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  • Efficient mapping layout in 2D side-scroller, and collisions between character and the world

    - by Jack
    I haven't touched Visual Studio for a couple months now, but I was playing a game from the '90s toady and had an epiphany: I was looking for something what i didn't need, and I wasn't using what I knew correctly. One of those realizations was collision, so let me tell you a bit about my project that I was working on. The project's graphics looks like Mario or Dangerous Dave, etc., you get the idea - old-school pixels. So anyway I remember trying to think of something else than AABB for character form, but I couldn't think of anything. Perhaps I could get a suggestion for this? Another thing is the world - I don't want it to be just linear world, I want mountains, etc.. My idea is to use triangles, and no idea yet what to do if I want just part of the cube, say 3/4 or 2/4 or whatever. Hard-coding such things seems inefficient. P.S. I am not looking at the precision level offered by Box2D. Actually I remember trying to implement it at first, but I failed as my understanding of C++ wasn't advanced enough, as it'll be mentioned below. P.P.S. I am programming in C++, and I haven't done it for a couple months now. I have no means of testing it either, as my PC is broken down, and this one can barely run games from late '90s, not to speak about a compiler or a program with inefficient resource management... I am also not an expert (obviously), I don't even know if I can consider myself an average programmer. In short, I am simply curious about my thoughts and my past experience when programming the game. I may come back to it when my PC is fixed, I'm already filling a note about these things.

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  • Seeking an C/C++ OBJ geometry read/write that does not modify the representation

    - by Blake Senftner
    I am seeking a means to read and write OBJ geometry files with logic that does not modify the geometry representation. i.e. read geometry, immediately write it, and a diff of the source OBJ and the one just written will be identical. Every OBJ writing utility I've been able to find online fails this test. I am writing small command line tools to modify my OBJ geometries, and I need to write my results, not just read the geometry for rendering purposes. Simply needing to write the geometry knocks out 95% of the OBJ libraries on the web. Also, many of the popular libraries modify the geometry representation. For example, Nat Robbin's GLUT library includes the GLM library, which both converts quads to triangles, as well as reverses the topology (face ordering) of the geometry. It's still the same geometry, but if your tool chain expects a given topology, such as for rigging or morph targets, then GLM is useless. I'm not rendering in these tools, so dependencies like OpenGL or GLUT make no sense. And god forbid, do not "optimize" the geometry! Redundant vertices are on purpose for maintaining oneself on cache with our weird little low memory mobile devices.

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  • OpenGL Tessellation makes point

    - by urza57
    A little problem with my tessellation shader. I try to implement a simple tessellation shader but it only makes points. Here's my vertex shader : out vec4 ecPosition; out vec3 ecNormal; void main( void ) { vec4 position = gl_Vertex; gl_Position = gl_ModelViewProjectionMatrix * position; ecPosition = gl_ModelViewMatrix * position; ecNormal = normalize(gl_NormalMatrix * gl_Normal); } My tessellation control shader : layout(vertices = 3) out; out vec4 ecPosition3[]; in vec3 ecNormal[]; in vec4 ecPosition[]; out vec3 myNormal[]; void main() { gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position; myNormal[gl_InvocationID] = ecNormal[gl_InvocationID]; ecPosition3[gl_InvocationID] = ecPosition[gl_InvocationID]; gl_TessLevelOuter[0] = float(4.0); gl_TessLevelOuter[1] = float(4.0); gl_TessLevelOuter[2] = float(4.0); gl_TessLevelInner[0] = float(4.0); } And my Tessellation Evaluation shader: layout(triangles, equal_spacing, ccw) in; in vec3 myNormal[]; in vec4 ecPosition3[]; out vec3 ecNormal; out vec4 ecPosition; void main() { float u = gl_TessCoord.x; float v = gl_TessCoord.y; float w = gl_TessCoord.z; vec3 position = vec4(gl_in[0].gl_Position.xyz * u + gl_in[1].gl_Position.xyz * v + gl_in[2].gl_Position.xyz * w ); vec3 position2 = vec4(ecPosition3[0].xyz * u + ecPosition3[1].xyz * v + ecPosition3[2].xyz * w ); vec3 normal = myNormal[0] * u + myNormal[1] * v + myNormal[2] * w ); ecNormal = normal; gl_Position = vec4(position, 1.0); ecPosition = vec4(position2, 1.0); } Thank you !

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  • Incomplete mesh using DrawIndexedPrimitives after rotating mesh

    - by user1278255
    Through help on this site I was able to draw the triangles of an unrotated, nonscaled nontransformed mesh created in Blender and exported to OBJ, accurately imported through Assimp and rendered in XNA Graphics. However after applying rotation on a single axis in Blender(Z) and adding materials(I wanted to test loading of materials through Assimp) the same mesh appears incomplete. Is something wrong with my view matrix or is it something else? This is what the unrotated mesh looks like: http://www.4shared.com/photo/qXNUSvxtba/okcube.html Here is the rotated mesh: http://www.4shared.com/photo/HAys2rWvba/badcube.html Camera, View and Projection are defined as follows: cameraPos = new Vector3(0, 5, 9); viewMatrix = Matrix.CreateLookAt(cameraPos, new Vector3(0, 0, 1), new Vector3(0, 1, 0)); projectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, device.Viewport.AspectRatio, 1.0f, 200.0f); Rendering is done through this code: device.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.DarkSlateBlue, 1.0f, 0); effect = new BasicEffect(GraphicsDevice); effect.VertexColorEnabled = true; effect.View = viewMatrix; effect.Projection = projectionMatrix; effect.World = Matrix.Identity; foreach (EffectPass pass in effect.CurrentTechnique.Passes) { pass.Apply(); device.SetVertexBuffer(vertexBuffer); device.Indices = indexBuffer; device.DrawIndexedPrimitives(Microsoft.Xna.Framework.Graphics.PrimitiveType.TriangleList, 0, 0, oScene.Meshes[0].VertexCount, 0, mMesh.FaceCount); } base.Draw(gameTime);

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  • Toon shader with Texture. Can this be optimized?

