cut the landscape terrain into sectors and check collisions only in this sector.
do i have to check the collision with every triangle? are there algorithms to make this faster? i have found only bad tuts…how would you make this?
I would organize the terrain as quadtree, and store the bounding box of every quadtree node. Then you can simply test the bounding box of the car against the bounding box of a quadtree node.
If they don’t intersect there is no collision. If they intersect there may be a collision, and you have to check the next quadtree level. When you arrive at the bottom level of the quadtree, you have much fewer triangles left that need to be checked against the car geometry for real collisions.
For car/car collisions I would do the same, just check the bounding boxes of every car in the same sector, and if they overlap, check the real car geometry.