Optimizing OpenGL rendering

congard · 2019-06-12T14:23:35

Hello! I ran into a poor performance problem when rendering to OpenGL using Assimp. The scene has 266327 triangles. At the same time ~215k is a model of chess. I do not think that the problem is in shaders, because: 128x128 window: 44 (43.7657) FPS, 22.849 ms 256x256 window: 42 (40.9563) FPS, 24.4162 ms 512x512 window: 35 (34.8007) FPS, 28.7351 ms 1024x1024 window: 22 (21.084) FPS, 47.4293 ms But if I don’t draw chess, then in the window 1366x763: 55 (54.8424) FPS, 18.2341 ms Also, changing the resolution of the shadow map does not greatly affect the FPS. There are 2 point light sources on stage, with FPS loss when drawing this model for each of the passes ~10 FPS (from 23 to 55). Ie, there is no difference where I draw this model: in the depth map or in the "color texture". Losses ~ are the same. I load the model with the following parameters: aiProcess_Triangulate | aiProcess_CalcTangentSpace | aiProcess_JoinIdenticalVertices And render as follows: pointer(cs.inPosition, 3, model.shape->meshes[i].getVerticesBuffer()); pointer(cs.inNormal, 3, model.shape->meshes[i].getNormalsBuffer()); pointer(cs.inTangent, 3, model.shape->meshes[i].getTangentsBuffer()); pointer(cs.inBitangent, 3, model.shape->meshes[i].getBitangentsBuffer()); pointer(cs.inTexCoord, 2, model.shape->meshes[i].getTexCoordsBuffer()); if (model.shape->bonesPerVertex != 0) { pointer(cs.inBoneWeights, 4, model.shape->meshes[i].getBoneWeightsBuffer()); pointerui(cs.inBoneIds, 4, model.shape->meshes[i].getBoneIdsBuffer()); } modelMatrix = &model.transformation; updateMatrices(); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, model.shape->meshes[i].getIndicesBuffer()); glDrawElements(GL_TRIANGLES, model.shape->meshes[i].indices.size(), GL_UNSIGNED_INT, nullptr); Here is the scene itself: I will be grateful for the help!

Graphics and GPU Programming Programming OpenGL C++ Algorithm

Started by congard May 07, 2019 10:30 AM

20 comments, last by congard 5 years, 7 months ago

congard

Author

June 12, 2019 02:23 PM

Now I am fully confident that the problem is in my very weak video card. I wrote a small program for monitoring the GPU (It allowed me to monitor GPU utilization (screenshots are attached)) and launched glxgears. In the standard window size, it gave out ~800 fps. But as soon as I resized to fullscreen (1920x1080), the FPS dropped to 50! So I think I'm lucky that I get 36-38 frames in my application

Spoiler

1739723959_2019-06-1217-02-27.png.3afeca5f9cd0260fd8c572c1d8c7aaad.png 157463874_2019-06-1217-02-16.png.ff5dbb53b35419b0d584cf531bf23504.png 1596580451_2019-06-1217-01-55.png.60025449cf19b939707d953f9b07cab0.png

Optimizing OpenGL rendering

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Optimizing OpenGL rendering

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