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  • Why aren't tangent space normal maps completely blue?

    - by seahorse
    Why aren't normal maps just blue? I would think that normal maps should be predominantly blue in color because the Z component of the normal is represented by blue. Normals point out of the surface in the Z direction so we should see blue as the predominant colour since the Z component is dominant. By definition tangent space is perpendicular to the surface. At any point we should have the normal always pointing in the Z (blue direction) with no X (red direction) or Y (green direction). Thus the normal map (since it is a "normal map") should have the colour of the normals which is just blue (R = x = 0, G = y = 0, B = z = 1) with no shades in between. But normal maps are not so, and they have gradients of shades in them. Why is this so?

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  • Algorithm for waypoint path following?

    - by Thierry Savard Saucier
    I have a worldmap, with different cities on it. The player can choose a city from a menu, or click on an available cities on the world map, and the toon should walk over there. I want him to follow a predefined path. Lets say our hero is on the city 1. He clicks on city 4. I want him to follow the path to city 2 and from there to city 4. I was handling this easily with arrow movement (left right top bottom) since its a single check. Now I'm not sure how I should do this. Should I loop threw each possible path and check which one leads me to D the fastest ... and if I do how do I avoid running in circle forever with cities 1-5-2 ?

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  • Missing z-axis rotation for transforming between two vectors

    - by Steve Baughman
    I'm trying to rotate a cube so that it's facing up, but am getting hung up on the final implementation details. It now reliably will rotate the x,y axis to the correct side, but the z-axis is never rotating (See photos of before and after rotation). When I'm using the code below I always get '0' for my rotationVector.z. What am I missing here? // Define lookAt vector lookAtVector = GLKVector3Make(0,0,1); // Define axes vectors axes[0] = GLKVector3Make(0,0,1); axes[1] = GLKVector3Make(-1,0,0); axes[2] = GLKVector3Make(0,1,0); axes[3] = GLKVector3Make(1,0,0); axes[4] = GLKVector3Make(0,-1,0); axes[5] = GLKVector3Make(0,0,-1); CGFloat highest_dot = -1.0; GLKVector3 closest_axis; for(int i = 0; i < 6; i++) { // multiply cube's axes by existing matrix GLKVector3 axis = GLKMatrix4MultiplyVector3(matrix, axes[i]); CGFloat dot = GLKVector3DotProduct(axis, lookAtVector); if(dot > highest_dot) { closest_axis = axis; highest_dot = dot; } } GLKVector3 rotationVector = GLKVector3CrossProduct(closest_axis, lookAtVector); // Get angle between vectors CGFloat angle = atan2(GLKVector3Length(rotationVector), GLKVector3DotProduct(closest_axis, lookAtVector)); // normalize the rotation vector rotationVector = GLKVector3Normalize(rotationVector); // Create transform CATransform3D rotationTransform = CATransform3DMakeRotation(angle, rotationVector.x, rotationVector.y, rotationVector.z); // add rotation transform to existing transformation baseTransform = CATransform3DConcat(baseTransform, rotationTransform); return baseTransform; Before 3d Rotation After 3d Rotation Implementation based on this post

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  • (Quaternion based) Trouble moving foward based on model rotation

    - by ChocoMan
    Using quaternions, I'm having trouble moving my model in its facing direction. Currently the model moves can move in all cardinal directions with no problems. The problem comes when I rotate the move as it still travelling in the direction of world space. Meaning, if I'm moving forward, backward or any other direction while rotating the model, the model acts like its a figure skater spinning while traveling in the same direction. How do I update the direction of travel proper with the facing direction of the model? Rotates model on Y-axis: Yaw = pController.ThumbSticks.Right.X * MathHelper.ToRadians(speedAngleMAX); AddRotation = Quaternion.CreateFromYawPitchRoll(yaw, 0, 0); ModelLoad.MRotation *= AddRotation; MOrientation = Matrix.CreateFromQuaternion(ModelLoad.MRotation); Moves model forward: // Move Forward if (pController.IsButtonDown(Buttons.LeftThumbstickUp)) { SpeedX = (float)(Math.Sin(ModelLoad.ModelRotation)) * FWDSpeedMax * pController.ThumbSticks.Left.Y * (float)gameTime.ElapsedGameTime.TotalSeconds; SpeedZ = (float)(Math.Cos(ModelLoad.ModelRotation)) * FWDSpeedMax * pController.ThumbSticks.Left.Y * (float)gameTime.ElapsedGameTime.TotalSeconds; // Update model position ModelLoad._modelPos += Vector3.Forward * SpeedZ; ModelLoad._modelPos += Vector3.Left * SpeedX; }

