tycho61uk, on Nov 7 2005, 12:01 PM, said:
Collision is a problem with 2D and 3D games. Why do you think that the asteroids in EV don't collide with each other, or with your ship? It's a performance issue. Seemed very odd at first, but we've all since accepted it. For a 3D EV engine, with the action confined to a 2D plane, you could do just the same thing - there's no need to calculate asteroid collisions except with munitions, as is the case with EV.
For 3D object collisions, you could use bounding spheres as a simple reject check, before examining the polys more closely for the actual collision. That works well and is pretty fast.
It's actually more demanding on the CPU to check for collisions between 2D sprites - you have to examine them at the pixel level in the mask.
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Hmm, cool idea. I didn't really think pixel masks were all that difficult on the CPU. As far as the bounding spheres go, though, how would things interact if you were to have only a small portion of a large ship overlapping with another large ship? That would look kinda weird if one of them disappears, and if it goes under the other ship, does it cast a shadow? How does the shadow distance relate?