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  • MySQL Queries using Doctrine & CodeIgniter

    - by 01010011
    Hi, How do I write plane SQL queries using Doctrine connection object and display the results? For example, how do I perform: SELECT * FROM table_name WHERE column_name LIKE '%anything_similar_to_this%'; using Doctrine something like this (this example does not work) $search_key = 'search_for_this'; $conn = Doctrine_Manager::connection(); $conn->execute('SELECT * FROM table_name WHERE column_name LIKE ?)', $search_key); echo $conn;

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  • Deferred rendering with VSM - Scaling light depth loses moments

    - by user1423893
    I'm calculating my shadow term using a VSM method. This works correctly when using forward rendered lights but fails with deferred lights. // Shadow term (1 = no shadow) float shadow = 1; // [Light Space -> Shadow Map Space] // Transform the surface into light space and project // NB: Could be done in the vertex shader, but doing it here keeps the // "light shader" abstraction and doesn't limit the number of shadowed lights float4x4 LightViewProjection = mul(LightView, LightProjection); float4 surf_tex = mul(position, LightViewProjection); // Re-homogenize // 'w' component is not used in later calculations so no need to homogenize (it will equal '1' if homogenized) surf_tex.xyz /= surf_tex.w; // Rescale viewport to be [0,1] (texture coordinate system) float2 shadow_tex; shadow_tex.x = surf_tex.x * 0.5f + 0.5f; shadow_tex.y = -surf_tex.y * 0.5f + 0.5f; // Half texel offset //shadow_tex += (0.5 / 512); // Scaled distance to light (instead of 'surf_tex.z') float rescaled_dist_to_light = dist_to_light / LightAttenuation.y; //float rescaled_dist_to_light = surf_tex.z; // [Variance Shadow Map Depth Calculation] // No filtering float2 moments = tex2D(ShadowSampler, shadow_tex).xy; // Flip the moments values to bring them back to their original values moments.x = 1.0 - moments.x; moments.y = 1.0 - moments.y; // Compute variance float E_x2 = moments.y; float Ex_2 = moments.x * moments.x; float variance = E_x2 - Ex_2; variance = max(variance, Bias.y); // Surface is fully lit if the current pixel is before the light occluder (lit_factor == 1) // One-tailed inequality valid if float lit_factor = (rescaled_dist_to_light <= moments.x - Bias.x); // Compute probabilistic upper bound (mean distance) float m_d = moments.x - rescaled_dist_to_light; // Chebychev's inequality float p = variance / (variance + m_d * m_d); p = ReduceLightBleeding(p, Bias.z); // Adjust the light color based on the shadow attenuation shadow *= max(lit_factor, p); This is what I know for certain so far: The lighting is correct if I do not try and calculate the shadow term. (No shadows) The shadow term is correct when calculated using forward rendered lighting. (VSM works with forward rendered lights) With the current rescaled light distance (lightAttenuation.y is the far plane value): float rescaled_dist_to_light = dist_to_light / LightAttenuation.y; The light is correct and the shadow appears to be zoomed in and misses the blurring: When I do not rescale the light and use the homogenized 'surf_tex': float rescaled_dist_to_light = surf_tex.z; the shadows are blurred correctly but the lighting is incorrect and the cube model is no longer lit Why is scaling by the far plane value (LightAttenuation.y) zooming in too far? The only other factor involved is my world pixel position, which is calculated as follows: // [Position] float4 position; // [Screen Position] position.xy = input.PositionClone.xy; // Use 'x' and 'y' components already homogenized for uv coordinates above position.z = tex2D(DepthSampler, texCoord).r; // No need to homogenize 'z' component position.z = 1.0 - position.z; position.w = 1.0; // 1.0 = position.w / position.w // [World Position] position = mul(position, CameraViewProjectionInverse); // Re-homogenize position (xyz AND w, otherwise shadows will bend when camera is close) position.xyz /= position.w; position.w = 1.0; Using the inverse matrix of the camera's view x projection matrix does work for lighting but maybe it is incorrect for shadow calculation? EDIT: Light calculations for shadow including 'dist_to_light' // Work out the light position and direction in world space float3 light_position = float3(LightViewInverse._41, LightViewInverse._42, LightViewInverse._43); // Direction might need to be negated float3 light_direction = float3(-LightViewInverse._31, -LightViewInverse._32, -LightViewInverse._33); // Unnormalized light vector float3 dir_to_light = light_position - position; // Direction from vertex float dist_to_light = length(dir_to_light); // Normalise 'toLight' vector for lighting calculations dir_to_light = normalize(dir_to_light); EDIT2: These are the calculations for the moments (depth) //============================================= //---[Vertex Shaders]-------------------------- //============================================= DepthVSOutput depth_VS( float4 Position : POSITION, uniform float4x4 shadow_view, uniform float4x4 shadow_view_projection) { DepthVSOutput output = (DepthVSOutput)0; // First transform position into world space float4 position_world = mul(Position, World); output.position_screen = mul(position_world, shadow_view_projection); output.light_vec = mul(position_world, shadow_view).xyz; return output; } //============================================= //---[Pixel Shaders]--------------------------- //============================================= DepthPSOutput depth_PS(DepthVSOutput input) { DepthPSOutput output = (DepthPSOutput)0; // Work out the depth of this fragment from the light, normalized to [0, 1] float2 depth; depth.x = length(input.light_vec) / FarPlane; depth.y = depth.x * depth.x; // Flip depth values to avoid floating point inaccuracies depth.x = 1.0f - depth.x; depth.y = 1.0f - depth.y; output.depth = depth.xyxy; return output; } EDIT 3: I have tried the folloiwng: float4 pp; pp.xy = input.PositionClone.xy; // Use 'x' and 'y' components already homogenized for uv coordinates above pp.z = tex2D(DepthSampler, texCoord).r; // No need to homogenize 'z' component pp.z = 1.0 - pp.z; pp.w = 1.0; // 1.0 = position.w / position.w // Determine the depth of the pixel with respect to the light float4x4 LightViewProjection = mul(LightView, LightProjection); float4x4 matViewToLightViewProj = mul(CameraViewProjectionInverse, LightViewProjection); float4 vPositionLightCS = mul(pp, matViewToLightViewProj); float fLightDepth = vPositionLightCS.z / vPositionLightCS.w; // Transform from light space to shadow map texture space. float2 vShadowTexCoord = 0.5 * vPositionLightCS.xy / vPositionLightCS.w + float2(0.5f, 0.5f); vShadowTexCoord.y = 1.0f - vShadowTexCoord.y; // Offset the coordinate by half a texel so we sample it correctly vShadowTexCoord += (0.5f / 512); //g_vShadowMapSize This suffers the same problem as the second picture. I have tried storing the depth based on the view x projection matrix: output.position_screen = mul(position_world, shadow_view_projection); //output.light_vec = mul(position_world, shadow_view); output.light_vec = output.position_screen; depth.x = input.light_vec.z / input.light_vec.w; This gives a shadow that has lots surface acne due to horrible floating point precision errors. Everything is lit correctly though. EDIT 4: Found an OpenGL based tutorial here I have followed it to the letter and it would seem that the uv coordinates for looking up the shadow map are incorrect. The source uses a scaled matrix to get the uv coordinates for the shadow map sampler /// <summary> /// The scale matrix is used to push the projected vertex into the 0.0 - 1.0 region. /// Similar in role to a * 0.5 + 0.5, where -1.0 < a < 1.0. /// <summary> const float4x4 ScaleMatrix = float4x4 ( 0.5, 0.0, 0.0, 0.0, 0.0, -0.5, 0.0, 0.0, 0.0, 0.0, 0.5, 0.0, 0.5, 0.5, 0.5, 1.0 ); I had to negate the 0.5 for the y scaling (M22) in order for it to work but the shadowing is still not correct. Is this really the correct way to scale? float2 shadow_tex; shadow_tex.x = surf_tex.x * 0.5f + 0.5f; shadow_tex.y = surf_tex.y * -0.5f + 0.5f; The depth calculations are exactly the same as the source code yet they still do not work, which makes me believe something about the uv calculation above is incorrect.