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  • Tools for assembling textures into DDS files

    - by Nicol Bolas
    There are plenty of tools for making images. I'm not looking for one of those; I have many tools for creating an image. I've got tools for compressing images, generating mipmaps, and even for poking at their basic data format. My issue is with texture assembly. DDS files support cubemaps, array textures, and even cubemap arrays. But I don't know of a tool that can pack a series of images into a cubemap or the like. What tools are available for doing this kind of thing?

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  • Normals vs Normal maps

    - by KaiserJohaan
    I am using Assimp asset importer (http://assimp.sourceforge.net/lib_html/index.html) to parse 3d models. So far, I've simply pulled out the normal vectors which are defined for each vertex in my meshes. Yet I have also found various tutorials on normal maps... As I understand it for normal maps, the normal vectors are stored in each texel of a normal map, and you pull these out of the normal texture in the shader. Why is there two ways to get the normals, which one is considered best-practice and why?

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  • First Person Camera strafing at angle

    - by Linkandzelda
    I have a simple camera class working in directx 11 allowing moving forward and rotating left and right. I'm trying to implement strafing into it but having some problems. The strafing works when there's no camera rotation, so when the camera starts at 0, 0, 0. But after rotating the camera in either direction it seems to strafe at an angle or inverted or just some odd stuff. Here is a video uploaded to Dropbox showing this behavior. https://dl.dropboxusercontent.com/u/2873587/IncorrectStrafing.mp4 And here is my camera class. I have a hunch that it's related to the calculation for camera position. I tried various different calculations in strafe and they all seem to follow the same pattern and same behavior. Also the m_camera_rotation represents the Y rotation, as pitching isn't implemented yet. #include "camera.h" camera::camera(float x, float y, float z, float initial_rotation) { m_x = x; m_y = y; m_z = z; m_camera_rotation = initial_rotation; updateDXZ(); } camera::~camera(void) { } void camera::updateDXZ() { m_dx = sin(m_camera_rotation * (XM_PI/180.0)); m_dz = cos(m_camera_rotation * (XM_PI/180.0)); } void camera::Rotate(float amount) { m_camera_rotation += amount; updateDXZ(); } void camera::Forward(float step) { m_x += step * m_dx; m_z += step * m_dz; } void camera::strafe(float amount) { float yaw = (XM_PI/180.0) * m_camera_rotation; m_x += cosf( yaw ) * amount; m_z += sinf( yaw ) * amount; } XMMATRIX camera::getViewMatrix() { updatePosition(); return XMMatrixLookAtLH(m_position, m_lookat, m_up); } void camera::updatePosition() { m_position = XMVectorSet(m_x, m_y, m_z, 0.0); m_lookat = XMVectorSet(m_x + m_dx, m_y, m_z + m_dz, 0.0); m_up = XMVectorSet(0.0, 1.0, 0.0, 0.0); }

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  • libgdx intersection problem between rectangle and circle

