PCF

[Delt06]

Implement basic PCF.
Compare performance with VSM. Try checking if VSM can yield the same results with a lower resolution.

[Delt06]

4 tap PCF's performance impact is almost negligible, so it comes down to the difference in shadow map rendering.

Rendering time (in millions of clock cycles)
VSM (1024x1024): 1.721
PCF (1024x1024): 0.431
PCF (2048x2048): 0.648.

Even with higher resolution, PCF is much faster than VSM. They, however, yield completely different visual results. Shadows with PCF are more detailed, yet they have aliasing even with a larger atlas size. VSM can remove aliasing even with the smallest atlas sizes, but it does not capture small details. Therefore, it is primarily a stylistic choice rather than based on performance.