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  • Why are my Unity procedural animations jerky?

    - by Phoenix Perry
    I'm working in Unity and getting some crazy weird motion behavior. I have a plane and I'm moving it. It's ever so slightly getting about 1 pixel bigger and smaller. It looks like the it's kind of getting squeezed sideways by a pixel. I'm moving a plane by cos and sin so it will spin on the x and z axes. If the planes are moving at Time.time, everything is fine. However, if I put in slower speed multiplier, I get an amazingly weird jerk in my animation. I get it with or without the lerp. How do I fix it? I want it to move very slowly. Is there some sort of invisible grid in unity? Some sort of minimum motion per frame? I put a visual sample of the behavior here. Here's the relevant code: public void spin() { for (int i = 0; i < numPlanes; i++ ) { GameObject g = planes[i] as GameObject; //alt method //currentRotation += speed * Time.deltaTime * 100; //rotation.eulerAngles = new Vector3(0, currentRotation, 0); //g.transform.position = rotation * rotationRadius; //sine method g.GetComponent<PlaneSetup>().pos.x = g.GetComponent<PlaneSetup>().radiusX * (Mathf.Cos((Time.time*speed) + g.GetComponent<PlaneSetup>().startAngle)); g.GetComponent<PlaneSetup>().pos.z = g.GetComponent<PlaneSetup>().radius * Mathf.Sin((Time.time*speed) + g.GetComponent<PlaneSetup>().startAngle); g.GetComponent<PlaneSetup>().pos.y = g.GetComponent<Transform>().position.y; ////offset g.GetComponent<PlaneSetup>().pos.z += 20; g.GetComponent<PlaneSetup>().posLerp.x = Mathf.Lerp(g.transform.position.x,g.GetComponent<PlaneSetup>().pos.x, .5f); g.GetComponent<PlaneSetup>().posLerp.z = Mathf.Lerp(g.transform.position.z, g.GetComponent<PlaneSetup>().pos.z, .5f); g.GetComponent<PlaneSetup>().posLerp.y = g.GetComponent<Transform>().position.y; g.transform.position = g.GetComponent<PlaneSetup>().posLerp; } Invoke("spin",0.0f); } The full code is on github. There is literally nothing else going on. I've turned off all other game objects so it's only the 40 planes with a texture2D shader. I removed it from Invoke and tried it in Update -- still happens. With a set frame rate or not, the same problem occurs. Tested it in Fixed Update. Same issue. The script on the individual plane doesn't even have an update function in it. The data on it could functionally live in a struct. I'm getting between 90 and 123 fps. Going to investigate and test further. I put this in an invoke function to see if I could get around it just occurring in update. There are no physics on these shapes. It's a straight procedural animation. Limited it to 1 plane - still happens. Thoughts? Removed the shader - still happening.

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  • Calculate the Intersection of Two Volumes

    - by igrad
    If you've ever played The Swapper, you'll have a good idea of what I'm asking about. I need to check for, and isolate, areas of a rectangle that may intersect with either a circle or another rectangle. These selected areas will receive special properties, and the areas will be non-static, since the intersecting shapes themselves will also be dynamic. My first thought was to use raycasting detection, though I've only seen that in use with circles, or even ellipses. I'm curious if there's a method of using raycasting with a more rectangular approach, or if there's a totally different method already in use to accomplish this task. I would like something more exact than checking in large chunks, and since I'm using SDL2 with a logical renderer size of 1920x1080, checking if each pixel is intersecting is out of the question, as it would slow things down past a playable speed. I already have a multi-shape collision function-template in place, and I could use that, though it only checks if sides or corners are intersecting; it does not compute the overlapping area, or even find the circle's secant line, though I can't imagine it would be overly complex to implement. TL;DR: I need to find and isolate areas of a rectangle that may intersect with a circle or another rectangle without checking every single pixel on-screen.

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  • RenderTarget2D behavior in XNA

    - by Utkarsh Sinha
    I've been dabbling with XNA for a couple of days now. This chunk of code doesn't work as I expect. The goal is to render sprites individually and composite them on another rendertarget. P = RenderTarget2D(with RenderTargetUsage.PreserveContents) D = RenderTarget2D(with RenderTargetUsage.DiscardContents) for all sprites: graphicsDevice.SetRenderTarget(D); <draw sprite i> graphicsDevice.SetRenderTarget(P); <Draw D> graphicsDevice.SetRenderTarget(null); <Draw P> The result I get is - only the last sprite is visible. I'm sure I'm missing some piece of information about RenderTarget2D. Any hints on what that might be? Cross posted from - http://stackoverflow.com/questions/9970349/weird-rendertarget2d-behaviour

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  • What is a better abstraction layer for D3D9 and OpenGL vertex data management?

