RectangleLight: fix crash

Author: LeoVgr

h3d/scene/pbr/RectangleLight.hx

@@ -182,6 +182,7 @@ class RectangleLight extends Light {
 		points.push(p2);
 
 		primitive = new h3d.prim.Polygon(points);
+		cast (primitive, h3d.prim.Polygon).addNormals();
 		return primitive;
 	}
 

h3d/shader/pbr/Light.hx

@@ -216,6 +216,7 @@ class RectangleLight extends Light {
 
 		var view : Vec3;
 		var normal : Vec3;
+		final epsilon : Float = 0.00001;
 
 		function getIntersectionPoint(rayOrigin : Vec3, rayDirection : Vec3, p0 : Vec3, p1 : Vec3, p2 : Vec3) : Vec3 {
 			var planeNormal = cross(p1 - p0, p2 - p1).normalize();
@@ -276,13 +277,13 @@ class RectangleLight extends Light {
 			var delta = closestPointDiffuse - transformedPosition;
 			pbrLightDirection = normalize(delta);
 
-			var xyEpsilon = horizontalFallOff - horizontalAngle;
+			var xyEpsilon = horizontalFallOff - horizontalAngle + epsilon;
 			var xyLightDir = invLightDir - dot(invLightDir, up) * up;
 			var xyDelta = delta - dot(delta, up) * up;
 			var xyTheta = dot(xyDelta.normalize(), xyLightDir.normalize());
 			var horizontalFalloff = saturate((xyTheta - horizontalAngle) / xyEpsilon);
 
-			var xzEpsilon = verticalFallOff - verticalAngle;
+			var xzEpsilon = verticalFallOff - verticalAngle + epsilon;
 			var xzLightDir = invLightDir - dot(invLightDir, right) * right;
 			var xzDelta = delta - dot(delta, right) * right;
 			var xzTheta = dot(xzDelta.normalize(), xzLightDir.normalize());