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  • Billboarding + aligning with velocity direction

    - by roxlu
    I'm working on a particle system where I'm orientating the billboard using the inverted orientation matrix of my camera. This works quite well and my quad are rotated correctly towards the camera. But, now I want to to rotate the quads in such a way that they point towards the direction they are going to. In 2D this can be done by normalizing the velocity vector and using that vector for a rotation around the Z-axis (where vel.x = cos(a) and vel.y = sin(a)). But how does this work in 3D? Thanks roxlu

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  • Basic shadow mapping fails on NVIDIA card?

    - by James
    Recently I switched from an AMD Radeon HD 6870 card to an (MSI) NVIDIA GTX 670 for performance reasons. I found however that my implementation of shadow mapping in all my applications failed. In a very simple shadow POC project the problem appears to be that the scene being drawn never results in a draw to the depth map and as a result the entire depth map is just infinity, 1.0 (Reading directly from the depth component after draw (glReadPixels) shows every pixel is infinity (1.0), replacing the depth comparison in the shader with a comparison of the depth from the shadow map with 1.0 shadows the entire scene, and writing random values to the depth map and then not calling glClear(GL_DEPTH_BUFFER_BIT) results in a random noisy pattern on the scene elements - from which we can infer that the uploading of the depth texture and comparison within the shader are functioning perfectly.) Since the problem appears almost certainly to be in the depth render, this is the code for that: const int s_res = 1024; GLuint shadowMap_tex; GLuint shadowMap_prog; GLint sm_attr_coord3d; GLint sm_uniform_mvp; GLuint fbo_handle; GLuint renderBuffer; bool isMappingShad = false; //The scene consists of a plane with box above it GLfloat scene[] = { -10.0, 0.0, -10.0, 0.5, 0.0, 10.0, 0.0, -10.0, 1.0, 0.0, 10.0, 0.0, 10.0, 1.0, 0.5, -10.0, 0.0, -10.0, 0.5, 0.0, -10.0, 0.0, 10.0, 0.5, 0.5, 10.0, 0.0, 10.0, 1.0, 0.5, ... }; //Initialize the stuff used by the shadow map generator int initShadowMap() { //Initialize the shadowMap shader program if (create_program("shadow.v.glsl", "shadow.f.glsl", shadowMap_prog) != 1) return -1; const char* attribute_name = "coord3d"; sm_attr_coord3d = glGetAttribLocation(shadowMap_prog, attribute_name); if (sm_attr_coord3d == -1) { fprintf(stderr, "Could not bind attribute %s\n", attribute_name); return 0; } const char* uniform_name = "mvp"; sm_uniform_mvp = glGetUniformLocation(shadowMap_prog, uniform_name); if (sm_uniform_mvp == -1) { fprintf(stderr, "Could not bind uniform %s\n", uniform_name); return 0; } //Create a framebuffer glGenFramebuffers(1, &fbo_handle); glBindFramebuffer(GL_FRAMEBUFFER, fbo_handle); //Create render buffer glGenRenderbuffers(1, &renderBuffer); glBindRenderbuffer(GL_RENDERBUFFER, renderBuffer); //Setup the shadow texture glGenTextures(1, &shadowMap_tex); glBindTexture(GL_TEXTURE_2D, shadowMap_tex); glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, s_res, s_res, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); return 0; } //Delete stuff void dnitShadowMap() { //Delete everything glDeleteFramebuffers(1, &fbo_handle); glDeleteRenderbuffers(1, &renderBuffer); glDeleteTextures(1, &shadowMap_tex); glDeleteProgram(shadowMap_prog); } int loadSMap() { //Bind MVP stuff glm::mat4 view = glm::lookAt(glm::vec3(10.0, 10.0, 5.0), glm::vec3(0.0, 0.0, 0.0), glm::vec3(0.0, 1.0, 0.0)); glm::mat4 projection = glm::ortho<float>(-10,10,-8,8,-10,40); glm::mat4 mvp = projection * view; glm::mat4 biasMatrix( 0.5, 0.0, 0.0, 0.0, 0.0, 0.5, 0.0, 0.0, 0.0, 0.0, 0.5, 0.0, 0.5, 0.5, 0.5, 1.0 ); glm::mat4 lsMVP = biasMatrix * mvp; //Upload light source matrix to the main shader programs glUniformMatrix4fv(uniform_ls_mvp, 1, GL_FALSE, glm::value_ptr(lsMVP)); glUseProgram(shadowMap_prog); glUniformMatrix4fv(sm_uniform_mvp, 1, GL_FALSE, glm::value_ptr(mvp)); //Draw to the framebuffer (with depth buffer only draw) glBindFramebuffer(GL_FRAMEBUFFER, fbo_handle); glBindRenderbuffer(GL_RENDERBUFFER, renderBuffer); glBindTexture(GL_TEXTURE_2D, shadowMap_tex); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, shadowMap_tex, 0); glDrawBuffer(GL_NONE); glReadBuffer(GL_NONE); GLenum result = glCheckFramebufferStatus(GL_FRAMEBUFFER); if (GL_FRAMEBUFFER_COMPLETE != result) { printf("ERROR: Framebuffer is not complete.\n"); return -1; } //Draw shadow scene printf("Creating shadow buffers..\n"); int ticks = SDL_GetTicks(); glClear(GL_DEPTH_BUFFER_BIT); //Wipe the depth buffer glViewport(0, 0, s_res, s_res); isMappingShad = true; //DRAW glEnableVertexAttribArray(sm_attr_coord3d); glVertexAttribPointer(sm_attr_coord3d, 3, GL_FLOAT, GL_FALSE, 5*4, scene); glDrawArrays(GL_TRIANGLES, 0, 14*3); glDisableVertexAttribArray(sm_attr_coord3d); isMappingShad = false; glBindFramebuffer(GL_FRAMEBUFFER, 0); printf("Render Sbuf in %dms (GLerr: %d)\n", SDL_GetTicks() - ticks, glGetError()); return 0; } This is the full code for the POC shadow mapping project (C++) (Requires SDL 1.2, SDL-image 1.2, GLEW (1.5) and GLM development headers.) initShadowMap is called, followed by loadSMap, the scene is drawn from the camera POV and then dnitShadowMap is called. I followed this tutorial originally (Along with another more comprehensive tutorial which has disappeared as this guy re-configured his site but used to be here (404).) I've ensured that the scene is visible (as can be seen within the full project) to the light source (which uses an orthogonal projection matrix.) Shader utilities function fine in non-shadow-mapped projects. I should also note that at no point is the GL error state set. What am I doing wrong here and why did this not cause problems on my AMD card? (System: Ubuntu 12.04, Linux 3.2.0-49-generic, 64 bit, with the nvidia-experimental-310 driver package. All other games are functioning fine so it's most likely not a card/driver issue.)

