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  • How to implement efficient Fog of War?

    - by Cambrano
    I've asked a question how to implement Fog Of War(FOW) with shaders. Well I've got this working. I use the vertex color to identify the alpha of a single vertex. I guess the most of you know what the FOW of Age of Empires was like, anyway I'll shortly explain it: You have a map. Everything is unexplored(solid black / 100% transparency) at the beginning. When your NPC's / other game units explore the world (by moving around mostly) they unshadow the map. That means. Everything in a specific radius (viewrange) around a NPC is visible (0%transparency). Anything that is out of viewrange but already explored is visible but shadowed (50% transparency). So yeah, AoE had relatively huge maps. Requirements was something around 100mhz etc. So it should be relatively easy to implement something to solve this problem - actually. Okay. I'm currently adding planes above my world and set the color per vertex. Why do I use many planes ? Unity has a vertex limit of 65.000 per mesh. According to the size of my tiles and the size of my map I need more than one plane. So I actually need a lot of planes. This is obviously pita for my FPS. Well so my question is, what are simple (in sense of performance) techniques to implement a FOW shader? Okay some simplified code what I'm doin so far: // Setup for (int x = 0; x < (Map.Dimension/planeSize); x++) { for (int z = 0; z < (Map.Dimension/planeSize); z++) { CreateMeshAt(x*planeSize, 3, z*planeSize) } } // Explore (is called from NPCs when walking for example) for (int x = ((int) from.x - radius); x < from.x + radius; x ++) { for (int z = ((int) from.z - radius); z < from.z + radius; z ++) { if (from.Distance(x, 1, z) > radius) continue; _transparency[x/tileSize, z/tileSize] = 0.5f; } } // Update foreach(GameObject plane in planes){ foreach(Vector3 vertex in vertices){ Vector3 worldPos = GetWorldPos(vertex); vertex.Color = new Color(0,0,0, _transparency[worldPos.x/tileSize, worldPos.z/tileSize]); } } My shader just sets the transparency of the vertex now, which comes from the vertex color channel

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  • consume a .net webservice using jQuery

    - by Babunareshnarra
    Implementation shows the way to consume web service using jQuery. The client side AJAX with HTTP POST request is significant when it comes to loading speed and responsiveness.Following is the service created that return's string in JSON.[WebMethod][ScriptMethod(ResponseFormat = ResponseFormat.Json)]public string getData(string marks){    DataTable dt = retrieveDataTable("table", @"              SELECT * FROM TABLE WHERE MARKS='"+ marks.ToString() +"' ");    List<object> RowList = new List<object>();    foreach (DataRow dr in dt.Rows)    {        Dictionary<object, object> ColList = new Dictionary<object, object>();        foreach (DataColumn dc in dt.Columns)        {            ColList.Add(dc.ColumnName,            (string.Empty == dr[dc].ToString()) ? null : dr[dc]);        }        RowList.Add(ColList);    }    JavaScriptSerializer js = new JavaScriptSerializer();    string JSON = js.Serialize(RowList);    return JSON;}Consuming the webservice $.ajax({    type: "POST",    data: '{ "marks": "' + val + '"}', // This is required if we are using parameters    contentType: "application/json",    dataType: "json",    url: "/dataservice.asmx/getData",    success: function(response) {               RES = JSON.parse(response.d);        var obj = JSON.stringify(RES);     }     error: function (msg) {                    alert('failure');     }});Remember to reference jQuery library on the page.

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  • How can I attach a model to the bone of another model?

    - by kaykayman
    I am trying to attach one animated model to one of the bones of another animated model in an XNA game. I've found a few questions/forum posts/articles online which explain how to attach a weapon model to the bone of another model (which is analogous to what I'm trying to achieve), but they don't seem to work for me. So as an example: I want to attach Model A to a specific bone in Model B. Question 1. As I understand it, I need to calculate the transforms which are applied to the bone on Model B and apply these same transforms to every bone in Model A. Is this right? Question 2. This is my code for calculating the Transforms on a specific bone. private Matrix GetTransformPaths(ModelBone bone) { Matrix result = Matrix.Identity; while (bone != null) { result = result * bone.Transform; bone = bone.Parent; } return result; } The maths of Matrices is almost entirely lost on me, but my understanding is that the above will work its way up the bone structure to the root bone and my end result will be the transform of the original bone relative to the model. Is this right? Question 3. Assuming that this is correct I then expect that I should either apply this to each bone in Model A, or in my Draw() method: private void DrawModel(SceneModel model, GameTime gametime) { foreach (var component in model.Components) { Matrix[] transforms = new Matrix[component.Model.Bones.Count]; component.Model.CopyAbsoluteBoneTransformsTo(transforms); Matrix parenttransform = Matrix.Identity; if (!string.IsNullOrEmpty(component.ParentBone)) parenttransform = GetTransformPaths(model.GetBone(component.ParentBone)); component.Player.Update(gametime.ElapsedGameTime, true, Matrix.Identity); Matrix[] bones = component.Player.GetSkinTransforms(); foreach (SkinnedEffect effect in mesh.Effects) { effect.SetBoneTransforms(bones); effect.EnableDefaultLighting(); effect.World = transforms[mesh.ParentBone.Index] * Matrix.CreateRotationY(MathHelper.ToRadians(model.Angle)) * Matrix.CreateTranslation(model.Position) * parenttransform; effect.View = getView(); effect.Projection = getProjection(); effect.Alpha = model.Opacity; } } mesh.Draw(); } I feel as though I have tried every conceivable way of incorporating the parenttransform value into the draw method. The above is my most recent attempt. Is what I'm trying to do correct? And if so, is there a reason it doesn't work? The above Draw method seems to transpose the models x/z position - but even at these wrong positions, they do not account for the animation of Model B at all. Note: As will be evident from the code my "model" is comprised of a list of "components". It is these "components" that correspond to a single "Microsoft.Xna.Framework.Graphics.Model"

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  • generate parent child relation from the array to print a multi-level menu?

    - by Karthick Selvam
    How to get parent child relation from this array to print a multi-level menu $menus = array ( 0 => array ( 'id'=>0, 'check' => 1, 'display' =>'Arete Home', 'ordering' => -10, 'parent' => none, ), 1 => array ( 'id'=>1, 'check' => 1, 'display' => 'Submit Paper', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 2 => array ( 'id'=>2, 'check' => 1, 'display' => 'Buy Now', 'ordering' => -10, 'parent' => 1, 'subordering' => -10, ), 1461 => array ( 'id'=>1461, 'check' => 1, 'display' => 'Where are We?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1463 => array ( 'id'=>1463, 'check' => 1, 'display' =>' About Me?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1464 => array ( 'id'=>1464, 'check' => 1, 'display' => 'About You?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1465 => array ( 'id'=>1465, 'check' => 1, 'display' => 'About who?', 'ordering' => -10, 'parent' => 1, 'subordering' => -10, ), ); code sample: foreach($menus as $id=>$values) { $values['parent']=isset($values['parent']) ? $values['parent'] : 0; $menus[$values['parent']]['childs'][$id]=$values; unset($menus[$id]); } foreach($menus as $id1=>$value2) { $value2['parent']=isset($value2['parent']) ? $value2['parent'] : 0; $menus[$value2['parent']]['childs'][$id1]=$value2; unset($menus[$id1]); }

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  • ReSharper 5.0s LINQ Refactoring Continues to be Amazing!

