Advertisement Jump to content
  • Advertisement


  • Content Count

  • Joined

  • Last visited

Community Reputation

100 Neutral

About AnujKalia

  • Rank
  1. Hi all! We've implemented a hybrid shadow algorithm where shadow mapping gives us some boundary pixels which need to be further checked. One of the ways to check whether this boundary pixel is in shadow (or not) is to shoot a ray towards the light and check for intersection with the scene's triangles. Currently, we're thinking of storing the scene in an octree (in the texture memory of the GPU). Then shoot rays from every pixel and check for intersection by traversing the octree in the fragment shader. Can you point me to some tutorials/papers regarding such intersection detection? I couldn't find much information about how the octree should be stored in the texture, and how the octree should be traversed inside the fragment shader etc..
  2. Best of luck to all appearing for JEE. Special wishes for my students at Vidyamandir. I'm already looking forward to seeing you people here!
  3. AnujKalia

    Shadow volume hybrid algorithm

    I found the solution. Its not OK.
  4. Hi all! We've implemented Eric Chan's hybrid algorithm for accurate shadows, and we're now taking another step. Our shadow volumes algorithm involves extruding silhouette edges in the Geometry Shader. The question I want to ask is this: Suppose in the Geometry Shader, we were able to check whether a silhouette edge is already in shadow (using, perhaps, the shadow map). Is it O.K to not extrude this silhouette edge? i.e. simply neglect the shadow planes that will be created when this edge is extruded? We're only dealing with watertight meshes, if that is relevant. We expect some performance gain if we can reject some edges inside the geometry shader, as that will reduce the fragment shader's load. Thanks for your help!
  5. connecting to Y U NO WORK?
  6. Hi! Does someone know where I can find good code for Shadow Volumes (Z-fail using a geometry shader)? Actually I have written some code for it and it would be good to have a reference to check for bugs etc.
  7. 8 years after playing Age of Mythology, I tried writing the game. You can download the it from: Unzip, run oalinst.exe, lower sound and then run anuj.exe. Press 's' for shadows, and 't' for using your gold.
  8. Hi! I am searching for some cool applications of shaders (openGL) for a 4-months long college project. We want to write shaders for certain graphics applications which people sometimes do on the CPU, but which perform better when done on the GPU using shaders. We have thought about the following 2 applications: 1)Shadow Voumes: create the shadow planes using the Geometry Shader. 2)Hardware Skinning/Animation: use vertex shaders to apply bone matrix transformations. Can some share more interesting applications of shaders (Vertex/Geometry/Fragment) which we can consider in our project? Thanks!
  9. AnujKalia

