output.depthBuffer = output.position; //output.depthBuffer.w = 1.0f; //worldposition = mul(output.position,WVP); //output.viewDirection = cameraDirection.xyz - worldposition.xyz; //output.viewDirection = normalize(output.viewDirection); return output; } [/code] Somethings are commented out but will be in place when fixed. I'm probably not connecting something correctly.

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• List of Commonly Used Value Types in XNA Games

  - by Michael B. McLaughlin

  Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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• Simple Preferred time control using silverlight 3.

  - by mohanbrij

  Here I am going to show you a simple preferred time control, where you can select the day of the week and the time of the day. This can be used in lots of place where you may need to display the users preferred times. Sample screenshot is attached below. This control is developed using Silverlight 3 and VS2008, I am also attaching the source code with this post. This is a very basic example. You can download and customize if further for your requirement if you want. I am trying to explain in few words how this control works and what are the different ways in which you can customize it further. File: PreferredTimeControl.xaml, in this file I have just hardcoded the controls and their positions which you can see in the screenshot above. In this example, to change the start day of the week and time, you will have to go and change the design in XAML file, its not controlled by your properties or implementation classes. You can also customize it to change the start day of the week, Language, Display format, styles, etc, etc. File: PreferredTimeControl.xaml.cs, In this control using the code below, first I am taking all the checkbox from my form and store it in the Global Variable, which I can use across my page. List<CheckBox> checkBoxList; #region Constructor public PreferredTimeControl() { InitializeComponent(); GetCheckboxes();//Keep all the checkbox in List in the Load itself } #endregion #region Helper Methods private List<CheckBox> GetCheckboxes() { //Get all the CheckBoxes in the Form checkBoxList = new List<CheckBox>(); foreach (UIElement element in LayoutRoot.Children) { if (element.GetType().ToString() == "System.Windows.Controls.CheckBox") { checkBoxList.Add(element as CheckBox); } } return checkBoxList; } Then I am exposing the two methods which you can use in the container form to get and set the values in this controls. /// <summary> /// Set the Availability on the Form, with the Provided Timings /// </summary> /// <param name="selectedTimings">Provided timings comes from the DB in the form 11,12,13....37 /// Where 11 refers to Monday Morning, 12 Tuesday Morning, etc /// Here 1, 2, 3 is for Morning, Afternoon and Evening respectively, and for weekdays /// 1,2,3,4,5,6,7 where 1 is for Monday, Tuesday, Wednesday, Thrusday, Friday, Saturday and Sunday respectively /// So if we want Monday Morning, we can can denote it as 11, similarly for Saturday Evening we can write 36, etc /// </param> public void SetAvailibility(string selectedTimings) { foreach (CheckBox chk in checkBoxList) { chk.IsChecked = false; } if (!String.IsNullOrEmpty(selectedTimings)) { string[] selectedString = selectedTimings.Split(','); foreach (string selected in selectedString) { foreach (CheckBox chk in checkBoxList) { if (chk.Tag.ToString() == selected) { chk.IsChecked = true; } } } } } /// <summary> /// Gets the Availibility from the selected checkboxes /// </summary> /// <returns>String in the format of 11,12,13...41,42...31,32...37</returns> public string GetAvailibility() { string selectedText = string.Empty; foreach (CheckBox chk in GetCheckboxes()) { if (chk.IsChecked == true) { selectedText = chk.Tag.ToString() + "," + selectedText; } } return selectedText; }   In my example I am using the matrix format for Day and Time, for example Monday=1, Tuesday=2, Wednesday=3, Thursday = 4, Friday = 5, Saturday = 6, Sunday=7. And Morning = 1, Afternoon =2, Evening = 3. So if I want to represent Morning-Monday I will have to represent it as 11, Afternoon-Tuesday as 22, Morning-Wednesday as 13, etc. And in the other way to set the values in the control I am passing the values in the control in the same format as preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); So this will set the checkbox value for Morning-Monday, Morning-Tuesday, Morning-Wednesday, Morning-Saturday, Afternoon of Tuesday and Afternoon of Wednesday. To implement this control, first I have to import this control in xmlns namespace as xmlns:controls="clr-namespace:PreferredTimeControlApp" and finally put in your page wherever you want, <Grid x:Name="LayoutRoot" Style="{StaticResource LayoutRootGridStyle}"> <Border x:Name="ContentBorder" Style="{StaticResource ContentBorderStyle}"> <controls:PreferredTimeControl x:Name="preferredTimeControl"></controls:PreferredTimeControl> </Border> </Grid> And in the code behind you can just include this code: private void InitializeControl() { preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); } And you are ready to go. For more details you can refer to my code attached. I know there can be even simpler and better way to do this. Let me know if any other ideas. Sorry, Guys Still I have used Silverlight 3 and VS2008, as from the system I am uploading this is still not upgraded, but still you can use the same code with Silverlight 4 and VS2010 without any changes. May be just it will ask you to upgrade your project which will take care of rest. Download Source Code.   Thanks ~Brij

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• Downloading stuff from Oracle: an example

  - by user12587121

  Introduction Oracle has a lot of software on offer.  Components of the stack can evolve at different rates and different versions of the components may be in use at any given time.  All this means that even the process of downloading the bits you need can be somewhat daunting.  Here, by way of example, and hopefully to convince you that there is method in the downloading madness,  we describe how to go about downloading the bits for Oracle Identity Manager  (OIM) 11.1.1.5.Firstly, a couple of preliminary points: Folks with Oracle products already installed and looking for bug fixes, patch bundles or patch sets would go directly to the Oracle support website. This Oracle document is a comprehensive description of the Oracle FMW download process and the licensing that applies to downloaded software.   Downloading Oracle Identity Manager 11.1.1.5     To be sure we download the right versions, first locate the Certification Matrix for OIM 11.1.1.5: first go to the Fusion Certification Page then go to the “System Requirements and Supported Platforms for Oracle Identity and Access Management 11gR1” link. Let’s assume you have a 64 bit Linux Machine and an Oracle database already.  Then our  goal is to end up with a list of files like the following: jdk-6u29-linux-x64.bin                    (Java JDK)V26017-01.zip                             (the Repository Creation Utility to create the DB schemas)wls1035_generic.jar                       (the Weblogic Application Server)ofm_iam_generic_11.1.1.5.0_disk1_1of1.zip (the Identity Managament bits)ofm_soa_generic_11.1.1.5.0_disk1_1of2.zip (the SOA bits)ofm_soa_generic_11.1.1.5.0_disk1_2of2.zip jdevstudio11115install.exe                (optional: JDeveloper IDE)soa-jdev-extension.zip                    (optional: SOA extensions for JDeveloper) Downloading the bits 1.    Download the Java JDK, 64 bit version 1.6.0_24+.2.    Download the RCU: here you will see that the RCU is mentioned on the Identity Management home page but no link is provided.  Do not panic.  Due to the amount and turnover of software available only the latest versions are available for download from the main Oracle site.  Over time software gets moved on to the Oracle edelivery site and it is here that we find the RCU version we require: a.    Go to edelivery: https://edelivery.oracle.com b.    Choose Pack ‘ Oracle Fusion Middleware’ and ‘Linux x86-64’ c.    Click on ‘Oracle Fusion Middleware 11g Media Pack for Linux x86-64’ d.    Download: ‘Oracle Fusion Middleware Repository Creation Utility 11g (11.1.1.5.0) for Linux x86’ (V26017.zip) 3.    Download the Weblogic Application Server: WLS 10.3.54.    Download the Oracle Identity Manager bits: one point to clarify here is that currently  the Identity Management bits come in two trains, essentially one for the Directory Services piece and the other for the Access Management and Identity Management parts.  We need to be careful not to confuse the two, in particular to be clear which of the trains is being referred to by  the documentation: a.   So, with this in mind, go to ‘ Oracle Identity and Access Management (11.1.1.5.0)’ and download Disk1. 5.    Download the SOA bits: a.    Go to the edelivery area as for the RCU and download: i.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 1 of 2) ii.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 2 of 2) 6.    You will want to download some development tooling (for plugins or BPEL workflow development): a.    Download Jdeveloper 11.1.1.5 (11.1.1.6 may work but best to stick to the versions that correspond to the WLS version we are using) b.    Go to the site for  SOA tools and download the SOA Composite Editor 11.1.1.5 That’s it, you may proceed to the installation. 