    In this post, well take a straight forward procedure based set of code and convert it to LINQ using a ReSharper from JetBrains suggestion.   Ive found that in general, when I do things with foreach syntax, there is often a better way in Linq to do this.  The better does not jump out [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Finding furthermost point in game world

    - by user13414
    I am attempting to find the furthermost point in my game world given the player's current location and a normalized direction vector in screen space. My current algorithm is: convert player world location to screen space multiply the direction vector by a large number (2000) and add it to the player's screen location to get the distant screen location convert the distant screen location to world space create a line running from the player's world location to the distant world location loop over the bounding "walls" (of which there are always 4) of my game world check whether the wall and the line intersect if so, where they intersect is the furthermost point of my game world in the direction of the vector Here it is, more or less, in code: public Vector2 GetFurthermostWorldPoint(Vector2 directionVector) { var screenLocation = entity.WorldPointToScreen(entity.Location); var distantScreenLocation = screenLocation + (directionVector * 2000); var distantWorldLocation = entity.ScreenPointToWorld(distantScreenLocation); var line = new Line(entity.Center, distantWorldLocation); float intersectionDistance; Vector2 intersectionPoint; foreach (var boundingWall in entity.Level.BoundingWalls) { if (boundingWall.Intersects(line, out intersectionDistance, out intersectionPoint)) { return intersectionPoint; } } Debug.Assert(false, "No intersection found!"); return Vector2.Zero; } Now this works, for some definition of "works". I've found that the further out my distant screen location is, the less chance it has of working. When digging into the reasons why, I noticed that calls to Viewport.Unproject could result in wildly varying return values for points that are "far away". I wrote this stupid little "test" to try and understand what was going on: [Fact] public void wtf() { var screenPositions = new Vector2[] { new Vector2(400, 240), new Vector2(400, -2000), }; var viewport = new Viewport(0, 0, 800, 480); var projectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, viewport.Width / viewport.Height, 1, 200000); var viewMatrix = Matrix.CreateLookAt(new Vector3(400, 630, 600), new Vector3(400, 345, 0), new Vector3(0, 0, 1)); var worldMatrix = Matrix.Identity; foreach (var screenPosition in screenPositions) { var nearPoint = viewport.Unproject(new Vector3(screenPosition, 0), projectionMatrix, viewMatrix, worldMatrix); var farPoint = viewport.Unproject(new Vector3(screenPosition, 1), projectionMatrix, viewMatrix, worldMatrix); Console.WriteLine("For screen position {0}:", screenPosition); Console.WriteLine(" Projected Near Point = {0}", nearPoint.TruncateZ()); Console.WriteLine(" Projected Far Point = {0}", farPoint.TruncateZ()); Console.WriteLine(); } } The output I get on the console is: For screen position {X:400 Y:240}: Projected Near Point = {X:400 Y:629.571 Z:599.0967} Projected Far Point = {X:392.9302 Y:-83074.98 Z:-175627.9} For screen position {X:400 Y:-2000}: Projected Near Point = {X:400 Y:626.079 Z:600.7554} Projected Far Point = {X:390.2068 Y:-767438.6 Z:148564.2} My question is really twofold: what am I doing wrong with the unprojection such that it varies so wildly and, thus, does not allow me to determine the corresponding world point for my distant screen point? is there a better way altogether to determine the furthermost point in world space given a current world space location, and a directional vector in screen space?

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  • Drawing 2D Grid in 3D View - Need help with method

    - by Deukalion
    I'm trying to draw a simple 2D grid for an editor, to able to navigate more clearly around the 3D space, but I can't render it: Grid2D class, creates a grid of a certain size at a location and should just draw lines. public class Grid2D : IShape { private VertexPositionColor[] _vertices; private Vector2 _size; private Vector3 _location; private int _faces; public Grid2D(Vector2 size, Vector3 location, Color color) { float x = 0, y = 0; if (size.X < 1f) { size.X = 1f; } if (size.Y < 1f) { size.Y = 1f; } _size = size; _location = location; List<VertexPositionColor> vertices = new List<VertexPositionColor>(); _faces = 0; for (y = -size.Y; y <= size.Y; y++) { vertices.Add(new VertexPositionColor(location + new Vector3(-size.X, y, 0), color)); vertices.Add(new VertexPositionColor(location + new Vector3(size.X, y, 0), color)); _faces++; } for (x = -size.X; x <= size.X; x++) { vertices.Add(new VertexPositionColor(location + new Vector3(x, -size.Y, 0), color)); vertices.Add(new VertexPositionColor(location + new Vector3(x, size.Y, 0), color)); _faces++; } _vertices = vertices.ToArray(); } public void Render(GraphicsDevice device) { device.DrawUserPrimitives<VertexPositionColor>(PrimitiveType.LineList, _vertices, 0, _faces); } } Like this: +----+----+----+----+ | | | | | +----+----+----+----+ | | | | | +----+----+----+----+ | | | | | +----+----+----+----+ | | | | | +----+----+----+----+ Anyone knows what I'm doing wrong? If I add a Shape without texture, it's set automatically to VertexColorEnabled and TextureEnabled = false. This is how I render it: foreach (RenderObject render in _renderObjects) { render.Effect.Projection = projection; render.Effect.View = view; render.Effect.World = world; foreach (EffectPass pass in render.Effect.CurrentTechnique.Passes) { pass.Apply(); try { // Could be a Grid2D render.Shape.Render(_device); } catch { throw; } } } Exception is thrown: The current vertex shader declaration does not include all the elements required by the current Vertex Shader. Normal0 is missing. Simply put, I can't figure out how to draw a few lines. I want to draw them one at a time and I guess that's the problem I haven't figured out, and even when I tried rendering vertices[i], vertices[i+1] and primitiveCount = 1, vertices = 2, and so on it didn't work either. Any suggestions?

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  • Zenoss Setup for Windows Servers