    - by Sam Hocevar
    My rendering code has always been OpenGL. I now need to support a platform that does not have OpenGL, so I have to add an abstraction layer that wraps OpenGL and Direct3D 9. I will support Direct3D 11 later. TL;DR: the differences between OpenGL and Direct3D cause redundancy for the programmer, and the data layout feels flaky. For now, my API works a bit like this. This is how a shader is created: Shader *shader = Shader::Create( " ... GLSL vertex shader ... ", " ... GLSL pixel shader ... ", " ... HLSL vertex shader ... ", " ... HLSL pixel shader ... "); ShaderAttrib a1 = shader->GetAttribLocation("Point", VertexUsage::Position, 0); ShaderAttrib a2 = shader->GetAttribLocation("TexCoord", VertexUsage::TexCoord, 0); ShaderAttrib a3 = shader->GetAttribLocation("Data", VertexUsage::TexCoord, 1); ShaderUniform u1 = shader->GetUniformLocation("WorldMatrix"); ShaderUniform u2 = shader->GetUniformLocation("Zoom"); There is already a problem here: once a Direct3D shader is compiled, there is no way to query an input attribute by its name; apparently only the semantics stay meaningful. This is why GetAttribLocation has these extra arguments, which get hidden in ShaderAttrib. Now this is how I create a vertex declaration and two vertex buffers: VertexDeclaration *decl = VertexDeclaration::Create( VertexStream<vec3,vec2>(VertexUsage::Position, 0, VertexUsage::TexCoord, 0), VertexStream<vec4>(VertexUsage::TexCoord, 1)); VertexBuffer *vb1 = new VertexBuffer(NUM * (sizeof(vec3) + sizeof(vec2)); VertexBuffer *vb2 = new VertexBuffer(NUM * sizeof(vec4)); Another problem: the information VertexUsage::Position, 0 is totally useless to the OpenGL/GLSL backend because it does not care about semantics. Once the vertex buffers have been filled with or pointed at data, this is the rendering code: shader->Bind(); shader->SetUniform(u1, GetWorldMatrix()); shader->SetUniform(u2, blah); decl->Bind(); decl->SetStream(vb1, a1, a2); decl->SetStream(vb2, a3); decl->DrawPrimitives(VertexPrimitive::Triangle, NUM / 3); decl->Unbind(); shader->Unbind(); You see that decl is a bit more than just a D3D-like vertex declaration, it kinda takes care of rendering as well. Does this make sense at all? What would be a cleaner design? Or a good source of inspiration?

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  • How to slow down a sprite that updates every frame?

    - by xiaohouzi79
    I am going through a Allegro 5 tutorial which has a game loop. There is also a variable "active" which determines if a key is being held down. Thus if the left key is being held down active is on and it begins looping through the row on the sprite sheet that corresponds to moving left. The problem is that this logic is checked everytime the loop is performed thus at approximately 60 fps the three images that are used to do the left walking animation cycle round super fast which means my character looks like it is in a rush. Total beginner question: so what is the correct way to slow down the transition between sprites so that the walking looks like it is done at a moderate pace. Here is the code used to transition across the sprite between the three different phases of the person walking: if (active) { sourceX += al_get_bitmap_width(player) / 3; } else { sourceX = 32; } if (sourceX >= al_get_bitmap_width(player)) { sourceX = 0; } I can kind of guess what it should be in plain English: update sourceX only every certain part of a second but I can't think of how to put this into code.

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  • Using idle time in turn-based (RPG) games for updating

    - by The Communist Duck
    If you take any turn based RPG game there will be large periods of time when nothing is happening because the game is looping over 'wait_for_player_input'. Naturally it seems sensible to use this time to update things. However, this immediately seems to suggest that it would need to be threaded. Is this sort of design possible in a single thread? loop: if not check_something_pressed: update_a_very_small_amount else keep going But if we says 'a_very_small_amount' is only updating a single object each loop, it's going to be very slow at updating. How would you go about this, preferably in a single thread? EDIT: I've tagged this language-agnostic as that seems the sensible thing, though anything more specific to Python would be great. ;-)

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  • Can I use GLFW and GLEW together in the same code

    - by Brendan Webster
    I use the g++ compiler, which could be causing the main problem, but I'm using GLFW for window and input management, and I am using GLEW so that I can use OpenGL 3.x functionality. I loaded in models and then tried to make Vertex and Index buffers for the data, but it turned out that I kept getting segmentation faults in the program. I finally figured out that GLEW just wasn't working with GLFW included. Do they not work together? Also I've done the context creation through GLFW so that may be another factor in the problem.

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  • XNA Masking Mayhem

    - by TropicalFlesh
    I'd like to start by mentioning that I'm just an amateur programmer of the past 2 years with no formal training and know very little about maximizing the potential of graphics hardware. I can write shaders and manipulate a multi-layered drawing environment, but I've basically stuck to minimalist pixel shaders. I'm working on putting dynamic point light shadows in my 2d sidescroller, and have had it working to a reasonable degree. Just chucking it in without working on serious optimizations outside of basic culling, I can get 50 lights or so onscreen at once and still hover around 100 fps. The only issue is that I'm on a very high end machine and would like to target the game at as many platforms I can, low and high end. The way I'm doing shadows involves a lot of masking before I can finally draw the light to my light layer. Basically, my technique to achieveing such shadows is as follows. See pics in this album http://imgur.com/a/m2fWw#0 The dark gray represents the background tiles, the light gray represents the foreground tiles, and the yellow represents the shadow-emitting foreground tile. I'll draw the light using a radial gradient and a color of choice I'll then exclude light from the mask by drawing some geometry extending through the tile from my point light. I actually don't mask the light yet at this point, but I'm just illustrating the technique in this image Finally, I'll re-include the foreground layer in my mask, as I only want shadows to collect on the background layer and finally multiply the light with it's mask to the light layer My question is simple - How can I go about reducing the amount of render target switches I need to do to achieve the following: a. Draw mask to exclude shadows from the foreground to it's own target once per frame b. For each light that emits shadows, -Begin light mask as full white -Render shadow geometry as transparent with an opaque blendmode to eliminate shadowed areas from the mask -Render foreground mask back over the light mask to reintroduce light to the foreground c. Multiply light texture with it's individual mask to the main light layer.