    - by Chris
    My collision detection in libgdx is somehow buggy. player.png is 20*80px and ball.png 25*25px. Code: @Override public void create() { // ... batch = new SpriteBatch(); playerTex = new Texture(Gdx.files.internal("data/player.png")); ballTex = new Texture(Gdx.files.internal("data/ball.png")); player = new Rectangle(); player.width = 20; player.height = 80; player.x = Gdx.graphics.getWidth() - player.width - 10; player.y = 300; ball = new Circle(); ball.x = Gdx.graphics.getWidth() / 2; ball.y = Gdx.graphics.getHeight() / 2; ball.radius = ballTex.getWidth() / 2; } @Override public void render() { Gdx.gl.glClearColor(1, 1, 1, 1); Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); camera.update(); // draw player, ball batch.setProjectionMatrix(camera.combined); batch.begin(); batch.draw(ballTex, ball.x, ball.y); batch.draw(playerTex, player.x, player.y); batch.end(); // update player position if(Gdx.input.isKeyPressed(Keys.DOWN)) player.y -= 250 * Gdx.graphics.getDeltaTime(); if(Gdx.input.isKeyPressed(Keys.UP)) player.y += 250 * Gdx.graphics.getDeltaTime(); if(Gdx.input.isKeyPressed(Keys.LEFT)) player.x -= 250 * Gdx.graphics.getDeltaTime(); if(Gdx.input.isKeyPressed(Keys.RIGHT)) player.x += 250 * Gdx.graphics.getDeltaTime(); // don't let the player leave the field if(player.y < 0) player.y = 0; if(player.y > 600 - 80) player.y = 600 - 80; // check collision if (Intersector.overlaps(ball, player)) Gdx.app.log("overlaps", "yes"); }

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  • Unity3d vector and matrix operations

    - by brandon
    I have the following three vectors: posA: (1,2,3) normal: (0,1,0) offset: (2,3,1) I want to get the vector representing the position which is offset in the direction of the normal from posA. I know how to do this by cheating (not using matrix operations): Vector3 result = new Vector3(posA.x + normal.x*offset.x posA.y + normal.y*offset.y, posA.z + normal.z*offset.z); I know how to do this mathematically Note: [] indicates a column vector, {} indicates a row vector result = [1,2,3] + {2,3,1}*{[0,0,0],[0,1,0],[0,0,0]} What I don't know is which is better to use and if it's the latter how do I do this in unity? I only know of 4x4 matrices in unity. I don't like the first option because you are instantiating a new vector instead of just modifying the original. Suggestions? Note: by asking which is better, I am asking for a quantifiable reason, not just a preference.

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  • How can I implement 2D cel shading in XNA?

    - by Artii
    So I was just wondering on how to give a scene I am rendering a hand drawn look (like say Crayon Physics). I don't really want to preprocess the sprites and was thinking of using a shader. Cel shading supplies the effect I want to achieve, but I am only aware of the 3D instances for it. So I wanted to ask if anyone knew a way to get this effect in 2D, or if cel shading would work just as fine on 2D scenes?

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  • Island Generation Library

    - by thatguy
    Can anyone recommend a tile map generator (written in Java is a plus), where one can control some land types? For example: islands, large continents, singe large continent, archipelago, etc. I've been reading through many posts on the subject, it almost seems like many are just rolling their own. Before creating my own, I'm wondering if there's already an open source implementation that I might not be finding. If not, it seems like using Perlin Noise is a popular choice. Some articles I've been reading: http://simblob.blogspot.com/2010/01/simple-map-generation.html Generate islands/continents with simplex noise https://sites.google.com/site/minecraftlandgenerator/

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  • Retrieving model position after applying modeltransforms in XNA

    - by Glen Dekker
    For this method that the goingBeyond XNA tutorial provides, it would be really convenient if I could retrieve the new position of the model after I apply all the transforms to the mesh. I have edited the method a little for what I need. Does anyone know a way I can do this? public void DrawModel( Camera camera ) { Matrix scaleY = Matrix.CreateScale(new Vector3(1, 2, 1)); Matrix temp = Matrix.CreateScale(100f) * scaleY * rotationMatrix * translationMatrix * Matrix.CreateRotationY(MathHelper.Pi / 6) * translationMatrix2; Matrix[] modelTransforms = new Matrix[model.Bones.Count]; model.CopyAbsoluteBoneTransformsTo(modelTransforms); if (camera.getDistanceFromPlayer(position+position1) > 3000) return; foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.EnableDefaultLighting(); effect.World = modelTransforms[mesh.ParentBone.Index] * temp * worldMatrix; effect.View = camera.viewMatrix; effect.Projection = camera.projectionMatrix; } mesh.Draw(); } }