    - by Jay Fox
    Recently I was saddled with standing up Zenoss for our enterprise.  We're running about 1200 servers, so manually touching each box was not an option.  We use LANDesk for a lot of automated installs and patching - more about that later.The steps below may not necessarily have to be completed in this order - it's just the way I did it.STEP ONE:Setup a standard AD user.  We want to do this so there's minimal security exposure.  Call the account what ever you want "domain/zenoss" for our examples.***********************************************************STEP TWO:Make the following local groups accessible by your zenoss account.Distributed COM UsersPerformance Monitor UsersEvent Log Readers (which doesn't exist on pre-2008 machines)Here's the Powershell script I used to setup access to these local groups:# Created to add Active Directory account to local groups# Must be run from elevated prompt, with permissions on the remote machine(s).# Create txt file should contain the names of the machines that need the account added, one per line.# Script will process machines line by line.foreach($i in (gc c:\tmp\computers.txt)){# Add the user to the first group$objUser=[ADSI]("WinNT://domain/zenoss")$objGroup=[ADSI]("WinNT://$i/Distributed COM Users")$objGroup.PSBase.Invoke("Add",$objUser.PSBase.Path)# Add the user to the second group$objUser=[ADSI]("WinNT://domain/zenoss")$objGroup=[ADSI]("WinNT://$i/Performance Monitor Users")$objGroup.PSBase.Invoke("Add",$objUser.PSBase.Path)# Add the user to the third group - Group doesn't exist on < Server 2008#$objUser=[ADSI]("WinNT://domain/zenoss")#$objGroup=[ADSI]("WinNT://$i/Event Log Readers")#$objGroup.PSBase.Invoke("Add",$objUser.PSBase.Path)}**********************************************************STEP THREE:Setup security on the machines namespace so our domain/zenoss account can access itThe default namespace for zenoss is:  root/cimv2Here's the Powershell script:#Grant account defined below (line 11) access to WMI Namespace#Has to be run as account with permissions on remote machinefunction get-sid{Param ($DSIdentity)$ID = new-object System.Security.Principal.NTAccount($DSIdentity)return $ID.Translate( [System.Security.Principal.SecurityIdentifier] ).toString()}$sid = get-sid "domain\zenoss"$SDDL = "A;;CCWP;;;$sid" $DCOMSDDL = "A;;CCDCRP;;;$sid"$computers = Get-Content "c:\tmp\computers.txt"foreach ($strcomputer in $computers){    $Reg = [WMIClass]"\\$strcomputer\root\default:StdRegProv"    $DCOM = $Reg.GetBinaryValue(2147483650,"software\microsoft\ole","MachineLaunchRestriction").uValue    $security = Get-WmiObject -ComputerName $strcomputer -Namespace root/cimv2 -Class __SystemSecurity    $converter = new-object system.management.ManagementClass Win32_SecurityDescriptorHelper    $binarySD = @($null)    $result = $security.PsBase.InvokeMethod("GetSD",$binarySD)    $outsddl = $converter.BinarySDToSDDL($binarySD[0])    $outDCOMSDDL = $converter.BinarySDToSDDL($DCOM)    $newSDDL = $outsddl.SDDL += "(" + $SDDL + ")"    $newDCOMSDDL = $outDCOMSDDL.SDDL += "(" + $DCOMSDDL + ")"    $WMIbinarySD = $converter.SDDLToBinarySD($newSDDL)    $WMIconvertedPermissions = ,$WMIbinarySD.BinarySD    $DCOMbinarySD = $converter.SDDLToBinarySD($newDCOMSDDL)    $DCOMconvertedPermissions = ,$DCOMbinarySD.BinarySD    $result = $security.PsBase.InvokeMethod("SetSD",$WMIconvertedPermissions)     $result = $Reg.SetBinaryValue(2147483650,"software\microsoft\ole","MachineLaunchRestriction", $DCOMbinarySD.binarySD)}***********************************************************STEP FOUR:Get the SID for our zenoss account.Powershell#Provide AD User get SID$objUser = New-Object System.Security.Principal.NTAccount("domain", "zenoss") $strSID = $objUser.Translate([System.Security.Principal.SecurityIdentifier]) $strSID.Value******************************************************************STEP FIVE:Modify the Service Control Manager to allow access to the zenoss AD account.This command can be run from an elevated command line, or through Powershellsc sdset scmanager "D:(A;;CC;;;AU)(A;;CCLCRPRC;;;IU)(A;;CCLCRPRC;;;SU)(A;;CCLCRPWPRC;;;SY)(A;;KA;;;BA)(A;;CCLCRPRC;;;PUT_YOUR_SID_HERE_FROM STEP_FOUR)S:(AU;FA;KA;;;WD)(AU;OIIOFA;GA;;;WD)"******************************************************************In step two the script plows through a txt file that processes each computer listed on each line.  For the other scripts I ran them on each machine using LANDesk.  You can probably edit those scripts to process a text file as well.That's what got me off the ground monitoring the machines using Zenoss.  Hopefully this is helpful for you.  Watch the line breaks when copy the scripts.

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  • Syncing client and server CRUD operations using json and php

    - by Justin
    I'm working on some code to sync the state of models between client (being a javascript application) and server. Often I end up writing redundant code to track the client and server objects so I can map the client supplied data to the server models. Below is some code I am thinking about implementing to help. What I don't like about the below code is that this method won't handle nested relationships very well, I would have to create multiple object trackers. One work around is for each server model after creating or loading, simply do $model->clientId = $clientId; IMO this is a nasty hack and I want to avoid it. Adding a setCientId method to all my model object would be another way to make it less hacky, but this seems like overkill to me. Really clientIds are only good for inserting/updating data in some scenarios. I could go with a decorator pattern but auto generating a proxy class seems a bit involved. I could use a generic proxy class that uses a __call function to allow for original object data to be accessed, but this seems wrong too. Any thoughts or comments? $clientData = '[{name: "Bob", action: "update", id: 1, clientId: 200}, {name:"Susan", action:"create", clientId: 131} ]'; $jsonObjs = json_decode($clientData); $objectTracker = new ObjectTracker(); $objectTracker->trackClientObjs($jsonObjs); $query = $this->em->createQuery("SELECT x FROM Application_Model_User x WHERE x.id IN (:ids)"); $query->setParameters("ids",$objectTracker->getClientSpecifiedServerIds()); $models = $query->getResults(); //Apply client data to server model foreach ($models as $model) { $clientModel = $objectTracker->getClientJsonObj($model->getId()); ... } //Create new models and persist foreach($objectTracker->getNewClientObjs() as $newClientObj) { $model = new Application_Model_User(); .... $em->persist($model); $objectTracker->trackServerObj($model); } $em->flush(); $resourceResponse = $objectTracker->createResourceResponse(); //Id mappings will be an associtave array representing server id resources with client side // id. //This method Dosen't seem to flexible if we want to return additional data with each resource... //Would have to modify the returned data structure, seems like tight coupling... //Ex return value: //[{clientId: 200, id:1} , {clientId: 131, id: 33}];

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  • XNA ModelMesh.Draw vs GraphicsDevice.DrawIndexedPrimitives

    - by cubrman
    I am using XNA 4.0 and I wonder if drawing models with multiple meshes is better by filling the vertex and index buffers first and calling GraphicsDevice.DrawIndexedPrimitives() or by simply using good ol' foreach(...) {ModelMesh.Draw()}. Is it possible to add data to vertex/index buffers at all in order to pack all the models on the scene in them and then call Draw only once per frame? I would appreciate a link to an in-depth explanation. Thanks.

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  • Creating an object that is ready to be used & unset properties - with IoC

    - by GetFuzzy
    I have a question regarding the specifics of object creation and the usage of properties. A best practice is to put all the properties into a state such that the object is useful when its created. Object constructors help ensure that required dependencies are created. I've found myself following a pattern lately, and then questioning its appropriateness. The pattern looks like this... public class ThingProcesser { public List<Thing> CalculatedThings { get; set; } public ThingProcesser() { CalculatedThings = new List<Thing>(); } public double FindCertainThing() { CheckForException(); foreach (var thing in CalculatedThings) { //do some stuff with things... } } public double FindOtherThing() { CheckForException(); foreach (var thing in CalculatedThings) { //do some stuff with things... } } private void CheckForException() { if (CalculatedThings.Count < 2) throw new InvalidOperationException("Calculated things must have more than 2 items"); } } The list of items is not being changed, just looked through by the methods. There are several methods on the class, and to avoid having to pass the list of things to each function as a method parameter, I set it once on the class. While this works, does it violate the principle of least astonishment? Since starting to use IoC I find myself not sticking things into the constructor, to avoid having to use a factory pattern. For example, I can argue with myself and say well the ThingProcessor really needs a List to work, so the object should be constructed like this. public class ThingProcesser { public List<Thing> CalculatedThings { get; set; } public ThingProcesser(List<Thing> calculatedThings) { CalculatedThings = calculatedThings; } } However, if I did this, it would complicate things for IoC, and this scenario hardly seems appropriate for something like the factory pattern. So in summary, are there some good guidelines for when something should be part of the object state, vs. passed as a method parameter? When using IoC, is the factory pattern the best way to deal with objects that need created with state? If something has to be passed to multiple methods in a class, does that render it a good candidate to be part of the objects state?

