Merge pull request #3 from sigma-axis/alpha

アルファ値で加重平均するように変更．

Author: Mr-Ojii

script/RotBlur_M.frag

@@ -5,7 +5,6 @@ in vec2 TexCoord;
 layout(location = 0) out vec4 FragColor;
 
 uniform sampler2D texture0;
-uniform float stepAngle;
 uniform int quality;
 uniform vec2 resolution;
 uniform vec2 pivot;
@@ -17,13 +16,21 @@ void main() {
     vec2 uv1 = (TexCoord * resolution - pivot) * rPos;
     vec2 uv2 = uv1;
     vec4 color = texture(texture0, clamp((uv1 + pivot) / resolution, 0, 1));
+    color.rgb *= color.a;
 
     for(int i = 1; i <= quality; i++){
         uv1 *= rot1;
-        color += texture(texture0, clamp((uv1 + pivot) / resolution, 0, 1));
+        vec4 c = texture(texture0, clamp((uv1 + pivot) / resolution, 0, 1));
+        c.rgb *= c.a;
+        color += c;
 
         uv2 *= rot2;
-        color += texture(texture0, clamp((uv2 + pivot) / resolution, 0, 1));
+        c = texture(texture0, clamp((uv2 + pivot) / resolution, 0, 1));
+        c.rgb *= c.a;
+        color += c;
     }
-    FragColor = color / (quality * 2 + 1);
+
+    color.rgb /= color.a;
+    color.a /= quality * 2 + 1;
+    FragColor = color;
 }