🔒 Locked

shadow volume clipping

Started by w_poons Sep 14, 2005 at 4:36 AM 0 replies 850+ views

Original Post

Sep 14, 2005 at 4:36 AM

i`m trying to sort out which objects can't cast a shadow visible in the scene. only objects which are in the convex hull of the light and the view frustum are possible shadow casters. the concept is clear to me, but i have some implementation problems. o) how can i get the corners of the far clipping plane? (i'm using an infinite projection matrix). i know how to get the points of the near clipping plane. just project these with the projection matrix? o) how can i build the convex hull in a fast way? because there are only 9 points and the spatial relationsship between some points are known i thought there could be a fast way of determining the convex hull. thanks for your help, poons

w_poons

Sep 15, 2005 at 1:21 AM

i thought over it and i think i came up with a solution for problem number 2. because the frustum is itself convex i only have to add the light position. if the light pos. is inside the frustum then the convex hull is the frustum. if the light is outside remove all planes (triangles) that are visible to the light and then add a triangle fan from the light pos. to the open edges.

but i have still problems to get the corner points of the frustum. anybody some idea?

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.