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  • OpenGL Performance Questions

    - by Daniel
    This subject, as with any optimisation problem, gets hit on a lot, but I just couldn't find what I (think) I want. A lot of tutorials, and even SO questions have similar tips; generally covering: Use GL face culling (the OpenGL function, not the scene logic) Only send 1 matrix to the GPU (projectionModelView combination), therefore decreasing the MVP calculations from per vertex to once per model (as it should be). Use interleaved Vertices Minimize as many GL calls as possible, batch where appropriate And possibly a few/many others. I am (for curiosity reasons) rendering 28 million triangles in my application using several vertex buffers. I have tried all the above techniques (to the best of my knowledge), and received almost no performance change. Whilst I am receiving around 40FPS in my implementation, which is by no means problematic, I am still curious as to where these optimisation 'tips' actually come into use? My CPU is idling around 20-50% during rendering, therefore I assume I am GPU bound for increasing performance. Note: I am looking into gDEBugger at the moment Cross posted at StackOverflow

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  • Shadow mapping with deffered shading for directional lights - shadow map projection problem

    - by Harry
    I'm trying to implement shadow mapping to my engine. I started with directional lights because they seemed to be the easiest one, but I was wrong :) I have implemented deferred shading and I retrieve position from depth. I think that there is the biggest problem but code looks ok for me. Now more about problem: Shadow map projected onto meshes looks bad scaled and translated and also some informations from shadow map texture aren't visible. You can see it on this screen: http://img5.imageshack.us/img5/2254/93dn.png Yelow frustum is light frustum and I have mixed shadow map preview and actual scene. As you can see shadows are in wrong place and shadow of cone and sphere aren't visible. Could you look at my codes and tell me where I have a mistake? // create shadow map if(!_shd)glGenTextures(1, &_shd); glBindTexture(GL_TEXTURE_2D, _shd); glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 1024, 1024, 0, GL_DEPTH_COMPONENT, GL_FLOAT,NULL); // shadow map size glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, _shd, 0); glDrawBuffer(GL_NONE); // setting camera Vector dire=Vector(0,0,1); ACamera.setLookAt(dire,Vector(0)); ACamera.setPerspectiveView(60.0f,1,0.1f,10.0f); // currently needed for proper frustum corners calculation Vector min(ACamera._point[0]),max(ACamera._point[0]); for(int i=0;i<8;i++){ max=Max(max,ACamera._point[i]); min=Min(min,ACamera._point[i]); } ACamera.setOrthogonalView(min.x,max.x,min.y,max.y,-max.z,-min.z); glBindFramebuffer(GL_DRAW_FRAMEBUFFER, _s_buffer); // framebuffer for shadow map // rendering to depth buffer glBindFramebuffer(GL_DRAW_FRAMEBUFFER, _g_buffer); Shaders["DirLight"].set(true); Matrix4 bias; bias.x.set(0.5,0.0,0.0,0.0); bias.y.set(0.0,0.5,0.0,0.0); bias.z.set(0.0,0.0,0.5,0.0); bias.w.set(0.5,0.5,0.5,1.0); Shaders["DirLight"].set("textureMatrix",ACamera.matrix*Projection3D*bias); // order of multiplications are 100% correct, everything gives mi the same result as using glm glActiveTexture(GL_TEXTURE5); glBindTexture(GL_TEXTURE_2D,_shd); lightDir(dir); // light calculations Vertex Shader makes nothing related to shadow calculatons Pixel shader function which calculates if pixel is in shadow or not: float readShadowMap(vec3 eyeDir) { // retrieve depth of pixel float z = texture2D(depth, gl_FragCoord.xy/screen).z; vec3 pos = vec3(gl_FragCoord.xy/screen, z); // transform by the projection and view inverse vec4 worldSpace = inverse(View)*inverse(ProjectionMatrix)*vec4(pos*2-1,1); worldSpace /= worldSpace.w; vec4 coord=textureMatrix*worldSpace; float vis=1.0f; if(texture2D(shadow, coord.xy).z < coord.z-0.001)vis=0.2f; return vis; } I also have question about shadows specifically for directional light. Currently I always look at 0,0,0 position and in further implementation I have to move light frustum along to camera frustum. I've found how to do this here: http://www.gamedev.net/topic/505893-orthographic-projection-for-shadow-mapping/ but it doesn't give me what I want. Maybe because of problems mentioned above, but I want know your opinion. EDIT: vec4 worldSpace is position read from depht of the scene (not shadow map). Maybe I wasn't precise so I'll try quick explain what is what: View is camera view matrix, ProjectionMatrix is camera projection,. First I try to get world space position from depth map and then multiply it by textureMatrix which is light view *light projection*bias. Rest of code is the same as in many tutorials. I can't use vertex shader to make something like gl_Position=textureMatrix*gl_Vertex and get it interpolated in fragment shader because of deffered rendering use so I want get it from depht buffer. EDIT2: I also tried make it as in Coding Labs tutorial about Shadow Mapping with Deferred Rendering but unfortunately this either works wrong.

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  • How do I move the camera sideways in Libgdx?

    - by Bubblewrap
    I want to move the camera sideways (strafe). I had the following in mind, but it doesn't look like there are standard methods to achieve this in Libgdx. If I want to move the camera sideways by x, I think I need to do the following: Create a Matrix4 mat Determine the orthogonal vector v between camera.direction and camera.up Translate mat by v*x Multiply camera.position by mat Will this approach do what I think it does, and is it a good way to do it? And how can I do this in libgdx? I get "stuck" at step 2, as I have not found any standard method in Libgdx to calculate an orthogonal vector. EDIT: I think I can use camera.direction.crs(camera.up) to find v. I'll try this approach tonight and see if it works. EDIT2: I got it working and didn't need the matrix after all: Vector3 right = camera.direction.cpy().crs(camera.up).nor(); camera.position.add(right.mul(x));

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  • First time shadow mapping problems

