Line / Axis aligned box intersection

[ErUs]

Has anyone got any code to check intersection and return an intersection point?

My fails at certain angles:

Code: Select all

#include "intersection.h"

using namespace irr;
using namespace core;

inline bool GetIntersection(f32 fDst1, f32 fDst2, 
		vector3df P1,  vector3df P2,  vector3df &Hit) {
	if ( (fDst1 * fDst2) >= 0.0f) 
		return 0;

	if ( fDst1 == fDst2) 
		return 0; 

	Hit = P1 + (P2-P1) * ( -fDst1/(fDst2-fDst1) );

	return 1;
}

inline bool InBox(vector3df Hit, vector3df B1, vector3df B2, const int AXis) {
	if ( AXis==1 && Hit.Z > B1.Z && 
		Hit.Z < B2.Z && Hit.Y > B1.Y && Hit.Y < B2.Y) 
	return 1;

	if ( AXis==2 && Hit.Z > B1.Z && 
		Hit.Z < B2.Z && Hit.X > B1.X && Hit.X < B2.X) 
	return 1;

	if ( AXis==3 && Hit.X > B1.X && Hit.X < B2.X &&
		 Hit.Y > B1.Y && Hit.Y < B2.Y) 

	return 1;
return 0;
}

// returns true if line (L1, L2) intersects with the boX (B1, B2)
// returns intersection point in Hit
bool CheckLineBox( vector3df B1, vector3df B2, 
		vector3df L1, vector3df L2, vector3df &Hit) {
	if (L2.X < B1.X && L1.X < B1.X) return false;
	if (L2.X > B2.X && L1.X > B2.X) return false;
	if (L2.Y < B1.Y && L1.Y < B1.Y) return false;
	if (L2.Y > B2.Y && L1.Y > B2.Y) return false;
	if (L2.Z < B1.Z && L1.Z < B1.Z) return false;
	if (L2.Z > B2.Z && L1.Z > B2.Z) return false;
	if (L1.X > B1.X && L1.X < B2.X &&
			L1.Y > B1.Y && L1.Y < B2.Y &&
			L1.Z > B1.Z && L1.Z < B2.Z) {
		Hit = L1; 
		return true;
	}

	if ((GetIntersection( L1.X-B1.X, L2.X-B1.X, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 1)) || 
		(GetIntersection( L1.Y-B1.Y, L2.Y-B1.Y, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 2))  || 
		(GetIntersection( L1.Z-B1.Z, L2.Z-B1.Z, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 3)) || 
		(GetIntersection( L1.X-B2.X, L2.X-B2.X, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 1)) || 
		(GetIntersection( L1.Y-B2.Y, L2.Y-B2.Y, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 2)) || 
		(GetIntersection( L1.Z-B2.Z, L2.Z-B2.Z, L1, L2, Hit) && 
		InBox(Hit, B1, B2, 3)))
		return true;

	return false;
}