Shadow map is never large enough

Shadow map resolution is a big limiting factor. Especially for large scale scene.

If the shadow map covers a large scene, it tends to show artifacts in detailed small object

If the shadow map focuses on the small object, it will miss a big part of scene

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Aliasing is bad 😈

One big issue with shadow mapping is aliasing.

The shadow map resolution is very limited. For multiple points in camera view, there can be a single corresponding pixel in the shadow map, which will result in jagged shadow 😭

Another bad thing about classic shadow mapping is that the shadow is always sharp. Very unrealistic 😭

Sample more!

Now we improve it: For each point in world, we get a 5x5 neighbors of the shadow map!

In this way, we can get a nice SMOOTH shadow!

But at what price to pay …

What’s bad about it? It needs a lot more data. In this 5x5 case, 25x more data! It can be very slow.

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Game Graphics Simplified

Game Graphics Simplified

I'm a game graphics engineer. I over-simplify game rendering techniques to make them overly simple and fun!