SDL GPU: Intersect scissor with viewport #244
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The idea makes sense, so we just have to expand on this a bit - let's update the scissor rect whenever the viewport changes too; for example we may have a scissor bigger than the viewport, but when the viewport gets larger we need to tell SDL_GPU that the scissor rect intersection is also larger now.
src/FNA3D_Driver_SDL.c
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| SDL_Rect newRect; | ||
| newRect.x = MAX(x1, x2); | ||
| newRect.y = MAX(y1, y2); | ||
| newRect.w = MIN(x1 + w1, x2 + w2) - newRect.x; | ||
| newRect.h = MIN(y1 + h1, y2 + h2) - newRect.y; |
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SDL_min and SDL_max should cover these macros; we may want to rip off SDL_rect to get a full picture (and catch the weird scenario where there is no intersection):
https://github.com/libsdl-org/SDL/blob/main/src/video/SDL_rect_impl.h#L86
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Changed to SDL_min/max macros, and added a warning when rects do not overlap.
Regarding updating scissor afterwards, it seems like SetRenderTargets actually resets the scissor afterwards:
https://github.com/FNA-XNA/FNA/blob/master/src/Graphics/GraphicsDevice.cs#L1029
If we wanted to sanity check the scissor rect beforehand, wouldn't it be better to do that in the C# side too?
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Yeah I think you're right - the only place where we update the viewport without updating the scissor is inside FNA3D_SetViewport itself, so I think it'd be a whole separate FNA3D issue if we needed to update the scissor rect while in that function.
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