    - by user1294203
    I have implemented basic shadow mapping for the first time in OpenGL using shaders and I'm facing some problems. Below you can see an example of my rendered scene: The process of the shadow mapping I'm following is that I render the scene to the framebuffer using a View Matrix from the light point of view and the projection and model matrices used for normal rendering. In the second pass, I send the above MVP matrix from the light point of view to the vertex shader which transforms the position to light space. The fragment shader does the perspective divide and changes the position to texture coordinates. Here is my vertex shader, #version 150 core uniform mat4 ModelViewMatrix; uniform mat3 NormalMatrix; uniform mat4 MVPMatrix; uniform mat4 lightMVP; uniform float scale; in vec3 in_Position; in vec3 in_Normal; in vec2 in_TexCoord; smooth out vec3 pass_Normal; smooth out vec3 pass_Position; smooth out vec2 TexCoord; smooth out vec4 lightspace_Position; void main(void){ pass_Normal = NormalMatrix * in_Normal; pass_Position = (ModelViewMatrix * vec4(scale * in_Position, 1.0)).xyz; lightspace_Position = lightMVP * vec4(scale * in_Position, 1.0); TexCoord = in_TexCoord; gl_Position = MVPMatrix * vec4(scale * in_Position, 1.0); } And my fragment shader, #version 150 core struct Light{ vec3 direction; }; uniform Light light; uniform sampler2D inSampler; uniform sampler2D inShadowMap; smooth in vec3 pass_Normal; smooth in vec3 pass_Position; smooth in vec2 TexCoord; smooth in vec4 lightspace_Position; out vec4 out_Color; float CalcShadowFactor(vec4 lightspace_Position){ vec3 ProjectionCoords = lightspace_Position.xyz / lightspace_Position.w; vec2 UVCoords; UVCoords.x = 0.5 * ProjectionCoords.x + 0.5; UVCoords.y = 0.5 * ProjectionCoords.y + 0.5; float Depth = texture(inShadowMap, UVCoords).x; if(Depth < (ProjectionCoords.z + 0.001)) return 0.5; else return 1.0; } void main(void){ vec3 Normal = normalize(pass_Normal); vec3 light_Direction = -normalize(light.direction); vec3 camera_Direction = normalize(-pass_Position); vec3 half_vector = normalize(camera_Direction + light_Direction); float diffuse = max(0.2, dot(Normal, light_Direction)); vec3 temp_Color = diffuse * vec3(1.0); float specular = max( 0.0, dot( Normal, half_vector) ); float shadowFactor = CalcShadowFactor(lightspace_Position); if(diffuse != 0 && shadowFactor > 0.5){ float fspecular = pow(specular, 128.0); temp_Color += fspecular; } out_Color = vec4(shadowFactor * texture(inSampler, TexCoord).xyz * temp_Color, 1.0); } One of the problems is self shadowing as you can see in the picture, the crate has its own shadow cast on itself. What I have tried is enabling polygon offset (i.e. glEnable(POLYGON_OFFSET_FILL), glPolygonOffset(GLfloat, GLfloat) ) but it didn't change much. As you see in the fragment shader, I have put a static offset value of 0.001 but I have to change the value depending on the distance of the light to get more desirable effects , which not very handy. I also tried using front face culling when I render to the framebuffer, that didn't change much too. The other problem is that pixels outside the Light's view frustum get shaded. The only object that is supposed to be able to cast shadows is the crate. I guess I should pick more appropriate projection and view matrices, but I'm not sure how to do that. What are some common practices, should I pick an orthographic projection? From googling around a bit, I understand that these issues are not that trivial. Does anyone have any easy to implement solutions to these problems. Could you give me some additional tips? Please ask me if you need more information on my code. Here is a comparison with and without shadow mapping of a close-up of the crate. The self-shadowing is more visible.

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  • install Cirrus Logic cs46xx (audio card) drivers

    - by Aikanáro
    I have two sounds cards, one is the on-board (it's VIA) the other is Cirrus Logic cs46xx. This is what lspci shows me: 04:04.0 Multimedia audio controller: Cirrus Logic CS 4614/22/24/30 [CrystalClear SoundFusion Audio Accelerator] (rev 01) It only show the cirrus logic, cause I disable the VIA card through BIOS. This page: http://es.driverscollection.com/?file_id=13152 gives me instructions to install it, but I can follow them because the folders indicates in the page do not matches with the ones that I see in my system. The alsa page: http://alsa-project.org/main/index.php/Matrix:Module-cs46xx, also give me instructions, but I don't understand it. For example, they say: type in a terminal: ./configure but don't say in what directory. I think that isn't instructions for begginers... Right now I can't heard anything. I decide to disable the VIA audio card, cause I've read they don't get along with linux, although i use the integrate VIA video card. I have ubuntu 11.10

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  • Rotate sprite to face 3D camera

    - by omikun
    I am trying to rotate a sprite so it is always facing a 3D camera. shaders->setUniform("camera", gCamera.matrix()); glm::mat4 scale = glm::scale(glm::mat4(), glm::vec3(5e5, 5e5, 5e5)); glm::vec3 look = gCamera.position(); glm::vec3 right = glm::cross(gCamera.up(), look); glm::vec3 up = glm::cross(look, right); glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), up) * scale; shaders->setUniform("model", newTransform); In the vertex shader: gl_Position = camera * model * vec4(vert, 1); The object will track the camera if I move the camera up or down, but if I rotate the camera around it, it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360. What am I doing wrong?

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  • The How-To Geek Guide to Audio Editing: Basic Noise Removal

    - by YatriTrivedi
    Laying down some vocals?  Starting your own podcast?  Here’s how to remove noise from a messy audio track in Audacity quickly and easily. This is the second part in our series covering how to edit audio and create music using your PC. Be sure to check out the first part in the series, where we covered the basics of using Audacity, and then check out how to add MP3 format support as well Latest Features How-To Geek ETC HTG Projects: How to Create Your Own Custom Papercraft Toy How to Combine Rescue Disks to Create the Ultimate Windows Repair Disk What is Camera Raw, and Why Would a Professional Prefer it to JPG? The How-To Geek Guide to Audio Editing: The Basics How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 Take Better Panoramic Photos with Any Camera Make Creating App Tabs Easier in Firefox Peach and Zelda Discuss the Benefits and Perks of Being Kidnapped [Video] The Life of Gadgets in Price and Popularity [Infographic] Apture Highlights Turns Your Cursor into a Search Tool Add Classic Sci-Fi Goodness to Your Desktop with the Matrix Theme for Windows 7

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  • Extreme Optimization – Numerical Algorithm Support

