[glTF] Load UINT8 indices into UINT16 buffer #482
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Without extensions, Vulkan only supports UINT16 and UINT32 index buffers. However, glTF allows UINT8 index buffers. We can support scenes with UINT8 indices by repacking them into a UINT16 buffer instead. This comes at the cost of a larger GPU buffer. This allows us to load more Khronos glTF-Sample-Assets like TextureCoordinateTest. Fixes google#453
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Seems like the required extension is https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_8bit_storage.html |
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Sg I'll look at adding UINT8 support to Geometry instead |
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Actually I'm looking at https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VK_KHR_index_type_uint8.html which I believe is required for VK_INDEX_TYPE_UINT8_KHR. That's what I think I need for UINT8 support in Geometry. I don't see that it's been promoted |
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Ahh right, index buffer, not storage buffer, sorry I missed that! |
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I tried on three devices I have (1 software lavapipe, and 2 android) and they all support VK_EXT_index_type_uint8. According to https://vulkan.gpuinfo.org/listextensions.php support for the extension is at 62%. Would it make sense to support UINT8 through the extension, or perhaps fall back to repacking if it is not available? |
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I like the idea of supporting the extension with this as a fallback. I'll look into how to make that happen. |
Without extensions, Vulkan only supports UINT16 and UINT32 index buffers. However, glTF allows UINT8 index buffers. We can support scenes with UINT8 indices by repacking them into a UINT16 buffer instead. This comes at the cost of a larger GPU buffer.
This allows us to load more Khronos glTF-Sample-Assets like TextureCoordinateTest.
Fixes #453