Hi guys, So I finally want to have shadow in my demo and decide to implement it using shadow map. However, I have trouble figuring out how to implement shadow map with direct light. The general process to my understanding is: 1) Render the scene from the light perspective -> shadow map in a buffer 2) Perform rendering, and compare the depth of current pixel with value read out from shadow map to perform shadow shading. For spot light there are demos so I can understand step 1 because a spot light has a definitive world position, hence we can construct its world-view-projection matrix. But the direct light ( like the sun ), we won't have a position for it. We usually only have direction where the light comes from. So how do you render shadow map for direct light? Thanks in advance for all the help.

Hi guys,

Thanks for helping.

@ Hodgman:

It's interesting when you bring up PSSM because I've been looking at the PSSM articles in GPU Gems 3 and also at several CSM in ShaderX series. I also look through the CSM demo from NVIDIA OpenGL SDK. However, all the splitting view frustum is kinda out of my understanding right now :(. I just want to have a shadow map first, then I will dive into the splitting frustum scheme.

So with that said, all the articles doesn't show me how to construct a bounding volume. I would greatly appreciate if you can point me to some resources :) ?

@ szecs:

You didn't see it coming did you :D ? It's interesting because I just watch your youtube demo a few days ago, but I didn't know it's you at the time. Great job on that.