glReadPixels runnable PBO example The example below generates either: one ppm per frame at 200 FPS and no extra dependencies, one png per frame at 600 FPS with libpng one mpg for all frames at 1200 FPS with FFmpeg on a ramfs. The better the compression, the larger the FPS, so we must be memory … Read more
It flows from the definition of a normal. Suppose you have the normal, N, and a vector, V, a tangent vector at the same position on the object as the normal. Then by definition N·V = 0. Tangent vectors run in the same direction as the surface of an object. So if your surface is … Read more
For starters I would use 4D -> 3D projection instead of cut by hyperplane. The result is not the same but will get you closer to your goal (so you can latter upgrade this to cut). So similarly like in 3D -> 2D conversions used in graphics you got 2 choices one is using perspective … Read more
My bet is on the color setting/mixing in fragment shader… you are setting output color more then once If I remember correctly on some gfx drivers that do a big problems for example everything after the line color = vec4(brownColor * (texture(diffuseMap, fsCoords).rgb + 0.25), 1.0);//add a fixed base color (0.25), because its dark as … Read more
For ray picking rendered objects (like by mouse) the best option is to use the already rendered buffers as there is very little cost of reading them in comparison to ray intersection tests on complex scene. The idea is to render each pick-able rendered object to separate buffer per each info you need about them … Read more
All of those operations copy the C++ object. Since your class did not define a copy constructor, you get the compiler-generated copy constructor. This simply copies all of the members of the object. Consider the first example: vector<BufferObject> bufVec; { BufferObject some_buffer; //Initialize some_buffer; bufVec.push_back(some_buffer); } bufVec.back(); //buffer doesn’t work. When you call push_back, it … Read more
After spending some reputation on a unsuccessful bounty to get some help on this issue, I finally realized how complex was the problem I was interested in. The few individuals that have accomplished this task don’t share much. During my research I found different ways to achieve what I was looking for. One of the … Read more
but I still don’t know whether or not the gl_FragCoord.z is linear. Whether gl_FragCoord.z is linear or not depends on, the projection matrix. While for Orthographic Projection gl_FragCoord.z is linear, for Perspective Projection it is not linear. In general, the depth (gl_FragCoord.z and gl_FragDepth) is calculated as follows (see GLSL gl_FragCoord.z Calculation and Setting gl_FragDepth): … Read more
+1 for interesting problem. Was curious so I tried to code this. I need the use of arrays so I chose #version 420 core. My app is rendering single quad covering screen with coordinates <-1,+1>. I am using whole ASCII 8×8 pixel 32×8 characters font texture I created some years ago: The vertex is simple: … Read more
Texture coordinates specify the point in the texture image that will correspond to the vertex you are specifying them for. Think of a rectangular rubber sheet with your texture image printed on it, where the length of each side is normalized to the range 0-1. Now let’s say you wanted to draw a triangle using … Read more