From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 25 Nov 2016 21:19:08 +0000 (+0200)
Subject: Account for scale when performing frustum culling
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=b6fd887102ab8e4109fa2edd40b9e51f80f88410;p=libs%2Fgl.git

Account for scale when performing frustum culling

It will still break with non-uniform scaling.
---

diff --git a/source/scene.cpp b/source/scene.cpp
index 1625ca32..6c3d2910 100644
--- a/source/scene.cpp
+++ b/source/scene.cpp
@@ -66,11 +66,15 @@ bool Scene::frustum_cull(const Renderable &renderable) const
 		return false;
 
 	Vector4 center = culling_matrix*(*matrix*compose(bsphere->get_center(), 1.0f));
-	float radius = bsphere->get_radius();
+	Vector4 x_axis = *matrix*Vector4(1.0f, 0.0f, 0.0f, 0.0f);
+	float radius_sq = bsphere->get_radius()*inner_product(x_axis, x_axis);
 
 	for(unsigned i=0; i<6; ++i)
-		if(inner_product(center, frustum_edges[i])>radius)
+	{
+		float distance = inner_product(center, frustum_edges[i]);
+		if(distance*distance>radius_sq)
 			return true;
+	}
 
 	return false;
 }