    - by JoshReuben
    Function Delegates Many calculations involve the repeated evaluation of one or more user-supplied functions eg Numerical integration. The EO MathLib provides delegate types for common function signatures and the FunctionFactory class can generate new delegates from existing ones. RealFunction delegate - takes one Double parameter – can encapsulate most of the static methods of the System.Math class, as well as the classes in the Extreme.Mathematics.SpecialFunctions namespace: var sin = new RealFunction(Math.Sin); var result = sin(1); BivariateRealFunction delegate - takes two Double parameters: var atan2 = new BivariateRealFunction (Math.Atan2); var result = atan2(1, 2); TrivariateRealFunction delegate – represents a function takes three Double arguments ParameterizedRealFunction delegate - represents a function taking one Integer and one Double argument that returns a real number. The Pow method implements such a function, but the arguments need order re-arrangement: static double Power(int exponent, double x) { return ElementaryFunctions.Pow(x, exponent); } ... var power = new ParameterizedRealFunction(Power); var result = power(6, 3.2); A ComplexFunction delegate - represents a function that takes an Extreme.Mathematics.DoubleComplex argument and also returns a complex number. MultivariateRealFunction delegate - represents a function that takes an Extreme.Mathematics.LinearAlgebra.Vector argument and returns a real number. MultivariateVectorFunction delegate - represents a function that takes a Vector argument and returns a Vector. FastMultivariateVectorFunction delegate - represents a function that takes an input Vector argument and an output Matrix argument – avoiding object construction  The FunctionFactory class RealFromBivariateRealFunction and RealFromParameterizedRealFunction helper methods - transform BivariateRealFunction or a ParameterizedRealFunction into a RealFunction delegate by fixing one of the arguments, and treating this as a new function of a single argument. var tenthPower = FunctionFactory.RealFromParameterizedRealFunction(power, 10); var result = tenthPower(x); Note: There is no direct way to do this programmatically in C# - in F# you have partial value functions where you supply a subset of the arguments (as a travelling closure) that the function expects. When you omit arguments, F# generates a new function that holds onto/remembers the arguments you passed in and "waits" for the other parameters to be supplied. let sumVals x y = x + y     let sumX = sumVals 10     // Note: no 2nd param supplied.     // sumX is a new function generated from partially applied sumVals.     // ie "sumX is a partial application of sumVals." let sum = sumX 20     // Invokes sumX, passing in expected int (parameter y from original)  val sumVals : int -> int -> int val sumX : (int -> int) val sum : int = 30 RealFunctionsToVectorFunction and RealFunctionsToFastVectorFunction helper methods - combines an array of delegates returning a real number or a vector into vector or matrix functions. The resulting vector function returns a vector whose components are the function values of the delegates in the array. var funcVector = FunctionFactory.RealFunctionsToVectorFunction(     new MultivariateRealFunction(myFunc1),     new MultivariateRealFunction(myFunc2));  The IterativeAlgorithm<T> abstract base class Iterative algorithms are common in numerical computing - a method is executed repeatedly until a certain condition is reached, approximating the result of a calculation with increasing accuracy until a certain threshold is reached. If the desired accuracy is achieved, the algorithm is said to converge. This base class is derived by many classes in the Extreme.Mathematics.EquationSolvers and Extreme.Mathematics.Optimization namespaces, as well as the ManagedIterativeAlgorithm class which contains a driver method that manages the iteration process.  The ConvergenceTest abstract base class This class is used to specify algorithm Termination , convergence and results - calculates an estimate for the error, and signals termination of the algorithm when the error is below a specified tolerance. Termination Criteria - specify the success condition as the difference between some quantity and its actual value is within a certain tolerance – 2 ways: absolute error - difference between the result and the actual value. relative error is the difference between the result and the actual value relative to the size of the result. Tolerance property - specify trade-off between accuracy and execution time. The lower the tolerance, the longer it will take for the algorithm to obtain a result within that tolerance. Most algorithms in the EO NumLib have a default value of MachineConstants.SqrtEpsilon - gives slightly less than 8 digits of accuracy. ConvergenceCriterion property - specify under what condition the algorithm is assumed to converge. Using the ConvergenceCriterion enum: WithinAbsoluteTolerance / WithinRelativeTolerance / WithinAnyTolerance / NumberOfIterations Active property - selectively ignore certain convergence tests Error property - returns the estimated error after a run MaxIterations / MaxEvaluations properties - Other Termination Criteria - If the algorithm cannot achieve the desired accuracy, the algorithm still has to end – according to an absolute boundary. Status property - indicates how the algorithm terminated - the AlgorithmStatus enum values:NoResult / Busy / Converged (ended normally - The desired accuracy has been achieved) / IterationLimitExceeded / EvaluationLimitExceeded / RoundOffError / BadFunction / Divergent / ConvergedToFalseSolution. After the iteration terminates, the Status should be inspected to verify that the algorithm terminated normally. Alternatively, you can set the ThrowExceptionOnFailure to true. Result property - returns the result of the algorithm. This property contains the best available estimate, even if the desired accuracy was not obtained. IterationsNeeded / EvaluationsNeeded properties - returns the number of iterations required to obtain the result, number of function evaluations.  Concrete Types of Convergence Test classes SimpleConvergenceTest class - test if a value is close to zero or very small compared to another value. VectorConvergenceTest class - test convergence of vectors. This class has two additional properties. The Norm property specifies which norm is to be used when calculating the size of the vector - the VectorConvergenceNorm enum values: EuclidianNorm / Maximum / SumOfAbsoluteValues. The ErrorMeasure property specifies how the error is to be measured – VectorConvergenceErrorMeasure enum values: Norm / Componentwise ConvergenceTestCollection class - represent a combination of tests. The Quantifier property is a ConvergenceTestQuantifier enum that specifies how the tests in the collection are to be combined: Any / All  The AlgorithmHelper Class inherits from IterativeAlgorithm<T> and exposes two methods for convergence testing. IsValueWithinTolerance<T> method - determines whether a value is close to another value to within an algorithm's requested tolerance. IsIntervalWithinTolerance<T> method - determines whether an interval is within an algorithm's requested tolerance.

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  • Limit the amount a camera can pitch

    - by ChocoMan
    I'm having problems trying to limit the range my camera can pitch. Currently my camera can pitch around a model without restriction, but having a hard time trying to find the value of the degree/radian the camera is currently at after pitching. Here is what I got so far: // Moves camera with thumbstick Pitch = pController.ThumbSticks.Right.Y * MathHelper.ToRadians(speedAngleMAX); // Pitch Camera around model public void cameraPitch(float pitch) { pitchAngle = ModelLoad.camTarget - ModelLoad.CameraPos; axisPitch = Vector3.Cross(Vector3.Up, pitchAngle); // pitch constrained to model's orientation axisPitch.Normalize(); ModelLoad.CameraPos = Vector3.Transform(ModelLoad.CameraPos - ModelLoad.camTarget, Matrix.CreateFromAxisAngle(axisPitch, pitch)) + ModelLoad.camTarget; } I've tried restraining the Y-camera position of ModelLoad.CameraPos.Y, but doing so gave me some unwanted results.

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  • Literature for Inverse Kinematics: Joint Limits and beyond

    - by Jeff
    Recently I've been playing around with Inverse Kinematics and have been pretty impressed with the results. Naturally I want to take it further, but have no clue where to start. In particular, I would like to introduce joint limits (ie for a prismatic joint how far it can move, hinge joint what angles it has to be between, etc etc). Currently I understand how to produce the Jacobian matrix for the various joint types. I am particularly looking for literature (preferably free, and preferably easy to understand) on various ways to implement joint limits. Also I would like to find out different ideas on how inverse kinematics can be used.