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• Off center projection

  - by N0xus

  I'm trying to implement the code that was freely given by a very kind developer at the following link: http://forum.unity3d.com/threads/142383-Code-sample-Off-Center-Projection-Code-for-VR-CAVE-or-just-for-fun Right now, all I'm trying to do is bring it in on one camera, but I have a few issues. My class, looks as follows: using UnityEngine; using System.Collections; public class PerspectiveOffCenter : MonoBehaviour { // Use this for initialization void Start () { } // Update is called once per frame void Update () { } public static Matrix4x4 GeneralizedPerspectiveProjection(Vector3 pa, Vector3 pb, Vector3 pc, Vector3 pe, float near, float far) { Vector3 va, vb, vc; Vector3 vr, vu, vn; float left, right, bottom, top, eyedistance; Matrix4x4 transformMatrix; Matrix4x4 projectionM; Matrix4x4 eyeTranslateM; Matrix4x4 finalProjection; ///Calculate the orthonormal for the screen (the screen coordinate system vr = pb - pa; vr.Normalize(); vu = pc - pa; vu.Normalize(); vn = Vector3.Cross(vr, vu); vn.Normalize(); //Calculate the vector from eye (pe) to screen corners (pa, pb, pc) va = pa-pe; vb = pb-pe; vc = pc-pe; //Get the distance;; from the eye to the screen plane eyedistance = -(Vector3.Dot(va, vn)); //Get the varaibles for the off center projection left = (Vector3.Dot(vr, va)*near)/eyedistance; right = (Vector3.Dot(vr, vb)*near)/eyedistance; bottom = (Vector3.Dot(vu, va)*near)/eyedistance; top = (Vector3.Dot(vu, vc)*near)/eyedistance; //Get this projection projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); //Fill in the transform matrix transformMatrix = new Matrix4x4(); transformMatrix[0, 0] = vr.x; transformMatrix[0, 1] = vr.y; transformMatrix[0, 2] = vr.z; transformMatrix[0, 3] = 0; transformMatrix[1, 0] = vu.x; transformMatrix[1, 1] = vu.y; transformMatrix[1, 2] = vu.z; transformMatrix[1, 3] = 0; transformMatrix[2, 0] = vn.x; transformMatrix[2, 1] = vn.y; transformMatrix[2, 2] = vn.z; transformMatrix[2, 3] = 0; transformMatrix[3, 0] = 0; transformMatrix[3, 1] = 0; transformMatrix[3, 2] = 0; transformMatrix[3, 3] = 1; //Now for the eye transform eyeTranslateM = new Matrix4x4(); eyeTranslateM[0, 0] = 1; eyeTranslateM[0, 1] = 0; eyeTranslateM[0, 2] = 0; eyeTranslateM[0, 3] = -pe.x; eyeTranslateM[1, 0] = 0; eyeTranslateM[1, 1] = 1; eyeTranslateM[1, 2] = 0; eyeTranslateM[1, 3] = -pe.y; eyeTranslateM[2, 0] = 0; eyeTranslateM[2, 1] = 0; eyeTranslateM[2, 2] = 1; eyeTranslateM[2, 3] = -pe.z; eyeTranslateM[3, 0] = 0; eyeTranslateM[3, 1] = 0; eyeTranslateM[3, 2] = 0; eyeTranslateM[3, 3] = 1f; //Multiply all together finalProjection = new Matrix4x4(); finalProjection = Matrix4x4.identity * projectionM*transformMatrix*eyeTranslateM; //finally return return finalProjection; } // Update is called once per frame public void FixedUpdate () { Camera cam = camera; //calculate projection Matrix4x4 genProjection = GeneralizedPerspectiveProjection( new Vector3(0,1,0), new Vector3(1,1,0), new Vector3(0,0,0), new Vector3(0,0,0), cam.nearClipPlane, cam.farClipPlane); //(BottomLeftCorner, BottomRightCorner, TopLeftCorner, trackerPosition, cam.nearClipPlane, cam.farClipPlane); cam.projectionMatrix = genProjection; } } My error lies in projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); The debugger states: Expression denotes a `type', where a 'variable', 'value' or 'method group' was expected. Thus, I changed the line to read: projectionM = new PerspectiveOffCenter(left, right, bottom, top, near, far); But then the error is changed to: The type 'PerspectiveOffCenter' does not contain a constructor that takes '6' arguments. For reasons that are obvious. So, finally, I changed the line to read: projectionM = new GeneralizedPerspectiveProjection(left, right, bottom, top, near, far); And the error I get is: is a 'method' but a 'type' was expected. With this last error, I'm not sure what it is I should do / missing. Can anyone see what it is that I'm missing to fix this error?

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• CSM DX11 issues

  - by KaiserJohaan

  I got CSM to work in OpenGL, and now Im trying to do the same in directx. I'm using the same math library and all and I'm pretty much using the alghorithm straight off. I am using right-handed, column major matrices from GLM. The light is looking (-1, -1, -1). The problem I have is twofolds; For some reason, the ground floor is causing alot of (false) shadow artifacts, like the vast shadowed area you see. I confirmed this when I disabled the ground for the depth pass, but thats a hack more than anything else The shadows are inverted compared to the shadowmap. If you squint you can see the chairs shadows should be mirrored instead. This is the first cascade shadow map, in range of the alien and the chair: I can't figure out why this is. This is the depth pass: for (uint32_t cascadeIndex = 0; cascadeIndex < NUM_SHADOWMAP_CASCADES; cascadeIndex++) { mShadowmap.BindDepthView(context, cascadeIndex); CameraFrustrum cameraFrustrum = CalculateCameraFrustrum(degreesFOV, aspectRatio, nearDistArr[cascadeIndex], farDistArr[cascadeIndex], cameraViewMatrix); lightVPMatrices[cascadeIndex] = CreateDirLightVPMatrix(cameraFrustrum, lightDir); mVertexTransformPass.RenderMeshes(context, renderQueue, meshes, lightVPMatrices[cascadeIndex]); lightVPMatrices[cascadeIndex] = gBiasMatrix * lightVPMatrices[cascadeIndex]; farDistArr[cascadeIndex] = -farDistArr[cascadeIndex]; } CameraFrustrum CalculateCameraFrustrum(const float fovDegrees, const float aspectRatio, const float minDist, const float maxDist, const Mat4& cameraViewMatrix) { CameraFrustrum ret = { Vec4(1.0f, 1.0f, -1.0f, 1.0f), Vec4(1.0f, -1.0f, -1.0f, 1.0f), Vec4(-1.0f, -1.0f, -1.0f, 1.0f), Vec4(-1.0f, 1.0f, -1.0f, 1.0f), Vec4(1.0f, -1.0f, 1.0f, 1.0f), Vec4(1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, 1.0f, 1.0f, 1.0f), Vec4(-1.0f, -1.0f, 1.0f, 1.0f), }; const Mat4 perspectiveMatrix = PerspectiveMatrixFov(fovDegrees, aspectRatio, minDist, maxDist); const Mat4 invMVP = glm::inverse(perspectiveMatrix * cameraViewMatrix); for (Vec4& corner : ret) { corner = invMVP * corner; corner /= corner.w; } return ret; } Mat4 CreateDirLightVPMatrix(const CameraFrustrum& cameraFrustrum, const Vec3& lightDir) { Mat4 lightViewMatrix = glm::lookAt(Vec3(0.0f), -glm::normalize(lightDir), Vec3(0.0f, -1.0f, 0.0f)); Vec4 transf = lightViewMatrix * cameraFrustrum[0]; float maxZ = transf.z, minZ = transf.z; float maxX = transf.x, minX = transf.x; float maxY = transf.y, minY = transf.y; for (uint32_t i = 1; i < 8; i++) { transf = lightViewMatrix * cameraFrustrum[i]; if (transf.z > maxZ) maxZ = transf.z; if (transf.z < minZ) minZ = transf.z; if (transf.x > maxX) maxX = transf.x; if (transf.x < minX) minX = transf.x; if (transf.y > maxY) maxY = transf.y; if (transf.y < minY) minY = transf.y; } Mat4 viewMatrix(lightViewMatrix); viewMatrix[3][0] = -(minX + maxX) * 0.5f; viewMatrix[3][1] = -(minY + maxY) * 0.5f; viewMatrix[3][2] = -(minZ + maxZ) * 0.5f; viewMatrix[0][3] = 0.0f; viewMatrix[1][3] = 0.0f; viewMatrix[2][3] = 0.0f; viewMatrix[3][3] = 1.0f; Vec3 halfExtents((maxX - minX) * 0.5, (maxY - minY) * 0.5, (maxZ - minZ) * 0.5); return OrthographicMatrix(-halfExtents.x, halfExtents.x, -halfExtents.y, halfExtents.y, halfExtents.z, -halfExtents.z) * viewMatrix; } And this is the pixel shader used for the lighting stage: #define DEPTH_BIAS 0.0005 #define NUM_CASCADES 4 cbuffer DirectionalLightConstants : register(CBUFFER_REGISTER_PIXEL) { float4x4 gSplitVPMatrices[NUM_CASCADES]; float4x4 gCameraViewMatrix; float4 gSplitDistances; float4 gLightColor; float4 gLightDirection; }; Texture2D gPositionTexture : register(TEXTURE_REGISTER_POSITION); Texture2D gDiffuseTexture : register(TEXTURE_REGISTER_DIFFUSE); Texture2D gNormalTexture : register(TEXTURE_REGISTER_NORMAL); Texture2DArray gShadowmap : register(TEXTURE_REGISTER_DEPTH); SamplerComparisonState gShadowmapSampler : register(SAMPLER_REGISTER_DEPTH); float4 ps_main(float4 position : SV_Position) : SV_Target0 { float4 worldPos = gPositionTexture[uint2(position.xy)]; float4 diffuse = gDiffuseTexture[uint2(position.xy)]; float4 normal = gNormalTexture[uint2(position.xy)]; float4 camPos = mul(gCameraViewMatrix, worldPos); uint index = 3; if (camPos.z > gSplitDistances.x) index = 0; else if (camPos.z > gSplitDistances.y) index = 1; else if (camPos.z > gSplitDistances.z) index = 2; float3 projCoords = (float3)mul(gSplitVPMatrices[index], worldPos); float viewDepth = projCoords.z - DEPTH_BIAS; projCoords.z = float(index); float visibilty = gShadowmap.SampleCmpLevelZero(gShadowmapSampler, projCoords, viewDepth); float angleNormal = clamp(dot(normal, gLightDirection), 0, 1); return visibilty * diffuse * angleNormal * gLightColor; } As you can see I am using depth bias and a bias matrix. Any hints on why this behaves so wierdly?