    - by Alex
    I am quite new to OpenGL, I have managed after long trial and error to integrate Nehe's Cel-Shading rendering with my Model loaders, and have them drawn using the Toon shade and outline AND their original texture at the same time. The result is actually a very nice Cel Shading effect of the model texture, but it is havling the speed of the program, it's quite very slow even with just 3 models on screen... Since the result was kind of hacked together, I am thinking that maybe I am performing some extra steps or extra rendering tasks that maybe are not needed, and are slowing down the game? Something unnecessary that maybe you guys could spot? Both MD2 and 3DS loader have an InitToon() function called upon creation to load the shader initToon(){ int i; // Looping Variable ( NEW ) char Line[255]; // Storage For 255 Characters ( NEW ) float shaderData[32][3]; // Storate For The 96 Shader Values ( NEW ) FILE *In = fopen ("Shader.txt", "r"); // Open The Shader File ( NEW ) if (In) // Check To See If The File Opened ( NEW ) { for (i = 0; i < 32; i++) // Loop Though The 32 Greyscale Values ( NEW ) { if (feof (In)) // Check For The End Of The File ( NEW ) break; fgets (Line, 255, In); // Get The Current Line ( NEW ) shaderData[i][0] = shaderData[i][1] = shaderData[i][2] = float(atof (Line)); // Copy Over The Value ( NEW ) } fclose (In); // Close The File ( NEW ) } else return false; // It Went Horribly Horribly Wrong ( NEW ) glGenTextures (1, &shaderTexture[0]); // Get A Free Texture ID ( NEW ) glBindTexture (GL_TEXTURE_1D, shaderTexture[0]); // Bind This Texture. From Now On It Will Be 1D ( NEW ) // For Crying Out Loud Don't Let OpenGL Use Bi/Trilinear Filtering! ( NEW ) glTexParameteri (GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri (GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage1D (GL_TEXTURE_1D, 0, GL_RGB, 32, 0, GL_RGB , GL_FLOAT, shaderData); // Upload ( NEW ) } This is the drawing for the animated MD2 model: void MD2Model::drawToon() { float outlineWidth = 3.0f; // Width Of The Lines ( NEW ) float outlineColor[3] = { 0.0f, 0.0f, 0.0f }; // Color Of The Lines ( NEW ) // ORIGINAL PART OF THE FUNCTION //Figure out the two frames between which we are interpolating int frameIndex1 = (int)(time * (endFrame - startFrame + 1)) + startFrame; if (frameIndex1 > endFrame) { frameIndex1 = startFrame; } int frameIndex2; if (frameIndex1 < endFrame) { frameIndex2 = frameIndex1 + 1; } else { frameIndex2 = startFrame; } MD2Frame* frame1 = frames + frameIndex1; MD2Frame* frame2 = frames + frameIndex2; //Figure out the fraction that we are between the two frames float frac = (time - (float)(frameIndex1 - startFrame) / (float)(endFrame - startFrame + 1)) * (endFrame - startFrame + 1); // I ADDED THESE FROM NEHE'S TUTORIAL FOR FIRST PASS (TOON SHADE) glHint (GL_LINE_SMOOTH_HINT, GL_NICEST); // Use The Good Calculations ( NEW ) glEnable (GL_LINE_SMOOTH); // Cel-Shading Code // glEnable (GL_TEXTURE_1D); // Enable 1D Texturing ( NEW ) glBindTexture (GL_TEXTURE_1D, shaderTexture[0]); // Bind Our Texture ( NEW ) glColor3f (1.0f, 1.0f, 1.0f); // Set The Color Of The Model ( NEW ) // ORIGINAL DRAWING CODE //Draw the model as an interpolation between the two frames glBegin(GL_TRIANGLES); for(int i = 0; i < numTriangles; i++) { MD2Triangle* triangle = triangles + i; for(int j = 0; j < 3; j++) { MD2Vertex* v1 = frame1->vertices + triangle->vertices[j]; MD2Vertex* v2 = frame2->vertices + triangle->vertices[j]; Vec3f pos = v1->pos * (1 - frac) + v2->pos * frac; Vec3f normal = v1->normal * (1 - frac) + v2->normal * frac; if (normal[0] == 0 && normal[1] == 0 && normal[2] == 0) { normal = Vec3f(0, 0, 1); } glNormal3f(normal[0], normal[1], normal[2]); MD2TexCoord* texCoord = texCoords + triangle->texCoords[j]; glTexCoord2f(texCoord->texCoordX, texCoord->texCoordY); glVertex3f(pos[0], pos[1], pos[2]); } } glEnd(); // ADDED THESE FROM NEHE'S FOR SECOND PASS (OUTLINE) glDisable (GL_TEXTURE_1D); // Disable 1D Textures ( NEW ) glEnable (GL_BLEND); // Enable Blending ( NEW ) glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA); // Set The Blend Mode ( NEW ) glPolygonMode (GL_BACK, GL_LINE); // Draw Backfacing Polygons As Wireframes ( NEW ) glLineWidth (outlineWidth); // Set The Line Width ( NEW ) glCullFace (GL_FRONT); // Don't Draw Any Front-Facing Polygons ( NEW ) glDepthFunc (GL_LEQUAL); // Change The Depth Mode ( NEW ) glColor3fv (&outlineColor[0]); // Set The Outline Color ( NEW ) // HERE I AM PARSING THE VERTICES AGAIN (NOT IN THE ORIGINAL FUNCTION) FOR THE OUTLINE AS PER NEHE'S TUT glBegin (GL_TRIANGLES); // Tell