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  • Simple iOS glDrawElements - BAD_ACCESS

    - by user699215
    You can copy paste this into the default OpenGl template created in Xcode. Why am I not seeing anything :-) It is strange as the glDrawArrays(GL_TRIANGLES, 0, 3); is working fine, but with glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, indices); Is giving BAD_ACCESS? Copy paste this into Xcode default OpenGl template: ViewController #import "ViewController.h" #define BUFFER_OFFSET(i) ((char *)NULL + (i)) // Uniform index. enum { UNIFORM_MODELVIEWPROJECTION_MATRIX, UNIFORM_NORMAL_MATRIX, NUM_UNIFORMS }; GLint uniforms[NUM_UNIFORMS]; // Attribute index. enum { ATTRIB_VERTEX, ATTRIB_NORMAL, NUM_ATTRIBUTES }; @interface ViewController () { GLKMatrix4 _modelViewProjectionMatrix; GLKMatrix3 _normalMatrix; float _rotation; GLuint _vertexArray; GLuint _vertexBuffer; NSArray* arrayOfVertex; } @property (strong, nonatomic) EAGLContext *context; @property (strong, nonatomic) GLKBaseEffect *effect; - (void)setupGL; - (void)tearDownGL; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; GLKView *view = (GLKView *)self.view; view.context = self.context; view.drawableDepthFormat = GLKViewDrawableDepthFormat24; [self setupGL]; } - (void)dealloc { [self tearDownGL]; if ([EAGLContext currentContext] == self.context) { [EAGLContext setCurrentContext:nil]; } } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; if ([self isViewLoaded] && ([[self view] window] == nil)) { self.view = nil; [self tearDownGL]; if ([EAGLContext currentContext] == self.context) { [EAGLContext setCurrentContext:nil]; } self.context = nil; } // Dispose of any resources that can be recreated. } GLuint vertexBufferID; GLuint indexBufferID; static const GLfloat vertices[9] = { -0.5, -0.5, 0.5, 0.5, -0.5, 0.5, -0.5, 0.5, 0.5 }; static const GLubyte indices[3] = { 0, 1, 2 }; - (void)setupGL { [EAGLContext setCurrentContext:self.context]; // [self loadShaders]; self.effect = [[GLKBaseEffect alloc] init]; self.effect.light0.enabled = GL_TRUE; self.effect.light0.diffuseColor = GLKVector4Make(1.0f, 0.4f, 0.4f, 1.0f); glEnable(GL_DEPTH_TEST); // glGenVertexArraysOES(1, &_vertexArray); // glBindVertexArrayOES(_vertexArray); glGenBuffers(1, &vertexBufferID); glBindBuffer(GL_ARRAY_BUFFER, vertexBufferID); glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); glGenBuffers(1, &indexBufferID); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBufferID); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW); glEnableVertexAttribArray(GLKVertexAttribPosition); glVertexAttribPointer(GLKVertexAttribPosition, // Specifies the index of the generic vertex attribute to be modified. 3, // Specifies the number of components per generic vertex attribute. Must be 1, 2, 3, 4. GL_FLOAT, // GL_FALSE, // 0, // BUFFER_OFFSET(0)); // // glBindVertexArrayOES(0); } - (void)tearDownGL { [EAGLContext setCurrentContext:self.context]; glDeleteBuffers(1, &_vertexBuffer); glDeleteVertexArraysOES(1, &_vertexArray); self.effect = nil; } #pragma mark - GLKView and GLKViewController delegate methods - (void)update { float aspect = fabsf(self.view.bounds.size.width / self.view.bounds.size.height); GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 0.1f, 100.0f); self.effect.transform.projectionMatrix = projectionMatrix; GLKMatrix4 baseModelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -4.0f); baseModelViewMatrix = GLKMatrix4Rotate(baseModelViewMatrix, _rotation, 0.0f, 1.0f, 0.0f); // Compute the model view matrix for the object rendered with GLKit GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -1.5f); modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f); modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix); self.effect.transform.modelviewMatrix = modelViewMatrix; // Compute the model view matrix for the object rendered with ES2 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 1.5f); modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f); modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix); _normalMatrix = GLKMatrix3InvertAndTranspose(GLKMatrix4GetMatrix3(modelViewMatrix), NULL); _modelViewProjectionMatrix = GLKMatrix4Multiply(projectionMatrix, modelViewMatrix); _rotation += self.timeSinceLastUpdate * 0.5f; } int i; - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect { glClearColor(0.65f, 0.65f, 0.65f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // glBindVertexArrayOES(_vertexArray); // Render the object with GLKit [self.effect prepareToDraw]; //glDrawArrays(GL_TRIANGLES, 0, 3); // Render the object again with ES2 // glDrawArrays(GL_TRIANGLES, 0, 3); glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, indices); } @end

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  • Problem using glm::lookat

    - by omikun
    I am trying to rotate a sprite so it is always facing a 3D camera. Object GLfloat vertexData[] = { // X Y Z U V 0.0f, 0.8f, 0.0f, 0.5f, 1.0f, -0.8f,-0.8f, 0.0f, 0.0f, 0.0f, 0.8f,-0.8f, 0.0f, 1.0f, 0.0f, }; Per frame transform glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), gCamera.up()); shaders->setUniform("camera", gCamera.matrix()); shaders->setUniform("model", newTransform); In the vertex shader: gl_Position = camera * model * vec4(vert, 1); The object will track the camera if I move the camera up or down, but if I move the camera left/right (spin the camera around the object's y axis), it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360. If I use -gCamera.up() instead, it would track the camera side to side, but spin the opposite direction when I move the camera up/down. What am I doing wrong?

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  • For normal mapping, why can we not simply add the tangent normal to the surface normal?

    - by sebf
    I am looking at implementing bump mapping (which in all implementations I have seen is really normal mapping), and so far all I have read says that to do this, we create a matrix to convert from world-space to tangent-space, in order to transform the lights and eye direction vectors into tangent space, so that the vectors from the normal map may be used directly in place of those passed through from the vertex shader. What I do not understand though, is why we cannot just use the normalised sum of the sampled-normal vector, and the surface-normal? (assuming we already transform and pass through the surface normal for the existing lighting functions) Take the diagram below; the normal is simply the deviation from the 'reference normal' for any given coordinate system, correct? And transforming the surface normal of a mapped surface from world space to tangent space makes it equivalent to the tangent space 'reference normal', no? If so, why do we transform all lighting vectors into tangent space, instead of simply transforming the sampled tangent once in the pixel shader?

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  • Raycasting mouse coordinates to rotated object?

    - by SPL
    I am trying to cast a ray from my mouse to a plane at a specified position with a known width and length and height. I know that you can use the NDC (Normalized Device Coordinates) to cast ray but I don't know how can I detect if the ray actually hit the plane and when it did. The plane is translated -100 on the Y and rotated 60 on the X then translated again -100. Can anyone please give me a good tutorial on this? For a complete noob! I am almost new to matrix and vector transformations.