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  • Need Help in optimizing a loop in C [migrated]

    - by WedaPashi
    I am trying to draw a Checkerboard pattern on a lcd using a GUI library called emWin. I have actually managed to draw it using the following code. But having these many loops in the program body for a single task, that too in the internal flash of the Microcontroller is not a good idea. Those who have not worked with emWin, I will try and explain a few things before we go for actual logic. GUI_REST is a structure which id define source files of emWin and I am blind to it. Rect, REct2,Rec3.. and so on till Rect10 are objects. Elements of the Rect array are {x0,y0,x1,y1}, where x0,y0 are starting locations of rectangle in X-Y plane and x1, y1 are end locations of Rectangle in x-Y plane. So, Rect={0,0,79,79} is a rectangle starts at top left of the LCD and is upto (79,79), so its a square basically. The function GUI_setBkColor(int color); sets the color of the background. The function GUI_setColor(int color); sets the color of the foreground. GUI_WHITE and DM_CHECKERBOARD_COLOR are two color values, #defineed GUI_FillRectEx(&Rect); will draw the Rectangle. The code below works fine but I want to make it smarter. GUI_RECT Rect = {0, 0, 79, 79}; GUI_RECT Rect2 = {80, 0, 159, 79}; GUI_RECT Rect3 = {160, 0, 239, 79}; GUI_RECT Rect4 = {240, 0, 319, 79}; GUI_RECT Rect5 = {320, 0, 399, 79}; GUI_RECT Rect6 = {400, 0, 479, 79}; GUI_RECT Rect7 = {480, 0, 559, 79}; GUI_RECT Rect8 = {560, 0, 639, 79}; GUI_RECT Rect9 = {640, 0, 719, 79}; GUI_RECT Rect10 = {720, 0, 799, 79}; WM_SelectWindow(Win_DM_Main); GUI_SetBkColor(GUI_BLACK); GUI_Clear(); for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect); Rect.y0 += 80; Rect.y1 += 80; } /* for(j=0,j<11;j++) { for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect); Rect.y0 += 80; Rect.y1 += 80; } Rect.x0 += 80; Rect.x1 += 80; } */ for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(DM_CHECKERBOARD_COLOR); else GUI_SetColor(GUI_WHITE); GUI_FillRectEx(&Rect2); Rect2.y0 += 80; Rect2.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect3); Rect3.y0 += 80; Rect3.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(DM_CHECKERBOARD_COLOR); else GUI_SetColor(GUI_WHITE); GUI_FillRectEx(&Rect4); Rect4.y0 += 80; Rect4.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect5); Rect5.y0 += 80; Rect5.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(DM_CHECKERBOARD_COLOR); else GUI_SetColor(GUI_WHITE); GUI_FillRectEx(&Rect6); Rect6.y0 += 80; Rect6.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect7); Rect7.y0 += 80; Rect7.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(DM_CHECKERBOARD_COLOR); else GUI_SetColor(GUI_WHITE); GUI_FillRectEx(&Rect8); Rect8.y0 += 80; Rect8.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(GUI_WHITE); else GUI_SetColor(DM_CHECKERBOARD_COLOR); GUI_FillRectEx(&Rect9); Rect9.y0 += 80; Rect9.y1 += 80; } for(i = 0; i < 6; i++) { if(i%2 == 0) GUI_SetColor(DM_CHECKERBOARD_COLOR); else GUI_SetColor(GUI_WHITE); GUI_FillRectEx(&Rect10); Rect10.y0 += 80; Rect10.y1 += 80; }