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• Not getting desired results with SSAO implementation

  - by user1294203

  After having implemented deferred rendering, I tried my luck with a SSAO implementation using this Tutorial. Unfortunately, I'm not getting anything that looks like SSAO, you can see my result below. You can see there is some weird pattern forming and there is no occlusion shading where there needs to be (i.e. in between the objects and on the ground). The shaders I implemented follow: #VS #version 330 core uniform mat4 invProjMatrix; layout(location = 0) in vec3 in_Position; layout(location = 2) in vec2 in_TexCoord; noperspective out vec2 pass_TexCoord; smooth out vec3 viewRay; void main(void){ pass_TexCoord = in_TexCoord; viewRay = (invProjMatrix * vec4(in_Position, 1.0)).xyz; gl_Position = vec4(in_Position, 1.0); } #FS #version 330 core uniform sampler2D DepthMap; uniform sampler2D NormalMap; uniform sampler2D noise; uniform vec2 projAB; uniform ivec3 noiseScale_kernelSize; uniform vec3 kernel[16]; uniform float RADIUS; uniform mat4 projectionMatrix; noperspective in vec2 pass_TexCoord; smooth in vec3 viewRay; layout(location = 0) out float out_AO; vec3 CalcPosition(void){ float depth = texture(DepthMap, pass_TexCoord).r; float linearDepth = projAB.y / (depth - projAB.x); vec3 ray = normalize(viewRay); ray = ray / ray.z; return linearDepth * ray; } mat3 CalcRMatrix(vec3 normal, vec2 texcoord){ ivec2 noiseScale = noiseScale_kernelSize.xy; vec3 rvec = texture(noise, texcoord * noiseScale).xyz; vec3 tangent = normalize(rvec - normal * dot(rvec, normal)); vec3 bitangent = cross(normal, tangent); return mat3(tangent, bitangent, normal); } void main(void){ vec2 TexCoord = pass_TexCoord; vec3 Position = CalcPosition(); vec3 Normal = normalize(texture(NormalMap, TexCoord).xyz); mat3 RotationMatrix = CalcRMatrix(Normal, TexCoord); int kernelSize = noiseScale_kernelSize.z; float occlusion = 0.0; for(int i = 0; i < kernelSize; i++){ // Get sample position vec3 sample = RotationMatrix * kernel[i]; sample = sample * RADIUS + Position; // Project and bias sample position to get its texture coordinates vec4 offset = projectionMatrix * vec4(sample, 1.0); offset.xy /= offset.w; offset.xy = offset.xy * 0.5 + 0.5; // Get sample depth float sample_depth = texture(DepthMap, offset.xy).r; float linearDepth = projAB.y / (sample_depth - projAB.x); if(abs(Position.z - linearDepth ) < RADIUS){ occlusion += (linearDepth <= sample.z) ? 1.0 : 0.0; } } out_AO = 1.0 - (occlusion / kernelSize); } I draw a full screen quad and pass Depth and Normal textures. Normals are in RGBA16F with the alpha channel reserved for the AO factor in the blur pass. I store depth in a non linear Depth buffer (32F) and recover the linear depth using: float linearDepth = projAB.y / (depth - projAB.x); where projAB.y is calculated as: and projAB.x as: These are derived from the glm::perspective(gluperspective) matrix. z_n and z_f are the near and far clip distance. As described in the link I posted on the top, the method creates samples in a hemisphere with higher distribution close to the center. It then uses random vectors from a texture to rotate the hemisphere randomly around the Z direction and finally orients it along the normal at the given pixel. Since the result is noisy, a blur pass follows the SSAO pass. Anyway, my position reconstruction doesn't seem to be wrong since I also tried doing the same but with the position passed from a texture instead of being reconstructed. I also tried playing with the Radius, noise texture size and number of samples and with different kinds of texture formats, with no luck. For some reason when changing the Radius, nothing changes. Does anyone have any suggestions? What could be going wrong?

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• OpenGL 3 and the Radeon HD 4850x2

  - by rotard

  A while ago, I picked up a copy of the OpenGL SuperBible fifth edition and slowly and painfully started teaching myself OpenGL the 3.3 way, after having been used to the 1.0 way from school way back when. Making things more challenging, I am primarily a .NET developer, so I was working in Mono with the OpenTK OpenGL wrapper. On my laptop, I put together a program that let the user walk around a simple landscape using a couple shaders that implemented per-vertex coloring and lighting and texture mapping. Everything was working brilliantly until I ran the same program on my desktop. Disaster! Nothing would render! I have chopped my program down to the point where the camera sits near the origin, pointing at the origin, and renders a square (technically, a triangle fan). The quad renders perfectly on my laptop, coloring, lighting, texturing and all, but the desktop renders a small distorted non-square quadrilateral that is colored incorrectly, not affected by the lights, and not textured. I suspect the graphics card is at fault, because I get the same result whether I am booted into Ubuntu 10.10 or Win XP. I did find that if I pare the vertex shader down to ONLY outputting the positional data and the fragment shader to ONLY outputting a solid color (white) the quad renders correctly. But as SOON as I start passing in color data (whether or not I use it in the fragment shader) the output from the vertex shader is distorted again. The shaders follow. I left the pre-existing code in, but commented out so you can get an idea what I was trying to do. I'm a noob at glsl so the code could probably be a lot better. My laptop is an old lenovo T61p with a Centrino (Core 2) Duo and an nVidia Quadro graphics card running Ubuntu 10.10 My desktop has an i7 with a Radeon HD 4850 x2 (single card, dual GPU) from Saphire dual booting into Ubuntu 10.10 and Windows XP. The problem occurs in both XP and Ubuntu. Can anyone see something wrong that I am missing? What is "special" about my HD 4850x2? string vertexShaderSource = @" #version 330 precision highp float; uniform mat4 projection_matrix; uniform mat4 modelview_matrix; //uniform mat4 normal_matrix; //uniform mat4 cmv_matrix; //Camera modelview. Light sources are transformed by this matrix. //uniform vec3 ambient_color; //uniform vec3 diffuse_color; //uniform vec3 diffuse_direction; in vec4 in_position; in vec4 in_color; //in vec3 in_normal; //in vec3 in_tex_coords; out vec4 varyingColor; //out vec3 varyingTexCoords; void main(void) { //Get surface normal in eye coordinates //vec4 vEyeNormal = normal_matrix * vec4(in_normal, 0); //Get vertex position in eye coordinates //vec4 vPosition4 = modelview_matrix * vec4(in_position, 0); //vec3 vPosition3 = vPosition4.xyz / vPosition4.w; //Get vector to light source in eye coordinates //vec3 lightVecNormalized = normalize(diffuse_direction); //vec3 vLightDir = normalize((cmv_matrix * vec4(lightVecNormalized, 0)).xyz); //Dot product gives us diffuse intensity //float diff = max(0.0, dot(vEyeNormal.xyz, vLightDir.xyz)); //Multiply intensity by diffuse color, force alpha to 1.0 //varyingColor.xyz = in_color * diff * diffuse_color.xyz; varyingColor = in_color; //varyingTexCoords = in_tex_coords; gl_Position = projection_matrix * modelview_matrix * in_position; }"; string fragmentShaderSource = @" #version 330 //#extension GL_EXT_gpu_shader4 : enable precision highp float; //uniform sampler2DArray colorMap; //in vec4 varyingColor; //in vec3 varyingTexCoords; out vec4 out_frag_color; void main(void) { out_frag_color = vec4(1,1,1,1); //out_frag_color = varyingColor; //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, varyingTexCoords.st); //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, vec3(varyingTexCoords.st, 0)); //out_frag_color = vec4(varyingColor, 1) * texture2DArray(colorMap, varyingTexCoords); }"; Note that in this code the color data is accepted but not actually used. The geometry is outputted the same (wrong) whether the fragment shader uses varyingColor or not. Only if I comment out the line varyingColor = in_color; does the geometry output correctly. Originally the shaders took in vec3 inputs, I only modified them to take vec4s while troubleshooting.