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  • Yet another frustum culling question

    - by Christian Frantz
    This one is kinda specific. If I'm to implement frustum culling in my game, that means each one of my cubes would need a bounding sphere. My first question is can I make the sphere so close to the edge of the cube that its still easily clickable for destroying and building? Frustum culling is easily done in XNA as I've recently learned, I just need to figure out where to place the code for the culling. I'm guessing in my method that draws all my cubes but I could be wrong. My camera class currently implements a bounding frustum which is in the update method like so frustum.Matrix = (view * proj); Simple enough, as I can call that when I have a camera object in my class. This works for now, as I only have a camera in my main game class. The problem comes when I decide to move my camera to my player class, but I can worry about that later. ContainmentType CurrentContainmentType = ContainmentType.Disjoint; CurrentContainmentType = CamerasFrustrum.Contains(cubes.CollisionSphere); Can it really be as easy as adding those two lines to my foreach loop in my draw method? Or am I missing something bigger here? UPDATE: I have added the lines to my draw methods and it works great!! So great infact that just moving a little bit removes the whole map. Many factors could of caused this, so I'll try to break it down. cubeBoundingSphere = new BoundingSphere(cubePosition, 0.5f); This is in my cube constructor. cubePosition is stored in an array, The vertices that define my cube are factors of 1 ie: (1,0,1) so the radius should be .5. I least I think it should. The spheres are created every time a cube is created of course. ContainmentType CurrentContainmentType = ContainmentType.Disjoint; foreach (Cube block in cube.cubes) { CurrentContainmentType = cam.frustum.Contains(cube.cubeBoundingSphere); ///more code here if (CurrentContainmentType != ContainmentType.Disjoint) { cube.Draw(effect); } Within my draw method. Now I know this works because the map disappears, its just working wrong. Any idea on what I'm doing wrong?

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  • Help with calculation to steer ship in 3d space

    - by Aaron Anodide
    I'm a beginner using XNA to try and make a 3D Asteroids game. I'm really close to having my space ship drive around as if it had thrusters for pitch and yaw. The problem is I can't quite figure out how to translate the rotations, for instance, when I pitch forward 45 degrees and then start to turn - in this case there should be rotation being applied to all three directions to get the "diagonal yaw" - right? I thought I had it right with the calculations below, but they cause a partly pitched forward ship to wobble instead of turn.... :( Here's current (almost working) calculations for the Rotation acceleration: float accel = .75f; // Thrust +Y / Forward if (currentKeyboardState.IsKeyDown(Keys.I)) { this.ship.AccelerationY += (float)Math.Cos(this.ship.RotationZ) * accel; this.ship.AccelerationX += (float)Math.Sin(this.ship.RotationZ) * -accel; this.ship.AccelerationZ += (float)Math.Sin(this.ship.RotationX) * accel; } // Rotation +Z / Yaw if (currentKeyboardState.IsKeyDown(Keys.J)) { this.ship.RotationAccelerationZ += (float)Math.Cos(this.ship.RotationX) * accel; this.ship.RotationAccelerationY += (float)Math.Sin(this.ship.RotationX) * accel; this.ship.RotationAccelerationX += (float)Math.Sin(this.ship.RotationY) * accel; } // Rotation -Z / Yaw if (currentKeyboardState.IsKeyDown(Keys.K)) { this.ship.RotationAccelerationZ += (float)Math.Cos(this.ship.RotationX) * -accel; this.ship.RotationAccelerationY += (float)Math.Sin(this.ship.RotationX) * -accel; this.ship.RotationAccelerationX += (float)Math.Sin(this.ship.RotationY) * -accel; } // Rotation +X / Pitch if (currentKeyboardState.IsKeyDown(Keys.F)) { this.ship.RotationAccelerationX += accel; } // Rotation -X / Pitch if (currentKeyboardState.IsKeyDown(Keys.D)) { this.ship.RotationAccelerationX -= accel; } I'm combining that with drawing code that does a rotation to the model: public void Draw(Matrix world, Matrix view, Matrix projection, TimeSpan elsapsedTime) { float seconds = (float)elsapsedTime.TotalSeconds; // update velocity based on acceleration this.VelocityX += this.AccelerationX * seconds; this.VelocityY += this.AccelerationY * seconds; this.VelocityZ += this.AccelerationZ * seconds; // update position based on velocity this.PositionX += this.VelocityX * seconds; this.PositionY += this.VelocityY * seconds; this.PositionZ += this.VelocityZ * seconds; // update rotational velocity based on rotational acceleration this.RotationVelocityX += this.RotationAccelerationX * seconds; this.RotationVelocityY += this.RotationAccelerationY * seconds; this.RotationVelocityZ += this.RotationAccelerationZ * seconds; // update rotation based on rotational velocity this.RotationX += this.RotationVelocityX * seconds; this.RotationY += this.RotationVelocityY * seconds; this.RotationZ += this.RotationVelocityZ * seconds; Matrix translation = Matrix.CreateTranslation(PositionX, PositionY, PositionZ); Matrix rotation = Matrix.CreateRotationX(RotationX) * Matrix.CreateRotationY(RotationY) * Matrix.CreateRotationZ(RotationZ); model.Root.Transform = rotation * translation * world; model.CopyAbsoluteBoneTransformsTo(boneTransforms); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = boneTransforms[mesh.ParentBone.Index]; effect.View = view; effect.Projection = projection; effect.EnableDefaultLighting(); } mesh.Draw(); } }

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  • Flattening System.Web.UI ControlCollection

    - by evovision
    Hi,   Sometimes one may need to get a list of child controls inside specific container and don't care about the underlying hierarchy.   The result is beautifully achieved using this extension method:   using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;    public static class ControlCollectionExtensionMethods    {        public static IEnumerable<Control> FlattenedList(this ControlCollection controls)        {            foreach (Control ctrl in controls)            {                  // return parent control                   yield return ctrl;                              // and dive into child collection                   foreach (Control child in ctrl.Controls.FlattenedList())                         yield return child;            }        }    }   P.S.: don't forget about namespaces when using it in your code, if above class is wrapped into namespace, for example: Sample, the source code file with calling code must explicitly reference it: using Sample;

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  • Is this a valid implementation of the repository pattern?