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  • Off center projection

    - by N0xus
    I'm trying to implement the code that was freely given by a very kind developer at the following link: http://forum.unity3d.com/threads/142383-Code-sample-Off-Center-Projection-Code-for-VR-CAVE-or-just-for-fun Right now, all I'm trying to do is bring it in on one camera, but I have a few issues. My class, looks as follows: using UnityEngine; using System.Collections; public class PerspectiveOffCenter : MonoBehaviour { // Use this for initialization void Start () { } // Update is called once per frame void Update () { } public static Matrix4x4 GeneralizedPerspectiveProjection(Vector3 pa, Vector3 pb, Vector3 pc, Vector3 pe, float near, float far) { Vector3 va, vb, vc; Vector3 vr, vu, vn; float left, right, bottom, top, eyedistance; Matrix4x4 transformMatrix; Matrix4x4 projectionM; Matrix4x4 eyeTranslateM; Matrix4x4 finalProjection; ///Calculate the orthonormal for the screen (the screen coordinate system vr = pb - pa; vr.Normalize(); vu = pc - pa; vu.Normalize(); vn = Vector3.Cross(vr, vu); vn.Normalize(); //Calculate the vector from eye (pe) to screen corners (pa, pb, pc) va = pa-pe; vb = pb-pe; vc = pc-pe; //Get the distance;; from the eye to the screen plane eyedistance = -(Vector3.Dot(va, vn)); //Get the varaibles for the off center projection left = (Vector3.Dot(vr, va)*near)/eyedistance; right = (Vector3.Dot(vr, vb)*near)/eyedistance; bottom = (Vector3.Dot(vu, va)*near)/eyedistance; top = (Vector3.Dot(vu, vc)*near)/eyedistance; //Get this projection projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); //Fill in the transform matrix transformMatrix = new Matrix4x4(); transformMatrix[0, 0] = vr.x; transformMatrix[0, 1] = vr.y; transformMatrix[0, 2] = vr.z; transformMatrix[0, 3] = 0; transformMatrix[1, 0] = vu.x; transformMatrix[1, 1] = vu.y; transformMatrix[1, 2] = vu.z; transformMatrix[1, 3] = 0; transformMatrix[2, 0] = vn.x; transformMatrix[2, 1] = vn.y; transformMatrix[2, 2] = vn.z; transformMatrix[2, 3] = 0; transformMatrix[3, 0] = 0; transformMatrix[3, 1] = 0; transformMatrix[3, 2] = 0; transformMatrix[3, 3] = 1; //Now for the eye transform eyeTranslateM = new Matrix4x4(); eyeTranslateM[0, 0] = 1; eyeTranslateM[0, 1] = 0; eyeTranslateM[0, 2] = 0; eyeTranslateM[0, 3] = -pe.x; eyeTranslateM[1, 0] = 0; eyeTranslateM[1, 1] = 1; eyeTranslateM[1, 2] = 0; eyeTranslateM[1, 3] = -pe.y; eyeTranslateM[2, 0] = 0; eyeTranslateM[2, 1] = 0; eyeTranslateM[2, 2] = 1; eyeTranslateM[2, 3] = -pe.z; eyeTranslateM[3, 0] = 0; eyeTranslateM[3, 1] = 0; eyeTranslateM[3, 2] = 0; eyeTranslateM[3, 3] = 1f; //Multiply all together finalProjection = new Matrix4x4(); finalProjection = Matrix4x4.identity * projectionM*transformMatrix*eyeTranslateM; //finally return return finalProjection; } // Update is called once per frame public void FixedUpdate () { Camera cam = camera; //calculate projection Matrix4x4 genProjection = GeneralizedPerspectiveProjection( new Vector3(0,1,0), new Vector3(1,1,0), new Vector3(0,0,0), new Vector3(0,0,0), cam.nearClipPlane, cam.farClipPlane); //(BottomLeftCorner, BottomRightCorner, TopLeftCorner, trackerPosition, cam.nearClipPlane, cam.farClipPlane); cam.projectionMatrix = genProjection; } } My error lies in projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); The debugger states: Expression denotes a `type', where a 'variable', 'value' or 'method group' was expected. Thus, I changed the line to read: projectionM = new PerspectiveOffCenter(left, right, bottom, top, near, far); But then the error is changed to: The type 'PerspectiveOffCenter' does not contain a constructor that takes '6' arguments. For reasons that are obvious. So, finally, I changed the line to read: projectionM = new GeneralizedPerspectiveProjection(left, right, bottom, top, near, far); And the error I get is: is a 'method' but a 'type' was expected. With this last error, I'm not sure what it is I should do / missing. Can anyone see what it is that I'm missing to fix this error?

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  • HTML5 game engine for a 2D or 2.5D RPG style "map walk"

    - by stargazer
    please help me to choose a HTML5 game engine or Javascript libraries I want to do the following in the game: when the game starts a part the huge map (full size of the map: about 7 screens) is shown. The map itself is completely designed in the editor mapeditor.org (or in some comparable editor - if you know a good alternative to mapeditor.org - let me know) and loaded at runtime or at design time. The game engine should support loading of isometric maps (well, in worst case only orthogonal maps will be sufficient) both "tile layer" and "object layer" from mapeditor.org should be supported. Scrolling/performance of this map should be fast enough. The map and the game should be either in 2D (orthogonal map) or in 2.5D (isometric map) The game engine should support movement of sprites with animation. Let say I have a sprite for "human" with animation sequences showing "walking" in 8 directions - it should be imported into game engine and should "walk" on the map without writing a lot of Javascript code. Automatic scrolling of the map the "human" nears the screen border. Collision detection, "solid" objects. The mapeditor.org supports properies on tiles. Let say I assign a "solid" property to some tiles in editor. It should be easy to check this "solid" property in the game engine and implement kind of "solid" behavior, so the animanted sprites do not walk through the walls. Collision detection - it should be easy to implement some custom functionality like "when sprite A is close to sprite B - call this function" Showing "dialogs" or popup windows on top of the map - should be easy to implement. Cross-browser audio support - (it is implemented quite well in construct 2 from scirra, so I'm looking for the comparable audio quality) The game itself is a king of RPG but without fighting scenes and without huge "inventory". The main character just walking on the map, discovers some things, there are dialogs and sounds. The functionality of this example from sprite.js http://batiste.dosimple.ch/sprite.js/tests/mapeditor/map_reader.html is very close to what I'm developing. But I'm not a Javascript guru (and a very lazy guy) and would like to write even less Javascript code as in the example...

