I wondered about that. And I was tired last night (seems I always get on these forums late!), so my description wasn’t very accurate. What I want is to build a decal mesh that conforms to the surface of another mesh, something more than just simple quads that are parallel to another surface.
Imagine non-planar decals that conform to a highly-tessellated terrain mesh. This is a good way to render extra detail upon a terrain mesh. As long as you’re careful with render order and Z-bias, you can build up quite a lot of detail for only a little overdraw cost.
Here’s a description of the algorithm from someone on the Gamedev forums:
Wolfire’s blog has an indepth article (with pictors!) using the same algorithm: Projected decals upon terrain.
I was just curious if there were already clippers in Panda, and if not, what would be the best way to extract an arbitrary set of triangles as described from the entire scene graph. I don’t particularly care if this all occurs in Python, either, because as stated in the quote, this clipping is only done initially.
I understand if there is no code to do this in Panda, as you said, normally you don’t actually care much about the view->clip->-rasterization phases of 3d as it’s done by the driver/hardware. If not, what would be the best way to extract scenegraph triangles while taking advantage of Panda’s culling code?