From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 7 Oct 2021 15:04:19 +0000 (+0300)
Subject: Use the shadow camera's projection matrix to form the shadow matrix
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=a313d4a1050815d987f855cafaea046dba158625;p=libs%2Fgl.git

Use the shadow camera's projection matrix to form the shadow matrix

This makes it easier to support different types of projection, such as
perspective projection for point lights.
---

diff --git a/source/effects/shadowmap.cpp b/source/effects/shadowmap.cpp
index 1b5f531b..a0627faa 100644
--- a/source/effects/shadowmap.cpp
+++ b/source/effects/shadowmap.cpp
@@ -153,10 +153,8 @@ void ShadowMap::setup_frame(Renderer &renderer)
 		l.shadow_camera.set_orthographic(radius*2, radius*2);
 		l.shadow_camera.set_depth_clip(-radius, radius);
 
-		Matrix shadow_matrix = l.shadow_camera.get_object_matrix();
-		shadow_matrix.scale(radius*2, radius*2, -radius*2);
-		shadow_matrix.translate(-0.5, -0.5, depth_bias/l.region.width-0.5);
-		shadow_matrix.invert();
+		Matrix to_texcoord = Matrix().translate(Vector3(0.5f, 0.5f, 0.5f-depth_bias/l.region.width)).scale(0.5f);
+		Matrix shadow_matrix = to_texcoord*l.shadow_camera.get_projection_matrix()*l.shadow_camera.get_view_matrix();
 
 		shdata.uniform(format("shadows[%d].shd_world_matrix", l.index), shadow_matrix);
 	}