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  • How I Work: Staying Productive Whilst Traveling

    - by BuckWoody
    I travel a lot. Not like some folks that are gone every week, mind you, although in the last month I’ve been to: Cambridge, UK; Anchorage, AK; San Jose, CA; Copenhagen, DK, Boston, MA; and I’m currently en-route to Anaheim, CA.  While this many places in a month is a bit unusual for me, I would say I travel frequently. I’ve travelled most of my 28+ years in IT, and at one time was a consultant traveling weekly.   With that much time away from my primary work location, I have to find ways to stay productive. Some might say “just rest – take a nap!” – but I’m not able to do that. For one thing, I’m a very light sleeper and I’ve never slept on a plane - even a 30+ hour trip to New Zealand in Business Class - so that just isn’t option. I also am not always in the plane, of course. There’s the hotel, the taxi/bus/train, the airport and then all that over again when I arrive. Since my regular jobs have many demands, I have to get work done.   Note: No, I’m not always focused on work. I need downtime just like everyone else. Sometimes I just think, watch a movie or listen to tunes – and I give myself permission to do that anytime – sometimes the whole trip. I have too fewheartbeats left in life to only focus on work – it’s just not that important, and neither am I. Some of these tasks are letters to friends and family, or other personal things. What I’m talking about here is a plan, not some task list I have to follow. When I get to the location I’m traveling to, I always build in as much time as I can to ensure I enjoy those sights and the people I’m with. I would find traveling to be a waste if not for that.   The Unrealistic Expectation As I would evaluate the trip I was taking – say a 6-8 hour flight – I would expect to get 10-12 hours of work done. After all, there’s the time at the airport, the taxi and so on, and then of course the time in the air with all of the room, power, internet and everything else I needed to get my work done. I would pile up tasks at home, pack my bags, and head happily to the magical land of the TSA.   Right. On return from the trip, I had accomplished little, had more e-mails and other work that had piled up, and I was tired, hungry, and unorganized. This had to change. So, I decided to do three things: Segment my work Set realistic expectations Plan accordingly  Segmenting By Available Resources The first task was to decide what kind of work I could do in each location – if any. I found that I was dependent on a few things to get work done, such as power, the Internet, and a place to sit down. Before I fly, I take some time at home to get all of the work I’d like to accomplish while away segmented into these areas, and print that out on paper, which goes in my suit-coat pocket along with a mechanical pencil. I print my tickets, and I’m all set for the adventure ahead. Then I simply do each kind of work whenever I’m in that situation. No power There are certain times when I don’t have power available. But not only that, I might not even be able to use most of my electronics. So I now schedule as many phone calls as I can for the taxi/bus/train ride and the airports as I can. I have a paper notebook (Moleskine, of course) and a pencil and I print out any notes or numbers I need prior to the trip. Once I’m airborne or at the airport, I work on my laptop. I check and respond to e-mails, create slides, write code, do architecture, whatever I can.  If I can’t use any electronics, or once the power runs out, I schedule time for reading. I can read at the airport or anywhere, actually, even in-flight or any other transport. I “read with a pencil”, meaning I take a lot of notes, which I liketo put in OneNote, but since in most cases I don’t have power, I use the Moleskine to do that. Speaking of which, sometimes as I’m thinking I come up with new topics, ideas, blog posts, or things to teach in my classes. Once again I take out the notebook and write it down. All of these notes get a check-mark when I get back to the office and transfer the writing to OneNote. I’ve tried those “smart pens” and so on to automate this, but it just never works out. Pencil and paper are just fine. As I mentioned, sometime I just need to think. I’ll do nothing, and let my mind wander, thinking of nothing in particular, or some math problem or science question I’m interested in. My only issue with this is that I communicate tothink, and I don’t want to drive people crazy by being that guy that won’t shut up, so I think in a different way. Power, but no Internet or Phone If I have power but no Internet or phone, I focus on the laptop and the tablet as before, and I also recharge my other gadgets. Power, Internet, Phone and a Place to Work At first I thought that when I arrived at the hotel or event I could get the same amount of work done that I do at the office. Not so. There’s simply too many distractions, things you need, or other issues that allow this. Of course, Ican work on any device, read, think, write or whatever, but I am simply not as productive as I am in my home office. So I plan for about 25-50% as much work getting done in this environment as I think I could really do. I’ve done some measurements, and this holds out to be true almost every time. The key is that I re-set my expectations (and my co-worker’s expectations as well) that this is the case. I use the Out-Of-Office notices to let people know that I’m just not going to be 100% at this time – it’s hard for everyone, but it’s more honest and realistic, and I’d rather they know that – and that I realize that – than to let them think I’m totally available. Because I’m not – I’m traveling. I don’t tend to put too much detail, because after all I don’t necessarily want to let people know when I’m not home :) but I do think it’s important to let people that depend on my know that I’ll get back with them later. I hope this helps you think through your own methodology of staying productive when you travel. Or perhaps you just go offline, and don’t worry about any of this – good for you! That’s completely valid as well.   (Oh, and yes, I wrote this at 35K feet, on Alaska Airlines on a trip. :)  Practice what you preach, Buck.)