OpenGL What We Want To Draw for(int i = 0; i < numTriangles; i++) { MD2Triangle* triangle = triangles + i; for(int j = 0; j < 3; j++) { MD2Vertex* v1 = frame1->vertices + triangle->vertices[j]; MD2Vertex* v2 = frame2->vertices + triangle->vertices[j]; Vec3f pos = v1->pos * (1 - frac) + v2->pos * frac; Vec3f normal = v1->normal * (1 - frac) + v2->normal * frac; if (normal[0] == 0 && normal[1] == 0 && normal[2] == 0) { normal = Vec3f(0, 0, 1); } glNormal3f(normal[0], normal[1], normal[2]); MD2TexCoord* texCoord = texCoords + triangle->texCoords[j]; glTexCoord2f(texCoord->texCoordX, texCoord->texCoordY); glVertex3f(pos[0], pos[1], pos[2]); } } glEnd (); // Tell OpenGL We've Finished glDepthFunc (GL_LESS); // Reset The Depth-Testing Mode ( NEW ) glCullFace (GL_BACK); // Reset The Face To Be Culled ( NEW ) glPolygonMode (GL_BACK, GL_FILL); // Reset Back-Facing Polygon Drawing Mode ( NEW ) glDisable (GL_BLEND); } Whereas this is the drawToon function in the 3DS loader void Model_3DS::drawToon() { float outlineWidth = 3.0f; // Width Of The Lines ( NEW ) float outlineColor[3] = { 0.0f, 0.0f, 0.0f }; // Color Of The Lines ( NEW ) //ORIGINAL CODE if (visible) { glPushMatrix(); // Move the model glTranslatef(pos.x, pos.y, pos.z); // Rotate the model glRotatef(rot.x, 1.0f, 0.0f, 0.0f); glRotatef(rot.y, 0.0f, 1.0f, 0.0f); glRotatef(rot.z, 0.0f, 0.0f, 1.0f); glScalef(scale, scale, scale); // Loop through the objects for (int i = 0; i < numObjects; i++) { // Enable texture coordiantes, normals, and vertices arrays if (Objects[i].textured) glEnableClientState(GL_TEXTURE_COORD_ARRAY); if (lit) glEnableClientState(GL_NORMAL_ARRAY); glEnableClientState(GL_VERTEX_ARRAY); // Point them to the objects arrays if (Objects[i].textured) glTexCoordPointer(2, GL_FLOAT, 0, Objects[i].TexCoords); if (lit) glNormalPointer(GL_FLOAT, 0, Objects[i].Normals); glVertexPointer(3, GL_FLOAT, 0, Objects[i].Vertexes); // Loop through the faces as sorted by material and draw them for (int j = 0; j < Objects[i].numMatFaces; j ++) { // Use the material's texture Materials[Objects[i].MatFaces[j].MatIndex].tex.Use(); // AFTER THE TEXTURE IS APPLIED I INSERT THE TOON FUNCTIONS HERE (FIRST PASS) glHint (GL_LINE_SMOOTH_HINT, GL_NICEST); // Use The Good Calculations ( NEW ) glEnable (GL_LINE_SMOOTH); // Cel-Shading Code // glEnable (GL_TEXTURE_1D); // Enable 1D Texturing ( NEW ) glBindTexture (GL_TEXTURE_1D, shaderTexture[0]); // Bind Our Texture ( NEW ) glColor3f (1.0f, 1.0f, 1.0f); // Set The Color Of The Model ( NEW ) glPushMatrix(); // Move the model glTranslatef(Objects[i].pos.x, Objects[i].pos.y, Objects[i].pos.z); // Rotate the model glRotatef(Objects[i].rot.z, 0.0f, 0.0f, 1.0f); glRotatef(Objects[i].rot.y, 0.0f, 1.0f, 0.0f); glRotatef(Objects[i].rot.x, 1.0f, 0.0f, 0.0f); // Draw the faces using an index to the vertex array glDrawElements(GL_TRIANGLES, Objects[i].MatFaces[j].numSubFaces, GL_UNSIGNED_SHORT, Objects[i].MatFaces[j].subFaces); glPopMatrix(); } glDisable (GL_TEXTURE_1D); // Disable 1D Textures ( NEW ) // THIS IS AN ADDED SECOND PASS AT THE VERTICES FOR THE OUTLINE glEnable (GL_BLEND); // Enable Blending ( NEW ) glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA); // Set The Blend Mode ( NEW ) glPolygonMode (GL_BACK, GL_LINE); // Draw Backfacing Polygons As Wireframes ( NEW ) glLineWidth (outlineWidth); // Set The Line Width ( NEW ) glCullFace (GL_FRONT); // Don't Draw Any Front-Facing Polygons ( NEW ) glDepthFunc (GL_LEQUAL); // Change The Depth Mode ( NEW ) glColor3fv (&outlineColor[0]); // Set The Outline Color ( NEW ) for (int j = 0; j < Objects[i].numMatFaces; j ++) { glPushMatrix(); // Move the model glTranslatef(Objects[i].pos.x, Objects[i].pos.y, Objects[i].pos.z); // Rotate the model glRotatef(Objects[i].rot.z, 0.0f, 0.0f, 1.0f); glRotatef(Objects[i].rot.y, 0.0f, 1.0f, 0.0f); glRotatef(Objects[i].rot.x, 1.0f, 0.0f, 0.0f); // Draw the faces using an index to the vertex array glDrawElements(GL_TRIANGLES, Objects[i].MatFaces[j].numSubFaces, GL_UNSIGNED_SHORT, Objects[i].MatFaces[j].subFaces); glPopMatrix(); } glDepthFunc (GL_LESS); // Reset The Depth-Testing Mode ( NEW ) glCullFace (GL_BACK); // Reset The Face To Be Culled ( NEW ) glPolygonMode (GL_BACK, GL_FILL); // Reset Back-Facing Polygon Drawing Mode ( NEW ) glDisable (GL_BLEND); glPopMatrix(); } Finally this is the tex.Use() function that loads a BMP texture and somehow gets blended perfectly with the Toon shading void GLTexture::Use() { glEnable(GL_TEXTURE_2D); // Enable texture mapping glBindTexture(GL_TEXTURE_2D, texture[0]); // Bind the texture as the current one }