    - by user1578653
    I've been reading up about the repository pattern, with a view to implementing it in my own application. Almost all examples I've found on the internet use some kind of existing framework rather than showing how to implement it 'from scratch'. Here's my first thoughts of how I might implement it - I was wondering if anyone could advise me on whether this is correct? I have two tables, named CONTAINERS and BITS. Each CONTAINER can contain any number of BITs. I represent them as two classes: class Container{ private $bits; private $id; //...and a property for each column in the table... public function __construct(){ $this->bits = array(); } public function addBit($bit){ $this->bits[] = $bit; } //...getters and setters... } class Bit{ //some properties, methods etc... } Each class will have a property for each column in its respective table. I then have a couple of 'repositories' which handle things to do with saving/retrieving these objects from the database: //repository to control saving/retrieving Containers from the database class ContainerRepository{ //inject the bit repository for use later public function __construct($bitRepo){ $this->bitRepo = $bitRepo; } public function getById($id){ //talk directly to Oracle here to all column data into the object //get all the bits in the container $bits = $this->bitRepo->getByContainerId($id); foreach($bits as $bit){ $container->addBit($bit); } //return an instance of Container } public function persist($container){ //talk directly to Oracle here to save it to the database //if its ID is NULL, create a new container in database, otherwise update the existing one //use BitRepository to save each of the Bits inside the Container $bitRepo = $this->bitRepo; foreach($container->bits as $bit){ $bitRepo->persist($bit); } } } //repository to control saving/retrieving Bits from the database class BitRepository{ public function getById($id){} public function getByContainerId($containerId){} public function persist($bit){} } Therefore, the code I would use to get an instance of Container from the database would be: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = $containerRepo->getById($id); Or to create a new one and save to the database: $bitRepo = new BitRepository(); $containerRepo = new ContainerRepository($bitRepo); $container = new Container(); $container->setSomeProperty(1); $bit = new Bit(); $container->addBit($bit); $containerRepo->persist($container); Can someone advise me as to whether I have implemented this pattern correctly? Thanks!

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  • SSAS processing error: Client unable to establish connection; 08001; Encryption not supported on the client.; 08001

    - by Kevin Shyr
    After getting the cube to successfully deploy and process on Friday, I was baffled on Monday that the newly added dimension caused the cube processing to break.  I then followed the first instinct, discarded all my changes to reverted back to the version on Friday, and had no luck.  The error message (attached below) did not help as I was looking for some kind of SQL service error.  After examining the windows server log and the SQL server log, I just couldn't see anything wrong with it.After swearing for some time, and with the help of going off and working on something else for a while.  I came back to the solution and looked at the data source.  Even though I know I have never changed the provider (the default setup gave me SQL native client), I decided to change it and give OLE DB a try.This simple change allows my cube to process successfully again.  While I don't understand why the same settings that worked last week doesn't work this week, I don't have all the information to say with certainty that nothing has changed in the environment (firewall changes, server updates, etc.).SSAS processing error:<Batch >  <Parallel>    <Process xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ddl2="http://schemas.microsoft.com/analysisservices/2003/engine/2" xmlns:ddl2_2="http://schemas.microsoft.com/analysisservices/2003/engine/2/2" xmlns:ddl100_100="http://schemas.microsoft.com/analysisservices/2008/engine/100/100" xmlns:ddl200="http://schemas.microsoft.com/analysisservices/2010/engine/200" xmlns:ddl200_200="http://schemas.microsoft.com/analysisservices/2010/engine/200/200">      <Object>        <DatabaseID>DWH Sales Facts</DatabaseID>        <CubeID>DWH Sales Facts</CubeID>      </Object>      <Type>ProcessFull</Type>      <WriteBackTableCreation>UseExisting</WriteBackTableCreation>    </Process>  </Parallel></Batch>                Processing Dimension 'Date' completed.                                Errors and Warnings from Response                OLE DB error: OLE DB or ODBC error: A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.; 08001; Client unable to establish connection; 08001; Encryption not supported on the client.; 08001.                Errors in the high-level relational engine. A connection could not be made to the data source with the DataSourceID of 'DWH Sales Facts', Name of 'DWH Sales Facts'.                Errors in the OLAP storage engine: An error occurred while the dimension, with the ID of 'Currency', Name of 'Currency' was being processed.                Errors in the OLAP storage engine: An error occurred while the 'Currency Dim ID' attribute of the 'Currency' dimension from the 'DWH Sales Facts' database was being processed.                Internal error: The operation terminated unsuccessfully.                Server: The operation has been cancelled.

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  • GPU Debugging with VS 11

    - by Daniel Moth
    With VS 11 Developer Preview we have invested tremendously in parallel debugging for both CPU (managed and native) and GPU debugging. I'll be doing a whole bunch of blog posts on those topics, and in this post I just wanted to get people started with GPU debugging, i.e. with debugging C++ AMP code. First I invite you to watch 6 minutes of a glimpse of the C++ AMP debugging experience though this video (ffw to minute 51:54, up until minute 59:16). Don't read the rest of this post, just go watch that video, ideally download the High Quality WMV. Summary GPU debugging essentially means debugging the lambda that you pass to the parallel_for_each call (plus any functions you call from the lambda, of course). CPU debugging means debugging all the code above and below the parallel_for_each call, i.e. all the code except the restrict(direct3d) lambda and the functions that it calls. With VS 11 you have to choose what debugger you want to use for a particular debugging session, CPU or GPU. So you can place breakpoints all over your code, then choose what debugger you want (CPU or GPU), and you'll only be able to hit breakpoints for the code type that the debugger engine understands – the remaining breakpoints will appear as unbound. If you want to hit the unbound breakpoints, you'd have to stop debugging, and start again with the other debugger. Sorry. We suck. We know. But once you are past that limitation, I think you'll find the experience truly rewarding – seriously! Switching debugger engines With the Developer Preview bits, one way to switch the debugger engine is through the project properties – see the screenshots that follow. This one is showing the CPU option selected, which is basically the default that you are all familiar with: This screenshot is showing the GPU option selected, by changing the debugger launcher (notice that this applies for both the local and remote case): You actually do not have to open the project properties just for switching the debugger engine, you can switch the selection from the toolbar in VS 11 Developer Preview too – see following screenshot (the effect is the same as if you opened the project properties and switched there) Breakpoint behavior Here are two screenshots, one showing a debugging session for CPU and the other a debugging session for GPU (notice the unbound breakpoints in each case) …and here is the GPU case (where we cannot bind the CPU breakpoints but can the GPU breakpoint, which is actually hit) Give C++ AMP debugging a try So to debug your C++ AMP code, pull down the drop down under the 'play' button to select the 'GPU C++ Direct3D Compute Debugger' menu option, then hit F5 (or the 'play' button itself). Then you can explore debugging by exploring the menus under the Debug and under the Debug->Windows menus. One way to do that exploration is through the C++ AMP debugging walkthrough on MSDN. Another way to explore the C++ AMP debugging experience, you can use the moth.cpp code file, which is what I used in my BUILD session debugger demo. Note that for my demo I was using the latest internal VS11 bits, so your experience with the Developer Preview bits won't be identical to what you saw me demonstrate, but it shouldn't be far off. Stay tuned for a lot more content on the parallel debugger in VS 11, both CPU and GPU, both managed and native. Comments about this post by Daniel Moth welcome at the original blog.

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  • When to implement: Together with or after the source product?