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  • Lighting get darker when texture is aplied

    - by noah
    Im using OpenGL ES 1.1 for iPhone. I'm attempting to implement a skybox in my 3d world and started out by following one of Jeff Lamarches tutorials on creating textures. Heres the tutorial: iphonedevelopment.blogspot.com/2009/05/opengl-es-from-ground-up-part-6_25.html Ive successfully added the image to my 3d world but am not sure why the lighting on the other shapes has changed so much. I want the shapes to be the original color and have the image in the background. Before: https://www.dropbox.com/s/ojmb8793vj514h0/Screen%20Shot%202012-10-01%20at%205.34.44%20PM.png After: https://www.dropbox.com/s/8v6yvur8amgudia/Screen%20Shot%202012-10-01%20at%205.35.31%20PM.png Heres the init OpenGL: - (void)initOpenGLES1 { glShadeModel(GL_SMOOTH); // Enable lighting glEnable(GL_LIGHTING); // Turn the first light on glEnable(GL_LIGHT0); const GLfloat lightAmbient[] = {0.2, 0.2, 0.2, 1.0}; const GLfloat lightDiffuse[] = {0.8, 0.8, 0.8, 1.0}; const GLfloat matAmbient[] = {0.3, 0.3, 0.3, 0.5}; const GLfloat matDiffuse[] = {1.0, 1.0, 1.0, 1.0}; const GLfloat matSpecular[] = {1.0, 1.0, 1.0, 1.0}; const GLfloat lightPosition[] = {0.0, 0.0, 1.0, 0.0}; const GLfloat lightShininess = 100.0; //Configure OpenGL lighting glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmbient); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiffuse); glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, matSpecular); glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, lightShininess); glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient); glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse); glLightfv(GL_LIGHT0, GL_POSITION, lightPosition); // Define a cutoff angle glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 40.0); // Set the clear color glClearColor(0, 0, 0, 1.0f); // Projection Matrix config glMatrixMode(GL_PROJECTION); glLoadIdentity(); CGSize layerSize = self.view.layer.frame.size; // Swapped height and width for landscape mode gluPerspective(45.0f, (GLfloat)layerSize.height / (GLfloat)layerSize.width, 0.1f, 750.0f); [self initSkyBox]; // Modelview Matrix config glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // This next line is not really needed as it is the default for OpenGL ES glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glDisable(GL_BLEND); // Enable depth testing glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LESS); glDepthMask(GL_TRUE); } Heres the drawSkybox that gets called in the drawFrame method: -(void)drawSkyBox { glDisable(GL_LIGHTING); glDisable(GL_DEPTH_TEST); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_NORMAL_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); static const SSVertex3D vertices[] = { {-1.0, 1.0, -0.0}, { 1.0, 1.0, -0.0}, {-1.0, -1.0, -0.0}, { 1.0, -1.0, -0.0} }; static const SSVertex3D normals[] = { {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0} }; static const GLfloat texCoords[] = { 0.0, 0.5, 0.5, 0.5, 0.0, 0.0, 0.5, 0.0 }; glLoadIdentity(); glTranslatef(0.0, 0.0, -3.0); glBindTexture(GL_TEXTURE_2D, texture[0]); glVertexPointer(3, GL_FLOAT, 0, vertices); glNormalPointer(GL_FLOAT, 0, normals); glTexCoordPointer(2, GL_FLOAT, 0, texCoords); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDisableClientState(GL_VERTEX_ARRAY); glDisableClientState(GL_NORMAL_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glEnable(GL_LIGHTING); glEnable(GL_DEPTH_TEST); } Heres the init Skybox: -(void)initSkyBox { // Turn necessary features on glEnable(GL_TEXTURE_2D); glEnable(GL_BLEND); glBlendFunc(GL_ONE, GL_SRC_COLOR); // Bind the number of textures we need, in this case one. glGenTextures(1, &texture[0]); // create a texture obj, give unique ID glBindTexture(GL_TEXTURE_2D, texture[0]); // load our new texture name into the current texture glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); NSString *path = [[NSBundle mainBundle] pathForResource:@"space" ofType:@"jpg"]; NSData *texData = [[NSData alloc] initWithContentsOfFile:path]; UIImage *image = [[UIImage alloc] initWithData:texData]; GLuint width = CGImageGetWidth(image.CGImage); GLuint height = CGImageGetHeight(image.CGImage); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); void *imageData = malloc( height * width * 4 ); // times 4 because will write one byte for rgb and alpha CGContextRef cgContext = CGBitmapContextCreate( imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big ); // Flip the Y-axis CGContextTranslateCTM (cgContext, 0, height); CGContextScaleCTM (cgContext, 1.0, -1.0); CGColorSpaceRelease( colorSpace ); CGContextClearRect( cgContext, CGRectMake( 0, 0, width, height ) ); CGContextDrawImage( cgContext, CGRectMake( 0, 0, width, height ), image.CGImage ); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData); CGContextRelease(cgContext); free(imageData); [image release]; [texData release]; } Any help is greatly appreciated.

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  • Webcast: Applications Integration Architecture

    - by LuciaC
    Webcast: Applications Integration Architecture - Overview and Best Practices Date:  November 12, 2013.Join us for an Overview and Best Practices live webcast on Applications Integration Architecture (AIA). We are covering following topics in this Webcast : AIA Overview AIA - Where it Stands Pre-Install, Pre-Upgrade Concerns Understanding Dependency Certification Matrix Documentation Information Center Demonstration - How to evaluate certified combination Software Download/Installable Demonstration - edelivery Download Overview Reference Information Q & A (15 Minutes)  We will be holding 2 separate sessions to accommodate different timezones: EMEA / APAC - timezone Session : Tuesday, 12-NOV-2013 at 09:00 UK / 10:00 CET / 14:30 India / 18:00 Japan / 20:00 AEDT Details & Registration : Doc ID 1590146.1 Direct registration link USA - timezone Session : Wednesday, 13-NOV-2013 at 18:00 UK / 19:00 CET / 10:00 PST / 11:00 MST / 13:00 EST Details & Registration : Doc ID 1590147.1 Direct registration link If you have any question about the schedules or if you have a suggestion for an Advisor Webcast to be planned in future, please send an E-Mail to Ruediger Ziegler. Remember that you can access a full listing of all future webcasts as well as replays from Doc ID 740966.1.

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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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  • Nothing drawing on screen OpenGL with GLSL