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  • Skyrim Nexus Mods on Xbox 360 by use of dawnguard?

    - by user17895
    i think it's possible i opened up the dawnguard marketplace content and it consists 3 files: dawnguard.bsa < mod dawnguard.esp <- mod installing file. and spa.bin <-dont know where this is for. and it has been confirmed you can use the top 2 files on pc for a not fully functional dawnguard (barely functional to be exact) and if we could just replace or add a few other bsa and esp files to this marketplace content we could get mods up and running on xbox altough i need confirmation on this. I also have no clue where the spa.bin file for is, i need to examine it some further. Further this is adding a few non-distributed Files to marketplace content and wont get you booted from XBL. Also if anyone wants to examine these files for further information i will gladly share them with you. if you have any information or answers please email me at [email protected] thx

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  • JOGL hardware based shadow mapping - computing the texture matrix

    - by axel22
    I am implementing hardware shadow mapping as described here. I've rendered the scene successfully from the light POV, and loaded the depth buffer of the scene into a texture. This texture has correctly been loaded - I check this by rendering a small thumbnail, as you can see in the screenshot below, upper left corner. The depth of the scene appears to be correct - objects further away are darker, and that are closer to the light are lighter. However, I run into trouble while rendering the scene from the camera's point of view using the depth texture - the texture on the polygons in the scene is rendered in a weird, nondeterministic fashion, as shown in the screenshot. I believe I am making an error while computing the texture transformation matrix, but I am unsure where exactly. Since I have no matrix utilities in JOGL other then the gl[Load|Mult]Matrix procedures, I multiply the matrices using them, like this: void calcTextureMatrix() { glPushMatrix(); glLoadIdentity(); glLoadMatrixf(biasmatrix, 0); glMultMatrixf(lightprojmatrix, 0); glMultMatrixf(lightviewmatrix, 0); glGetFloatv(GL_MODELVIEW_MATRIX, shadowtexmatrix, 0); glPopMatrix(); } I obtained these matrices by using the glOrtho and gluLookAt procedures: glLoadIdentity() val wdt = width / 45 val hgt = height / 45 glOrtho(wdt, -wdt, -hgt, hgt, -45.0, 45.0) glGetFloatv(GL_MODELVIEW_MATRIX, lightprojmatrix, 0) glLoadIdentity() glu.gluLookAt( xlook + lightpos._1, ylook + lightpos._2, lightpos._3, xlook, ylook, 0.0f, 0.f, 0.f, 1.0f) glGetFloatv(GL_MODELVIEW_MATRIX, lightviewmatrix, 0) My bias matrix is: float[] biasmatrix = new float[16] { 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.5f, 0.5f, 0.5f, 1.f } After applying the camera projection and view matrices, I do: glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR) glTexGenfv(GL_S, GL_EYE_PLANE, shadowtexmatrix, 0) glEnable(GL_TEXTURE_GEN_S) for each component. Does anybody know why the texture is not being rendered correctly? Thank you.

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  • 2D OBB collision detection, resolving collisions?

    - by Milo
    I currently use OBBs and I have a vehicle that is a rigid body and some buildings. Here is my update() private void update() { camera.setPosition((vehicle.getPosition().x * camera.getScale()) - ((getWidth() ) / 2.0f), (vehicle.getPosition().y * camera.getScale()) - ((getHeight() ) / 2.0f)); //camera.move(input.getAnalogStick().getStickValueX() * 15.0f, input.getAnalogStick().getStickValueY() * 15.0f); if(input.isPressed(ControlButton.BUTTON_GAS)) { vehicle.setThrottle(1.0f, false); } if(input.isPressed(ControlButton.BUTTON_BRAKE)) { vehicle.setBrakes(1.0f); } vehicle.setSteering(input.getAnalogStick().getStickValueX()); vehicle.update(16.6666f / 1000.0f); ArrayList<Building> buildings = city.getBuildings(); for(Building b : buildings) { if(vehicle.getRect().overlaps(b.getRect())) { vehicle.update(-17.0f / 1000.0f); break; } } } The collision detection works well. What doesn't is how they are dealt with. My goal is simple. If the vehicle hits a building, it should stop, and never go into the building. When I apply negative torque to reverse the car should not feel buggy and move away from the building. I don't want this to look buggy. This is my rigid body class: class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position, getWidth(), getHeight(), angle); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { //integrate physics //linear Vector2D acceleration = Vector2D.scalarDivide(forces, mass); velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); c = Vector2D.add(getRect().getCenter(), Vector2D.scalarMultiply(velocity , timeStep)); setCenter(c.x, c.y); forces = new Vector2D(0,0); //clear forces //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { Matrix mat = new Matrix(); float[] Vector2Ds = new float[2]; Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); return new Vector2D(Vector2Ds[0], Vector2Ds[1]); } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { Matrix mat = new Matrix(); float[] Vectors = new float[2]; Vectors[0] = world.x; Vectors[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vectors); return new Vector2D(Vectors[0], Vectors[1]); } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { Vector2D tangent = new Vector2D(-worldOffset.y, worldOffset.x); return Vector2D.add( Vector2D.scalarMultiply(tangent, angularVelocity) , velocity); } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces = Vector2D.add(forces ,worldForce); //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } } Essentially, when any rigid body hits a building it should exhibit the same behavior. How is collision solving usually done? Thanks

