WebGPURenderer: instance mesh use binding group instead of attribute #28726
Conversation
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@sunag @RenaudRohlinger Please review this PR |
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Initially we used binding buffer, but the size was very limited, I think having both options is great. |
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Can I merge this PR or you think on doing some other revision? |
Please review again. I found that WebGPU also limits uniform buffer max size https://www.w3.org/TR/webgpu/#dom-supported-limits-maxuniformbufferbindingsize. And the data in the uniform buffer must be aligned to 16 bytes. Since InstanceColor is a vec3 and occupies 12 bytes, I removed the optimization for InstanceColor. If I change instanceColor to vec4 in InstanceMesh.js, it will affect a lot of code. Therefore, I want to run a benchmark to determine if change instanceColor is worthwhile in another PR. |
📦 Bundle sizeFull ESM build, minified and gzipped.
🌳 Bundle size after tree-shakingMinimal build including a renderer, camera, empty scene, and dependencies.
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@sunag I have solved code confit, please review again. Thanks! |
Description
Make instance objects use binding group instead of attribute
For instancing, it is preferable to use binding group buffers rather than attributes. I know in the initial versions of Three.js, uniforms had size limitations, leading to the use of attributes as a workaround.
However, WebGPU recommends using binding groups to pass values to the GPU. This approach eliminates the need for additional computations.
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After
In WebGL2, we can use UBOs (Uniform Buffer Objects) to achieve the same functionality. However, UBOs have a size limit of 64kB in spec. To accommodate this limitation, I restrict the instance count, allowing the application to run under different conditions with varying counts. (In fact, I found that the UBO max size is far more than 64kb in my device.)
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