    Shadow mapping: Objects are textured

    Turns out the issue has been raised earlier at :
  10. I am using a shadow mapping code from Paul's Projects. It works fine for untextured objects but not for textured objects: #define WIN32_LEAN_AND_MEAN #include <Windows.h> #include <stdio.h> #include <gl/glew.h> #include <gl/glfw.h> #include <gl/GLU.h> #include "Maths/Maths.h" GLuint textureID; VECTOR3D cameraPosition(-2.5f, 3.5f,-2.5f); //Camera & light positions VECTOR3D lightPosition(2.0f, 3.0f,-2.0f); GLUquadricObj *quadric; const int shadowMapSize=600; //Size of shadow map GLuint shadowMapTexture; //Textures int windowWidth, windowHeight; //window size MATRIX4X4 lightProjectionMatrix, lightViewMatrix; //Matrices MATRIX4X4 cameraProjectionMatrix, cameraViewMatrix; void DrawScene(float angle) { //glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glBindTexture(GL_TEXTURE_2D,textureID); glPushMatrix(); glColor3f(.8,.8,.8); gluSphere(quadric,.5,50,50); glTranslatef(-1,-.6,.4); gluSphere(quadric,.5,50,50); glPopMatrix(); glPushMatrix(); glBegin(GL_POLYGON); glTexCoord2f(.5,.5); glVertex2f(.5,.5); glTexCoord2f(.5,-.5); glVertex2f(.5,-.5); glTexCoord2f(-.5,-.5); glVertex2f(-.5,-.5); glTexCoord2f(-.5,.5); glVertex2f(-.5,.5); glEnd(); glPopMatrix(); } bool Init(void) //Called for initiation { glMatrixMode(GL_MODELVIEW); //Load identity modelview glLoadIdentity(); glShadeModel(GL_SMOOTH); glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glColor4f(1.0f, 1.0f, 1.0f, 1.0f); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); //Depth states glClearDepth(1.0f); glDepthFunc(GL_LEQUAL); glEnable(GL_DEPTH_TEST); glEnable(GL_CULL_FACE); //We use glScale when drawing the scene glEnable(GL_NORMALIZE); //Create the shadow map texture glGenTextures(1, &shadowMapTexture); glBindTexture(GL_TEXTURE_2D, shadowMapTexture); glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, shadowMapSize, shadowMapSize, 0,GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); //Use the color as the ambient and diffuse material glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE); glEnable(GL_COLOR_MATERIAL); //White specular material color, shininess 16 glMaterialfv(GL_FRONT, GL_SPECULAR, white); glMaterialf(GL_FRONT, GL_SHININESS, 16.0f); //Calculate & save matrices glPushMatrix(); glLoadIdentity(); gluPerspective(45.0f, (float)windowWidth/windowHeight, 1.0f, 100.0f); glGetFloatv(GL_MODELVIEW_MATRIX, cameraProjectionMatrix); glLoadIdentity(); gluLookAt(cameraPosition.x, cameraPosition.y, cameraPosition.z,0.0f, 0.0f, 0.0f,0.0f, 1.0f, 0.0f); glGetFloatv(GL_MODELVIEW_MATRIX, cameraViewMatrix); glLoadIdentity(); gluPerspective(45.0f, 1.0f, 2.0f, 8.0f); glGetFloatv(GL_MODELVIEW_MATRIX, lightProjectionMatrix); glLoadIdentity(); gluLookAt(lightPosition.x, lightPosition.y, lightPosition.z,0.0f, 0.0f, 0.0f,0.0f, 1.0f, 0.0f); glGetFloatv(GL_MODELVIEW_MATRIX, lightViewMatrix); glPopMatrix(); glGenTextures(1,&textureID); // Generate and bind our texture ID printf("\n\ntextureID=%d\n",textureID); glBindTexture(GL_TEXTURE_2D,textureID); printf("check\n%d\n",glfwLoadTexture2D("ranger.tga",GLFW_BUILD_MIPMAPS_BIT|GLFW_ORIGIN_UL_BIT)); glTexParameteri( GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR ); // Use trilinear interpolation (GL_LINEAR_MIPMAP_LINEAR) glTexParameteri( GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR ); return true; } //Called to draw scene void Display(void) { printf("here"); //First pass - from light's point of view glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadMatrixf(lightProjectionMatrix); glMatrixMode(GL_MODELVIEW); glLoadMatrixf(lightViewMatrix); glViewport(0, 0, shadowMapSize, shadowMapSize); //Use viewport the same size as the shadow map glCullFace(GL_FRONT); //Draw back faces into the shadow map glShadeModel(GL_FLAT); //Disable color writes, and use flat shading for speed glColorMask(0, 0, 0, 0); DrawScene(0); //Draw the scene glBindTexture(GL_TEXTURE_2D, shadowMapTexture); //Read the depth buffer into the shadow map texture glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, shadowMapSize, shadowMapSize); //restore states glCullFace(GL_BACK); glShadeModel(GL_SMOOTH); glColorMask(1, 1, 1, 1); //2nd pass - Draw from camera's point of view glClear(GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadMatrixf(cameraProjectionMatrix); glMatrixMode(GL_MODELVIEW); glLoadMatrixf(cameraViewMatrix); glViewport(0, 0, windowWidth, windowHeight); glLightfv(GL_LIGHT1, GL_POSITION, VECTOR4D(lightPosition)); //Use dim light to represent shadowed areas glLightfv(GL_LIGHT1, GL_AMBIENT, white*0.2f); glLightfv(GL_LIGHT1, GL_DIFFUSE, white*0.2f); glLightfv(GL_LIGHT1, GL_SPECULAR, black); glEnable(GL_LIGHT1); glEnable(GL_LIGHTING); DrawScene(0); //3rd pass glLightfv(GL_LIGHT1, GL_DIFFUSE, white); //Draw with bright light glLightfv(GL_LIGHT1, GL_SPECULAR, white); //Calculate texture matrix for projection //This matrix takes us from eye space to the light's clip space //It is postmultiplied by the inverse of the current view matrix when specifying texgen static MATRIX4X4 biasMatrix(0.5f, 0.0f, 0.0f, 0.0f, 0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 0.0f, 0.5f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f); //bias from [-1, 1] to [0, 1] MATRIX4X4 textureMatrix=biasMatrix*lightProjectionMatrix*lightViewMatrix; //Set up texture coordinate