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  • xna download website source code

    - by Emre Canbazoglu
    I have to download the html code of a web site during the game. I am taking the poster url of a movie from the imdb web site by scrapping the html ( also other informations ). I have to do the download process many times during the game for different movies. I can download and scrap the html but downloading the html takes too much time and it causes the game to slow down(freeze while downloading). How can I solve this problem? My one approach is to download and scrap all the information and store them in a database before the game and during the game access this information from the database. I think this will work properly but that is not what I exactly want. It would be better if it is dynamic. I also thought of using multi-threading but I am a bit confused about how to implement threading in xna. I read some articles about it but it is not so clear. I mean when should I start the thread and what about the update function etc. I need your help guys

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  • as3 3D camera lookat

    - by Johannes Jensen
    I'm making a 3D camera scene in Flash, draw using drawTriangles() and rotated and translated using a Matrix3D. I've got the camera to look after a specific point, but only on the Y-axis, using the x and z coordinates, here is my code so far: var dx:Number = camera.x - lookAt.x; var dy:Number = camera.y - lookAt.y; var dz:Number = camera.z - lookAt.z; camera.rotationY = Math.atan2(dz, dx) * (180 / Math.PI) + 270; so no matter the x or z position, the point is always on the mid of the screen, IF and only if y matches with the camera. So what I need is to calculate the rotationX (which are measured in degrees not radians), and I was wondering how I would do this?

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  • Sliding collision response

    - by dbostream
    I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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  • Oscillating Sprite Movement in XNA

    - by Nick Van Hoogenstyn
    I'm working on a 2d game and am looking to make a sprite move horizontally across the screen in XNA while oscillating vertically (basically I want the movement to look like a sin wave). Currently for movement I'm using two vectors, one for speed and one for direction. My update function for sprites just contains this: Position += direction * speed * (float)t.ElapsedGameTime.TotalSeconds; How could I utilize this setup to create the desired movement? I'm assuming I'd call Math.Sin or Math.Cos, but I'm unsure of where to start to make this sort of thing happened. My attempt looked like this: public override void Update(GameTime t) { double msElapsed = t.TotalGameTime.Milliseconds; mDirection.Y = (float)Math.Sin(msElapsed); if (mDirection.Y >= 0) mSpeed.Y = moveSpeed; else mSpeed.Y = -moveSpeed; base.Update(t, mSpeed, mDirection); } moveSpeed is just some constant positive integer. With this, the sprite simply just continuously moves downward until it's off screen. Can anyone give me some info on what I'm doing wrong here? I've never tried something like this so if I'm doing things completely wrong, let me know!

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  • Collision Detection Game Design and Architecture

    - by Chompas
    I've reading some articles about collision detection. My question here is about ideas on the design for it. Baically I have a C++ game that has a main loop with entities with an update method. Based on keyboard input, these characters updates their positions. My question is not about how to detect collisions, it's about getting ideas in which is the best way to implement this. The game has a main character but also enemies that have to collide between them, so I'm not sure where to make all the iterations for checking collisions and if the right way is to check everything against everything. Thanks in advance.

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  • SlimDX and Parsing .X Files