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  • AIA - Server Topologien und Deployment

    - by Hans Viehmann
    Es gibt ein neues White Paper, in dem die verschiedenen Varianten von AIA Topologien ausführlich beschrieben sind. Die unterschiedlichen Möglichkeiten ergeben sich vor allem aus dem Betrieb mehrerer AIA Instanzen parallel (z.B. Aufteilung in Dev/Test/Prod, Aufteilung zur Lastverteilung, Zuordnung zu unterschiedlichen Geografien, ...). Weitere Variationsmöglichkeiten bietet die Verteilung der unterschiedlichen Bestandteile des DB-Schemas (AIA Metadaten, Cross-Referencing Daten, AIA Lifecycle Repository, JMS Schema, etc.). Und schließlich können auch verschiedene Topologien der SOA Laufzeitumgebung, wie beispielsweise SOA Cluster, unterstützt werden. Diese Varianten mit ihren typischen Einsatzfeldern werden in dem Dokument ebenso beschrieben, wie deren Umsetzung mit Hilfe des Installers.In einem zweiten Teil befasst sich das White Paper mit dem Deployment der AIA Artefakte in diese Topologien, und zwar insbesondere mit dem Tool-Support durch die "Project Lifecycle Workbench" und dem "AIA Installation Driver". Erstere ist eine neue Komponente in AIA 11gR1, die in der Lage ist, am Ende des Entwicklungszyklus Deployment Pläne zu generieren, während der ebenfalls neue "AIA Installation Driver" dann die Artefakte dann in die Zielumgebung überträgt.Das White Paper ist noch nicht auf oracle.com verfügbar und ist leider so umfangreich, dass es nicht auf auf blogs.oracle.com hochgeladen werden kann. Bei Interesse verschicke ich es aber gern per Mail.

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  • Screen space to world space

    - by user13414
    I am writing a 2D game where my game world has x axis running left to right, y axis running top to bottom, and z axis out of the screen: Whilst my game world is top-down, the game is rendered on a slight tilt: I'm working on projecting from world space to screen space, and vice-versa. I have the former working as follows: var viewport = new Viewport(0, 0, this.ScreenWidth, this.ScreenHeight); var screenPoint = viewport.Project(worldPoint.NegateY(), this.ProjectionMatrix, this.ViewMatrix, this.WorldMatrix); The NegateY() extension method does exactly what it sounds like, since XNA's y axis runs bottom to top instead of top to bottom. The screenshot above shows this all working. Basically, I have a bunch of points in 3D space that I then render in screen space. I can modify camera properties in real time and see it animate to the new position. Obviously my actual game will use sprites rather than points and the camera position will be fixed, but I'm just trying to get all the math in place before getting to that. Now, I am trying to convert back the other way. That is, given an x and y point in screen space above, determine the corresponding point in world space. So if I point the cursor at, say, the bottom-left of the green trapezoid, I want to get a world space reading of (0, 480). The z coordinate is irrelevant. Or, rather, the z coordinate will always be zero when mapping back to world space. Essentially, I want to implement this method signature: public Vector2 ScreenPointToWorld(Vector2 point) I've tried several things to get this working but am just having no luck. My latest thinking is that I need to call Viewport.Unproject twice with differing near/far z values, calculate the resultant Ray, normalize it, then calculate the intersection of the Ray with a Plane that basically represents ground-level of my world. However, I got stuck on the last step and wasn't sure whether I was over-complicating things. Can anyone point me in the right direction on how to achieve this?

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  • /planes and /clubs or /wiki/planes and /wiki/clubs

    - by Jelmer
    I am currently working on a nice application about which I can't share all the details, but it will have some sort of a wiki part. In this wiki, you will be able to change the planes as well as the clubs, maybe in the future it will be possible to change the countries and manufacturers as well. But I have to think about this and I have to check how good this is. But, you will understand that it has to be expendable! That is really important. Use the planes controller with a edit page and the same for the clubs Route the planes and clubs controller to the wiki controller, so we have 1 nice "path" to edit this stuff. I want to have it called wiki that is for sure. Because that is what it is, but I am storing the planes and clubs data in its down table in my database. I think that is kinda obvious since it has to be maintainable. Right now you could edit a plane via the url: example.com/wiki/planes/edit/Duo_Discus.html Do you think that is better than example.com/planes/edit/Duo_Discus.html since it is easy to understand for the user, that he is working in the wiki instead of in the planes ? Or do you think this will break the user experience?

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  • Can you recover from a backup with bad blocks?