    - by Jeremy Oosthuizen
    Somebody recently relayed a prospect's question to me: How hard would it be to implement OUBI after the source product (CC&B, WAM or NMS) has already been implemented? Fact is that MOST non-OUBI Data Warehouse / Business Intelligence implementations take place after the source application(s) are in place and hopefully stable. If an organization decides that they need better reporting and management information, then the logical path (see The Data Warehouse Institute's Data Warehouse Maturity Model) is to a Data Warehouse -- no matter when their last applications were implemented. If there is a pre-built Data Warehouse for their specific application, or even for the desired business process in their industry, they're in luck. Else they have to design and build from scratch, using a toolset. The implementation of a toolset is unlike the implementation of OUBI which, like OBI Apps, contain pre-built ETL routines and user content. Much has been written before about the advantages of that. So, because OUBI is designed specifically for Oracle Utilities transactional products, we often implement them in parallel -- with OUBI lagging a little behind by necessity, like Reporting. Customers know from the start they're going to need the solution, and therefore purchase the products at the same time. My biggest argument FOR a parallel installation/implementation of OUBI with the source product is two-fold: - There could be things (which is the technical term for data elements) that customers figure out they need when implementing OUBI, which are often easier added to the source product's implementation project, than to add later; - OUBI's ETL often points out errors (severe or not) with converted data, which are easier to fix during the source product's implementation project, or it may even be impossible to fix afterwards. The Conversion routines sometimes miss these errors, because the source system can live with the not-quite-perfect converted data. If the data can't be properly extracted, i.e. the proper Dimensions linked to the Facts, then it can't get into OUBI. That means it can't be analyzed effectively along with the rest of the organization's data. Then there is also the throw-away-work argument, which may be significant. The operational / transactional system cannot go live without reports on Day 1. A lot of those reports would be taken care of by the implementation of OUBI. If OUBI is implemented after go-live, those reports STILL have to be built during the source product's implementation project, but they become throw-away after the OUBI implementation. I have sometimes been told that it is better to implement OUBI after the source product, because it cuts down on scope and risk for the source product's implementation project. All I can say to that, is bah humbug. No, seriously, given the arguments above, planning has to include the OUBI implementation and it has to be managed properly -- just like any other implementation. If so, it should not add any risk and it should be included in the scope from the start. The answer to the prospect's question is therefore that it is not that much more difficult; after all, most DW/BI implemenations are done like that. They just have to consider the points above.

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  • Triangle Line-Segment Intersection - detecting near misses

    - by Will
    A ray is a very poor approximation of a player! I think approximating a player with a sphere traveling a straight line each game tick will solve my problems of the player intersecting edges of scenery because their line segment missed it yet their own model is not infinitely thin... I have a 3D triangle and a line segment. I have the normal triangle-line-segment intersection code which I admit I have only a woolly grasp of. To model movement and compute collisions of the player I have to determine if a line passes within sphere-radius of a triangle. But I can find no convenient line near-miss intersection code! Here's the classic triangle intersection ### commented ### code with my starting assumptions: function triangle_ray_intersection(a,b,c,ray_origin,ray_dir,ray_radius) { // http://softsurfer.com/Archive/algorithm_0105/algorithm_0105.htm#intersect_RayTriangle%28%29 // get triangle edge vectors and plane normal var u = vec3_sub(b,a); var v = vec3_sub(c,a); var n = vec3_cross(u,v); if(n[0]==0 && n[1]==0 && n[2]==0) return null; // triangle is degenerate var w0 = vec3_sub(ray_origin,a); var j = vec3_dot(n,ray_dir); if(Math.abs(j) < 0.00000001) { //### if parallel, might still pass within ray_radius of it return null; // parallel, disjoint or on plane } var i = -vec3_dot(n,w0); // get intersect point of ray with triangle plane var k = i / j; if(k < 0.0) return null; // ray goes away from triangle //### as its a line segment, k > 1+ray_radius means no intersect var hit = vec3_add(ray_origin,vec3_scale(ray_dir,k)); // intersect point of ray and plane // is I inside T? //### here I'm a bit lost; this is presumably computing barycentric coordinates? var uu = vec3_dot(u,u); var uv = vec3_dot(u,v); var vv = vec3_dot(v,v); var w = vec3_sub(hit,a); var wu = vec3_dot(w,u); var wv = vec3_dot(w,v); var D = uv * uv - uu * vv; var s = (uv * wv - vv * wu) / D; //### therefore, compute if its within ray_radius scaled to the 0..1 of barycentric coordinates? if(s<0.0 || s>1.0) return null; // I is outside T var t = (uv * wu - uu * wv) / D; if(t<0.0 || (s+t)>1.0) return null; // I is outside T //### finally, if it passses a barycentric test it might still be too far //### to a point; must check that its distance from a corner is within ray_radius too if more than one barycentric coord is >1 //### so we have rounded corners... return [hit,n]; // I is in T } Given the distance between the point of plane intersection and each corner, I ought to be able to determine distance at world scale of how far beyond the edge - beyond 1.0 in barycentric coordinates for each axis - that point is... At this point my head explodes! Is this the right track? What's the actual code? UPDATE: you can earn 100 pts on SO if you answer this question there...! How can you determine if a line segment passes within some distance of a triangle?

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  • Analysis Services (SSAS) - Unexpected Internal Error when processing (ProcessUpdate). Workaround/Resolution

    - by James Rogers
    Many implementations require the use of ProcessUpdate to support Type 1 slowly changing dimensions. ProcessUpdate drops all of the affected indexes and aggregations in partitions affected by data that changes in the Dimension on which the ProcessUpdate is being performed. Twice now I have had situations where the processing fails with "Internal error: An unexpected exception occurred." Any subsequent ProcessUpdate processing will also fail with the same error. In talking with Microsoft the issue is corrupt indexes for the Dimension(s) being processed in the partitions of the affected measure group. I cannot guarantee that the following will correct your problem but it did in my case and saved us quite a bit of down time.   Workaround: ProcessIndexes on the entire cube that is being processed and throwing the error. This corrected the problem on both 2008 and 2008 R2.   Pros:  Does not require a complete rebuild of the data (ProcessFull) for either the Dimension or Cube. User access can continue while this ProcessIndexes in underway.   Cons: Can take a long time, especially on large cubes with many partitions, dimensions and/or aggregations. Query Performance is usually severely impacted due to the memory and CPU requirements for Aggregation and Index building   <Batch http://schemas.microsoft.com/analysisservices/2003/engine"http://schemas.microsoft.com/analysisservices/2003/engine">  <Parallel>     <Process xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ddl2="http://schemas.microsoft.com/analysisservices/2003/engine/2" xmlns:ddl2_2="http://schemas.microsoft.com/analysisservices/2003/engine/2/2" xmlns:ddl100_100="http://schemas.microsoft.com/analysisservices/2008/engine/100/100" xmlns:ddl200="http://schemas.microsoft.com/analysisservices/2010/engine/200" xmlns:ddl200_200="http://schemas.microsoft.com/analysisservices/2010/engine/200/200">       <Object>         <DatabaseID>MyDatabase</DatabaseID>         <CubeID>MyCube</CubeID>       </Object>       <Type>ProcessIndexes</Type>       <WriteBackTableCreation>UseExisting</WriteBackTableCreation>     </Process>  </Parallel> </Batch>   The cube where the corruption exists can be found by having Profiler running while the ProcessUpdate is executing. The first partition that displays the "The Job has ended in failure." message in the TextData column will be part of the cube/measuregroup that has the corruption. You can try to run ProcessIndexes on just that measure group. This may correct the problem and save additional time if you have other large measure groups in the cube that are not affected by the corruption.   Remember to execute your normal ProcessUpdate batch after the successful completion of the ProcessIndexes. The ProcessIndexes does not pick up data changes.   Things that did not work: ProcessClearIndexes - why this doesn't work and ProcessIndexes does is unclear at this point. ProcessFull on the partition in question. In my latest case, this would clear up the problem for that partition. However, the next partition the ProcessUpdate touched that had data in it would generate and error. This leads me to believe the corruption problem will exist in all partitions in the affected measure group that have data in them.   NOTE: I experience this problem in both a SQL 2008 and SQL 2008 R2 Analysis Services environment, on separate built from the same relational database. This leads me to believe that some data condition in the tables used for the Dimension processing caused the corruption since the two environments were on physically separate hardware. I am waiting on Microsoft to analyze the dumps to give us more insight into what actually caused the corruption and will update this post accordingly.