    - by P. Avery
    I'm trying to parse a .x file using SlimDX. I can create the XFile object and register templates but I'm having problems with the enumeration object. The enumeration object has a child count of 0 for a file I know to have valid data. Here is code to create file, enumeration, and data objects: public void Parse(string filename, string templates, ref Frame aParam) { XFile xfile = null; XFileEnumerationObject enumObj = null; XFileData dataObj = null; // create file object xfile = new XFile(); // register templates if (xfile.RegisterTemplates(XFile.DefaultTemplates).IsFailure) { Console.WriteLine(Result.Last); xfile.Dispose(); return; } // create enumeration object enumObj = xfile.CreateEnumerationObject(filename, System.Runtime.InteropServices.CharSet.Auto); if (enumObj == null) { xfile.Dispose(); return; } // get child count( returns 0 here ) long ncElements = enumObj.ChildCount; for (int i = 0; i < ncElements; ++i) { // never reached... dataObj = enumObj.GetChild(i); if (dataObj.IsReference) continue; try { Parse(dataObj, ref aParam); } catch (Exception e) { e.Write(); } finally { dataObj.Dispose(); } } enumObj.Dispose(); xfile.Dispose(); } ...There are no exceptions thrown by this function...the child count is 0 so the conditional loop breaks right away, the file objects are disposed of and the function returns... Here is .x file...a simple cube: xof 0303txt 0032 Frame Root { FrameTransformMatrix { 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000;; } Frame Cube { FrameTransformMatrix { 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 0.000000, 1.000000;; } Mesh Cube{ //Cube Mesh 36; -1.000000; 1.000000; 1.000000;, -1.000000;-1.000000; 1.000000;, 0.999999;-1.000001; 1.000000;, -1.000000;-1.000000;-1.000000;, 1.000000;-1.000000;-1.000000;, 0.999999;-1.000001; 1.000000;, 1.000000; 0.999999; 1.000000;, -1.000000; 1.000000; 1.000000;, 0.999999;-1.000001; 1.000000;, -1.000000; 1.000000;-1.000000;, -1.000000;-1.000000;-1.000000;, -1.000000; 1.000000; 1.000000;, -1.000000; 1.000000; 1.000000;, 1.000000; 0.999999; 1.000000;, 1.000000; 1.000000;-1.000000;, 1.000000; 0.999999; 1.000000;, 0.999999;-1.000001; 1.000000;, 1.000000;-1.000000;-1.000000;, -1.000000;-1.000000;-1.000000;, -1.000000;-1.000000; 1.000000;, -1.000000; 1.000000; 1.000000;, 1.000000; 1.000000;-1.000000;, 1.000000;-1.000000;-1.000000;, -1.000000; 1.000000;-1.000000;, 1.000000; 1.000000;-1.000000;, 1.000000; 0.999999; 1.000000;, 1.000000;-1.000000;-1.000000;, -1.000000; 1.000000;-1.000000;, -1.000000; 1.000000; 1.000000;, 1.000000; 1.000000;-1.000000;, -1.000000;-1.000000; 1.000000;, -1.000000;-1.000000;-1.000000;, 0.999999;-1.000001; 1.000000;, 1.000000;-1.000000;-1.000000;, -1.000000;-1.000000;-1.000000;, -1.000000; 1.000000;-1.000000;; 12; 3;0;1;2;, 3;3;4;5;, 3;6;7;8;, 3;9;10;11;, 3;12;13;14;, 3;15;16;17;, 3;18;19;20;, 3;21;22;23;, 3;24;25;26;, 3;27;28;29;, 3;30;31;32;, 3;33;34;35;; MeshNormals { //Mesh Normals 36; 0.000000;-0.000000; 1.000000;, 0.000000;-0.000000; 1.000000;, 0.000000;-0.000000; 1.000000;, -0.000000;-1.000000;-0.000000;, -0.000000;-1.000000;-0.000000;, -0.000000;-1.000000;-0.000000;, -0.000000;-0.000000; 1.000000;, -0.000000;-0.000000; 1.000000;, -0.000000;-0.000000; 1.000000;, -1.000000; 0.000000;-0.000000;, -1.000000; 0.000000;-0.000000;, -1.000000; 0.000000;-0.000000;, 0.000000; 1.000000; 0.000000;, 0.000000; 1.000000; 0.000000;, 0.000000; 1.000000; 0.000000;, 1.000000;-0.000001; 0.000000;, 1.000000;-0.000001; 0.000000;, 1.000000;-0.000001; 0.000000;, -1.000000; 0.000000;-0.000000;, -1.000000; 0.000000;-0.000000;, -1.000000; 0.000000;-0.000000;, 0.000000; 0.000000;-1.000000;, 0.000000; 0.000000;-1.000000;, 0.000000; 0.000000;-1.000000;, 1.000000; 0.000000;-0.000000;, 1.000000; 0.000000;-0.000000;, 1.000000; 0.000000;-0.000000;, 0.000000; 1.000000; 0.000000;, 0.000000; 1.000000; 0.000000;, 0.000000; 1.000000; 0.000000;, -0.000000;-1.000000; 0.000000;, -0.000000;-1.000000; 0.000000;, -0.000000;-1.000000; 0.000000;, 0.000000;-0.000000;-1.000000;, 0.000000;-0.000000;-1.000000;, 0.000000;-0.000000;-1.000000;; 12; 3;0;1;2;, 3;3;4;5;, 3;6;7;8;, 3;9;10;11;, 3;12;13;14;, 3;15;16;17;, 3;18;19;20;, 3;21;22;23;, 3;24;25;26;, 3;27;28;29;, 3;30;31;32;, 3;33;34;35;; } //End of Mesh Normals MeshMaterialList { //Mesh Material List 1; 12; 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0;; Material Material { 0.640000; 0.640000; 0.640000; 1.000000;; 96.078431; 0.500000; 0.500000; 0.500000;; 0.000000; 0.000000; 0.000000;; TextureFilename {"Yellow.jpg";} } } //End of Mesh Material List MeshTextureCoords UVMap{ //Mesh UV Coordinates 36; 0.000000; 1.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 1.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 0.000000;, 0.000000; 1.000000;, 1.000000; 1.000000;, 1.000000; 0.000000;; } //End of Mesh UV Coordinates } //End of Mesh Mesh } //End of Cube } //End of Root Frame

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  • Efficient skeletal animation

    - by Will
    I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them! In skeletal animation e.g. MD5 files, each individual vertex can be attached to an arbitrary number of joints. How can you efficiently support this whilst doing the interpolation in GLSL? Or do engines do their animation on the CPU? Or do engines set arbitrary limits on maximum joints per vertex and invoke nop multiplies for those joints that don't use the maximum number? Are there games that use skeletal animation in an RTS-like setting thus proving that on integrated graphics cards I have nothing to worry about in going the bones route?

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  • Implementing camera for 2d side scroller game ?

    - by Mr.Gando
    Hello, I'm implementing a 2D side scroller for iOS (using C/C++ with OpenGL) (beat'em up style like double dragon/final fight ). My scenes are composed of one cyclical background image ( the end of the image connects perfectly with the beginning ). This is to produce a cyclical scroll effect. I was wondering how could I implement a camera that follows my player movement ? ( Resources / Links are greatly appreciated with explanations :) )

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  • Using virtual functions

    - by Tucker Morgan
    I am starting to use virtual functions, and i am programming a simple text game, my question is this, if i have a virtual function called spec_abil with in a Super class called rpg_class. If you allow the player to class what class they want to play, say a mage class, a archer class, and a warrior class, which all have their own spec_abil function. How do you write it so that the program knows which one to use depending on the chosen class.