    - by Macbook-Recovery
    The hard drive in my Macbook recently gave up while using it on the plane (dual prop, lots of vibration unfortunately). I have a backup of its contents from a few weeks ago, but there are files that aren't included in it that I would like to recover. As it stands right now, I have it plugged to my macbook by USB. Snow leopard recognizes it, but can't mount it. Therefore, tools like Diskwarrior and Techtools do not work. I started doing a clone of it with Data Rescue 3, but after 7 hours of activity (20% through the drive), it has copied 130 GB of the drive but reports all of the data as "bad blocks". My question is this: Is any data recoverable if the clone is completely composed of bad blocks?

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  • Multithreading in Windows Phone 7 emulator: A bug

    - by Laurent Bugnion
    Multithreading is supported in Windows Phone 7 Silverlight applications, however the emulator has a bug (which I discovered and was confirmed to me by the dev lead of the emulator team): If you attempt to start a background thread in the MainPage constructor, the thread never starts. The reason is a problem with the emulator UI thread which doesn’t leave any time to the background thread to start. Thankfully there is a workaround (see code below). Also, the bug should be corrected in a future release, so it’s not a big deal, even though it is really confusing when you try to understand why the *%&^$£% thread is not &$%&%$£ starting (that was me in the plane the other day ;) This code does not work: public partial class MainPage : PhoneApplicationPage { public MainPage() { InitializeComponent(); SupportedOrientations = SupportedPageOrientation.Portrait | SupportedPageOrientation.Landscape; var counter = 0; ThreadPool.QueueUserWorkItem(o => { while (true) { Dispatcher.BeginInvoke(() => { textBlockListTitle.Text = (counter++).ToString(); }); } }); } } This code does work: public MainPage() { InitializeComponent(); SupportedOrientations = SupportedPageOrientation.Portrait | SupportedPageOrientation.Landscape; var counter = 0; ThreadPool.QueueUserWorkItem(o => { while (true) { Dispatcher.BeginInvoke(() => { textBlockListTitle.Text = (counter++).ToString(); }); // NOTICE THIS LINE!!! Thread.Sleep(0); } }); } Note that even if the thread is started in a later event (for example Click of a Button), the behavior without the Thread.Sleep(0) is not good in the emulator. As of now, i would recommend always sleeping when starting a new thread. Happy coding: Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • Minecraft-style player-gound collision detection

    - by khyperia
    The title pretty much says it all... (Minecraft is a game consisting of evenly-spaced cubes for terrain, like voxels) Note: I am using C# XNA. I am pretty sure AABB is the way to go, yet I don't know how to implement it. I admit, I'm almost looking for code, but theories/ideas are very welcome. Important capabilities of my code: I have a function that can get a block anywhere in the world, and get a BoundingBox for that cube. Hence, I have created a BoundingBox for the player to collide with those cubes. My idea was to get the blocks around the player (maybe 4x6x4) and test against those. The problems I have been having: Say the world is a flat plane. If I use the method of go the shortest distance out, then if the player is slightly clipped into the ground (from gravity), but even slighter into the next block over, then the player will be pushed sideways (and so cannot walk along ground). Of course, this is assuming I react to every block intersected. Another problem is knowing which direction to go (aka negative x or positive). That takes me to my final problem- Getting the amount of intersection, in the correct direction (+ or -) has been tough for me. I hope I haven't been too hard to understand, I'm not too good at explaining things... And if this question has already been asked, I'm sorry, I looked for it... for 3 days straight. One last thing, if someone knows exactly how minecraft does it, or has source (I know MC modders have the source, how else would they mod), please point me to it.

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  • Unity custom shaders and z-fighting

    - by Heisenbug
    I've just readed a chapter of Unity iOS Essential by Robert Wiebe. It shows a solution for handling z-figthing problem occuring while rendering a street on a plane with the same y offset. Basically it modified Normal-Diffuse shader provided by Unity, specifing the (texture?) offset in -1, -1. Here's basically what the shader looks like: Shader "Custom/ModifiedNormalDiffuse" { Properties { _Color ("Main Color", Color) = (1,1,1,1) _MainTex ("Base (RGB)", 2D) = "white" {} } SubShader { Offset -1,-1 //THIS IS THE ADDED LINE Tags { "RenderType"="Opaque" } LOD 200 CGPROGRAM #pragma surface surf Lambert sampler2D _MainTex; fixed4 _Color; struct Input { float2 uv_MainTex; }; void surf (Input IN, inout SurfaceOutput o) { half4 c = tex2D (_MainTex, IN.uv_MainTex) *_Color; o.Albedo = c.rgb; o.Alpha = c.a; } ENDCG } FallBack "Diffuse" } Ok. That's simple and it works. The author says about it: ...we could use a copy of the shader that draw the road at an Offset of -1, -1 so that whenever the two textures are drawn, the road is always drawn last. I don't know CG nor GLSL, but I've a little bit of experience with HLSL. Anyway I can't figure out what exactly is going on. Could anyone explain me what exactly Offset directly does, and how is solves z-fighting problems?

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  • How many disks to use for eight channel RAID controller

    - by Tvrtko
    I have a 3ware 8 channel SAS controller and a back plane extender (also 8 channel) which can take 16 drives. I will be creating a single RAID 10 volume. I know that adding more drives has positive effect on performance, but I'm not sure if adding more than 8 drives on an 8 channel controller will have any positive impact at all. Am I wrong? Should I put 16 drives for best performance? Would 8 drives give me the same performance?

