[iliketrains]

Rendering only one large triangle can be faster than two. First one triangle needs less memory, less vertex processing, etc.

Second, modern GPUs render pixels in groups of 2x2 up to 8x8 "tiles". If only one pixel from this group is part of a triangle, the entire group will be rendered. When two triangles form a quad, the entire area along the diagonal "seam" will be rendered twice. The smaller quads you have, the more overhead.

Also see https://www.saschawillems.de/blog/2016/08/13/vulkan-tutorial...

[HWR_14]

I disagree, with the exception of the case you link to where half the pixels are outside the viewport or maybe where a sufficient percentage are outside the viewport.

> When two triangles form a quad, the entire area along the diagonal "seam" will be rendered twice

This may be true, but I'm pretty sure that this is more than made up for by the additional pixels in the single triangle circumscribing the quad. In fact, I'm willing to bet that it's a mathematical certainty for any rectangle, although I didn't do enough of the math to prove it.

Instead, I would say that most rendering, especially of hundreds of thousands of 2D shapes, are going to be pixel limited. So trading pixels for vertices is a poor trade.

[gmueckl]

It depends on the size of the sprites in this case. Small sprites will benefit from being drawn as single triangles.

These "shadow" pixel shader invocations are a very real pain when it comes to rendering highly detailed models. The hardware rasterization pipeline can't cope well with huge amounts of really tiny triangles. That's the reason why UE5 Nanite uses a software GPU rasterizer for the high geometry density sections of a model - it's faster! Large area primitives will be rendered normally AFAIK.