Remove primitive restart

[weihuoya]

Is there any reason to use such feature? it just make code complex.

[degasus]

It reduces the generate index buffer size. And its hard code is well separated. But you might argue about its speedup...

[stenzek]

Is there a reason not to use it? My suspicion would be that fewer transfers across PCIe could lead to better performance on low-end systems. But I'm happy to be corrected if the numbers say it's not any slower...

[weihuoya]

the mapped gpu memory is constant size, not baseed on data size. and is it really reduces generate index buffer size? use 4 indices per triangle.

[stenzek]

Yes, the mapping is a constant size, but it's a persistent (and potentially coherent) mapping. There is no implicit copy of the entire buffer, the only bytes copied are the ones which are written.

edit: yes, it's fewer indices for triangle lists, but for triangle strips or quads, it'll cause additional indices.

[degasus]

The GC GPU does not support indexed vertices. So to avoid redundant transforming & lighting, high polygon games use triangle_strips for their big meshes. This fits better to the primitive_restart path, and it was the reason to implement it many years ago.
But honestly, I was told that the strips generator with primitive restart was slower for some other developer by a small margin. So I wonder if you are able to confirm the same behavior. And if so, I wonder if the strip merger has an implementation issue or if the algorithmn is slower in general.

[weihuoya]

oh, i'm not familiar with this.:laughing:

with this changes, run stereo mode in vulkan backend, game will crash in some place, don't known where going wrong.