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  • ODI 11g – Oracle Multi Table Insert

    - by David Allan
    With the IKM Oracle Multi Table Insert you can generate Oracle specific DML for inserting into multiple target tables from a single query result – without reprocessing the query or staging its result. When designing this to exploit the IKM you must split the problem into the reusable parts – the select part goes in one interface (I named SELECT_PART), then each target goes in a separate interface (INSERT_SPECIAL and INSERT_REGULAR). So for my statement below… /*INSERT_SPECIAL interface */ insert  all when 1=1 And (INCOME_LEVEL > 250000) then into SCOTT.CUSTOMERS_NEW (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /* INSERT_REGULAR interface */ when 1=1  then into SCOTT.CUSTOMERS_SPECIAL (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /*SELECT*PART interface */ select        CUSTOMERS.EMAIL EMAIL,     CUSTOMERS.CREDIT_LIMIT CREDIT_LIMIT,     UPPER(CUSTOMERS.NAME) NAME,     CUSTOMERS.USER_MODIFIED USER_MODIFIED,     CUSTOMERS.DATE_MODIFIED DATE_MODIFIED,     CUSTOMERS.BIRTH_DATE BIRTH_DATE,     CUSTOMERS.MARITAL_STATUS MARITAL_STATUS,     CUSTOMERS.ID ID,     CUSTOMERS.USER_CREATED USER_CREATED,     CUSTOMERS.GENDER GENDER,     CUSTOMERS.DATE_CREATED DATE_CREATED,     CUSTOMERS.INCOME_LEVEL INCOME_LEVEL from    SCOTT.CUSTOMERS   CUSTOMERS where    (1=1) Firstly I create a SELECT_PART temporary interface for the query to be reused and in the IKM assignment I state that it is defining the query, it is not a target and it should not be executed. Then in my INSERT_SPECIAL interface loading a target with a filter, I set define query to false, then set true for the target table and execute to false. This interface uses the SELECT_PART query definition interface as a source. Finally in my final interface loading another target I set define query to false again, set target table to true and execute to true – this is the go run it indicator! To coordinate the statement construction you will need to create a package with the select and insert statements. With 11g you can now execute the package in simulation mode and preview the generated code including the SQL statements. Hopefully this helps shed some light on how you can leverage the Oracle MTI statement. A similar IKM exists for Teradata. The ODI IKM Teradata Multi Statement supports this multi statement request in 11g, here is an extract from the paper at www.teradata.com/white-papers/born-to-be-parallel-eb3053/ Teradata Database offers an SQL extension called a Multi-Statement Request that allows several distinct SQL statements to be bundled together and sent to the optimizer as if they were one. Teradata Database will attempt to execute these SQL statements in parallel. When this feature is used, any sub-expressions that the different SQL statements have in common will be executed once, and the results shared among them. It works in the same way as the ODI MTI IKM, multiple interfaces orchestrated in a package, each interface contributes some SQL, the last interface in the chain executes the multi statement.

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  • F# and the rose-tinted reflection

    - by CliveT
    We're already seeing increasing use of many cores on client desktops. It is a change that has been long predicted. It is not just a change in architecture, but our notions of efficiency in a program. No longer can we focus on the asymptotic complexity of an algorithm by counting the steps that a single core processor would take to execute it. Instead we'll soon be more concerned about the scalability of the algorithm and how well we can increase the performance as we increase the number of cores. This may even lead us to throw away our most efficient algorithms, and switch to less efficient algorithms that scale better. We might even be willing to waste cycles in order to speculatively execute at the algorithm rather than the hardware level. State is the big headache in this parallel world. At the hardware level, main memory doesn't necessarily contain the definitive value corresponding to a particular address. An update to a location might still be held in a CPU's local cache and it might be some time before the value gets propagated. To get the latest value, and the notion of "latest" takes a lot of defining in this world of rapidly mutating state, the CPUs may well need to communicate to decide who has the definitive value of a particular address in order to avoid lost updates. At the user program level, this means programmers will need to lock objects before modifying them, or attempt to avoid the overhead of locking by understanding the memory models at a very deep level. I think it's this need to avoid statefulness that has led to the recent resurgence of interest in functional languages. In the 1980s, functional languages started getting traction when research was carried out into how programs in such languages could be auto-parallelised. Sadly, the impracticality of some of the languages, the overheads of communication during this parallel execution, and rapid improvements in compiler technology on stock hardware meant that the functional languages fell by the wayside. The one thing that these languages were good at was getting rid of implicit state, and this single idea seems like a solution to the problems we are going to face in the coming years. Whether these languages will catch on is hard to predict. The mindset for writing a program in a functional language is really very different from the way that object-oriented problem decomposition happens - one has to focus on the verbs instead of the nouns, which takes some getting used to. There are a number of hybrid functional/object languages that have been becoming more popular in recent times. These half-way houses make it easy to use functional ideas for some parts of the program while still allowing access to the underlying object-focused platform without a great deal of impedance mismatch. One example is F# running on the CLR which, in Visual Studio 2010, has because a first class member of the pack. Inside Visual Studio 2010, the tooling for F# has improved to the point where it is easy to set breakpoints and watch values change while debugging at the source level. In my opinion, it is the tooling support that will enable the widespread adoption of functional languages - without this support, people will put off any transition into the functional world for as long as they possibly can. Without tool support it will make it hard to learn these languages. One tool that doesn't currently support F# is Reflector. The idea of decompiling IL to a functional language is daunting, but F# is potentially so important I couldn't dismiss the idea. As I'm currently developing Reflector 6.5, I thought it wise to take four days just to see how far I could get in doing so, even if it achieved little more than to be clearer on how much was possible, and how long it might take. You can read what happened here, and of the insights it gave us on ways to improve the tool.