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  • Xna Equivalent of Viewport.Unproject in a draw call as a matrix transformation

    - by Nick Crowther
    I am making a 2D sidescroller and I would like to draw my sprite to world space instead of client space so I do not have to lock it to the center of the screen and when the camera stops the sprite will walk off screen instead of being stuck at the center. In order to do this I wanted to make a transformation matrix that goes in my draw call. I have seen something like this: http://stackoverflow.com/questions/3570192/xna-viewport-projection-and-spritebatch I have seen Matrix.CreateOrthographic() used to go from Worldspace to client space but, how would I go about using it to go from clientspace to worldspace? I was going to try putting my returns from the viewport.unproject method I have into a scale matrix such as: blah = Matrix.CreateScale(unproject.X,unproject.Y,0); however, that doesn't seem to work correctly. Here is what I'm calling in my draw method(where X is the coordinate my camera should follow): Vector3 test = screentoworld(X, graphics); var clienttoworld = Matrix.CreateScale(test.X,test.Y, 0); animationPlayer.Draw(theSpriteBatch, new Vector2(X.X,X.Y),false,false,0,Color.White,new Vector2(1,1),clienttoworld); Here is my code in my unproject method: Vector3 screentoworld(Vector2 some, GraphicsDevice graphics): Vector2 Position =(some.X,some.Y); var project = Matrix.CreateOrthographic(5*graphicsdevice.Viewport.Width, graphicsdevice.Viewport.Height, 0, 1); var viewMatrix = Matrix.CreateLookAt( new Vector3(0, 0, -4.3f), new Vector3(X.X,X.Y,0), Vector3.Up); //I have also tried substituting (cam.Position.X,cam.Position.Y,0) in for the (0,0,-4.3f) Vector3 nearSource = new Vector3(Position, 0f); Vector3 nearPoint = graphicsdevice.Viewport.Unproject(nearSource, project, viewMatrix, Matrix.Identity); return nearPoint;

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  • Cannot compute wNear and wFar from projection matrix

    - by DeadMG
    I've got the following error from Direct3D when attempting to render in 3D: Direct3D9: (WARN) :Cannot compute WNear and WFar from the supplied projection matrix Direct3D9: (WARN) :Setting wNear to 0.0 and wFar to 1.0 My projection matrix is as follows: D3DXMatrixPerspectiveFovLH( &Projection, D3DXToRadian(90), (float)GetDimensions().x / (float)GetDimensions().y, NearPlane, FarPlane ); D3DCALL(device->SetTransform( D3DTS_PROJECTION, &Projection )); The NearPlane is 0.1f, the FarPlane is 40.0f, and the dimensions are 1920x1018. This code was working earlier but I appear to have broken it, and I'm not sure where the fault is. Previously I've only encountered it if NearPlane was 0, and Google hasn't suggested any other causes either. Any suggestions?

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  • Producing a smooth mesh from density cloud and marching cubes

