README.md

Box-Box Collision Detection

SIMD optimized box box collision detection.

A default cube is located at origin, has xyz coordinates (±1, ±1, ±1). All 3d cubes can be considered as some transformation applied to the default cube. In particular, scale on xyz axis first, then rotate, then translation.

This code is a fast way to test if 2 cubes has collision.

See here for the explanation.

How to use it

void test(){
  Cube c1,c2; // create 2 default cubes
  // init c1
  {
    c1.m_rotation = vec4(x,y,z,w);  // set quaternion
    c1.m_translation = vec4(x,y,z,1);  // set translation on xyz axis, last element 1 doesn't matter here
    c1.m_scale = vec4(x,y,z,1); // set scale on xyz axis, last element 1 doesn't matter here
  }
  // init c2
  {
    // ...
  }
  bool collision = c1.Collision(c2); // return true if collision, false no collision
}

How to verify the result

To verify the result, you can use Blender. When you open Blender, it will create a default cube automatically. On the right side of screen, there is a Transform panel, you can set Location, Rotation, Scale. Remember to change Rotation Mode to Quaternion. Then you can create another cube, set its property. Then see if they have collision.

Others

1. Matrix inverse is not optimized yet.
2. Not tested, but I think my code should work for all affine transformations, not just scale, rotate, translation.