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  • Give a session on C++ AMP – here is how

    - by Daniel Moth
    Ever since presenting on C++ AMP at the AMD Fusion conference in June, then the Gamefest conference in August, and the BUILD conference in September, I've had numerous requests about my material from folks that want to re-deliver the same session. The C++ AMP session I put together has evolved over the 3 presentations to its final form that I used at BUILD, so that is the one I recommend you base yours on. Please get the slides and the recording from channel9 (I'll refer to slide numbers below). This is how I've been presenting the C++ AMP session: Context (slide 3, 04:18-08:18) Start with a demo, on my dual-GPU machine. I've been using the N-Body sample (for VS 11 Developer Preview). (slide 4) Use an nvidia slide that has additional examples of performance improvements that customers enjoy with heterogeneous computing. (slide 5) Talk a bit about the differences today between CPU and GPU hardware, leading to the fact that these will continue to co-exist and that GPUs are great for data parallel algorithms, but not much else today. One is a jack of all trades and the other is a number cruncher. (slide 6) Use the APU example from amd, as one indication that the hardware space is still in motion, emphasizing that the C++ AMP solution is a data parallel API, not a GPU API. It has a future proof design for hardware we have yet to see. (slide 7) Provide more meta-data, as blogged about when I first introduced C++ AMP. Code (slide 9-11) Introduce C++ AMP coding with a simplistic array-addition algorithm – the slides speak for themselves. (slide 12-13) index<N>, extent<N>, and grid<N>. (Slide 14-16) array<T,N>, array_view<T,N> and comparison between them. (Slide 17) parallel_for_each. (slide 18, 21) restrict. (slide 19-20) actual restrictions of restrict(direct3d) – the slides speak for themselves. (slide 22) bring it altogether with a matrix multiplication example. (slide 23-24) accelerator, and accelerator_view. (slide 26-29) Introduce tiling incl. tiled matrix multiplication [tiling probably deserves a whole session instead of 6 minutes!]. IDE (slide 34,37) Briefly touch on the concurrency visualizer. It supports GPU profiling, but enhancements specific to C++ AMP we hope will come at the Beta timeframe, which is when I'll be spending more time talking about it. (slide 35-36, 51:54-59:16) Demonstrate the GPU debugging experience in VS 11. Summary (slide 39) Re-iterate some of the points of slide 7, and add the point that the C++ AMP spec will be open for other compiler vendors to implement, even on other platforms (in fact, Microsoft is actively working on that). (slide 40) Links to content – see slide – including where all your questions should go: http://social.msdn.microsoft.com/Forums/en/parallelcppnative/threads.   "But I don't have time for a full blown session, I only need 2 (or just 1, or 3) C++ AMP slides to use in my session on related topic X" If all you want is a small number of slides, you can take some from the session above and customize them. But because I am so nice, I have created some slides for you, including talking points in the notes section. Download them here. Comments about this post by Daniel Moth welcome at the original blog.

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  • SQL Azure: Notes on Building a Shard Technology

    - by Herve Roggero
    In Chapter 10 of the book on SQL Azure (http://www.apress.com/book/view/9781430229612) I am co-authoring, I am digging deeper in what it takes to write a Shard. It's actually a pretty cool exercise, and I wanted to share some thoughts on how I am designing the technology. A Shard is a technology that spreads the load of database requests over multiple databases, as transparently as possible. The type of shard I am building is called a Vertical Partition Shard  (VPS). A VPS is a mechanism by which the data is stored in one or more databases behind the scenes, but your code has no idea at design time which data is in which database. It's like having a mini cloud for records instead of services. Imagine you have three SQL Azure databases that have the same schema (DB1, DB2 and DB3), you would like to issue a SELECT * FROM Users on all three databases, concatenate the results into a single resultset, and order by last name. Imagine you want to ensure your code doesn't need to change if you add a new database to the shard (DB4). Now imagine that you want to make sure all three databases are queried at the same time, in a multi-threaded manner so your code doesn't have to wait for three database calls sequentially. Then, imagine you would like to obtain a breadcrumb (in the form of a new, virtual column) that gives you a hint as to which database a record came from, so that you could update it if needed. Now imagine all that is done through the standard SqlClient library... and you have the Shard I am currently building. Here are some lessons learned and techniques I am using with this shard: Parellel Processing: Querying databases in parallel is not too hard using the Task Parallel Library; all you need is to lock your resources when needed Deleting/Updating Data: That's not too bad either as long as you have a breadcrumb. However it becomes more difficult if you need to update a single record and you don't know in which database it is. Inserting Data: I am using a round-robin approach in which each new insert request is directed to the next database in the shard. Not sure how to deal with Bulk Loads just yet... Shard Databases:  I use a static collection of SqlConnection objects which needs to be loaded once; from there on all the Shard commands use this collection Extension Methods: In order to make it look like the Shard commands are part of the SqlClient class I use extension methods. For example I added ExecuteShardQuery and ExecuteShardNonQuery methods to SqlClient. Exceptions: Capturing exceptions in a multi-threaded code is interesting... but I kept it simple for now. I am using the ConcurrentQueue to store my exceptions. Database GUID: Every database in the shard is given a GUID, which is calculated based on the connection string's values. DataTable. The Shard methods return a DataTable object which can be bound to objects.  I will be sharing the code soon as an open-source project in CodePlex. Please stay tuned on twitter to know when it will be available (@hroggero). Or check www.bluesyntax.net for updates on the shard. Thanks!

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  • Give a session on C++ AMP – here is how

    - by Daniel Moth
    Ever since presenting on C++ AMP at the AMD Fusion conference in June, then the Gamefest conference in August, and the BUILD conference in September, I've had numerous requests about my material from folks that want to re-deliver the same session. The C++ AMP session I put together has evolved over the 3 presentations to its final form that I used at BUILD, so that is the one I recommend you base yours on. Please get the slides and the recording from channel9 (I'll refer to slide numbers below). This is how I've been presenting the C++ AMP session: Context (slide 3, 04:18-08:18) Start with a demo, on my dual-GPU machine. I've been using the N-Body sample (for VS 11 Developer Preview). (slide 4) Use an nvidia slide that has additional examples of performance improvements that customers enjoy with heterogeneous computing. (slide 5) Talk a bit about the differences today between CPU and GPU hardware, leading to the fact that these will continue to co-exist and that GPUs are great for data parallel algorithms, but not much else today. One is a jack of all trades and the other is a number cruncher. (slide 6) Use the APU example from amd, as one indication that the hardware space is still in motion, emphasizing that the C++ AMP solution is a data parallel API, not a GPU API. It has a future proof design for hardware we have yet to see. (slide 7) Provide more meta-data, as blogged about when I first introduced C++ AMP. Code (slide 9-11) Introduce C++ AMP coding with a simplistic array-addition algorithm – the slides speak for themselves. (slide 12-13) index<N>, extent<N>, and grid<N>. (Slide 14-16) array<T,N>, array_view<T,N> and comparison between them. (Slide 17) parallel_for_each. (slide 18, 21) restrict. (slide 19-20) actual restrictions of restrict(direct3d) – the slides speak for themselves. (slide 22) bring it altogether with a matrix multiplication example. (slide 23-24) accelerator, and accelerator_view. (slide 26-29) Introduce tiling incl. tiled matrix multiplication [tiling probably deserves a whole session instead of 6 minutes!]. IDE (slide 34,37) Briefly touch on the concurrency visualizer. It supports GPU profiling, but enhancements specific to C++ AMP we hope will come at the Beta timeframe, which is when I'll be spending more time talking about it. (slide 35-36, 51:54-59:16) Demonstrate the GPU debugging experience in VS 11. Summary (slide 39) Re-iterate some of the points of slide 7, and add the point that the C++ AMP spec will be open for other compiler vendors to implement, even on other platforms (in fact, Microsoft is actively working on that). (slide 40) Links to content – see slide – including where all your questions should go: http://social.msdn.microsoft.com/Forums/en/parallelcppnative/threads.   "But I don't have time for a full blown session, I only need 2 (or just 1, or 3) C++ AMP slides to use in my session on related topic X" If all you want is a small number of slides, you can take some from the session above and customize them. But because I am so nice, I have created some slides for you, including talking points in the notes section. Download them here. Comments about this post by Daniel Moth welcome at the original blog.

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