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  • Can't read .cso files but I can read their .hlsl versions?

    - by Jader J Rivera
    Well I've been trying to read a .cso file to use as a shader for a DirectX program I'm currently making. Problem is no matter how I implemented a way to read the file it never worked. And after fidgeting around I discover that it's only the .cso files I can't read. I can read anything else (which means it works) even their .hlsl files. Which is strange because the .hlsl (high level shader language) files are supposed to turn into .cso (compiled shader object) files. What I'm currently doing is: vector<byte> Read(string File){ vector<byte> Text; fstream file(File, ios::in | ios::ate | ios::binary); if(file.is_open()){ Text.resize(file.tellg()); file.seekg(0 , ios::beg); file.read(reinterpret_cast<char*>(&Text[0]), Text.size()); file.close(); } return Text; }; If I then implement it. Read("VertexShader.hlsl"); //Works Read("VertexShader.cso"); //Doesn't Works?!?! And I need the .cso version of the shader to draw my sexy triangles. Without it my life and application will never continue and I have no idea what could be wrong. (I've also asked this at stack overflow but still no answers.)

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  • What is UVIndex and how do I use it on OpenGL?

    - by Delta
    I am a noob in OpenGL ES 2.0 (for WebGL) and I'm trying to draw a simple model I've made with a 3D tool and exported to .fbx format. I've been able to draw some models that only have: A vertex buffer, a index buffer for the vertices, a normal buffer and a texture coordinate buffer, but this model now has a "UVIndex" and I'm not sure where am I supposed to put this UVIndex. My code looks like this: GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.VertexBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["vPosition"],3,GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.NormalBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["vNormal"], 3, GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ARRAY_BUFFER, this.Model.House.TexCoordBuffer); GL.vertexAttribPointer(this.Shader.TextureAndLighting.Attribute["TexCoord"], 2, GL.FLOAT, false, 0, 0); GL.bindBuffer(GL.ELEMENT_ARRAY_BUFFER, this.Model.House.IndexBuffer); GL.bindTexture(GL.TEXTURE_2D, this.Texture.HTex1); GL.activeTexture(GL.TEXTURE0); GL.drawElements(GL.TRIANGLES, this.Model.House.IndexBuffer.Length, GL.UNSIGNED_SHORT, 0); But my model renders totally incorrect and I think it has to do with the fact that I am ignoring this "UVIndex" in the .fbx file, since I've never drawn any model that uses this UVIndex I really have no clue on what to do with it. This is the json file containing the model's data: http://pastebin.com/raw.php?i=G294TVmz

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  • Drawing a sprite or text causes the OpenGl rendering to 'disappear' in SFML

    - by Ken
    I'm using some SFML built in functions to draw sprites and text as an overlay on top of some OpenGL rending in an SFML RenderWindow. The opengl rendering appears fine until I add the code to draw the sprites or text. The sprite or text drawing causes the OpenGL stuff to disappear. The follow code show what I'm trying to do sf::RenderWindow window(sf::VideoMode(viewport.width,viewport.height,32), "SFML Window"); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0,viewport.width,0,viewport.height,0,1); while (window.pollEvent(Event)) { //event handling... //begin drawing glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glBegin(GL_TRIANGLES); glColor3f(col.x,col.y,col.z); for(int i=0;i<3;i++) glVertex2f(pos.x+verts[i].x,pos.y+verts[i].y); glEnd(); // adding this line causes all the previous opengl triangles not to appear window.draw("Sometext"); window.display(); }

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  • how to properly implement alpha blending in a complex 3d scene

    - by Gajet
    I know this question might sound a bit easy to answer but It's driving me crazy. There are too many possible situations that a good alpha blending mechanism should handle, and for each Algorithm I can think of there is something missing. these are the methods I've though about so far: first of I though about object sorting by depth, this one simply fails because Objects are not simple shapes, they might have curves and might loop inside each other. so I can't always tell which one is closer to camera. then I thought about sorting triangles but this one also might fail, thought I'm not sure how to implement it there is a rare case that might again cause problem, in which two triangle pass through each other. again no one can tell which one is nearer. the next thing was using depth buffer, at least the main reason we have depth buffer is because of the problems with sorting that I mentioned but now we get another problem. Since objects might be transparent, in a single pixel there might be more than one object visible. So for which Object should I store pixel depth? I then thought maybe I can only store the most front Object depth, and using that determine how should I blend next draw calls at that pixel. But again there was a problem, think about 2 semi transparent planes with a solid plane in middle of them. I was going to render the solid plane at the end, one can see the most distant plane. note that I was going to merge every two planes until there is only one color left for that pixel. Obviously I can use sorting methods too because of the same reasons I've explained above. Finally the only thing I imagine being able to work is to render all objects into different render targets and then sort those layers and display the final output. But this time I don't know how can I implement this algorithm.

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  • Learning OpenGL GLSL - VAO buffer problems?

    - by Bleary
    I've just started digging through OpenGL and GLSL, and now stumbled on something I can't get my head around this one!? I've stepped back to loading a simple cube and using a simple shader on it, but the result is triangles drawn incorrectly and/or missing. The code I had working perfectly on meshes, but was attempting to move to using VAOs so none of the code for storing the vertices and indices has changed. http://i.stack.imgur.com/RxxZ5.jpg http://i.stack.imgur.com/zSU50.jpg What I have for creating the VAO and buffers is this //Create the Vertex array object glGenVertexArrays(1, &vaoID); // Finally create our vertex buffer objects glGenBuffers(VBO_COUNT, mVBONames); glBindVertexArray(vaoID); // Save vertex attributes into GPU glBindBuffer(GL_ARRAY_BUFFER, mVBONames[VERTEX_VBO]); // Copy data into the buffer object glBufferData(GL_ARRAY_BUFFER, lPolygonVertexCount*VERTEX_STRIDE*sizeof(GLfloat), lVertices, GL_STATIC_DRAW); glEnableVertexAttribArray(pos); glVertexAttribPointer(pos, 3, GL_FLOAT, GL_FALSE, VERTEX_STRIDE*sizeof(GLfloat),0); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mVBONames[INDEX_VBO]); glBufferData(GL_ELEMENT_ARRAY_BUFFER, lPolygonCount*sizeof(unsigned int), lIndices, GL_STATIC_DRAW); glBindVertexArray(0); And the code for drawing the mesh. glBindVertexArray(vaoID); glUseProgram(shader->programID); GLsizei lOffset = mSubMeshes[pMaterialIndex]->IndexOffset*sizeof(unsigned int); const GLsizei lElementCount = mSubMeshes[pMaterialIndex]->TriangleCount*TRIAGNLE_VERTEX_COUNT; glDrawElements(GL_TRIANGLES, lElementCount, GL_UNSIGNED_SHORT, reinterpret_cast<const GLvoid*>(lOffset)); // All the points are indeed in the correct place!? //glPointSize(10.0f); //glDrawElements(GL_POINTS, lElementCount, GL_UNSIGNED_SHORT, 0); glUseProgram(0); glBindVertexArray(0); Eyes have become bleary looking at this today so any thoughts or a fresh set of eyes would be greatly appreciated.

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  • Can't use SFML sprite drawing and OpenGL rendering at the same time

    - by Ken
    I'm using some SFML built in functions to draw sprites and text as an overlay on top of some OpenGL rending in an SFML RenderWindow. The opengl rendering appears fine until I add the code to draw the sprites or text. The sprite or text drawing causes the OpenGL stuff to disappear. The follow code show what I'm trying to do sf::RenderWindow window(sf::VideoMode(viewport.width,viewport.height,32), "SFML Window"); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0,viewport.width,0,viewport.height,0,1); while (window.pollEvent(Event)) { //event handling... //begin drawing glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glBegin(GL_TRIANGLES); glColor3f(col.x,col.y,col.z); for(int i=0;i<3;i++) glVertex2f(pos.x+verts[i].x,pos.y+verts[i].y); glEnd(); // adding this line causes all the previous opengl triangles not to appear window.draw("Sometext"); window.display(); }

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  • Triangulating a partially triangulated mesh (2D)

