Support A2C for groundcover

files/shaders/groundcover_fragment.glsl

@@ -30,11 +30,7 @@ centroid varying vec3 shadowDiffuseLighting;
 
 #include "shadows_fragment.glsl"
 #include "lighting.glsl"
-
-float calc_coverage(float a, float alpha_ref, float falloff_rate)
-{
-    return clamp(falloff_rate * (a - alpha_ref) + alpha_ref, 0.0, 1.0);
-}
+#include "alpha.glsl"
 
 void main()
 {
@@ -55,12 +51,13 @@ void main()
     gl_FragData[0] = vec4(1.0);
 #endif
 
-    gl_FragData[0].a = calc_coverage(gl_FragData[0].a, 128.0/255.0, 4.0);
-
-    float shadowing = unshadowedLightRatio(linearDepth);
     if (euclideanDepth > @groundcoverFadeStart)
         gl_FragData[0].a *= 1.0-smoothstep(@groundcoverFadeStart, @groundcoverFadeEnd, euclideanDepth);
 
+    alphaTest();
+
+    float shadowing = unshadowedLightRatio(linearDepth);
+
     vec3 lighting;
 #if !PER_PIXEL_LIGHTING
     lighting = passLighting + shadowDiffuseLighting * shadowing;