How do you do this: a 'dissolve' effect.

I wonder how would you do the effect of having a texture dissolve, or, better, having an object, and then make it dissolve in a ‘random pattern’…I think it has to do with pixel or vertex shaders, but Im not sure…Maybe you can point me to some resources…Thanks…

I think the standard way is to use the stencil buffer. You have an example in the glut source distribution also available here

The Rage128CrossFade sample does something like this with the stencil buffer. The 3D scenes on either side of the transition are just toruses, but could be whatever 3D geometry you want. To get a dissolve, just use a different pattern than the plasma pattern used in this sample.