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• Understanding implementation of glu.PickMatrix()

  - by stoney78us

  I am working on an OpenGL project which requires object selection feature. I use OpenTK framework to do this; however OpenTK doesn't support glu.PickMatrix() method to define the picking region. I ended up googling its implementation and here is what i got: void GluPickMatrix(double x, double y, double deltax, double deltay, int[] viewport) { if (deltax <= 0 || deltay <= 0) { return; } GL.Translate((viewport[2] - 2 * (x - viewport[0])) / deltax, (viewport[3] - 2 * (y - viewport[1])) / deltay, 0); GL.Scale(viewport[2] / deltax, viewport[3] / deltay, 1.0); } I totally fail to understand this piece of code. Moreover, this doesn't work with my following code sample: //selectbuffer private int[] _selectBuffer = new int[512]; private void Init() { float[] triangleVertices = new float[] { 0.0f, 1.0f, 0.0f, -1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f }; float[] _triangleColors = new float[] { 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f }; GL.GenBuffers(2, _vBO); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleVertices.Length), _triangleVertices, BufferUsageHint.StaticDraw); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[1]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleColors.Length), _triangleColors, BufferUsageHint.StaticDraw); GL.ColorPointer(3, ColorPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.ColorArray); //Selectbuffer set up GL.SelectBuffer(512, _selectBuffer); } private void glControlWindow_Paint(object sender, PaintEventArgs e) { GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); float[] eyes = { 0.0f, 0.0f, -10.0f }; float[] target = { 0.0f, 0.0f, 0.0f }; Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); //45 degree = 0.785398163 rads Matrix4 view = Matrix4.LookAt(eyes[0], eyes[1], eyes[2], target[0], target[1], target[2], 0, 1, 0); Matrix4 model = Matrix4.Identity; Matrix4 MV = view * model; //First Clear Buffers GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); GL.LoadIdentity(); GL.LoadMatrix(ref MV); GL.Viewport(0, 0, glControlWindow.Width, glControlWindow.Height); GL.Enable(EnableCap.DepthTest); //Enable correct Z Drawings GL.DepthFunc(DepthFunction.Less); //Enable correct Z Drawings GL.MatrixMode(MatrixMode.Modelview); GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); //Finally... GraphicsContext.CurrentContext.VSync = true; //Caps frame rate as to not over run GPU glControlWindow.SwapBuffers(); //Takes from the 'GL' and puts into control } private void DrawTriangle() { GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.DrawArrays(BeginMode.Triangles, 0, 3); GL.DisableClientState(ArrayCap.VertexArray); } //mouse click event implementation private void glControlWindow_MouseClick(object sender, System.Windows.Forms.MouseEventArgs e) { //Enter Select mode. Pretend drawing. GL.RenderMode(RenderingMode.Select); int[] viewport = new int[4]; GL.GetInteger(GetPName.Viewport, viewport); GL.PushMatrix(); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GluPickMatrix(e.X, e.Y, 5, 5, viewport); Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); // this projection matrix is the same as one in glControlWindow_Paint method. GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); int i = 0; int hits; GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); i++; GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); hits = GL.RenderMode(RenderingMode.Render); .....hits processing code goes here... GL.PopMatrix(); glControlWindow.Invalidate(); } I expect to get only one hit everytime i click inside a triangle, but i always get 2 no matter where i click. I suspect there is something wrong with the implementation of the GluPickMatrix, I haven't figured out yet.

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• In 3D camera math, calculate what Z depth is pixel unity for a given FOV

  - by badweasel

  I am working in iOS and OpenGL ES 2.0. Through trial and error I've figured out a frustum to where at a specific z depth pixels drawn are 1 to 1 with my source textures. So 1 pixel in my texture is 1 pixel on the screen. For 2d games this is good. Of course it means that I also factor in things like the size of the quad and the size of the texture. For example if my sprite is a quad 32x32 pixels. The quad size is 3.2 units wide and tall. And the texcoords are 32 / the size of the texture wide and tall. Then the frustum is: matrixFrustum(-(float)backingWidth/frustumScale,(float)backingWidth/frustumScale, -(float)backingHeight/frustumScale, (float)backingHeight/frustumScale, 40, 1000, mProjection); Where frustumScale is 800 for a retina screen. Then at a distance of 800 from camera the sprite is pixel for pixel the same as photoshop. For 3d games sometimes I still want to be able to do this. But depending on the scene I sometimes need the FOV to be different things. I'm looking for a way to figure out what Z depth will achieve this same pixel unity for a given FOV. For this my mProjection is set using: matrixPerspective(cameraFOV, near, far, (float)backingWidth / (float)backingHeight, mProjection); With testing I found that at an FOV of 45.0 a Z of 38.5 is very close to pixel unity. And at an FOV of 30.0 a Z of 59.5 is about right. But how can I calculate a value that is spot on? Here's my matrixPerspecitve code: void matrixPerspective(float angle, float near, float far, float aspect, mat4 m) { //float size = near * tanf(angle / 360.0 * M_PI); float size = near * tanf(degreesToRadians(angle) / 2.0); float left = -size, right = size, bottom = -size / aspect, top = size / aspect; // Unused values in perspective formula. m[1] = m[2] = m[3] = m[4] = 0; m[6] = m[7] = m[12] = m[13] = m[15] = 0; // Perspective formula. m[0] = 2 * near / (right - left); m[5] = 2 * near / (top - bottom); m[8] = (right + left) / (right - left); m[9] = (top + bottom) / (top - bottom); m[10] = -(far + near) / (far - near); m[11] = -1; m[14] = -(2 * far * near) / (far - near); } And my mView is set using: lookAtMatrix(cameraPos, camLookAt, camUpVector, mView); * UPDATE * I'm going to leave this here in case anyone has a different solution, can explain how they do it, or why this works. This is what I figured out. In my system I use a 10th scale unit to pixels on non-retina displays and a 20th scale on retina displays. The iPhone is 640 pixels wide on retina and 320 pixels wide on non-retina (obsolete). So if I want something to be the full screen width I divide by 20 to get the OpenGL unit width. Then divide that by 2 to get the left and right unit position. Something 32 units wide centered on the screen goes from -16 to +16. Believe it or not I have an excel spreadsheet do all this math for me and output all the vertex data for my sprite sheet. It's an arbitrary thing I made up to do .1 units = 1 non-retina pixel or 2 retina pixels. I could have made it .01 units = 2 pixels and someday I might switch to that. But for now it's the other. So the width of the screen in units is 32.0, and that means the left most pixel is at -16.0 and the right most is at 16.0. After messing a bit I figured out that if I take the [0] value of an identity modelViewProjection matrix and multiply it by 16 I get the depth required to get 1:1 pixels. I don't know why. I don't know if the 16 is related to the screen size or just a lucky guess. But I did a test where I placed a sprite at that calculated depth and varied the FOV through all the valid values and the object stays steady on screen with 1:1 pixels. So now I'm just calculating the unityDepth that way. If someone gives me a better answer I'll checkmark it.

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• How to move a rectangle properly?

  - by bodycountPP

  I recently started to learn OpenGL. Right now I finished the first chapter of the "OpenGL SuperBible". There were two examples. The first had the complete code and showed how to draw a simple triangle. The second example is supposed to show how to move a rectangle using SpecialKeys. The only code provided for this example was the SpecialKeys method. I still tried to implement it but I had two problems. In the previous example I declared and instaciated vVerts in the SetupRC() method. Now as it is also used in the SpecialKeys() method, I moved the declaration and instantiation to the top of the code. Is this proper c++ practice? I copied the part where vertex positions are recalculated from the book, but I had to pick the vertices for the rectangle on my own. So now every time I press a key for the first time the rectangle's upper left vertex is moved to (-0,5:-0.5). This ok because of GLfloat blockX = vVerts[0]; //Upper left X GLfloat blockY = vVerts[7]; // Upper left Y But I also think that this is the reason why my rectangle is shifted in the beginning. After the first time a key was pressed everything works just fine. Here is my complete code I hope you can help me on those two points. GLBatch squareBatch; GLShaderManager shaderManager; //Load up a triangle GLfloat vVerts[] = {-0.5f,0.5f,0.0f, 0.5f,0.5f,0.0f, 0.5f,-0.5f,0.0f, -0.5f,-0.5f,0.0f}; //Window has changed size, or has just been created. //We need to use the window dimensions to set the viewport and the projection matrix. void ChangeSize(int w, int h) { glViewport(0,0,w,h); } //Called to draw the scene. void RenderScene(void) { //Clear the window with the current clearing color glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT); GLfloat vRed[] = {1.0f,0.0f,0.0f,1.0f}; shaderManager.UseStockShader(GLT_SHADER_IDENTITY,vRed); squareBatch.Draw(); //perform the buffer swap to display the back buffer glutSwapBuffers(); } //This function does any needed initialization on the rendering context. //This is the first opportunity to do any OpenGL related Tasks. void SetupRC() { //Blue Background glClearColor(0.0f,0.0f,1.0f,1.0f); shaderManager.InitializeStockShaders(); squareBatch.Begin(GL_QUADS,4); squareBatch.CopyVertexData3f(vVerts); squareBatch.End(); } //Respond to arrow keys by moving the camera frame of reference void SpecialKeys(int key,int x,int y) { GLfloat stepSize = 0.025f; GLfloat blockSize = 0.5f; GLfloat blockX = vVerts[0]; //Upper left X GLfloat blockY = vVerts[7]; // Upper left Y if(key == GLUT_KEY_UP) { blockY += stepSize; } if(key == GLUT_KEY_DOWN){blockY -= stepSize;} if(key == GLUT_KEY_LEFT){blockX -= stepSize;} if(key == GLUT_KEY_RIGHT){blockX += stepSize;} //Recalculate vertex positions vVerts[0] = blockX; vVerts[1] = blockY - blockSize*2; vVerts[3] = blockX + blockSize * 2; vVerts[4] = blockY - blockSize *2; vVerts[6] = blockX+blockSize*2; vVerts[7] = blockY; vVerts[9] = blockX; vVerts[10] = blockY; squareBatch.CopyVertexData3f(vVerts); glutPostRedisplay(); } //Main entry point for GLUT based programs int main(int argc, char** argv) { //Sets the working directory. Not really needed gltSetWorkingDirectory(argv[0]); //Passes along the command-line parameters and initializes the GLUT library. glutInit(&argc,argv); //Tells the GLUT library what type of display mode to use, when creating the window. //Double buffered window, RGBA-Color mode,depth-buffer as part of our display, stencil buffer also available glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL); //Window size glutInitWindowSize(800,600); glutCreateWindow("MoveRect"); glutReshapeFunc(ChangeSize); glutDisplayFunc(RenderScene); glutSpecialFunc(SpecialKeys); //initialize GLEW library GLenum err = glewInit(); //Check that nothing goes wrong with the driver initialization before we try and do any rendering. if(GLEW_OK != err) { fprintf(stderr,"Glew Error: %s\n",glewGetErrorString); return 1; } SetupRC(); glutMainLoop(); return 0; }

