Detecting collisions with Bounding Volume Hierarchies #gamedev #gaming #noita-like #algorithm

Added: 2026-05-05

[00:00:00]For all of these shapes, the same general idea applies.

[00:00:03]Reduce the shape into triangles, then search for occlusions at those triangles using something called a bounding volume hierarchy.

[00:00:10]Rather than check each triangle for occlusions each frame, objects are first checked using their bounding box.

[00:00:16]If the best fit box surrounding an object doesn't intersect with that of another, you can quickly rule out a collision.

[00:00:22]If there is a collision, you can then rule out entire regions of triangles by splitting the bounding box into smaller boxes and seeing if those intersect, ruling out every triangle within each bounding box that doesn't overlap.

[00:00:34]If you repeat this, you eventually end up with only the triangles that intersect.

[00:00:38]From there, you can apply the force and direction from that collision based on the triangle's normal, that is, the line that's perpendicular to the plane of the triangle, and the motion of the objects.