    - by teodron
    Referring to the above exhibits, this is the scenario I am working with: starting with a planar graph (in my case, a 2D mesh) with a given triangulation, based on a certain criterion, the graph nodes are labeled as RED and BLACK. (A) a subgraph containing all the RED nodes (with edges between only the directly connected neighbours) is formed (note: although this figure shows a tree forming, it may well happen that the subgraph contain loops) (B) Problem: I need to quickly build a triangulation around the subgraph (e.g. as shown in figure C), but under the constraint that I have to keep the already present edges in the final result. Question: Is there a fast way of achieving this given a partially triangulated mesh? Ideally, the complexity should be in the O(n) class. Some side-remarks: it would be nice for the triangulation algorithm to take into account a certain vertex priority when adding edges (e.g. it should always try to build a "1-ring" structure around the most important nodes first - I can implement iteratively such a routine, but it's O(n^2) ). it would also be nice to reflect somehow the "hop distance" when adding edges: add edges first between the nodes that were "closer" to each other given the start topology. Nevertheless, disregarding the remarks, is there an already known scenario similar to this one where a triangulation is built upon a partially given set of triangles/edges?

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  • Checking for collisions on a 3D heightmap

    - by Piku
    I have a 3D heightmap drawn using OpenGL (which isn't important). It's represented by a 2D array of height data. To draw this I go through the array using each point as a vertex. Three vertices are wound together to form a triangle, two triangles to make a quad. To stop the whole mesh being tiny I scale this by a certain amount called 'gridsize'. This produces a fairly nice and lumpy, angular terrain kind of similar to something you'd see in old Atari/Amiga or DOS '3D' games (think Virus/Zarch on the Atari ST). I'm now trying to work out how to do collision with the terrain, testing to see if the player is about to collide with a piece of scenery sticking upwards or fall into a hole. At the moment I am simply dividing the player's co-ordinates by the gridsize to find which vertex the player is on top of and it works well when the player is exactly over the corner of a triangle piece of terrain. However... How can I make it more accurate for the bits between the vertices? I get confused since they don't exist in my heightmap data, they're a product of the GPU trying to draw a triangle between three points. I can calculate the height of the point closest to the player, but not the space between them. I.e if the player is hovering over the centre of one of these 'quads', rather than over the corner vertex of one, how do I work out the height of the terrain below them? Later on I may want the player to slide down the slopes in the terrain.

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  • Octrees and Vertex Buffer Objects

    - by sharethis
    As many others I want to code a game with a voxel based terrain. The data is represented by voxels which are rendered using triangles. I head of two different approaches and want to combine them. First, I could once divide the space in chunks of a fixed size like many games do. What I could do now is to generate a polygon shape for each chunk and store that in a vertex buffer object (vbo). Each time a voxel changes, the polygon and vbo of its chunk is recreated. Additionally it is easy to dynamically load and reload parts of the terrain. Another approach would be to use octrees and divide the space in eight cubes which are divided again and again. So I could efficiently render the terrain because I don't have to go deeper in a solid cube and can draw that as a single one (with a repeated texture). What I like to use for my game is an octree datastructure. But I can't imagine how to use vbos with that. How is that done, or is this impossible?

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  • Is using a dedicated thread just for sending gpu commands a good idea?

    - by tigrou
    The most basic game loop is like this : while(1) { update(); draw(); swapbuffers(); } This is very simple but have a problem : some drawing commands can be blocking and cpu will wait while he could do other things (like processing next update() call). Another possible solution i have in mind would be to use two threads : one for updating and preparing commands to be sent to gpu, and one for sending these commands to the gpu : //first thread while(1) { update(); render(); // use gamestate to generate all needed triangles and commands for gpu // put them in a buffer, no command is send to gpu // two buffers will be used, see below pulse(); //signal the other thread data is ready } //second thread while(1) { wait(); // wait for second thread for data to come send_data_togpu(); // send prepared commands from buffer to graphic card swapbuffers(); } also : two buffers would be used, so one buffer could be filled with gpu commands while the other would be processed by gpu. Do you thing such a solution would be effective ? What would be advantages and disadvantages of such a solution (especially against a simpler solution (eg : single threaded with triple buffering enabled) ?

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  • How can I render a semi transparent model with OpenGL correctly?

    - by phobitor
    I'm using OpenGL ES 2 and I want to render a simple model with some level of transparency. I'm just starting out with shaders, and I wrote a simple diffuse shader for the model without any issues but I don't know how to add transparency to it. I tried to set my fragment shader's output (gl_FragColor) to a non opaque alpha value but the results weren't too great. It sort of works, but it looks like certain model triangles are only rendered based on the camera position... It's really hard to describe what's wrong so please watch this short video I recorded: http://www.youtube.com/watch?v=s0JqA0rZabE I thought this was a depth testing issue so I tried playing around with enabling/disabling depth testing and back face culling. Enabling back face culling changes the output slightly but the problem in the video is still there. Enabling/disabling depth testing doesn't seem to do anything. Could anyone explain what I'm seeing and how I can add some simple transparency to my model with the shader? I'm not looking for advanced order independent transparency implementations. edit: Vertex Shader: // color varying for fragment shader varying mediump vec3 LightIntensity; varying highp vec3 VertexInModelSpace; void main() { // vec4 LightPosition = vec4(0.0, 0.0, 0.0, 1.0); vec3 LightColor = vec3(1.0, 1.0, 1.0); vec3 DiffuseColor = vec3(1.0, 0.25, 0.0); // find the vector from the given vertex to the light source vec4 vertexInWorldSpace = gl_ModelViewMatrix * vec4(gl_Vertex); vec3 normalInWorldSpace = normalize(gl_NormalMatrix * gl_Normal); vec3 lightDirn = normalize(vec3(LightPosition-vertexInWorldSpace)); // save vertexInWorldSpace VertexInModelSpace = vec3(gl_Vertex); // calculate light intensity LightIntensity = LightColor * DiffuseColor * max(dot(lightDirn,normalInWorldSpace),0.0); // calculate projected vertex position gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } Fragment Shader: // varying to define color varying vec3 LightIntensity; varying vec3 VertexInModelSpace; void main() { gl_FragColor = vec4(LightIntensity,0.5); }

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  • OpenGL directional light creating black spots

