Use new cgi source.

Framework/lights/quad_light.cpp

@@ -52,10 +52,22 @@ namespace embree {
     Light_EvalRes QuadLight_eval(const Light* super,
                                  const Sample& dg,
                                  const Vec3fa& dir) {
+
+		const QuadLight* self = (QuadLight*)super;
         Light_EvalRes res;
         res.value = Vec3fa(0, 0, 0);
         res.dist = inf;
         res.pdf = 0.f;
+
+		Vec3fa normal = normalize(cross(self->edge2, self->edge1)); // Recalculate normal for safety
+		float dotProd = dot(normal, dir);
+
+		if (dotProd > 0) { 
+			res.value = self->radiance; 
+			res.dist = 0.f; 
+			res.pdf = self->ppdf; 
+		}
+
         return res;
     }