Trees and tree collision.

I made this tree last night, and started working on extending the collision testing system (which currently only tests for collisions against the terrain).

The UV mapping leaves something to be desired, but I'm in a bit of a rush.

I do UV mapping in 3D Coat. You might notice that I didn’t map one of the branches at the top left properly.

~3000 triangle tree mesh. This mesh is a bit wasteful, and 1000 triangles would probably be enough to represent this tree. Time permitting, some retopology is in order.

Clearly, I can’t afford to test every collidable object for collision against 3000+ triangles in every tree. So I bound the tree by a sphere or rectangular prism, register that sphere/box into the collision grid, and test for collision against that first.

~80 triangle tree collision mesh. I can reduce this further to maybe 20-30 triangles, if there's time or if it's necessary.

If an object collided with the tree’s box (shown in orange in the picture above), then I test against a lower resolution triangle mesh. The one shown has more triangles than I’d like. This mesh was just automatically generated by my 3D software’s “optimize” tool. When I have time, I’ll reduce this mesh by hand. The roots of the tree for example, will almost always be 90% underground, so testing against many triangles for the tree roots is unnecessary.