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• C++ vs Matlab vs Python as a main language for Computer Vision Postgraduate

  - by Hough

  Hi all, Firstly, sorry for a somewhat long question but I think that many people are in the same situation as me and hopefully they can also gain some benefit from this. I'll be starting my PhD very soon which involve the fields of computer vision, pattern recognition and machine learning. Currently, I'm using opencv (2.1) C++ interface and I especially like its powerful Mat class and the overloaded operations available for matrix and image seamless operations and transformations. I've also tried (and implemented many small vision projects) using opencv python interface (new bindings; opencv 2.1) and I really enjoy python's ability to integrate opencv, numpy, scipy and matplotlib. But recently, I went back to opencv C++ interface because I felt that the official python new bindings were not stable enough and no overloaded operations are available for matrices and images, not to mention the lack of machine learning modules and slow speeds in certain operations. I've also used Matlab extensively in the past and although I've used mex files and other means to speed up the program, I just felt that Matlab's performance was inadequate for real-time vision tasks, be it for fast prototyping or not. When the project becomes larger and larger, many tasks have to be re-written in C and compiled into Mex files increasingly and Matlab becomes nothing more than a glue language. Here comes the sub-questions: For postgrad studies in these fields (machine learning, vision, pattern recognition), what is your main or ideal programming language for rapid prototyping of ideas and testing algorithms contained in papers? For postgrad studies, can you list down the pros and cons of using the following languages? C++ (with opencv + gsl + svmlib + other libraries) vs Matlab (with all its toolboxes) vs python (with the imcomplete opencv bindings + numpy + scipy + matplotlib). Are there computer vision PhD/postgrad students here who are using only C++ (with all its availabe libraries including opencv) without even needing to resort to Matlab or python? In other words, given the current existing computer vision or machine learning libraries, is C++ alone sufficient for fast prototyping of ideas? If you're currently using Java or C# for your postgrad work, can you list down the reasons why they should be used and how they compare to other languages in terms of available libraries? What is the de facto vision/machine learning programming language and its associated libraries used in your university research group? Thanks in advance.

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• Flash -> ByteArray -> AMFPHP -> Invalid Image !??

  - by undefined

  Hi, Im loading images into Flash and using JPGEncoder to encode the image to a ByteArray and send this to AMF PHP which writes out the bytearray to a file. This all appears to work correctly and I can download the resulting file in Photoshop CS4 absolutely fine. When i try to open it from the desktop or open it back in Flash it doesnt work... Picasa my default image browser says "Invalid" Here is the code i use to write the bytearray to a file - $jpg = $GLOBALS["HTTP_RAW_POST_DATA"]; file_put_contents($filename, $jpg); That's it ... I use the NetConnection class to connect and call the service, do I need to say Im sending jpg data? I assumed that JPGEncoder took care of that. How can I validate the bytearray before writing the file? Do I need to set MIME type or something .. excuse the slightly noob questions, a little knowledge can be a dangerous thing. Thanks --------------------------------------- PART II ------------------------------------------ Here is some code - 1) load the image into Flash player item.load(); function _onImageDataLoaded(evt:Event):void { var tmpFileRef:FileReference=FileReference(evt.target); image_loader=new Loader ; image_loader.contentLoaderInfo.addEventListener(Event.COMPLETE, _onImageLoaded); image_loader.loadBytes(tmpFileRef.data); } function _onImageLoaded(evt:Event):void { bitmap=Bitmap(evt.target.content); bitmap.smoothing=true; if (bitmap.width>MAX_WIDTH||bitmap.height>MAX_HEIGHT) { resizeBitmap(bitmap); } uploadResizedImage(bitmap); } function resizeBitmap(target:Bitmap):void { if (target.height>target.width) { target.width=MAX_WIDTH; target.scaleY=target.scaleX; } else if (target.width >= target.height) { target.height=MAX_HEIGHT; target.scaleX=target.scaleY; } } function uploadResizedImage(target:Bitmap):void { var _bmd:BitmapData=new BitmapData(target.width,target.height); _bmd.draw(target, new Matrix(target.scaleX, 0, 0, target.scaleY)); var encoded_jpg:JPGEncoder=new JPGEncoder(90); var jpg_binary:ByteArray=encoded_jpg.encode(_bmd); _uploadService=new NetConnection(); _uploadService.objectEncoding=ObjectEncoding.AMF3 _uploadService.connect("http://.../amfphp/gateway.php"); _uploadService.call("UploadService.receiveByteArray",new Responder(success, error), jpg_binary, currentImageFilename); } Many thanks for you help

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• Loading, listing, and using R Modules and Functions in PL/R

  - by Dave Jarvis

  I am having difficulty with: Listing the R packages and functions available to PostgreSQL. Installing a package (such as Kendall) for use with PL/R Calling an R function within PostgreSQL Listing Available R Packages Q.1. How do you find out what R modules have been loaded? SELECT * FROM r_typenames(); That shows the types that are available, but what about checking if Kendall( X, Y ) is loaded? For example, the documentation shows: CREATE TABLE plr_modules ( modseq int4, modsrc text ); That seems to allow inserting records to dictate that Kendall is to be loaded, but the following code doesn't explain, syntactically, how to ensure that it gets loaded: INSERT INTO plr_modules VALUES (0, 'pg.test.module.load <-function(msg) {print(msg)}'); Q.2. What would the above line look like if you were trying to load Kendall? Q.3. Is it applicable? Installing R Packages Using the "synaptic" package manager the following packages have been installed: r-base r-base-core r-base-dev r-base-html r-base-latex r-cran-acepack r-cran-boot r-cran-car r-cran-chron r-cran-cluster r-cran-codetools r-cran-design r-cran-foreign r-cran-hmisc r-cran-kernsmooth r-cran-lattice r-cran-matrix r-cran-mgcv r-cran-nlme r-cran-quadprog r-cran-robustbase r-cran-rpart r-cran-survival r-cran-vr r-recommended Q.4. How do I know if Kendall is in there? Q.5. If it isn't, how do I find out what package it is in? Q.6. If it isn't in a package suitable for installing with apt-get (aptitude, synaptic, dpkg, what have you), how do I go about installing it on Ubuntu? Q.7. Where are the installation steps documented? Calling R Functions I have the following code: EXECUTE 'SELECT ' 'regr_slope( amount, year_taken ),' 'regr_intercept( amount, year_taken ),' 'corr( amount, year_taken ),' 'sum( measurements ) AS total_measurements ' 'FROM temp_regression' INTO STRICT slope, intercept, correlation, total_measurements; This code calls the PostgreSQL function corr to calculate Pearson's correlation over the data. Ideally, I'd like to do the following (by switching corr for plr_kendall): EXECUTE 'SELECT ' 'regr_slope( amount, year_taken ),' 'regr_intercept( amount, year_taken ),' 'plr_kendall( amount, year_taken ),' 'sum( measurements ) AS total_measurements ' 'FROM temp_regression' INTO STRICT slope, intercept, correlation, total_measurements; Q.8. Do I have to write plr_kendall myself? Q.9. Where can I find a simple example that walks through: Loading an R module into PG. Writing a PG wrapper for the desired R function. Calling the PG wrapper from a SELECT. For example, would the last two steps look like: create or replace function plr_kendall( _float8, _float8 ) returns float as ' agg_kendall(arg1, arg2) ' language 'plr'; CREATE AGGREGATE agg_kendall ( sfunc = plr_array_accum, basetype = float8, -- ??? stype = _float8, -- ??? finalfunc = plr_kendall ); And then the SELECT as above? Thank you!