    - by AnonymousDeveloper
    I probably ought to start by saying that I suspect the problem is that one of my vectors is not in the correct "space", but I don't know for sure. I am having a strange problem with a directional light. When I move the camera away from (0.0, 0.0, 0.0) it creates tiny black spots that grow larger as the distance increases. I apologize ahead of time for the length of the code. Vertex shader: #version 410 core in vec3 vf_normal; in vec3 vf_bitangent; in vec3 vf_tangent; in vec2 vf_textureCoordinates; in vec3 vf_vertex; out vec3 tc_normal; out vec3 tc_bitangent; out vec3 tc_tangent; out vec2 tc_textureCoordinates; out vec3 tc_vertex; uniform mat3 vf_m_normal; uniform mat4 vf_m_model; uniform mat4 vf_m_mvp; uniform mat4 vf_m_projection; uniform mat4 vf_m_view; uniform float vf_te_inner; uniform float vf_te_outer; void main() { tc_normal = vf_normal; tc_bitangent = vf_bitangent; tc_tangent = vf_tangent; tc_textureCoordinates = vf_textureCoordinates; tc_vertex = vf_vertex; gl_Position = vf_m_mvp * vec4(vf_vertex, 1.0); } Tessellation Control shader: #version 410 core layout (vertices = 3) out; in vec3 tc_normal[]; in vec3 tc_bitangent[]; in vec3 tc_tangent[]; in vec2 tc_textureCoordinates[]; in vec3 tc_vertex[]; out vec3 te_normal[]; out vec3 te_bitangent[]; out vec3 te_tangent[]; out vec2 te_textureCoordinates[]; out vec3 te_vertex[]; uniform float vf_te_inner; uniform float vf_te_outer; uniform vec4 vf_l_color; uniform vec3 vf_l_position; uniform mat4 vf_m_depthBias; uniform mat4 vf_m_model; uniform mat4 vf_m_mvp; uniform mat4 vf_m_projection; uniform mat4 vf_m_view; uniform sampler2D vf_t_diffuse; uniform sampler2D vf_t_normal; uniform sampler2DShadow vf_t_shadow; uniform sampler2D vf_t_specular; #define ID gl_InvocationID float getTessLevelInner(float distance0, float distance1) { float avgDistance = (distance0 + distance1) / 2.0; return clamp((vf_te_inner - avgDistance), 1.0, vf_te_inner); } float getTessLevelOuter(float distance0, float distance1) { float avgDistance = (distance0 + distance1) / 2.0; return clamp((vf_te_outer - avgDistance), 1.0, vf_te_outer); } void main() { te_normal[gl_InvocationID] = tc_normal[gl_InvocationID]; te_bitangent[gl_InvocationID] = tc_bitangent[gl_InvocationID]; te_tangent[gl_InvocationID] = tc_tangent[gl_InvocationID]; te_textureCoordinates[gl_InvocationID] = tc_textureCoordinates[gl_InvocationID]; te_vertex[gl_InvocationID] = tc_vertex[gl_InvocationID]; float eyeToVertexDistance0 = distance(vec3(0.0), vec4(vf_m_view * vec4(tc_vertex[0], 1.0)).xyz); float eyeToVertexDistance1 = distance(vec3(0.0), vec4(vf_m_view * vec4(tc_vertex[1], 1.0)).xyz); float eyeToVertexDistance2 = distance(vec3(0.0), vec4(vf_m_view * vec4(tc_vertex[2], 1.0)).xyz); gl_TessLevelOuter[0] = getTessLevelOuter(eyeToVertexDistance1, eyeToVertexDistance2); gl_TessLevelOuter[1] = getTessLevelOuter(eyeToVertexDistance2, eyeToVertexDistance0); gl_TessLevelOuter[2] = getTessLevelOuter(eyeToVertexDistance0, eyeToVertexDistance1); gl_TessLevelInner[0] = getTessLevelInner(eyeToVertexDistance2, eyeToVertexDistance0); } Tessellation Evaluation shader: #version 410 core layout (triangles, equal_spacing, cw) in; in vec3 te_normal[]; in vec3 te_bitangent[]; in vec3 te_tangent[]; in vec2 te_textureCoordinates[]; in vec3 te_vertex[]; out vec3 g_normal; out vec3 g_bitangent; out vec4 g_patchDistance; out vec3 g_tangent; out vec2 g_textureCoordinates; out vec3 g_vertex; uniform float vf_te_inner; uniform float vf_te_outer; uniform vec4 vf_l_color; uniform vec3 vf_l_position; uniform mat4 vf_m_depthBias; uniform mat4 vf_m_model; uniform mat4 vf_m_mvp; uniform mat3 vf_m_normal; uniform mat4 vf_m_projection; uniform mat4 vf_m_view; uniform sampler2D vf_t_diffuse; uniform sampler2D vf_t_displace; uniform sampler2D vf_t_normal; uniform sampler2DShadow vf_t_shadow; uniform sampler2D vf_t_specular; vec2 interpolate2D(vec2 v0, vec2 v1, vec2 v2) { return vec2(gl_TessCoord.x) * v0 + vec2(gl_TessCoord.y) * v1 + vec2(gl_TessCoord.z) * v2; } vec3 interpolate3D(vec3 v0, vec3 v1, vec3 v2) { return vec3(gl_TessCoord.x) * v0 + vec3(gl_TessCoord.y) * v1 + vec3(gl_TessCoord.z) * v2; } float amplify(float d, float scale, float offset) { d = scale * d + offset; d = clamp(d, 0, 1); d = 1 - exp2(-2*d*d); return d; } float getDisplacement(vec2 t0, vec2 t1, vec2 t2) { float displacement = 0.0; vec2 textureCoordinates = interpolate2D(t0, t1, t2); vec2 vector = ((t0 + t1 + t2) / 3.0); float sampleDistance = sqrt((vector.x * vector.x) + (vector.y * vector.y)); sampleDistance /= ((vf_te_inner + vf_te_outer) / 2.0); displacement += texture(vf_t_displace, textureCoordinates).x; displacement += texture(vf_t_displace, textureCoordinates + vec2(-sampleDistance, -sampleDistance)).x; displacement += texture(vf_t_displace, textureCoordinates + vec2(-sampleDistance, sampleDistance)).x; displacement += texture(vf_t_displace, textureCoordinates + vec2( sampleDistance, sampleDistance)).x; displacement += texture(vf_t_displace, textureCoordinates + vec2( sampleDistance, -sampleDistance)).x; return (displacement / 5.0); } void main() { g_normal = normalize(interpolate3D(te_normal[0], te_normal[1], te_normal[2])); g_bitangent = normalize(interpolate3D(te_bitangent[0], te_bitangent[1], te_bitangent[2])); g_patchDistance = vec4(gl_TessCoord, (1.0 - gl_TessCoord.y)); g_tangent = normalize(interpolate3D(te_tangent[0], te_tangent[1], te_tangent[2])); g_textureCoordinates = interpolate2D(te_textureCoordinates[0], te_textureCoordinates[1], te_textureCoordinates[2]); g_vertex = interpolate3D(te_vertex[0], te_vertex[1], te_vertex[2]); float displacement = getDisplacement(te_textureCoordinates[0], te_textureCoordinates[1], te_textureCoordinates[2]); float d2 = min(min(min(g_patchDistance.x, g_patchDistance.y), g_patchDistance.z), g_patchDistance.w); d2 = amplify(d2, 50, -0.5); g_vertex += g_normal * displacement * 0.1 * d2; gl_Position = vf_m_mvp * vec4(g_vertex, 1.0); } Geometry shader: #version 410 core layout (triangles) in; layout (triangle_strip, max_vertices = 3) out; in vec3 g_normal[3]; in vec3 g_bitangent[3]; in vec4 g_patchDistance[3]; in vec3 g_tangent[3]; in vec2 g_textureCoordinates[3]; in vec3 g_vertex[3]; out vec3 f_tangent; out vec3 f_bitangent; out vec3 f_eyeDirection; out vec3 f_lightDirection; out vec3 f_normal; out vec4 f_patchDistance; out vec4 f_shadowCoordinates; out vec2 f_textureCoordinates; out vec3 f_vertex; uniform vec4 vf_l_color; uniform vec3 vf_l_position; uniform mat4 vf_m_depthBias; uniform mat4 vf_m_model; uniform mat4 vf_m_mvp; uniform mat3 vf_m_normal; uniform mat4 vf_m_projection; uniform mat4 vf_m_view; uniform sampler2D vf_t_diffuse; uniform sampler2D vf_t_normal; uniform sampler2DShadow vf_t_shadow; uniform sampler2D vf_t_specular; void main() { int index = 0; while (index < 3) { vec3 vertexNormal_cameraspace = vf_m_normal * normalize(g_normal[index]); vec3 vertexTangent_cameraspace = vf_m_normal * normalize(f_tangent); vec3 vertexBitangent_cameraspace = vf_m_normal * normalize(f_bitangent); mat3 TBN = transpose(mat3( vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace )); vec3 eyeDirection = -(vf_m_view * vf_m_model * vec4(g_vertex[index], 1.0)).xyz; vec3 lightDirection = normalize(-(vf_m_view * vec4(vf_l_position, 1.0)).xyz); f_eyeDirection = TBN * eyeDirection; f_lightDirection = TBN * lightDirection; f_normal = normalize(g_normal[index]); f_patchDistance = g_patchDistance[index]; f_shadowCoordinates = vf_m_depthBias * vec4(g_vertex[index], 1.0); f_textureCoordinates = g_textureCoordinates[index]; f_vertex = (vf_m_model * vec4(g_vertex[index], 1.0)).xyz; gl_Position = gl_in[index].gl_Position; EmitVertex(); index ++; } EndPrimitive(); } Fragment shader: #version 410 core in vec3 f_bitangent; in vec3 f_eyeDirection; in vec3 f_lightDirection; in vec3 f_normal; in vec4 f_patchDistance; in vec4 f_shadowCoordinates; in vec3 f_tangent; in vec2 f_textureCoordinates; in vec3 f_vertex; out vec4 fragColor; uniform vec4 vf_l_color; uniform vec3 vf_l_position; uniform mat4 vf_m_depthBias; uniform mat4 vf_m_model; uniform mat4 vf_m_mvp; uniform mat4 vf_m_projection; uniform mat4 vf_m_view; uniform sampler2D vf_t_diffuse; uniform sampler2D vf_t_normal; uniform sampler2DShadow vf_t_shadow; uniform sampler2D vf_t_specular; vec2 poissonDisk[16] = vec2[]( vec2(-0.94201624, -0.39906216), vec2( 0.94558609, -0.76890725), vec2(-0.09418410, -0.92938870), vec2( 0.34495938, 0.29387760), vec2(-0.91588581, 0.45771432), vec2(-0.81544232, -0.87912464), vec2(-0.38277543, 0.27676845), vec2( 0.97484398, 0.75648379), vec2( 0.44323325, -0.97511554), vec2( 0.53742981, -0.47373420), vec2(-0.26496911, -0.41893023), vec2( 0.79197514, 0.19090188), vec2(-0.24188840, 0.99706507), vec2(-0.81409955, 0.91437590), vec2( 0.19984126, 0.78641367), vec2( 0.14383161, -0.14100790) ); float random(vec3 seed, int i) { vec4 seed4 = vec4(seed,i); float dot_product = dot(seed4, vec4(12.9898, 78.233, 45.164, 94.673)); return fract(sin(dot_product) * 43758.5453); } float amplify(float d, float scale, float offset) { d = scale * d + offset; d = clamp(d, 0, 1); d = 1 - exp2(-2.0 * d * d); return d; } void main() { vec3 lightColor = vf_l_color.xyz; float lightPower = vf_l_color.w; vec3 materialDiffuseColor = texture(vf_t_diffuse, f_textureCoordinates).xyz; vec3 materialAmbientColor = vec3(0.1, 0.1, 0.1) * materialDiffuseColor; vec3 materialSpecularColor = texture(vf_t_specular, f_textureCoordinates).xyz; vec3 n = normalize(texture(vf_t_normal, f_textureCoordinates).rgb * 2.0 - 1.0); vec3 l = normalize(f_lightDirection); float cosTheta = clamp(dot(n, l), 0.0, 1.0); vec3 E = normalize(f_eyeDirection); vec3 R = reflect(-l, n); float cosAlpha = clamp(dot(E, R), 0.0, 1.0); float visibility = 1.0; float bias = 0.005 * tan(acos(cosTheta)); bias = clamp(bias, 0.0, 0.01); for (int i = 0; i < 4; i ++) { float shading = (0.5 / 4.0); int index = i; visibility -= shading * (1.0 - texture(vf_t_shadow, vec3(f_shadowCoordinates.xy + poissonDisk[index] / 3000.0, (f_shadowCoordinates.z - bias) / f_shadowCoordinates.w))); }\n" fragColor.xyz = materialAmbientColor + visibility * materialDiffuseColor * lightColor * lightPower * cosTheta + visibility * materialSpecularColor * lightColor * lightPower * pow(cosAlpha, 5); fragColor.w = texture(vf_t_diffuse, f_textureCoordinates).w; } The following images should be enough to give you an idea of the problem. Before moving the camera: Moving the camera just a little. Moving it to the center of the scene.

