[Merged by Bors] - Added set_scissor_rect to tracked render pass.

[StarArawn]

Objective And Solution

Add set_scissor_rect from wgpu-rs to the TrackedRenderPass. wgpu documentation can be found here:
https://docs.rs/wgpu/latest/wgpu/struct.RenderPass.html#method.set_scissor_rect

The reason for adding this is to cull fragments that are outside of the given rect. For my purposes this is extremely useful for UI.

[cart]

bors r+

[jakobhellermann]

Since the TrackedRenderPass is reused for all draw functions, does that mean that setting the scissor rect in one draw function will also set it for all subsequent ones? That seems unexpected.

[bors]

Pull request successfully merged into main.

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[StarArawn]

Since the TrackedRenderPass is reused for all draw functions, does that mean that setting the scissor rect in one draw function will also set it for all subsequent ones? That seems unexpected.

I used the same wording exactly as the wgpu documentation. It is a little strange with bevy's draw system and perhaps a new PR could address updating the documentation to be a bit more clear on that. I don't think we should clear out the scissor pass state in-between draw functions because it would likely slow things down. It would also require people to set scissor state for each draw call which is slower from a performance view point.