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zqf

Expanding on slab based line vs AABB

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I can't remember where I found the source for this, but I converted this algorithm from C to actionscript and it works perfectly, giving me the position of the hit if one has occurred.
However I'd like to extend it so it can give me the specific side that the ray hit, so I can use it for bouncing objects off. Is this possible with this algorithm (and if so how) or would it be better to use a different technique?

[CODE]
public static function LineSegmentVsTile(v1:LineSeg, AABB:ATile, impactPoint:Point):Boolean
{
var dirFracX:Number = 1 / v1.vx;
var dirFracY:Number = 1 / v1.vy;

var t1:Number = (AABB.position.x - v1.a.x) * dirFracX;
var t2:Number = ((AABB.position.x + (AABB.halfWidth * 2)) - v1.a.x) * dirFracX;
var t3:Number = (AABB.position.y - v1.a.y) * dirFracY;
var t4:Number = ((AABB.position.y + (AABB.halfHeight * 2)) - v1.a.y) * dirFracY;

var tmin:Number = Math.Max(Math.Min(t1, t2), Math.Min(t3, t4));
var tmax:Number = Math.Min(Math.Max(t1, t2), Math.Max(t3, t4));

if (tmax < 0)
{
return false;
}
else if (tmin > 1)
{
return false;
}
else if (tmin > tmax)
{
return false;
}
else
{
if (impactPoint)
{
var colX:Number = v1.vx * tmin;
var colY:Number = v1.vy * tmin;

impactPoint.x = v1.a.x + colX;
impactPoint.y = v1.a.y + colY;
}
return true;
}
}
[/CODE]

Thanks

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