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  • What is a simple deformer in which vertices deform linearly with control points?

    - by sebf
    In my project I want to deform a complex mesh, using a simpler 'proxy' mesh. In effect, each vertex of the proxy/collision mesh will be a control point/bone, which should deform the vertices of the main mesh attached to it depending on weight, but where the weight is not dependant on the absolute distance from the control point but rather distance relative to the other affecting control points. The point of this is to preserve complex three dimensional features of the main mesh while using physics implementations which expect something far simpler, low resolution, single surface, etc. Therefore, the vertices must deform linearly with their respective weighted control points (i.e. no falloff fields or all the mesh features will end up collapsed) - as if each vertex was linked to a point on the plane created by the attached control points and deformed with it. I have tried implementing the weight computation algorithm in this paper (page 4) but it is not working as expected and I am wondering if it is really the best way to do what I want. What is the simplest way to 'skin'* an arbitrary mesh, to another arbitrary mesh? *By skin I mean I need an algorithm to determine the best control points for a vertex, and their weights.

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  • Future Trends and Challenges for Aircraft Cabins

    - by Bill Evjen
    Ingo Wuggetzer The aircraft cabin changes from the 60s till now has worsened. First class is actually premium / economy is still moving down in quality The challenge is to do efficiency and comfort Graying population is a challenge will be 14% of the world’s population soon Obesity increasingly becoming an all-milieu core societal problem Will have impact on seat sizes Female forces – women will increasingly influence business and lifestyle There are now more women in college than men People want to be green and this reflects into aircrafts. You can now buy carbon-offsets when you buy a ticket in some airlines 20% are willing to pay for green products 13% would like to but are not doing it yet Seamless Connectivity Internet is obviously mainstream and the influence of our daily lives 2 billion users in 2010 One direction is going mobile Another direction is going social computing We have to explore this to use more with our products Convergence of products iPad usage on Finair , Virgin, Jetstar iPhone share 2% Other smartphones – 11% Feature Phone – 87% Plans to invest in technology trends within the next 3 years connectivity to/from aircraft – 21% major investment / 47% R&D nominal investment Web 2.0 – 22% major investment / 57% R&D nominal investment Cabin technical investments Lighting Wireless Sensors Displays People want to use technologies on the plane that they can use on the ground Planes have moved to digital in the last decade – now they are moving to wireless Data volumes are going through the roof – (Moore’s Law)

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  • Implementing Light Volume Front Faces

    - by cubrman
    I recently read an article about light indexed deferred rendering from here: http://code.google.com/p/lightindexed-deferredrender/ It explains its ideas in a clear way, but there was one point that I failed to understand. It in fact is one of the most interesting ones, as it explains how to implement transparency with this approach: Typically when rendering light volumes in deferred rendering, only surfaces that intersect the light volume are marked and lit. This is generally accomplished by a “shadow volume like” technique of rendering back faces – incrementing stencil where depth is greater than – then rendering front faces and only accepting when depth is less than and stencil is not zero. By only rendering front faces where depth is less than, all future lookups by fragments in the forward rendering pass will get all possible lights that could hit the fragment. Can anyone explain how exactly you need to render only front faces? Another question is why do you need the front faces at all? Why can't we simply render all the lights and store the ones that overlap at this pixel in a texture? Does this approach serves as a cut-off plane to discard lights blocked by opaque geometry?

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  • The Silverlight 4 Training Kit and Green Eggs &amp; Ham

    - by Jim Duffy
    Microsoft has released the Silverlight 4 Training Kit that steps you through the process of constructing Silverlight 4 business applications. “The Silverlight 4 Training Course includes a whitepaper explaining all of the new Silverlight 4 features, several hands-on-labs that explain the features, and a 8 unit course for building business applications with Silverlight 4. The business applications course includes 8 modules with extensive hands on labs as well as 25 accompanying videos that walk you through key aspects of building a business application with Silverlight. Key aspects in this course are working with numerous sandboxed and elevated out of browser features, the new RichTextBox control, implicit styling, webcam, drag and drop, multi touch, validation, authentication, MEF, WCF RIA Services, right mouse click, and much more!” What I think is pretty cool is that there are two ways to access this content, online and offline. Obviously the online version is great when you’re sitting at your desk and you’re connected to the web. What about when you don’t have a connection like when you’re located where you won’t eat green eggs & ham, like on a train or on plane perhaps? :-) You can download the offline version and hope that Sam I Am won’t be to distracting while you try to watch the videos or work your way through the labs. :-) Have a day. :-|

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  • How to remove seams from a tile map in 3D?

