From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 4 Dec 2015 18:41:43 +0000 (+0200)
Subject: Calculate depths in ZSortedScene more efficiently
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=b345b919f572b35042d7c50291422f2f917e5a08;p=libs%2Fgl.git

Calculate depths in ZSortedScene more efficiently
---

diff --git a/source/zsortedscene.cpp b/source/zsortedscene.cpp
index f61de577..0d50ae1e 100644
--- a/source/zsortedscene.cpp
+++ b/source/zsortedscene.cpp
@@ -28,13 +28,13 @@ void ZSortedScene::render(Renderer &renderer, const Tag &tag) const
 	if(!camera)
 		return SimpleScene::render(renderer, tag);
 
-	const Matrix &view_matrix = camera->get_matrix();
-
 	std::vector<DepthRenderable> sorted_renderables;
 	sorted_renderables.reserve(renderables.size());
 
-	float radius_factor = 1.0f-reference;
-	float sign = order*2.0f-1.0f;
+	const Vector3 &camera_pos = camera->get_position();
+	const Vector3 &look_dir = camera->get_look_direction();
+	float radius_factor = reference-1.0f;
+	float sign = 1.0f-order*2.0f;
 
 	bool use_frustum = setup_frustum(renderer);
 	for(RenderableSet::const_iterator i=renderables.begin(); i!=renderables.end(); ++i)
@@ -44,9 +44,9 @@ void ZSortedScene::render(Renderer &renderer, const Tag &tag) const
 			if(const Matrix *model_matrix = (*i)->get_matrix())
 			{
 				if(const Geometry::BoundingSphere<float, 3> *bsphere = (*i)->get_bounding_sphere())
-					z = (view_matrix**model_matrix*compose(bsphere->get_center(), 1.0f)).z+bsphere->get_radius()*radius_factor;
+					z = dot(*model_matrix*bsphere->get_center()-camera_pos, look_dir)+bsphere->get_radius()*radius_factor;
 				else
-					z = (view_matrix**model_matrix*Vector4(0.0f, 0.0f, 0.0f, 1.0f)).z;
+					z = dot(*model_matrix*Vector3()-camera_pos, look_dir);
 			}
 			sorted_renderables.push_back(DepthRenderable(z*sign, *i));
 		}