tank track vertex shader

hey all,

Has anyone had any success procedurally animating tank tracks with a vertex shader?

The animator i'm working with is another hobbyist - he dosn't normally do much animation (more involved in modelling/skinning) and he tells me that tank tracks are not the easiest thing to animate in 3d design packages. I want to help him out if I can.

I thought maybe i could try to use an equation for an ellipse and try to doctor it somehow to make it a bit more boxy, but i can't really see how to make it a 'boxy' ellipse without the shader really slowing down.

Use a stencil buffer. You can overlay images on top of the ground texture. However stencil buffers are very expensive and if the z depth is not done correctly your tank tracks will flicker on and off with the ground texture.

i wouldn't use stencil buffer for this unless there was no better method. you can do texture animations so that it looks like the treads are moving when the tank is moving.

http://www.gametutorials.com/Tutoria...OpenGL_Pg2.htm

Why not just use decals? That seems like it'd work pretty good. Whenever you draw the decals just turn off depth testing so it'll always render over the ground.

Thanks guys. I'll give all 3 a go and maybe come back with demos for them (assuming i can get them working properly). People can compare and contrast then.