几何检测 (四)

两个AABB的相交性检测

      检测两个静止AABB的相交性是很简单的，只需要在每一维上单独检查它们的重合程度即可。如果在所有维上都没有重合，那么这两个AABB就不会相交。intersectAABBs()就是用这项技术来实现的。

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01	//---------------------------------------------------------------------------

02	// Check if two AABBs intersect, and return true if so.  Optionally return

03	// the AABB of their intersection if an intersection is detected.

04	//---------------------------------------------------------------------------

05	bool intersectAABBs(const AABB3& box1, const AABB3& box2, AABB3* boxIntersect)

06

{

07	// Check for no overlap

08	if (box1.min.x > box2.max.x) return false;

09	if (box1.max.x < box2.min.x) return false;

10	if (box1.min.y > box2.max.y) return false;

11	if (box1.max.y < box2.min.y) return false;

12	if (box1.min.z > box2.max.z) return false;

13	if (box1.max.z < box2.min.z) return false;

14

15	// We have overlap.  Compute AABB of intersection, if they want it.

16	if (boxIntersect != NULL)

17

{

18	boxIntersect->min.x = max(box1.min.x, box2.min.x);

19	boxIntersect->max.x = min(box1.max.x, box2.max.x);

20	boxIntersect->min.y = max(box1.min.y, box2.min.y);

21	boxIntersect->max.y = min(box1.max.y, box2.max.y);

22	boxIntersect->min.z = max(box1.min.z, box2.min.z);

23	boxIntersect->max.z = min(box1.max.z, box2.max.z);

24

}

25

26	return true;

27