Optimize Your Meshes! // OpenGL Tutorial #48

In this video we learn how to optimize meshes and models using the Mesh Optimizer tool.
Mesh Optimizer: github.com/zeux/meshoptimizer
Arseny Kapoulkine on youtube: / @zeuxcg
Timecodes:
0:00 Intro
1:12 Installing Mesh Optimizer
2:33 Integration
2:47 SOA to AOS
8:11 Integration - continued
9:54 Optimization #1 - drop duplicate vertices
12:57 Optimization #2 - optimize the vertex cache
14:07 Optimization #3 - optimize overdraw
15:50 Optimization #4 - optimize the vertex buffer
16:37 Optimization #5 - mesh simplification
19:14 Outro
Make sure to watch all the previous tutorials in the "OpenGL For Beginners" playlist at • OpenGL for Beginners
Please visit ogldev.org to see more of my tutorials on modern OpenGL.
Link to source: github.com/emeiri/ogldev/blob...
If you want to get the same version of the code that was used in the video checkout the tag 'TUT_48_MESH_OPTIMIZER'.
OpenGL 4.6 specification: www.khronos.org/registry/Open...
Credits:
Models from McGuire Computer Graphics Archive: casual-effects.com/data/
Image: www.cleanpng.com/png-download...
GPU Image by rwindr from Pixabay
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Creative Commons - Attribution 3.0 Unported - CC BY 3.0
Free Download / Stream: bit.ly/405k8o8
Music promoted by Audio Library bit.ly/3Qbk2H1
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Enjoy,
Etay Meiri
#opengl #ogldev #opengtutorials

[@OGLDEV]

Clone the sources: git clone --recurse-submodules github.com/emeiri/ogldev.git If you want to get the same version that was used in the video you can checkout the tag 'TUT_48_MESH_OPTIMIZER'. Build on Windows: Open the Visual Studio solution: ogldev\Windows\ogldev_vs_2022\ogldev_vs_2022.sln Build the project 'OpenGL Tutorials\Tutorial48_MeshOptimizer' Notes: 1. I've implemented a similar change in the SkinnedMesh class which derives from BasicMesh. It is not presented in the video but you can check the sources for more details. Homework: 1. Try to productize the mesh simplification optimization to be used in a real game. The mesh should be loaded by Assimp once and then optimized for several levels of detail based on the users request. When rendering the proper LOD should be selected based on the distance from the camera.

[@cheerwizard21]

I am happy that your educational content is still alive and you didn't suspended this channel. Keep it up! 🙂

[@OGLDEV]

Thanks! 😃

[@syntaxed2]

Hell yeah! I was just looking at this the other day :) perfect timing!

[@OGLDEV]

Enjoy!

[@yuhaohan1451]

Thanks for the content!

[@OGLDEV]

My pleasure!

[@edwincarlsson9014]

Hi and thank you! Very informative. I’ve always thought that just Assimp is enough, but I’ll have to try to optimize my meshes! Question: My geometry shader only allows for a single diffuse, normal, and specular map (3 in total). How should I handle meshes that have several textures per vertex? I’m very stuck here.

[@OGLDEV]

You're welcome :-) Do you plan to use the same texture coordinates for each texture? Assimp supports loading multiple sets of texture coordinates per vertex (though I haven't used this feature yet). In general you need to assign a unique sampler for each texture and bind each texture to its corresponding sampler.

[@cheerwizard21]

1. Mix textures on CPU, if you mean several textures with similar format. Like several albedos per vertex. 2. Maybe try to use instance rendering as well and do rendering per instance with combination of geometry shader. That way to make draw call that send all instances to gpu, all instance can be stored in some sort of InstanceBuffer. In case of DX11 it's StructuredBuffer or in case of OpenGL it's - StorageBuffer. 3. Use Texture Array or Texture 3D and store texture index per instance or per vertex. 4. For optimization of 3. you can generate Texture Atlas, store atlas cells & locations into instance buffer and than send it to shaders. 5. You can use bindless textures feature in newer OpenGL. I don't really remember how to do it, since I switched to DX11 1 year ago.

[@crouette]

Any numbers on what are the frame rate improvements after the different optimizations (without simplification)?

[@OGLDEV]

I didn't get a chance to do such measurements myself on real workloads. I guess it will be very difficult to provide a general guidance such as "the library improves the performance by 1.5x" due to the vast difference between workloads and GPUs.