Apply shadow only to the naturally lit part of the fragment color (#11722)

Fragment color for nodes is now calculated from:

 * Texture color, highlighted by artificial light if present (light color conveyed via vertex color).
 * Texture color highlighted by natural light (conveyed via vertex color) filtered by shadow.
 * Reflected day/moonlight filtered by shadow (color and intensity), assuming some portion of the light is directly reflected from the materials.

1 files changed, 2 insertions, 3 deletions

diff --git a/client/shaders/shadow_shaders/pass1_trans_fragment.glsl b/client/shaders/shadow_shaders/pass1_trans_fragment.glsl
index 032cd9379..b267c2214 100644
--- a/client/shaders/shadow_shaders/pass1_trans_fragment.glsl
+++ b/client/shaders/shadow_shaders/pass1_trans_fragment.glsl
@@ -33,9 +33,8 @@ void main()
 	//col.rgb = col.a == 1.0 ? vec3(1.0) : col.rgb;
 #ifdef COLORED_SHADOWS
 	col.rgb *= varColor.rgb;
-	// alpha 0.0 results in all-white, 0.5 means full color, 1.0 means all black
-	// resulting color is used as a factor in the final shader
-	float packedColor = packColor(mix(mix(vec3(1.0), col.rgb, 2.0 * clamp(col.a, 0.0, 0.5)), black, 2.0 * clamp(col.a - 0.5, 0.0, 0.5)));
+	// premultiply color alpha (see-through side)
+	float packedColor = packColor(col.rgb * (1.0 - col.a));
 	gl_FragColor = vec4(depth, packedColor, 0.0,1.0);
 #else
 	gl_FragColor = vec4(depth, 0.0, 0.0, 1.0);