    - by codemonkey
    I hate to be asking this kind of question here, but I am at a complete loss as to what is going wrong, so please bear with me. I am trying to render a single cube (voxel) in the center of the screen, through OpenGL with GLSL on Mac I begin by setting up everything using glut glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGBA|GLUT_ALPHA|GLUT_DOUBLE|GLUT_DEPTH); glutInitWindowSize(DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT); glutCreateWindow("Cubez-OSX"); glutReshapeFunc(reshape); glutDisplayFunc(render); glutIdleFunc(idle); _electricSheepEngine=new ElectricSheepEngine(DEFAULT_WINDOW_WIDTH, DEFAULT_WINDOW_HEIGHT); _electricSheepEngine->initWorld(); glutMainLoop(); Then inside the engine init camera & projection matrices: cameraPosition=glm::vec3(2,2,2); cameraTarget=glm::vec3(0,0,0); cameraUp=glm::vec3(0,0,1); glm::vec3 cameraDirection=glm::normalize(cameraPosition-cameraTarget); cameraRight=glm::cross(cameraDirection, cameraUp); cameraRight.z=0; view=glm::lookAt(cameraPosition, cameraTarget, cameraUp); lensAngle=45.0f; aspectRatio=1.0*(windowWidth/windowHeight); nearClippingPlane=0.1f; farClippingPlane=100.0f; projection=glm::perspective(lensAngle, aspectRatio, nearClippingPlane, farClippingPlane); then init shaders and check compilation and bound attributes & uniforms to be correctly bound (my previous question) These are my two shaders, vertex: #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; gl_Position = mvp * vec4(position, 1.0); } and fragment: #version 120 varying vec3 fragColor; void main(void) { gl_FragColor = vec4(fragColor,1.0); } init the cube: setPosition(glm::vec3(0,0,0)); struct voxelData data[]={ //front face {{-1.0, -1.0, 1.0}, {0.0, 0.0, 1.0}}, {{ 1.0, -1.0, 1.0}, {0.0, 1.0, 1.0}}, {{ 1.0, 1.0, 1.0}, {0.0, 0.0, 1.0}}, {{-1.0, 1.0, 1.0}, {0.0, 1.0, 1.0}}, //back face {{-1.0, -1.0, -1.0}, {0.0, 0.0, 1.0}}, {{ 1.0, -1.0, -1.0}, {0.0, 1.0, 1.0}}, {{ 1.0, 1.0, -1.0}, {0.0, 0.0, 1.0}}, {{-1.0, 1.0, -1.0}, {0.0, 1.0, 1.0}} }; glGenBuffers(1, &modelVerticesBufferObject); glBindBuffer(GL_ARRAY_BUFFER, modelVerticesBufferObject); glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER, 0); const GLubyte indices[] = { // Front 0, 1, 2, 2, 3, 0, // Back 4, 6, 5, 4, 7, 6, // Left 2, 7, 3, 7, 6, 2, // Right 0, 4, 1, 4, 1, 5, // Top 6, 2, 1, 1, 6, 5, // Bottom 0, 3, 7, 0, 7, 4 }; glGenBuffers(1, &modelFacesBufferObject); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, modelFacesBufferObject); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0); and then the render call: glClearColor(0.52, 0.8, 0.97, 1.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); //use the shader glUseProgram(shaderProgram); //enable attributes in program glEnableVertexAttribArray(shaderAttribute_position); glEnableVertexAttribArray(shaderAttribute_color); //model matrix using model position vector glm::mat4 mvp=projection*view*voxel->getModelMatrix(); glUniformMatrix4fv(shaderAttribute_mvp, 1, GL_FALSE, glm::value_ptr(mvp)); glBindBuffer(GL_ARRAY_BUFFER, voxel->modelVerticesBufferObject); glVertexAttribPointer(shaderAttribute_position, // attribute 3, // number of elements per vertex, here (x,y) GL_FLOAT, // the type of each element GL_FALSE, // take our values as-is sizeof(struct voxelData), // coord every (sizeof) elements 0 // offset of first element ); glBindBuffer(GL_ARRAY_BUFFER, voxel->modelVerticesBufferObject); glVertexAttribPointer(shaderAttribute_color, // attribute 3, // number of colour elements per vertex, here (x,y) GL_FLOAT, // the type of each element GL_FALSE, // take our values as-is sizeof(struct voxelData), // coord every (sizeof) elements (GLvoid *)(offsetof(struct voxelData, color3D)) // offset of colour data ); //draw the model by going through its elements array glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, voxel->modelFacesBufferObject); int bufferSize; glGetBufferParameteriv(GL_ELEMENT_ARRAY_BUFFER, GL_BUFFER_SIZE, &bufferSize); glDrawElements(GL_TRIANGLES, bufferSize/sizeof(GLushort), GL_UNSIGNED_SHORT, 0); //close up the attribute in program, no more need glDisableVertexAttribArray(shaderAttribute_position); glDisableVertexAttribArray(shaderAttribute_color); but on screen all I get is the clear color :$ I generate my model matrix using: modelMatrix=glm::translate(glm::mat4(1.0), position); which in debug turns out to be for the position of (0,0,0): |1, 0, 0, 0| |0, 1, 0, 0| |0, 0, 1, 0| |0, 0, 0, 1| Sorry for such a question, I know it is annoying to look at someone's code, but I promise I have tried to debug around and figure it out as much as I can, and can't come to a solution Help a noob please? EDIT: Full source here, if anyone wants

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  • Opposite Force to Apply to a Collided Rigid Body?

    - by Milo
    I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the force to apply to a body after it collides with a wall. My rigid body looks like this: /our simulation object class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; private Vector2D v = new Vector2D(); //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; private Matrix mat = new Matrix(); private float[] Vector2Ds = new float[2]; private Vector2D tangent = new Vector2D(); private static Vector2D worldRelVec = new Vector2D(); private static Vector2D relWorldVec = new Vector2D(); private static Vector2D pointVelVec = new Vector2D(); private static Vector2D acceleration = new Vector2D(); public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; setLayer(LAYER_OBJECTS); } protected void rectChanged() { if(getWorld() != null) { getWorld().updateDynamic(this); } } //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.x,position.y, getWidth(), getHeight(), angle); rectChanged(); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { doUpdate(timeStep); } public void doUpdate(float timeStep) { //integrate physics //linear acceleration.x = forces.x / mass; acceleration.y = forces.y / mass; velocity.x += (acceleration.x * timeStep); velocity.y += (acceleration.y * timeStep); //velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); v.x = getRect().getCenter().getX() + (velocity.x * timeStep); v.y = getRect().getCenter().getY() + (velocity.y * timeStep); setCenter(v.x, v.y); forces.x = 0; //clear forces forces.y = 0; //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) { mat.reset(); Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); relWorldVec.x = Vector2Ds[0]; relWorldVec.y = Vector2Ds[1]; return relWorldVec; } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { mat.reset(); Vector2Ds[0] = world.x; Vector2Ds[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vector2Ds); worldRelVec.x = Vector2Ds[0]; worldRelVec.y = Vector2Ds[1]; return worldRelVec; } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { tangent.x = -worldOffset.y; tangent.y = worldOffset.x; pointVelVec.x = (tangent.x * angularVelocity) + velocity.x; pointVelVec.y = (tangent.y * angularVelocity) + velocity.y; return pointVelVec; } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces.x += worldForce.x; forces.y += worldForce.y; //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } public Vector2D getVelocity() { return velocity; } public void setVelocity(Vector2D velocity) { this.velocity = velocity; } } The way it is given force is by the applyForce method, this method considers angular torque. I'm just not sure how to come up with the vectors in the case where: RigidBody hits static entity RigidBody hits other RigidBody that may or may not be in motion. Would anyone know a way (without too complex math) that I could figure out the opposite force I need to apply to the car? I know the normal it is colliding with and how deep it collided. My main goal is so that say I hit a building from the side, well the car should not just stay there, it should slowly rotate out of it if I'm more than 45 degrees. Right now when I hit a wall I only change the velocity directly which does not consider angular force. Thanks!