generation. glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); glTexGenfv(GL_S, GL_EYE_PLANE, textureMatrix.GetRow(0)); glEnable(GL_TEXTURE_GEN_S); glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); glTexGenfv(GL_T, GL_EYE_PLANE, textureMatrix.GetRow(1)); glEnable(GL_TEXTURE_GEN_T); glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); glTexGenfv(GL_R, GL_EYE_PLANE, textureMatrix.GetRow(2)); glEnable(GL_TEXTURE_GEN_R); glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); glTexGenfv(GL_Q, GL_EYE_PLANE, textureMatrix.GetRow(3)); glEnable(GL_TEXTURE_GEN_Q); //Bind & enable shadow map texture glBindTexture(GL_TEXTURE_2D, shadowMapTexture); glEnable(GL_TEXTURE_2D); //Enable shadow comparison glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_COMPARE_R_TO_TEXTURE); //Shadow comparison should be true (ie not in shadow) if r<=texture glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB, GL_LEQUAL); //Shadow comparison should generate an INTENSITY result glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE_ARB, GL_INTENSITY); //Set alpha test to discard false comparisons glAlphaFunc(GL_GEQUAL, 0.99f); glEnable(GL_ALPHA_TEST); DrawScene(0); //Disable textures and texgen glDisable(GL_TEXTURE_2D); glDisable(GL_TEXTURE_GEN_S); glDisable(GL_TEXTURE_GEN_T); glDisable(GL_TEXTURE_GEN_R); glDisable(GL_TEXTURE_GEN_Q); //Restore other states glDisable(GL_LIGHTING); glDisable(GL_ALPHA_TEST); glfwSwapBuffers(); } //Called on window resize void Reshape(int w, int h) { windowWidth=w, windowHeight=h; glPushMatrix(); glLoadIdentity(); gluPerspective(45.0f, (float)windowWidth/windowHeight, 1.0f, 100.0f); glGetFloatv(GL_MODELVIEW_MATRIX, cameraProjectionMatrix); glPopMatrix(); } int main(int argc, char** argv) { glfwInit(); //start using glfw library glfwOpenWindowHint(GLFW_FSAA_SAMPLES,4); glfwOpenWindow(400,400,0,0,0,0,0,0,GLFW_WINDOW ); glfwSetWindowTitle( "anuj" ); Reshape(400,400); quadric = gluNewQuadric(); gluQuadricTexture(quadric,GL_TRUE); Init(); glewInit(); while(1) Display(); return 0; } I think the problem starts here when the program binds "shadowMapTexture" glBindTexture(GL_TEXTURE_2D, shadowMapTexture); glEnable(GL_TEXTURE_2D); However, the first line of my drawScene function binds it to a different texture: glBindTexture(GL_TEXTURE_2D,textureID); "textureID" is the texture I want to appear on my spheres. So, I can't use shadowMapTexture? Is there an alternative?
  11. Thanks for the suggestions GreyHound!
  12. It works like a charm with an nVidia card! Thanks Anshaman73! Still, any suggestions are welcome. I don't want to try and convert it to GLSL just now because I'm a little out of time! If someone wants to try it themselves, they can download the cal3D library from (cal3d-complete-0.10.0.tar.bz2)I'm running miniviewer_gl_vp from the examples folder. I guess you will need to build the cal3D libraries first.
  13. anything i can try to get it running on an ATI card? i'm going to try it on an nVidia card tonight but sadly i have to work on this ATI one!!!
  14. I ran the exe on 3 separate laptops, and found different results: ATI (1GB): no texture at all! ATI (512MB): bad texturing...can't describe how bad.. Intel Graphics (128MB): the texture appears perfectly! Could someone explain?
  15. Hi! Thanks for replying. You are right. Its a shader for hardware skinning that Cal3D provides as an example. But, I'm not using any fragment shader (is that a pixel shader?) and I'm expecting the default fragment shader to do its job. Also, I guess that the attributes are getting mapped correctly because the animation is working fine. Only the textures are not appearing! Here's some more code Creating the buffers: glGenBuffersARB(6, m_bufferObject); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[0]); glBufferDataARB(GL_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalVertexCount()*3*sizeof(float),(const void*)pVertexBuffer, GL_STATIC_DRAW_ARB); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[1]); glBufferDataARB(GL_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalVertexCount()*4*sizeof(float),(const void*)pWeightBuffer, GL_STATIC_DRAW_ARB); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[2]); glBufferDataARB(GL_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalVertexCount()*3*sizeof(float),(const void*)pNormalBuffer, GL_STATIC_DRAW_ARB); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[3]); glBufferDataARB(GL_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalVertexCount()*4*sizeof(float),(const void*)pMatrixIndexBuffer, GL_STATIC_DRAW_ARB); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[4]); glBufferDataARB(GL_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalVertexCount()*2*sizeof(float),(const void*)pTexCoordBuffer, GL_STATIC_DRAW_ARB); glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, m_bufferObject[5]); glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, m_calHardwareModel->getTotalFaceCount()*3*sizeof(CalIndex),(const void*)pIndexBuffer, GL_STATIC_DRAW_ARB); and here's the mapping: glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[0]); glVertexAttribPointerARB(0, 3 , GL_FLOAT, false, 0, NULL); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[1]); glVertexAttribPointerARB(1, 4 , GL_FLOAT, false, 0, NULL); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[2]); glVertexAttribPointerARB(2, 3 , GL_FLOAT, false, 0, NULL); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[3]); glVertexAttribPointerARB(3, 4 , GL_FLOAT, false, 0, NULL); glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_bufferObject[4]); glVertexAttribPointerARB(8, 2 , GL_FLOAT, false, 0, NULL); glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, m_bufferObject[5]);
  • Advertisement

Important Information

By using, you agree to our community Guidelines, Terms of Use, and Privacy Policy. is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!