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  • VisualStyleRenderer and themes (WinForms)

    - by Yves
    I have my own TreeView control which is completely OwnerDraw'ed: myTreeView.DrawMode = TreeViewDrawMode.OwnerDrawAll; What I try to achieve is to draw the opened/closed glyph according to the current explorer theme. Especially on Vista and Win7 boxes I'd like to see the new glyphes (black triangles) instead of the plus/minus signs. I know, for a non-OwnerDraw'ed TreeView this can be achieved as follows which works perfectly: myTreeView.HandleCreated += delegate(object sender, EventArgs args) { MyNativeMethods.SetWindowTheme(myTreeView.Handle, "explorer", null); }; I thought a VisualStyleRenderer let me paint the glyphs theme-aware: VisualStyleRenderer r = new VisualStyleRenderer(VisualStyleElement.TreeView.Glyph.Opened); r.DrawBackground(e.Graphics, e.Bounds); The code above unfortunately draws the minus sign in all cases. It looks like the VisualStyleRenderer does not honour the theme setting. Can someone shed some light on this? Thanks!

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  • How to use VisualStyleRenderer in Windows 7?

    - by Paulo Santos
    In a small project of mine I've came across the need of a collapsible group box. Searching the Net, I've found one here. In one of the comments there's an improvement on the original code that uses the VisualStyleRenderer class in order to acquire the TreeView open and closed glyph. Running the code it draws properly the Plus and Minus sing as Windows XP would draw it, however in Windows Vista and Windows 7 the glyph for open and closed nodes are small triangles. What kind of interface, class or PInvoke, I need to use in order to acquire the right glyph?

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  • Huge dataset point in polygon in .net (collision detection)

    - by Rickard Liljeberg
    I have a pretty big mesh with polygons, usually triangles but sometimes rectangles. Each point in my mesh has a value (value has nothing to do with coordinates). Now I am creating a second mesh in the same coordinate-space as the old mesh. I now want to interpolate out values for all points (vertices) in the new mesh using the values from the old mesh. Now I could loop each polygon in the new mesh and detect which old vertices are in each polygon by making 2d collision detection (altho even this I don't get to function properly so if anyone has simple and fast code for 2d collision detection (triangle is enough) I would gladly see it). However to my main point again. looping each old vertice for each new polygon seems less than efficient. is there a better way?

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  • Polygon with different line width (in R)

    - by Tal Galili
    Hi all, I would like to use a command like this: plot(c(1,8), 1:2, type="n") polygon(1:7, c(2,1,2,NA,2,1,2), col=c("red", "blue"), # border=c("green", "yellow"), border=c(1,10), lwd=c(1:10)) To create two triangles, with different line widths. But the polygon command doesn't seem to recycle the "lwd" parameter as it does the col or the border parameters. I would like the resulting plot to look like what the following code will produce: plot(c(1,8), 1:2, type="n") polygon(1:3, c(2,1,2), col=c("red"), # border=c("green", "yellow"), border=c(1,10), lwd=c(1)) polygon(5:7, c(2,1,2), col=c( "blue"), # border=c("green", "yellow"), border=c(1,10), lwd=c(10)) So my questions are: Is there something like polygon that does what I asked for? (If not, I would do it by creating a new polygon function that will break the original x,y by their NA's, although I am not yet sure what is the smartest way to do that...) Thanks, Tal

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  • Math for a geodesic sphere

    - by Marcelo Cantos
    I'm trying to create a very specific geodesic tessellation, but I can't find anything online about it. It is normal to subdivide the triangles of an icosahedron into triangle patches and project them onto the sphere. However, I noticed an animated GIF on the Wikipedia entry for Geodesic Domes that appears not to follow this scheme. Geodesic spheres generally comprise a mixture of mostly hexagonal triangle patches, with pentagonal patches forming at the vertices of the original icosahedron; in most cases, these pentagons are linked together; that is, following a straight edge from the center of one pentagon leads to the center of another pentagon. In the Wikipedia animation, however, the edge from the center of one pentagon doesn't appear to intersect the center of an adjacent pentagons; instead it intersects the side of the other pentagon. Hopefully the drawing below makes this clear: Where can I go to learn about the math behind this particular geometry? Ideally, I'd like to know of an algorithm for generating such tessellations.

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  • Using glRotate and glTranslate with collision detection.

    - by Cetra
    Hey guys, Say I use glRotate to translate the current view based on some arbitrary user input (i.e, if key left is pressed then rtri+=2.5f) glRotatef(rtri,0.0f,1.0f,0.0f); Then I draw the triangle in the rotated position: glBegin(GL_TRIANGLES); // Drawing Using Triangles glVertex3f( 0.0f, 1.0f, 0.0f); // Top glVertex3f(-1.0f,-1.0f, 0.0f); // Bottom Left glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom Right glEnd(); // Finished Drawing The Triangle How do I get the resulting translated vertexes for use in collision detection? Or will I have to manually apply the transform myself and thus doubling up the work? The reason I ask is that I wouldn't mind implementing display lists.

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  • How to structure class to support imported 3d model ?

    - by brainydexter
    Hello, I've written a C++ library that reads in this 3d model file (collada DAE). uptil now, I would output a list of triangles and handle each at rendering stage. But now, I need to attach some Bounding sphere information with the imported model. I need some advice on how should I organize this in code. Here are some specs of the 3D file format: - 3D model is represented as a Tree consisting of nodes - each node can contain other nodes, geometry information, transformation etc My requirements: - a bounding sphere associated with each node, thereby yielding a tree of bounding sphere hierarchy for the model itself. - actual vertex information What would be the recommended way to deal with this situation? Thanks

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  • Simple Android OpenGL App Lag

    - by Eugene
    Hi, I have an Android OpenGL application which simply draws 2D squares (using 2 triangles) and animates them moving down the screen. I essentially do this by running: glLoadIdentity(), then glTranslatef, and finally glDrawElements all in a for loop. (The for loop is to draw all 10 blocks on the screen for every frame). In every drawFrame, the y-position of the blocks increments for the animation. The problem I'm having is strange. I run the application and the animation is laggy and not smooth. Then I re-run the application and I get a smooth animation. If I run again, I may get a smooth animation, or possibly not. Is my method correct, or is there a better way of doing this animation? Thanks for the help!

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