    - by Wardy
    Based on my results from this question I decided to build myself a 3D noise map containing float values in place of my existing boolean point values. The effect I'm trying to produce is something like this, rather than typical rolling hills; which should explain the "missing cubes" in the image below. If I render my density map in normal "minecraft mode" (1 block per point in the density map) varying the size of the cube based on the value in my density map (floats in the range 0 to 1) I get something like this: I'm now happy that I can produce a density map for the marching cubes algorithm (which will need a little tweaking) but for some reason when I run it through my implementation it's not producing what I expect. My problem is that I'm getting something like the first image in this answer to my previous question, when I want to achieve the effect in the second image. Upon further investigation I can't see how marching cubes does the "move vertex along the edge" type logic (i.e. the difference between the two images on my previous link). I see that it does do some interpolation, but I'm not convinced I have the correct understanding of what I think it should do, because the code in question appears to give the same result regardless of whether I use boolean or float values. I took the code from here which is a C# implementation of marching cubes, but instead of using the MarchingCubesPrimitive I modified it to accept an object of type IDrawable, containing lists for the various collections (vertices, normals, UVs, indices), the logic was otherwise untouched. My understanding is that given a very low isovalue the accuracy level of the surface being rendered should increase, so in short "less 45 degree slows more rolling hills" type mesh output. However this isn't what I'm seeing. Have I missed something or is the implementation flawed and need to be fixed? EDIT: A little more detail on what I am seeing when I "marching cube" the data. Ok so firstly, ignore the fact that the meshes created by the chunks don't "connect" (i'll probably raise another question about this later). Then look at the shaping of the island, it's too ... square, from the voxels rendered as boxes you get the impression there's a clean soft gradual hill and yet from the image there are sharp falling edges even in the most central areas where the gradient in the first image looks the most smooth. The data is "regenerated" each time I run this so no 2 islands come out the same, and it's purely random so not based on noise, but still, how can it look so smooth in 1 image and so not smooth in the other?

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  • How can I pass an array of floats to the fragment shader using textures?

    - by James
    I want to map out a 2D array of depth elements for the fragment shader to use to check depth against to create shadows. I want to be able to copy a float array into the GPU, but using large uniform arrays causes segfaults in openGL so that is not an option. I tried texturing but the best i got was to use GL_DEPTH_COMPONENT glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 512, 512, 0, GL_DEPTH_COMPONENT, GL_FLOAT, smap); Which doesn't work because that stores depth components (0.0 - 1.0) which I don't want because I have no idea how to calculate them using the depth value produced by the light sources MVP matrix multiplied by the coordinate of each vertex. Is there any way to store and access large 2D arrays of floats in openGL?

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  • running GL ES 2.0 code under Linux ( no Android no iOS )

    - by user827992
    I need to code OpenGL ES 2.0 bits and i would like to do this and run the programs on my desktop for practical reasons. Now, i already have tried the official GLES SDK from ATI for my videocard but it not even runs the examples that comes with the SDK itself, i'm not looking for performance here, even a software based rendering pipeline could be enough, i just need full support for GLES 2.0 and GLSL to code and run GL stuff. There is a reliable solution for this under Ubuntu Linux ?

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  • adapting a Unity gravitational script to allow moons

    - by PartyMix
    I'm using this script: http://wiki.unity3d.com/index.php/Simple_planetary_orbits to get a solar system going in Unity, but it doesn't seem to support creating bodies that orbit other moving bodies (or I am using it incorrectly). Any idea about how to modify it so that it does (or just use it correctly)? I've been beating my head against this problem for a couple hours, and I really don't feel like I have any idea what I'm doing. Thanks in advance.

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  • CreateRenderTarget returns 0x80070057 in big surface resolution

    - by senggen
    I have created the SLI merged desktop of three 1920x1680 monitors, so the desktop resolution is 5760x1080. There is a 0x80070057 error, while calling CreateRenderTarget to create the RT_Surface: IDirect3DSurface9* _render_surface; HRESULT hr = _device->CreateRenderTarget( _desktop_width * 2, _desktop_height + 1, D3DFMT_A8R8G8B8, D3DMULTISAMPLE_NONE, 0, TRUE, &_render_surface, NULL); It works OK with desktop resolution 1024x768, and the total resolution is 3072x768. In http://msdn.microsoft.com/en-us/library/windows/desktop/bb174361(v=vs.85).aspx, it says If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be one of the following: D3DERR_NOTAVAILABLE, D3DERR_INVALIDCALL, D3DERR_OUTOFVIDEOMEMORY, E_OUTOFMEMORY. and no description about 0x80070057. HRESULT: 0x80070057 (2147942487) Name: E_INVALIDARG Description: An invalid parameter was passed to the returning function Somebody please help me.

