As mentioned earlier, this algorithm often suffers from severe aliasing artifacts at the shadow's edges. This is due to the fact that the shadow map is essentially projected onto the scene when the depth comparison is made. If the projection causes the map to be magnified, aliasing artifacts appear.

The following image shows the aliasing of the shadow's edges:

The easiest solution is to simply increase the size of the shadow map. However, that may not be possible due to memory, CPU speed, or other constraints. There is a large number of techniques for improving the quality of the shadows produced by the shadow mapping algorithm such as resolution-matched shadow maps, cascaded shadow maps, variance shadow maps, perspective shadow maps, and many others. In the following recipes, we'll look at some ways to help you soften and anti-alias the edges of the shadows.