medfall

commit 849d34a0f7892d76e4680d442f394093fa52f6e6
parent 10f29dec0c134eb431ec6370ab945c38ae05f58c
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Mon Aug 28 17:47:15 +0100

Much better shadow map biasing

Diffstat:
shaders/shadowed_vertex_colours.glsl
 | 
13
+++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/shaders/shadowed_vertex_colours.glsl b/shaders/shadowed_vertex_colours.glsl
@@ -50,14 +50,23 @@ void main() {
 in VSOut v2f;
 out vec4 screen_colour;
 
+// http://the-witness.net/news/2013/09/shadow-mapping-summary-part-1/
+vec2 get_shadow_offsets( vec3 N, vec3 L ) {
+	float cos_alpha = dot_sat( N, L );
+	float offset_scale_N = sqrt( 1.0 - cos_alpha * cos_alpha );
+	float offset_scale_L = offset_scale_N / cos_alpha;
+	return vec2( offset_scale_N, min( 5.0, offset_scale_L ) );
+}
+
 void main() {
 	vec3 light_colour = vec3( 400.0, 400.0, 400.0 );
-	vec3 lightdir = normalize( v2f.position - light_pos );
+	vec3 lightdir = normalize( light_pos - v2f.position );
 	vec3 to_camera = normalize( camera_pos - v2f.position );
 
 	vec3 light_ndc = v2f.light_space_position.xyz / v2f.light_space_position.w;
 	vec3 light_norm = light_ndc * 0.5 + 0.5;
-	float bias2 = max( bias * ( 1.0 + dot( lightdir, v2f.normal ) ), bias / 100 );
+	vec2 offsets = get_shadow_offsets( v2f.normal, lightdir );
+	float bias = 0.00002 + 0.00001 * offsets.x + 0.00005 * offsets.y;
 
 	float shadow = 0;