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  • Corona SDK: Animation takes a long time to play after "prepare" step

    - by Michael Taufen
    First off, I'm using the current publicly available build, version 2011.704 I'm building a platformer, and have a character that runs along and jumps when the screen is tapped. While jumping, the animation code has him assume a svelte jumping pose, and upon the detection of a collision with the ground, he returns to running. All of this happens. The problem is that there is this strange gap of time, about 1/2 a second by the feel of it, where my character sits on the first frame of the run animation after landing, before it actually starts playing. This leads me to believe that the problem is somewhere between the "prepare" step of loading up a sprite set's animation sequence and the "play" step. Thanks in advance for any help :). My code for when my character lands is as follows: local function collisionHandler ( event ) if (event.object1.myName == "character") and (event.object2.type == "terrain") then inAir = false characterInstance:prepare( "run" ) -- TODO: time between prepare and play is curiously long... characterInstance:play() end end

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  • "Accumulate" buffer results in XNA4?

    - by Utkarsh Sinha
    I'm trying to simulate a "heightmap" buffer in XNA4.0 but the results don't look correct. Here's what I'm hoping to achieve: http://www.youtube.com/watch?feature=player_detailpage&v=-Q6ISVaM5Ww#t=517s (8:38). From what I understand, here are the steps to reach there: Pass height buffer + current entity's heightmap Generate a stencil and update the height buffer Render sprite+stencil For now, I'm just trying to get the height buffer thing to work. So here's the problem. Inside the draw loop, I do the following: Create a new render target & set it Draw the heightmap with a sprite batch(no shaders) graphicsDevice.SetRenderTarget(null) Draw the rendertarget with SpriteBatch I expected to see all entities' heightmaps. But only the last entity's heightmap is visible. Any hints on what I'm doing wrong? Here's the code inside the draw loop: RenderTarget2D tempDepthStencil = new RenderTarget2D(graphicsDevice, graphicsDevice.Viewport.Width, graphicsDevice.Viewport.Height, false, graphicsDevice.DisplayMode.Format, DepthFormat.None); graphicsDevice.SetRenderTarget(tempDepthStencil); // Gather depth information SpriteBatch depthStencilSpriteBatch = new SpriteBatch(graphicsDevice); depthStencilSpriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.None, RasterizerState.CullCounterClockwise); depthStencilSpriteBatch.Draw(texHeightmap, pos, null, Color.White, 0, Vector2.Zero, 1, spriteEffects, 1); depthStencilSpriteBatch.End(); graphicsDevice.SetRenderTarget(null); SpriteBatch b1 = new SpriteBatch(graphicsDevice); b1.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, null, null, null, null); b1.Draw((Texture2D)tempDepthStencil, Vector2.Zero, null, Color.White, 0, Vector2.Zero, 1, spriteEffects, 1); b1.End();

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  • Image with FadeIn effect blinks when added to scene

    - by Ef Es
    I am trying to add an image to the scene, but it should just be added to the scene invisible, FadeIn and then be deleted when the effect finishes. My problem is that the images blink once when they are added to the scene, then they do the intended effect. My best guess is that when they are added they show on the scene for a split second before starting the animation. I though of making them invisible for a split second before activating them, but I am not sure how to code it. const bool Sunbeams::add() { const CCSize kSceenSize = CCDirector::sharedDirector()->getWinSize(); const int nRayType = random( m_kRays.size()); const CCPoint kPosition( random( static_cast < int >( kSceenSize.width)), 0.0f); const float fDuration = random( m_fDurationVariance) + m_fDurationMin; CCSprite* pkLightBeam = CCSprite::spriteWithTexture( m_kRays[nRayType]); if ( !pkLightBeam) { msg::debug( "Sunbeams::add", "Failed to create sprite from ray '%d'!\n", m_kRays[nRayType]); return false; } pkLightBeam->setAnchorPoint( CCPointZero); pkLightBeam->setPosition( kPosition); m_kActiveBeams.push_back( pkLightBeam); CCDirector::sharedDirector()->getRunningScene()->addChild( pkLightBeam); CCActionInterval* pkAction = CCFadeIn::actionWithDuration( fDuration); CCActionInterval* pkActionBack = pkAction->reverse(); pkLightBeam->runAction( CCSequence::actions( pkAction, pkActionBack, 0)); return true; }