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  • Bodies do not stay sticked together by joint in retina display

    - by Mike JM
    I'm rehearsing on Box2D revolute joints. Everything's going pretty well except for one thing. For some reason bodies joined together with revolute joints do not stay sticked, they start getting apart from each other from the app start when I run it on retina device or simulator. On non retina device it works just fine, as expected. Here's the screenshot of the non-retina version: And here's the behavior when I run the same app on retina device/simulator: I'm taking content scale factor into account.

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  • Approaches to timed puzzle elements

    - by ndg
    I'm working on a side scrolling game that has a number of timed puzzle elements. As a simple example: I have a number of moving platforms that have been setup to transition in a pattern. Ideally I'd like to ensure that as the player first approaches them, they are in an ideal state -- whereby the player can witness the full transition and more experienced players (i.e: speedrunners) can complete the puzzle immediately without having to wait for the current transition to complete. The issue here, in a nutshell, is that because these platforms begin transitioning at the start of the level, it's impossible to correctly calculate when the player is likely to stumble upon them. I've done a fair bit of Googling but haven't managed to turn up any decent resources with regards to solving a problem like this. The obvious solution is to only begin updating the objects when the player (or more likely: the camera) first encounters them. But this becomes difficult when you consider more complicated situations. It seems like potentially the easiest way of handling this is to have an invisible trigger volume that will tell any puzzle elements located inside of it that the player has 'arrived' upon first colliding with the player. But this would mean I'd have to logically group puzzle elements, which could become fairly messy in a hurry. Take, for instance, a puzzle that appears to the right of the screen. It may take the player a number of seconds to reach it. It would look strange if the elements involved were to remain stationary. But by the time the player arrives, it's likely things will be 'out of sync'. I wanted to post here in the hopes that others know of, or have implemented, a decent solution to this problem?

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  • Convert ddply {plyr} to Oracle R Enterprise, or use with Embedded R Execution