    - by Grimshaw
    I am using my OpenGL custom engine to render a tilemap made with Tiled, using a well spread tileset from the web. There is nothing fancy going on. I load the TMX file from Tiled and generate vertex arrays and index arrays to render the tilemap. I am rendering this tilemap as a wall in my 3D world, meaning that I move around with a fly camera in my 3D world and at Z=0 there is a plane showing me my tiles. Everything is working correctly but I get ugly seems between the tiles. I've tried orthographic and perspective cameras and with either I found particular sets of parameters for the projection and view matrices where the artifacts did not show, but otherwise they are there 99% of the time in multiple patterns, depending on the zoom and camera parameters like field of view. Here's a screenshot of the artifact being shown: http://i.imgur.com/HNV1g4M.png Here's the tileset I am using (which Tiled also uses and renders correctly): http://i.imgur.com/SjjHK4q.png My tileset has no mipmaps and is set to GL_NEAREST and GL_CLAMP_TO_EDGE values. I've looked around many articles in the internet and nothing helped. I tried uv correction so the uv fall at half of the texel, rather than the end of the texel to prevent interpolating with the neighbour value(which is transparency). I tried debugging with my geometry and I verified that with no texture and a random color in each tile, I don't seem to see any seams. All vertices have integer coordinates, i.e, the first tile is a quad from (0,0) to (1,1) and so on. Tried adding a little offset both to the UV and to the vertices to see if the gaps cease to exist. Disabled multisampling too. Nothing fixed it so far. Thanks.

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  • Unity: parallel vectors and cross product, how to compare vectors

    - by Heisenbug
    I read this post explaining a method to understand if the angle between 2 given vectors and the normal to the plane described by them, is clockwise or anticlockwise: public static AngleDir GetAngleDirection(Vector3 beginDir, Vector3 endDir, Vector3 upDir) { Vector3 cross = Vector3.Cross(beginDir, endDir); float dot = Vector3.Dot(cross, upDir); if (dot > 0.0f) return AngleDir.CLOCK; else if (dot < 0.0f) return AngleDir.ANTICLOCK; return AngleDir.PARALLEL; } After having used it a little bit, I think it's wrong. If I supply the same vector as input (beginDir equal to endDir), the cross product is zero, but the dot product is a little bit more than zero. I think that to fix that I can simply check if the cross product is zero, means that the 2 vectors are parallel, but my code doesn't work. I tried the following solution: Vector3 cross = Vector3.Cross(beginDir, endDir); if (cross == Vector.zero) return AngleDir.PARALLEL; And it doesn't work because comparison between Vector.zero and cross is always different from zero (even if cross is actually [0.0f, 0.0f, 0.0f]). I tried also this: Vector3 cross = Vector3.Cross(beginDir, endDir); if (cross.magnitude == 0.0f) return AngleDir.PARALLEL; it also fails because magnitude is slightly more than zero. So my question is: given 2 Vector3 in Unity, how to compare them? I need the elegant equivalent version of this: if (beginDir.x == endDir.x && beginDir.y == endDir.y && beginDir.z == endDir.z) return true;

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  • Static "LoD" hack opinions

    - by David Lively
    I've been playing with implementing dynamic level of detail for rendering a very large mesh in XNA. It occurred to me that (duh) the whole point of this is to generate small triangles close to the camera, and larger ones far away. Given that, rather than constantly modifying or swapping index buffers based on a feature's rendered size or distance from the camera, it would be a lot easier (and potentially quite a bit faster), to render a single "fan" or flat wedge/frustum-shaped planar mesh that is tessellated into small triangles close to the near or small end of the frustum and larger ones at the far end, sort of like this (overhead view) (Pardon the gap in the middle - I drew one side and mirrored it) The triangle sizes are chosen so that all are approximately the same size when projected. Then, that mesh would be transformed to track the camera so that the Z axis (center vertical in this image) is always aligned with the view direction projected into the XZ plane. The vertex shader would then read terrain heights from a height texture and adjust the Y coordinate of the mesh to match a height field that defines the terrain. This eliminates the need for culling (since the mesh is generated to match the viewport dimensions) and the need to modify the index and/or vertex buffers when drawing the terrain. Obviously this doesn't address terrain with overhangs, etc, but that could be handled to a certain extent by including a second mesh that defines a sort of "ceiling" via a different texture. The other LoD schemes I've seen aren't particularly difficult to implement and, in some cases, are a lot more flexible, but this seemed like a decent quick-and-dirty way to handle height map-based terrain without getting into geometry manipulation. Has anyone tried this? Opinions?

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  • Transform coordinates from 3d to 2d without matrix or built in methods

    - by Thomas
    Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use matrices or built in transformation methods I need another way. I've tried implementing the next explanation + pseudo code: http://freespace.virgin.net/hugo.elias/routines/3d_to_2d.htm Unfortunately no luck there. I've replace all the input variables with data from my own camera and object classes. I have the following data: An object with a rotation, position vector and an array of 4 3d coords (its just a plane) a camera with a position and rotation vector the viewport - a square 600 x 600 surface. The example uses a zoom factor which I've set as 1 Most hits on google use either matrix calculations or don't implement camera rotation. Basic transformation should be like this: screen.x = x / z * zoom screen.y = y / z * zoom Can anyone point me in the right direction or explain to me howto achieve this? edit: Thanks for all your posts, I haven't been able to apply all this to my project yet but I hope to do this soon.

