We want crisp shadows for stuff thatвЂ™s near to the near plane, and we are absolutely fine with blurriness for objects that are hundreds of units away: itвЂ™s not going to be noticeable at all. The core insight in cascaded shadow mapping is, that we donвЂ™t need the same amount of shadow detail for things that are far from us. We can increase the resolution of the shadow maps to mitigate this, but GPU memory is a resource we should be conservative of.Д¬ascaded shadow mapping is a direct answer to the third point, however while implementing it we will solve the first two points, too. The shadow maps (even with advanced PCF functions) are blurry if we want the shadow rendering distance to be large, as we would in a game with a first-person camera.To achieve the best possible resolution for our shadow maps, the ortho matrix needs to be as tightly fit to the camera frustum as possible, because again: if itвЂ™s larger that means that less detail is spent on the objects that are actually visible. The shadow map orthographic projection matrix is not properly fitted onto the view frustum.

In reality we want the shadow maps to be created on objects that are in view, saving our precious GPU memory for things that matter. It would be best of course if we could shadow map the whole scene, with sufficient resolution, but on current hardware this is not feasible. The shadow map is always created around the origin, and not on the area the camera is actually looking at.However, if implemented as-is from the above referred tutorial, the avid OpenGL student will notice a few shortcomings. Shadow mapping as described on LearnOpenGL is a powerful, and relatively simple technique. CSM Guest-Articles/2021/CSM Cascaded Shadow Mapping

Ogre engine compute shader