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  • ray collision with rectangle and floating point accuracy

    - by phq
    I'm trying to solve a problem with a ray bouncing on a box. Actually it is a sphere but for simplicity the box dimensions are expanded by the sphere radius when doing the collision test making the sphere a single ray. It is done by projecting the ray onto all faces of the box and pick the one that is closest. However because I'm using floating point variables I fear that the projected point onto the surface might be interpreted as being below in the next iteration, also I will later allow the sphere to move which might make that scenario more likely. Also the bounce coefficient might be as low as zero, making the sphere continue along the surface. So my naive solution is to project not only forwards but backwards to catch those cases. That is where I got into problems shown in the figure: In the first iteration the first black arrow is calculated and we end up at a point on the surface of the box. In the second iteration the "back projection" hits the other surface making the second black arrow bounce on the wrong surface. If there are several boxes close to each other this has further consequences making the sphere fall through them all. So my main question is how to handle possible floating point accuracy when placing the sphere on the box surface so it does not fall through. In writing this question I got the idea to have a threshold to only accept back projections a certain amount much smaller than the box but larger than the possible accuracy limitation, this would only cause the "false" back projection when the sphere hit the box on an edge which would appear naturally. To clarify my original approach, the arrows shown in the image is not only the path the sphere travels but is also representing a single time step in the simulation. In reality the time step is much smaller about 0.05 of the box size. The path traveled is projected onto possible sides to avoid traveling past a thinner object at higher speeds. In normal situations the floating point accuracy is not an issue but there are two situations where I have the concern. When the new position at the end of the time step is located very close to the surface, very unlikely though. When using a bounce factor of 0, here it happens every time the sphere hit a box. To add some loss of accuracy, the motivation for my concern, is that the sphere and box are in different coordinate systems and thus the sphere location is transformed for every test. This last one is why I'm not willing to stand on luck that one floating point value lying on top of the box always will be interpreted the same. I did not know voronoi regions by name, but looking at it I'm not sure how it would be used in a projection scenario that I'm using here.

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  • Smooth Camera Rotation around 90 degrees

    - by Nicholas
    I'm developing a third person 3D platformer in XNA. My problem is when I try to rotate the camera around the player. I would like to rotate (and animate) the camera 90 degrees around the player. So the camera should rotate until it has reached 90 degrees from the starting position. I cannot figure out how to keep track of the rotation, and when the rotation has made the full 90 degrees. Currently my cameras update: public void Update(Vector3 playerPosition) { if (rotateCamera) { position = Vector3.Transform(position - playerPosition, Matrix.CreateRotationY(0.1f)) + playerPosition; } this.viewMatrix = Matrix.CreateLookAt(position, playerPosition, Vector3.Up); } The initial position of the camera is set in the constructor. The "rotateCamera" bool is set on keypress. Thanks for the help in advance. Cheers.

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  • How to make an object stay relative to another object

    - by Nick
    In the following example there is a guy and a boat. They have both a position, orientation and velocity. The guy is standing on the shore and would like to board. He changes his position so he is now standing on the boat. The boat changes velocity and orientation and heads off. My character however has a velocity of 0,0,0 but I would like him to stay onboard. When I move my character around, I would like to move as if the boat was the ground I was standing on. How do keep my character aligned properly with the boat? It is exactly like in World Of Warcraft, when you board a boat or zeppelin. This is my physics code for the guy and boat: this.velocity.addSelf(acceleration.multiplyScalar(dTime)); this.position.addSelf(this.velocity.clone().multiplyScalar(dTime)); The guy already has a reference to the boat he's standing on, and thus knows the boat's position, velocity, orientation (even matrices or quaternions can be used).

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