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• Extract information from conditional formula

  - by Ken Williams

  I'd like to write an R function that accepts a formula as its first argument, similar to lm() or glm() and friends. In this case, it's a function that takes a data frame and writes out a file in SVMLight format, which has this general form: <line> .=. <target> <feature>:<value> <feature>:<value> ... <feature>:<value> # <info> <target> .=. +1 | -1 | 0 | <float> <feature> .=. <integer> | "qid" <value> .=. <float> <info> .=. <string> for example, the following data frame: result qid f1 f2 f3 f4 f5 f6 f7 f8 1 -1 1 0.0000 0.1253 0.0000 0.1017 0.00 0.0000 0.0000 0.9999 2 -1 1 0.0098 0.0000 0.0000 0.0000 0.00 0.0316 0.0000 0.3661 3 1 1 0.0000 0.0000 0.1941 0.0000 0.00 0.0000 0.0509 0.0000 4 -1 2 0.0000 0.2863 0.0948 0.0000 0.34 0.0000 0.7428 0.0608 5 1 2 0.0000 0.0000 0.0000 0.4347 0.00 0.0000 0.9539 0.0000 6 1 2 0.0000 0.7282 0.9087 0.0000 0.00 0.0000 0.0000 0.0355 would be represented as follows: -1 qid:1 2:0.1253 4:0.1017 8:0.9999 -1 qid:1 1:0.0098 6:0.0316 8:0.3661 1 qid:1 3:0.1941 7:0.0509 -1 qid:2 2:0.2863 3:0.0948 5:0.3400 7:0.7428 8:0.0608 1 qid:2 4:0.4347 7:0.9539 1 qid:2 2:0.7282 3:0.9087 8:0.0355 The function I'd like to write would be called something like this: write.svmlight(result ~ f1+f2+f3+f4+f5+f6+f7+f8 | qid, data=mydata, file="out.txt") Or even write.svmlight(result ~ . | qid, data=mydata, file="out.txt") But I can't figure out how to use model.matrix() and/or model.frame() to know what columns it's supposed to write. Are these the right things to be looking at? Any help much appreciated!

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• OpenCV 2.4.2 on Matlab 2012b (Windows 7)

  - by Maik Xhani

  Hello i am trying to use OpenCV 2.4.2 in Matlab 2012b. I have tried those actions: downloaded OpenCV 2.4.2 used CMake on opencv folder using Visual Studio 10 and Visual Studio 10 Win64 compiler built Debug and Release version with Visual Studio first without any other option and then with D_SCL_SECURE=1 specified for every project changed Matlab's mexopts.bat and adding new lines refering to library and include (see bottom for mexopts.bat content) with Visual Studio 10 compiler tried to compile a simple file with a OpenCV library inclusion and all goes well. try to compile something that actually uses OpenCV commands and get errors. I used openmexopencv library and when tried to compile something i get this error cv.make mex -largeArrayDims -D_SECURE_SCL=1 -Iinclude -I"C:\OpenCV\build\include" -L"C:\OpenCV\build\x64\vc10\lib" -lopencv_calib3d242 -lopencv_contrib242 -lopencv_core242 -lopencv_features2d242 -lopencv_flann242 -lopencv_gpu242 -lopencv_haartraining_engine -lopencv_highgui242 -lopencv_imgproc242 -lopencv_legacy242 -lopencv_ml242 -lopencv_nonfree242 -lopencv_objdetect242 -lopencv_photo242 -lopencv_stitching242 -lopencv_ts242 -lopencv_video242 -lopencv_videostab242 src+cv\CamShift.cpp lib\MxArray.obj -output +cv\CamShift CamShift.cpp C:\Program Files\MATLAB\R2012b\extern\include\tmwtypes.h(821) : warning C4091: 'typedef ': ignorato a sinistra di 'wchar_t' quando non si dichiara alcuna variabile c:\program files\matlab\r2012b\extern\include\matrix.h(319) : error C4430: identificatore di tipo mancante, verr… utilizzato int. Nota: default-int non Š pi— supportato in C++ the content of my mexopts.bat is @echo off rem MSVC100OPTS.BAT rem rem Compile and link options used for building MEX-files rem using the Microsoft Visual C++ compiler version 10.0 rem rem $Revision: 1.1.6.4.2.1 $ $Date: 2012/07/12 13:53:59 $ rem Copyright 2007-2009 The MathWorks, Inc. rem rem StorageVersion: 1.0 rem C++keyFileName: MSVC100OPTS.BAT rem C++keyName: Microsoft Visual C++ 2010 rem C++keyManufacturer: Microsoft rem C++keyVersion: 10.0 rem C++keyLanguage: C++ rem C++keyLinkerName: Microsoft Visual C++ 2010 rem C++keyLinkerVersion: 10.0 rem rem ******************************************************************** rem General parameters rem ******************************************************************** set MATLAB=%MATLAB% set VSINSTALLDIR=c:\Program Files (x86)\Microsoft Visual Studio 10.0 set VCINSTALLDIR=%VSINSTALLDIR%\VC set OPENCVDIR=C:\OpenCV rem In this case, LINKERDIR is being used to specify the location of the SDK set LINKERDIR=c:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\ set PATH=%VCINSTALLDIR%\bin\amd64;%VCINSTALLDIR%\bin;%VCINSTALLDIR%\VCPackages;%VSINSTALLDIR%\Common7\IDE;%VSINSTALLDIR%\Common7\Tools;%LINKERDIR%\bin\x64;%LINKERDIR%\bin;%MATLAB_BIN%;%PATH% set INCLUDE=%OPENCVDIR%\build\include;%VCINSTALLDIR%\INCLUDE;%VCINSTALLDIR%\ATLMFC\INCLUDE;%LINKERDIR%\include;%INCLUDE% set LIB=%OPENCVDIR%\build\x64\vc10\lib;%VCINSTALLDIR%\LIB\amd64;%VCINSTALLDIR%\ATLMFC\LIB\amd64;%LINKERDIR%\lib\x64;%MATLAB%\extern\lib\win64;%LIB% set MW_TARGET_ARCH=win64 rem ******************************************************************** rem Compiler parameters rem ******************************************************************** set COMPILER=cl set COMPFLAGS=/c /GR /W3 /EHs /D_CRT_SECURE_NO_DEPRECATE /D_SCL_SECURE_NO_DEPRECATE /D_SECURE_SCL=0 /DMATLAB_MEX_FILE /nologo /MD set OPTIMFLAGS=/O2 /Oy- /DNDEBUG set DEBUGFLAGS=/Z7 set NAME_OBJECT=/Fo rem ******************************************************************** rem Linker parameters rem ******************************************************************** set LIBLOC=%MATLAB%\extern\lib\win64\microsoft set LINKER=link set LINKFLAGS=/dll /export:%ENTRYPOINT% /LIBPATH:"%LIBLOC%" libmx.lib libmex.lib libmat.lib /MACHINE:X64 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib opencv_calib3d242.lib opencv_contrib242.lib opencv_core242.lib opencv_features2d242.lib opencv_flann242.lib opencv_gpu242.lib opencv_haartraining_engine.lib opencv_imgproc242.lib opencv_highgui242.lib opencv_legacy242.lib opencv_ml242.lib opencv_nonfree242.lib opencv_objdetect242.lib opencv_photo242.lib opencv_stitching242.lib opencv_ts242.lib opencv_video242.lib opencv_videostab242.lib /nologo /manifest /incremental:NO /implib:"%LIB_NAME%.x" /MAP:"%OUTDIR%%MEX_NAME%%MEX_EXT%.map" set LINKOPTIMFLAGS= set LINKDEBUGFLAGS=/debug /PDB:"%OUTDIR%%MEX_NAME%%MEX_EXT%.pdb" set LINK_FILE= set LINK_LIB= set NAME_OUTPUT=/out:"%OUTDIR%%MEX_NAME%%MEX_EXT%" set RSP_FILE_INDICATOR=@ rem ******************************************************************** rem Resource compiler parameters rem ******************************************************************** set RC_COMPILER=rc /fo "%OUTDIR%mexversion.res" set RC_LINKER= set POSTLINK_CMDS=del "%LIB_NAME%.x" "%LIB_NAME%.exp" set POSTLINK_CMDS1=mt -outputresource:"%OUTDIR%%MEX_NAME%%MEX_EXT%;2" -manifest "%OUTDIR%%MEX_NAME%%MEX_EXT%.manifest" set POSTLINK_CMDS2=del "%OUTDIR%%MEX_NAME%%MEX_EXT%.manifest" set POSTLINK_CMDS3=del "%OUTDIR%%MEX_NAME%%MEX_EXT%.map"

