/*
 *  Author: Needles
 *  https://steamcommunity.com/profiles/76561198026257137/
 */

 printl("*** COLLISION");



::Collision <- {};



function Collision::PointInBox(point, mins, maxs)
{
	if (
		point.x > mins.x && point.x < maxs.x &&
		point.y > mins.y && point.y < maxs.y &&
		point.z > mins.z && point.z < maxs.z) {
		return true
	}

	return false;
}



function Collision::RaySphereIntersect(start, end, point, radius)
{
	if (radius == 0.0)
		return null;

	local n = (end - start)
	n.Norm();
	local l = point - start
	local ta = n.Dot(l);

	if (ta < 0)
		return null;

	local d = sqrt(l.Dot(l) - ta*ta);

	if (d > radius)
		return null;

	local tb = sqrt(radius*radius - d*d);

	return {
		t0 = ta - tb,
		t1 = ta + tb,
	};
}



function Collision::RayCylinderIntersect(start, end, point, radius, height)
{
	if (radius == 0.0 || height == 0.0)
		return null;

	local tz0 = (point.z - start.z) / (end.z - start.z);
	local tz1 = ((point.z + height) - start.z) / (end.z - start.z);

	start 	= Vector2D(start.x, start.y);
	end   	= Vector2D(end.x, end.y);
	point	= Vector2D(point.x, point.y);

	/*
	local n = (end - start)
	n.Norm();
	local l = point - start
	local ta = n.Dot(l);

	if (ta < 0)
		return null;

	local d = sqrt(l.Dot(l) - ta*ta);

	if (d > radius)
		return null;

	local tb = sqrt(radius*radius - d*d);

	local t0 = ta - tb;
	local t1 = ta + tb;
	*/
	//	@TODO	-	can't be bothered

	return ::Collision.RaySphereIntersect(start, end, point, radius);

}