    - by Mark Hornick
    The plyr package contains a set of tools for partitioning a problem into smaller sub-problems that can be more easily processed. One function within {plyr} is ddply, which allows you to specify subsets of a data.frame and then apply a function to each subset. The result is gathered into a single data.frame. Such a capability is very convenient. The function ddply also has a parallel option that if TRUE, will apply the function in parallel, using the backend provided by foreach. This type of functionality is available through Oracle R Enterprise using the ore.groupApply function. In this blog post, we show a few examples from Sean Anderson's "A quick introduction to plyr" to illustrate the correpsonding functionality using ore.groupApply. To get started, we'll create a demo data set and load the plyr package. set.seed(1) d <- data.frame(year = rep(2000:2014, each = 3),         count = round(runif(45, 0, 20))) dim(d) library(plyr) This first example takes the data frame, partitions it by year, and calculates the coefficient of variation of the count, returning a data frame. # Example 1 res <- ddply(d, "year", function(x) {   mean.count <- mean(x$count)   sd.count <- sd(x$count)   cv <- sd.count/mean.count   data.frame(cv.count = cv)   }) To illustrate the equivalent functionality in Oracle R Enterprise, using embedded R execution, we use the ore.groupApply function on the same data, but pushed to the database, creating an ore.frame. The function ore.push creates a temporary table in the database, returning a proxy object, the ore.frame. D <- ore.push(d) res <- ore.groupApply (D, D$year, function(x) {   mean.count <- mean(x$count)   sd.count <- sd(x$count)   cv <- sd.count/mean.count   data.frame(year=x$year[1], cv.count = cv)   }, FUN.VALUE=data.frame(year=1, cv.count=1)) You'll notice the similarities in the first three arguments. With ore.groupApply, we augment the function to return the specific data.frame we want. We also specify the argument FUN.VALUE, which describes the resulting data.frame. From our previous blog posts, you may recall that by default, ore.groupApply returns an ore.list containing the results of each function invocation. To get a data.frame, we specify the structure of the result. The results in both cases are the same, however the ore.groupApply result is an ore.frame. In this case the data stays in the database until it's actually required. This can result in significant memory and time savings whe data is large. R> class(res) [1] "ore.frame" attr(,"package") [1] "OREbase" R> head(res)    year cv.count 1 2000 0.3984848 2 2001 0.6062178 3 2002 0.2309401 4 2003 0.5773503 5 2004 0.3069680 6 2005 0.3431743 To make the ore.groupApply execute in parallel, you can specify the argument parallel with either TRUE, to use default database parallelism, or to a specific number, which serves as a hint to the database as to how many parallel R engines should be used. The next ddply example uses the summarise function, which creates a new data.frame. In ore.groupApply, the year column is passed in with the data. Since no automatic creation of columns takes place, we explicitly set the year column in the data.frame result to the value of the first row, since all rows received by the function have the same year. # Example 2 ddply(d, "year", summarise, mean.count = mean(count)) res <- ore.groupApply (D, D$year, function(x) {   mean.count <- mean(x$count)   data.frame(year=x$year[1], mean.count = mean.count)   }, FUN.VALUE=data.frame(year=1, mean.count=1)) R> head(res)    year mean.count 1 2000 7.666667 2 2001 13.333333 3 2002 15.000000 4 2003 3.000000 5 2004 12.333333 6 2005 14.666667 Example 3 uses the transform function with ddply, which modifies the existing data.frame. With ore.groupApply, we again construct the data.frame explicilty, which is returned as an ore.frame. # Example 3 ddply(d, "year", transform, total.count = sum(count)) res <- ore.groupApply (D, D$year, function(x) {   total.count <- sum(x$count)   data.frame(year=x$year[1], count=x$count, total.count = total.count)   }, FUN.VALUE=data.frame(year=1, count=1, total.count=1)) > head(res)    year count total.count 1 2000 5 23 2 2000 7 23 3 2000 11 23 4 2001 18 40 5 2001 4 40 6 2001 18 40 In Example 4, the mutate function with ddply enables you to define new columns that build on columns just defined. Since the construction of the data.frame using ore.groupApply is explicit, you always have complete control over when and how to use columns. # Example 4 ddply(d, "year", mutate, mu = mean(count), sigma = sd(count),       cv = sigma/mu) res <- ore.groupApply (D, D$year, function(x) {   mu <- mean(x$count)   sigma <- sd(x$count)   cv <- sigma/mu   data.frame(year=x$year[1], count=x$count, mu=mu, sigma=sigma, cv=cv)   }, FUN.VALUE=data.frame(year=1, count=1, mu=1,sigma=1,cv=1)) R> head(res)    year count mu sigma cv 1 2000 5 7.666667 3.055050 0.3984848 2 2000 7 7.666667 3.055050 0.3984848 3 2000 11 7.666667 3.055050 0.3984848 4 2001 18 13.333333 8.082904 0.6062178 5 2001 4 13.333333 8.082904 0.6062178 6 2001 18 13.333333 8.082904 0.6062178 In Example 5, ddply is used to partition data on multiple columns before constructing the result. Realizing this with ore.groupApply involves creating an index column out of the concatenation of the columns used for partitioning. This example also allows us to illustrate using the ORE transparency layer to subset the data. # Example 5 baseball.dat <- subset(baseball, year > 2000) # data from the plyr package x <- ddply(baseball.dat, c("year", "team"), summarize,            homeruns = sum(hr)) We first push the data set to the database to get an ore.frame. We then add the composite column and perform the subset, using the transparency layer. Since the results from database execution are unordered, we will explicitly sort these results and view the first 6 rows. BB.DAT <- ore.push(baseball) BB.DAT$index <- with(BB.DAT, paste(year, team, sep="+")) BB.DAT2 <- subset(BB.DAT, year > 2000) X <- ore.groupApply (BB.DAT2, BB.DAT2$index, function(x) {   data.frame(year=x$year[1], team=x$team[1], homeruns=sum(x$hr))   }, FUN.VALUE=data.frame(year=1, team="A", homeruns=1), parallel=FALSE) res <- ore.sort(X, by=c("year","team")) R> head(res)    year team homeruns 1 2001 ANA 4 2 2001 ARI 155 3 2001 ATL 63 4 2001 BAL 58 5 2001 BOS 77 6 2001 CHA 63 Our next example is derived from the ggplot function documentation. This illustrates the use of ddply within using the ggplot2 package. We first create a data.frame with demo data and use ddply to create some statistics for each group (gp). We then use ggplot to produce the graph. We can take this same code, push the data.frame df to the database and invoke this on the database server. The graph will be returned to the client window, as depicted below. # Example 6 with ggplot2 library(ggplot2) df <- data.frame(gp = factor(rep(letters[1:3], each = 10)),                  y = rnorm(30)) # Compute sample mean and standard deviation in each group library(plyr) ds <- ddply(df, .(gp), summarise, mean = mean(y), sd = sd(y)) # Set up a skeleton ggplot object and add layers: ggplot() +   geom_point(data = df, aes(x = gp, y = y)) +   geom_point(data = ds, aes(x = gp, y = mean),              colour = 'red', size = 3) +   geom_errorbar(data = ds, aes(x = gp, y = mean,                                ymin = mean - sd, ymax = mean + sd),              colour = 'red', width = 0.4) DF <- ore.push(df) ore.tableApply(DF, function(df) {   library(ggplot2)   library(plyr)   ds <- ddply(df, .(gp), summarise, mean = mean(y), sd = sd(y))   ggplot() +     geom_point(data = df, aes(x = gp, y = y)) +     geom_point(data = ds, aes(x = gp, y = mean),                colour = 'red', size = 3) +     geom_errorbar(data = ds, aes(x = gp, y = mean,                                  ymin = mean - sd, ymax = mean + sd),                   colour = 'red', width = 0.4) }) But let's take this one step further. Suppose we wanted to produce multiple graphs, partitioned on some index column. We replicate the data three times and add some noise to the y values, just to make the graphs a little different. We also create an index column to form our three partitions. Note that we've also specified that this should be executed in parallel, allowing Oracle Database to control and manage the server-side R engines. The result of ore.groupApply is an ore.list that contains the three graphs. Each graph can be viewed by printing the list element. df2 <- rbind(df,df,df) df2$y <- df2$y + rnorm(nrow(df2)) df2$index <- c(rep(1,300), rep(2,300), rep(3,300)) DF2 <- ore.push(df2) res <- ore.groupApply(DF2, DF2$index, function(df) {   df <- df[,1:2]   library(ggplot2)   library(plyr)   ds <- ddply(df, .(gp), summarise, mean = mean(y), sd = sd(y))   ggplot() +     geom_point(data = df, aes(x = gp, y = y)) +     geom_point(data = ds, aes(x = gp, y = mean),                colour = 'red', size = 3) +     geom_errorbar(data = ds, aes(x = gp, y = mean,                                  ymin = mean - sd, ymax = mean + sd),                   colour = 'red', width = 0.4)   }, parallel=TRUE) res[[1]] res[[2]] res[[3]] To recap, we've illustrated how various uses of ddply from the plyr package can be realized in ore.groupApply, which affords the user explicit control over the contents of the data.frame result in a straightforward manner. We've also highlighted how ddply can be used within an ore.groupApply call.

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