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• C++ vs Matlab vs Python as a main language for Computer Vision Research

  - by Hough

  Hi all, Firstly, sorry for a somewhat long question but I think that many people are in the same situation as me and hopefully they can also gain some benefit from this. I'll be starting my PhD very soon which involves the fields of computer vision, pattern recognition and machine learning. Currently, I'm using opencv (2.1) C++ interface and I especially like its powerful Mat class and the overloaded operations available for matrix and image operations and seamless transformations. I've also tried (and implemented many small vision projects) using opencv python interface (new bindings; opencv 2.1) and I really enjoy python's ability to integrate opencv, numpy, scipy and matplotlib. But recently, I went back to opencv C++ interface because I felt that the official python new bindings were not stable enough and no overloaded operations are available for matrices and images, not to mention the lack of machine learning modules and slow speeds in certain operations. I've also used Matlab extensively in the past and although I've used mex files and other means to speed up the program, I just felt that Matlab's performance was inadequate for real-time vision tasks, be it for fast prototyping or not. When the project becomes larger and larger, many tasks have to be re-written in C and compiled into Mex files increasingly and Matlab becomes nothing more than a glue language. Here comes the sub-questions: For carrying out research in these fields (machine learning, vision, pattern recognition), what is your main or ideal programming language for rapid prototyping of ideas and testing algorithms contained in papers? For computer vision research work, can you list down the pros and cons of using the following languages? C++ (with opencv + gsl + svmlib + other libraries) vs Matlab (with all its toolboxes) vs python (with the imcomplete opencv bindings + numpy + scipy + matplotlib). Are there computer vision PhD/postgrad students here who are using only C++ (with all its availabe libraries including opencv) without even needing to resort to Matlab or python? In other words, given the current existing computer vision or machine learning libraries, is C++ alone sufficient for fast prototyping of ideas? If you're currently using Java or C# for your research, can you list down the reasons why they should be used and how they compare to other languages in terms of available libraries? What is the de facto vision/machine learning programming language and its associated libraries used in your research group? Thanks in advance. Edit: As suggested, I've opened the question to both academic and non-academic computer vision/machine learning/pattern recognition researchers and groups.

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• Most efficient method to query a Young Tableau

  - by Matthieu M.

  A Young Tableau is a 2D matrix A of dimensions M*N such that: i,j in [0,M)x[0,N): for each p in (i,M), A[i,j] <= A[p,j] for each q in (j,N), A[i,j] <= A[i,q] That is, it's sorted row-wise and column-wise. Since it may contain less than M*N numbers, the bottom-right values might be represented either as missing or using (in algorithm theory) infinity to denote their absence. Now the (elementary) question: how to check if a given number is contained in the Young Tableau ? Well, it's trivial to produce an algorithm in O(M*N) time of course, but what's interesting is that it is very easy to provide an algorithm in O(M+N) time: Bottom-Left search: Let x be the number we look for, initialize i,j as M-1, 0 (bottom left corner) If x == A[i,j], return true If x < A[i,j], then if i is 0, return false else decrement i and go to 2. Else, if j is N-1, return false else increment j This algorithm does not make more than M+N moves. The correctness is left as an exercise. It is possible though to obtain a better asymptotic runtime. Pivot Search: Let x be the number we look for, initialize i,j as floor(M/2), floor(N/2) If x == A[i,j], return true If x < A[i,j], search (recursively) in A[0:i-1, 0:j-1], A[i:M-1, 0:j-1] and A[0:i-1, j:N-1] Else search (recursively) in A[i+1:M-1, 0:j], A[i+1:M-1, j+1:N-1] and A[0:i, j+1:N-1] This algorithm proceed by discarding one of the 4 quadrants at each iteration and running recursively on the 3 left (divide and conquer), the master theorem yields a complexity of O((N+M)**(log 3 / log 4)) which is better asymptotically. However, this is only a big-O estimation... So, here are the questions: Do you know (or can think of) an algorithm with a better asymptotical runtime ? Like introsort prove, sometimes it's worth switching algorithms depending on the input size or input topology... do you think it would be possible here ? For 2., I am notably thinking that for small size inputs, the bottom-left search should be faster because of its O(1) space requirement / lower constant term.

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• Corner Cases, Unexpected and Unusual Matlab

  - by Mikhail

  Over the years, reading others code, I encountered and collected some examples of Matlab syntax which can be at first unusual and counterintuitive. Please, feel free to comment or complement this list. I verified it r2006a. set([], 'Background:Color','red') Matlab is very forgiving sometimes. In this case, setting properties to an array of objects works also with nonsense properties, at least when the array is empty. myArray([1,round(end/2)]) This use of end keyword may seem unclean but is sometimes very handy instead of using length(myArray). any([]) ~= all([]) Surprisigly any([]) returns false and all([]) returns true. And I always thought that all is stronger then any. EDIT: with not empty argument all() returns true for a subset of values for which any() returns true (e.g. truth table). This means that any() false implies all() false. This simple rule is being violated by Matlab with [] as argument. Loren also blogged about it. Select(Range(ExcelComObj)) Procedural style COM object method dispatch. Do not wonder that exist('Select') returns zero! [myString, myCell] Matlab makes in this case an implicit cast of string variable myString to cell type {myString}. It works, also if I would not expect it to do so. [double(1.8), uint8(123)] => 2 123 Another cast example. Everybody would probably expect uint8 value being cast to double but Mathworks have another opinion. a = 5; b = a(); It looks silly but you can call a variable with round brackets. Actually it makes sense because this way you can execute a function given its handle. a = {'aa', 'bb' 'cc', 'dd'}; Surprsisingly this code neither returns a vector nor rises an error but defins matrix, using just code layout. It is probably a relict from ancient times. set(hobj, {'BackgroundColor','ForegroundColor'},{'red','blue'}) This code does what you probably expect it to do. That function set accepts a struct as its second argument is a known fact and makes sense, and this sintax is just a cell2struct away. Equvalence rules are sometimes unexpected at first. For example 'A'==65 returns true (although for C-experts it is self-evident). About which further unexpected/unusual Matlab features are you aware?

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• Why differs floating-point precision in C# when separated by parantheses and when separated by state

  - by Andreas Larsen

  I am aware of how floating point precision works in the regular cases, but I stumbled on an odd situation in my C# code. Why aren't result1 and result2 the exact same floating point value here? const float A; // Arbitrary value const float B; // Arbitrary value float result1 = (A*B)*dt; float result2 = (A*B); result2 *= dt; From this page I figured float arithmetic was left-associative and that this means values are evaluated and calculated in a left-to-right manner. The full source code involves XNA's Quaternions. I don't think it's relevant what my constants are and what the VectorHelper.AddPitchRollYaw() does. The test passes just fine if I calculate the delta pitch/roll/yaw angles in the same manner, but as the code is below it does not pass: X Expected: 0.275153548f But was: 0.275153786f [TestFixture] internal class QuaternionPrecisionTest { [Test] public void Test() { JoystickInput input; input.Pitch = 0.312312432f; input.Roll = 0.512312432f; input.Yaw = 0.912312432f; const float dt = 0.017001f; float pitchRate = input.Pitch * PhysicsConstants.MaxPitchRate; float rollRate = input.Roll * PhysicsConstants.MaxRollRate; float yawRate = input.Yaw * PhysicsConstants.MaxYawRate; Quaternion orient1 = Quaternion.Identity; Quaternion orient2 = Quaternion.Identity; for (int i = 0; i < 10000; i++) { float deltaPitch = (input.Pitch * PhysicsConstants.MaxPitchRate) * dt; float deltaRoll = (input.Roll * PhysicsConstants.MaxRollRate) * dt; float deltaYaw = (input.Yaw * PhysicsConstants.MaxYawRate) * dt; // Add deltas of pitch, roll and yaw to the rotation matrix orient1 = VectorHelper.AddPitchRollYaw( orient1, deltaPitch, deltaRoll, deltaYaw); deltaPitch = pitchRate * dt; deltaRoll = rollRate * dt; deltaYaw = yawRate * dt; orient2 = VectorHelper.AddPitchRollYaw( orient2, deltaPitch, deltaRoll, deltaYaw); } Assert.AreEqual(orient1.X, orient2.X, "X"); Assert.AreEqual(orient1.Y, orient2.Y, "Y"); Assert.AreEqual(orient1.Z, orient2.Z, "Z"); Assert.AreEqual(orient1.W, orient2.W, "W"); } } Granted, the error is small and only presents itself after a large number of iterations, but it has caused me some great headackes.

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• OpenGL 2D Texture Mapping problem.

