There is no need to initialize index buffers with zero since such
buffers always have to be filled by the caller. This change replaces
the allocation with malloc, so that GPU_indexbuf_init results in an
uninitialized buffer. In debug, and with asan, the buffer will be still
filled by something, but the caller should initialize zero indices
manually instead of relying on a default value.
For example, sometimes the cost of zeroing on allocation is similar to
the cost of filling the buffer with actual data. For a point cloud with
1'000'000 points, octahedron topology update on each frame of simulation
takes:
| | Main | PR |
| -------------------------- | ------- | ------- |
| GPU_indexbuf_init | 2.75 ms | 5233 ns |
| pointcloud_extract_indices | 6.95 ms | 4.64 ms |
Pull Request: https://projects.blender.org/blender/blender/pulls/141110
3e8250e60c