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  • Find points whose pairwise distances approximate a given distance matrix

    - by Stephan Kolassa
    Problem. I have a symmetric distance matrix with entries between zero and one, like this one: D = ( 0.0 0.4 0.0 0.5 ) ( 0.4 0.0 0.2 1.0 ) ( 0.0 0.2 0.0 0.7 ) ( 0.5 1.0 0.7 0.0 ) I would like to find points in the plane that have (approximately) the pairwise distances given in D. I understand that this will usually not be possible with strictly correct distances, so I would be happy with a "good" approximation. My matrices are smallish, no more than 10x10, so performance is not an issue. Question. Does anyone know of an algorithm to do this? Background. I have sets of probability densities between which I calculate Hellinger distances, which I would like to visualize as above. Each set contains no more than 10 densities (see above), but I have a couple of hundred sets. What I did so far. I did consider posting at math.SE, but looking at what gets tagged as "geometry" there, it seems like this kind of computational geometry question would be more on-topic here. If the community thinks this should be migrated, please go ahead. This looks like a straightforward problem in computational geometry, and I would assume that anyone involved in clustering might be interested in such a visualization, but I haven't been able to google anything. One simple approach would be to randomly plonk down points and perturb them until the distance matrix is close to D, e.g., using Simulated Annealing, or run a Genetic Algorithm. I have to admit that I haven't tried that yet, hoping for a smarter way. One specific operationalization of a "good" approximation in the sense above is Problem 4 in the Open Problems section here, with k=2. Now, while finding an algorithm that is guaranteed to find the minimum l1-distance between D and the resulting distance matrix may be an open question, it still seems possible that there at least is some approximation to this optimal solution. If I don't get an answer here, I'll mail the gentleman who posed that problem and ask whether he knows of any approximation algorithm (and post any answer I get to that here).

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  • How is software used in critical life-or-death systems tested?

    - by waiwai933
    An airplane, as opposed to, for example, a website, is a system where any failure in certain systems is completely unacceptable, since errors in e.g. flight monitoring can cause the autopilot to malfunction and do a dive. Obviously, this doesn't happen since the brilliant engineers at Boeing and Airbus have checks in the autopilot to make sure it doesn't suddenly decide a dive is a perfectly acceptable and safe maneuver. Or perhaps the computer crashes, and the pilots in the newer fly-by-wire aircraft can no longer actually fly the plane. Of course, there are various safety procedures and redundancies built into these systems to prevent a crash (of both the software and the aircraft). However, on the other hand, it's quite obvious that software isn't perfect—both open source and closed source software do crash regularly, and only the simplest "Hello World" program doesn't fail. How can the engineers who design the software systems in the aeronautic, medical, and other life-or-death industries manage to test their software so that it doesn't fail (and if it does fail, at least fail gracefully)? I'm desperately hoping that you're not all going to go: "Oh, I work for Boeing/Airbus/(some other company) and it's not! Have fun on your next flight/hospital visit."

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  • organization of DLL linked functions

    - by m25
    So this is a code organization question. I got my basic code working but when I expand it will be terrible. I have a DLL that I don't have a .lib for. Therefore I have to use the whole loadLibrary()/getprocaddress() combo. it works great. But this DLL that i'm referencing at 100+ functions. my current process is (1) typedef a type for the function. or typedef short(_stdcall *type1)(void); then (2) assign a function name that I want to use such as type1 function_1, then (3) I do the whole LoadLibrary, then do something like function_1 = (type1)GetProcAddress(hinstLib, "_mangled_funcName@5"); normally I would like to do all of my function definitions in a header file but because I have to do use the load library function, its not that easy. the code will be a mess. Right now i'm doing (1) and (2) in a header file and was considering making a function in another .cpp file to do the load library and dump all of the (3)'s in there. I considered using a namespace for the functions so I can use them in the main function and not have to pass over to the other function. Any other tips on how to organize this code to where it is readable and organized? My goals are to be able to use function_1 as a regular function in the main code. if I have to a ref::function_1 that would be okay but I would prefer to avoid it. this code for all practical purposes is just plane C at the moment. thanks in advance for any advice!

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  • Collision planes confusion

    - by Jeffrey
    I'm following this tutorial by thecplusplusguy and in the linked video he explain that for example for the world basement and walls we need to create the actual rendered (shown to the player) walls and then duplicate them, place them in the same coordinates as the rendered walls and call them collision (by defining their material to collision). Then it defines in the Object loader function that those objects with material == collision are collision planes and should not be rendered but just used to check collision. Now I'm pretty confused. Why would we add this kind of complexity to a problem that can easily be solved by a simple loadObject(string plane_object, bool check_collision);: Creating only the walls object (by loading .obj file in plane_object) Define them also as collision planes whenever the check_collision is set to true In this case we have lowered the complexity of his method and make it more flexible and faster to develop (faster because we don't always have to make a copy for each plane and flexible because we don't hardcode the Object loader). The only case in which this method could not work is when we need hidden collision planes, and for that we could modify the loadObject() function like this: loadObject(string plane_object, bool check_collision = true, bool hide_object = false); Creating only the walls object (by loading .obj file in plane_object) Define them also as collision planes whenever the check_collision is set to true And add the ability to actually show the object or hide it based on hide_object. The final question is: am I right? What would the possible problem encountered with my solution versus his?

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  • Cisco IOS router config -- how to disable SSH / SNMP on all but loopback address?

    - by chris
    Sorry for the naive question; a quick reading of the cisco docs doesn't answer this question... So I've got a router (say for the sake of argument a 4500 running IOS 15.x) It has interfaces in 3 different subnets -- 10.0.0.1/24, 10.0.1.1/24, and 10.0.2.1/24 It also has a loopback address of 172.16.0.33 How do I make it so that SSH / SNMP and other administrative traffic works on the 172 address but doesn't work on the IP addresses I wish to only use for L3 forwarding? Ideally this can be done by disabling the control plane access to these interfaces not just by using an ACL, but whatever, I don't actually care that much as long as it works... Thanks!

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