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  • Texture and Lighting Issue in 3D world

    - by noah
    Im using OpenGL ES 1.1 for iPhone. I'm attempting to implement a skybox in my 3d world and started out by following one of Jeff Lamarches tutorials on creating textures. Heres the tutorial: iphonedevelopment.blogspot.com/2009/05/opengl-es-from-ground-up-part-6_25.html Ive successfully added the image to my 3d world but am not sure why the lighting on the other shapes has changed so much. I want the shapes to be the original color and have the image in the background. Before: https://www.dropbox.com/s/ojmb8793vj514h0/Screen%20Shot%202012-10-01%20at%205.34.44%20PM.png After: https://www.dropbox.com/s/8v6yvur8amgudia/Screen%20Shot%202012-10-01%20at%205.35.31%20PM.png Heres the init OpenGL: - (void)initOpenGLES1 { glShadeModel(GL_SMOOTH); // Enable lighting glEnable(GL_LIGHTING); // Turn the first light on glEnable(GL_LIGHT0); const GLfloat lightAmbient[] = {0.2, 0.2, 0.2, 1.0}; const GLfloat lightDiffuse[] = {0.8, 0.8, 0.8, 1.0}; const GLfloat matAmbient[] = {0.3, 0.3, 0.3, 0.5}; const GLfloat matDiffuse[] = {1.0, 1.0, 1.0, 1.0}; const GLfloat matSpecular[] = {1.0, 1.0, 1.0, 1.0}; const GLfloat lightPosition[] = {0.0, 0.0, 1.0, 0.0}; const GLfloat lightShininess = 100.0; //Configure OpenGL lighting glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmbient); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiffuse); glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, matSpecular); glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, lightShininess); glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient); glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse); glLightfv(GL_LIGHT0, GL_POSITION, lightPosition); // Define a cutoff angle glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 40.0); // Set the clear color glClearColor(0, 0, 0, 1.0f); // Projection Matrix config glMatrixMode(GL_PROJECTION); glLoadIdentity(); CGSize layerSize = self.view.layer.frame.size; // Swapped height and width for landscape mode gluPerspective(45.0f, (GLfloat)layerSize.height / (GLfloat)layerSize.width, 0.1f, 750.0f); [self initSkyBox]; // Modelview Matrix config glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // This next line is not really needed as it is the default for OpenGL ES glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glDisable(GL_BLEND); // Enable depth testing glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LESS); glDepthMask(GL_TRUE); } Heres the drawSkybox that gets called in the drawFrame method: -(void)drawSkyBox { glDisable(GL_LIGHTING); glDisable(GL_DEPTH_TEST); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_NORMAL_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); static const SSVertex3D vertices[] = { {-1.0, 1.0, -0.0}, { 1.0, 1.0, -0.0}, {-1.0, -1.0, -0.0}, { 1.0, -1.0, -0.0} }; static const SSVertex3D normals[] = { {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0}, {0.0, 0.0, 1.0} }; static const GLfloat texCoords[] = { 0.0, 0.5, 0.5, 0.5, 0.0, 0.0, 0.5, 0.0 }; glLoadIdentity(); glTranslatef(0.0, 0.0, -3.0); glBindTexture(GL_TEXTURE_2D, texture[0]); glVertexPointer(3, GL_FLOAT, 0, vertices); glNormalPointer(GL_FLOAT, 0, normals); glTexCoordPointer(2, GL_FLOAT, 0, texCoords); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDisableClientState(GL_VERTEX_ARRAY); glDisableClientState(GL_NORMAL_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glEnable(GL_LIGHTING); glEnable(GL_DEPTH_TEST); } Heres the init Skybox: -(void)initSkyBox { // Turn necessary features on glEnable(GL_TEXTURE_2D); glEnable(GL_BLEND); glBlendFunc(GL_ONE, GL_SRC_COLOR); // Bind the number of textures we need, in this case one. glGenTextures(1, &texture[0]); // create a texture obj, give unique ID glBindTexture(GL_TEXTURE_2D, texture[0]); // load our new texture name into the current texture glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); NSString *path = [[NSBundle mainBundle] pathForResource:@"space" ofType:@"jpg"]; NSData *texData = [[NSData alloc] initWithContentsOfFile:path]; UIImage *image = [[UIImage alloc] initWithData:texData]; GLuint width = CGImageGetWidth(image.CGImage); GLuint height = CGImageGetHeight(image.CGImage); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); void *imageData = malloc( height * width * 4 ); // times 4 because will write one byte for rgb and alpha CGContextRef cgContext = CGBitmapContextCreate( imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big ); // Flip the Y-axis CGContextTranslateCTM (cgContext, 0, height); CGContextScaleCTM (cgContext, 1.0, -1.0); CGColorSpaceRelease( colorSpace ); CGContextClearRect( cgContext, CGRectMake( 0, 0, width, height ) ); CGContextDrawImage( cgContext, CGRectMake( 0, 0, width, height ), image.CGImage ); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData); CGContextRelease(cgContext); free(imageData); [image release]; [texData release]; } Any help is greatly appreciated.

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  • Translate extrinsic rotations to intrinsic rotations ( Euler angles )

    - by MineMan287
    The problem I have is very frustrating: I am using the Jitter Physics library which gives Quaternion rotations, you can extract the extrinsic rotations but I need intrinsic rotations to rotate in OpenTK (There are other reasons as well so I don't want to make OpenTK use a Matrix) GL.Rotate(xr, 1, 0, 0) GL.Rotate(yr, 0, 1, 0) GL.Rotate(zr, 0, 0, 1) EDIT : Response to the first answer Like This? GL.Rotate(zr, 0, 0, 1) GL.Rotate(yr, 0, 1, 0) GL.Rotate(xr, 1, 0, 0) Or This? GL.Rotate(xr, 1, 0, 0) GL.Rotate(yr, 0, 1, 0) GL.Rotate(zr, 0, 0, 1) GL.Rotate(zr, 0, 0, 1) GL.Rotate(yr, 0, 1, 0) GL.Rotate(xr, 1, 0, 0) GL.Rotate(xr, 1, 0, 0) GL.Rotate(yr, 0, 1, 0) GL.Rotate(zr, 0, 0, 1) I'm confused, please give an example

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  • Distance between two 3D objects' faces

    - by Arthur Gibraltar
    I'm really newbie on programming and I'm making some tests. I couldn't find nowhere on Internet how could I calculate the distance between two 3D objects' faces. Is there anyway? Detailing, as an example, I have two 3D cubes. Each one has a vector3 position designating it's center on the 3D space and an orientation matrix. And each cube has a size (float width, float height and float length). I could get a simple distance between them by calling Vector3.Distance(), but it doesn't consider its sizes, just the position. Then the distance would be between its centers. Is there any way to calculate the distance between the faces? Thanks for any reply.

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  • Help to understand the abstract factory pattern

    - by Chobeat
    I'm learning the 23 design patterns of the GoF. I think I've found a way to understand and simplify how the Abstract Factory works but I would like to know if this is a correct assumption or if I am wrong. What I want to know is if we can see the result of the Abstract Factory method as a matrix of possible products where there's a Product for every "Concrete Factory" x "AbstractProduct" where the Concrete Factory is a single implementation among the implementations of an AbstractFactory and an AbstractProduct is an interface among the interfaces to create Products. Is this correct or am I missing something?

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