  - by gutsblow

  Hi there, I am relatively new to OpenGL and I am having some issues when I am rendering an image as a texture for a QUAD which is as the same size of the image. Here is my code. I would be very grateful if someone helps me to solve this problem. The image appears way smaller and is squished. (BTW, the image dimensions are 500x375). glGenTextures( 1, &S_GLator_InputFrameTextureIDSu ); glBindTexture(GL_TEXTURE_2D, S_GLator_InputFrameTextureIDSu); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexImage2D( GL_TEXTURE_2D, 0, 4, S_GLator_EffectCommonData.mRenderBufferWidthSu, S_GLator_EffectCommonData.mRenderBufferHeightSu, 0, GL_RGBA, GL_UNSIGNED_BYTE, dataP); glBindTexture(GL_TEXTURE_2D, S_GLator_InputFrameTextureIDSu); glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, S_GLator_EffectCommonData.mRenderBufferWidthSu, S_GLator_EffectCommonData.mRenderBufferHeightSu, GL_RGBA, GL_UNSIGNED_BYTE, bufferP); //set the matrix modes glMatrixMode( GL_PROJECTION ); glLoadIdentity(); //gluPerspective( 45.0, (GLdouble)widthL / heightL, 0.1, 100.0 ); glOrtho (0, 1, 0, 1, -1, 1); // Set up the frame-buffer object just like a window. glViewport( 0, 0, widthL, heightL ); glDisable(GL_DEPTH_TEST); glClearColor( 0.0f, 0.0f, 0.0f, 0.0f ); glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); glBindTexture( GL_TEXTURE_2D, S_GLator_InputFrameTextureIDSu ); //Render the geometry to the frame-buffer object glBegin(GL_QUADS); //input frame glColor4f(1.f,1.f,1.f,1.f); glTexCoord2f(0.0f,0.0f); glVertex3f(0.f ,0.f ,0.0f); glTexCoord2f(1.0f,0.0f); glVertex3f(1.f ,0.f,0.0f); glTexCoord2f(1.0f,1.f); glVertex3f(1.f ,1.f,0.0f); glTexCoord2f(0.0f,1.f); glVertex3f(0.f ,1.f,0.0f); glEnd();

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• How to convert a 32bpp image to an indexed format?

  - by Ed Swangren

  So here are the details (I am using C# BTW): I receive a 32bpp image (JPEG compressed) from a server. At some point, I would like to use the Palette property of a bitmap to color over-saturated pixels (brightness 240) red. To do so, I need to get the image into an indexed format. I have tried converting the image to a GIF, but I get quality loss. I have tried creating a new bitmap in an index format by these methods: // causes a "Parameter not valid" error Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Indexed) // no error, but the resulting image is black due to information loss I assume Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Format8bppIndexed) I am at a loss now. The data in this image is changed constantly by the user, so I don't want to manually set pixels that have a brightness 240 if I can avoid it. If I can set the palette once when the image is created, my work is done. If I am going about this the wrong way to begin with please let me know. EDIT: Thanks guys, here is some more detail on what I am attempting to accomplish. We are scanning a tissue slide at high resolution (pathology application). I write the interface to the actual scanner. We use a line-scan camera. To test the line rate of the camera, the user scans a very small portion and looks at the image. The image is displayed next to a track bar. When the user moves the track bar (adjusting line rate), I change the overall intensity of the image in an attempt to model what it would look like at the new line rate. I do this using an ImageAttributes and ColorMatrix object currently. When the user adjusts the track bar, I adjust the matrix. This does not give me per pixel information, but the performance is very nice. I could use LockBits and some unsafe code here, but I would rather not rewrite it if possible. When the new image is created, I would like for all pixels with a brightness value of 240 to be colored red. I was thinking that defining a palette for the bitmap up front would be a clean way of doing this.

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• Model Fit of Binary GLM with more than 1 or 2 predictors

  - by Salmo salar

  I am trying to predict a binary GLM with multiple predictors. I can do it fine with one predictor variable however struggle when I use multiple Sample data: structure(list(attempt = structure(c(1L, 2L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 2L, 1L, 2L, 1L, 1L, 2L, 1L, 2L), .Label = c("1", "2"), class = "factor"), searchtime = c(137, 90, 164, 32, 39, 30, 197, 308, 172, 48, 867, 117, 63, 1345, 38, 122, 226, 397, 0, 106, 259, 220, 170, 102, 46, 327, 8, 10, 23, 108, 315, 318, 70, 646, 69, 97, 117, 45, 31, 64, 125, 17, 240, 63, 549, 1651, 233, 406, 334, 168, 127, 47, 881), mean.search.flow = c(15.97766667, 14.226, 17.15724762, 14.7465, 39.579, 23.355, 110.2926923, 71.95709524, 72.73666667, 32.37466667, 50.34905172, 27.98471429, 49.244, 109.1759778, 77.71733333, 37.446875, 101.23875, 67.78534615, 21.359, 36.54257143, 34.13961111, 64.35253333, 80.98554545, 61.50857143, 48.983, 63.81072727, 26.105, 46.783, 23.0605, 33.61557143, 46.31042857, 62.37061905, 12.565, 42.31983721, 15.3982, 14.49625, 23.77425, 25.626, 74.62485714, 170.1547778, 50.67125, 48.098, 66.83644444, 76.564875, 80.63189189, 136.0573243, 136.3484, 86.68688889, 34.82169565, 70.00415385, 64.67233333, 81.72766667, 57.74522034), Pass = structure(c(1L, 2L, 1L, 2L, 2L, 2L, 1L, 1L, 1L, 2L, 2L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 2L, 2L, 1L, 2L, 1L, 2L, 2L, 1L, 2L, 1L, 2L), .Label = c("0", "1"), class = "factor")), .Names = c("attempt", "searchtime", "mean.search.flow", "Pass"), class = "data.frame", row.names = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 24L, 25L, 26L, 28L, 29L, 30L, 31L, 32L, 33L, 34L, 35L, 36L, 37L, 38L, 39L, 40L, 50L, 51L, 53L, 54L, 60L, 61L, 62L, 63L, 64L, 65L, 66L, 67L, 68L, 69L, 70L, 71L, 72L)) First model with single predictor M2 <- glm(Pass ~ searchtime, data = DF3, family = binomial) summary(M2) drop1(M2, test = "Chi") Plot works fine P1 <- predict(M2, newdata = MyData, type = "link", se = TRUE) plot(x=MyData$searchtime, exp(P1$fit) / (1+exp(P1$fit)), type = "l", ylim = c(0,1), xlab = "search time", ylab = "pobability of passage") lines(MyData$searchtime, exp(P1$fit+1.96*P1$se.fit)/ (1 + exp(P1$fit + 1.96 * P1$se.fit)), lty = 2) lines(MyData$searchtime, exp(P1$fit-1.96*P1$se.fit)/ (1 + exp(P1$fit - 1.96 * P1$se.fit)), lty = 2) points(DF3$searchtime, DF3$Search.and.pass) Second model M2a <- glm(Pass ~ searchtime + mean.search.flow+ attempt, data = DF3, family = binomial) summary(M2a) drop1(M2a, test = "Chi") How do I plot this with "dummy" data? I have tried along the lines of Model.matrix and expand.grid, as you would do with glmer, but fail straight away due to the two categorical variables along with factor(attempt)

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• Android - OPENGL cube is NOT in the display

  - by Marc Ortiz

  I'm trying to display a square on my display and i can't. Whats my problem? How can I display it on the screen (center of the screen)? I let my code below! Here's my render class: public class GLRenderEx implements Renderer { private GLCube cube; Context c; GLCube quad; // ( NEW ) // Constructor public GLRenderEx(Context context) { // Set up the data-array buffers for these shapes ( NEW ) quad = new GLCube(); // ( NEW ) } // Call back when the surface is first created or re-created. @Override public void onSurfaceCreated(GL10 gl, EGLConfig config) { // NO CHANGE - SKIP } // Call back after onSurfaceCreated() or whenever the window's size changes. @Override public void onSurfaceChanged(GL10 gl, int width, int height) { // NO CHANGE - SKIP } // Call back to draw the current frame. @Override public void onDrawFrame(GL10 gl) { // Clear color and depth buffers using clear-values set earlier gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glLoadIdentity(); // Reset model-view matrix ( NEW ) gl.glTranslatef(-1.5f, 0.0f, -6.0f); // Translate left and into the // screen ( NEW ) // Translate right, relative to the previous translation ( NEW ) gl.glTranslatef(3.0f, 0.0f, 0.0f); quad.draw(gl); // Draw quad ( NEW ) } } And here is my square class: public class GLCube { private FloatBuffer vertexBuffer; // Buffer for vertex-array private float[] vertices = { // Vertices for the square -1.0f, -1.0f, 0.0f, // 0. left-bottom 1.0f, -1.0f, 0.0f, // 1. right-bottom -1.0f, 1.0f, 0.0f, // 2. left-top 1.0f, 1.0f, 0.0f // 3. right-top }; // Constructor - Setup the vertex buffer public GLCube() { // Setup vertex array buffer. Vertices in float. A float has 4 bytes ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); // Use native byte order vertexBuffer = vbb.asFloatBuffer(); // Convert from byte to float vertexBuffer.put(vertices); // Copy data into buffer vertexBuffer.position(0); // Rewind } // Render the shape public void draw(GL10 gl) { // Enable vertex-array and define its buffer gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); // Draw the primitives from the vertex-array directly gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } } Thanks!!

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