Allow independent distortion of rgb channels

shader/texture/barrel.frag

@@ -1,12 +1,12 @@
 #version 450 core
 in vec2 texPos;
 in vec2 distmask[10];
-in vec2 pinch[10];
+in vec2 pinchr[10];
+in vec2 pinchg[10];
+in vec2 pinchb[10];
 out vec4 fColor;
 layout (binding = 1) uniform sampler2D screenTexture;
 layout (location = 0) uniform int n;
-//float x = 1 - min(1, sqrt(distance(distmask[0],vec2(0,0))));
-//float x = 1 - min(1, dot(distmask,distmask));
 vec3 toYUV (vec3 rgb)
 { return rgb * mat3
     ( 0.299  , 0.587  , 0.114
@@ -23,17 +23,19 @@ vec3 toRGB (vec3 yuv)
 }
 void main()
 {
-    vec2 tpos = texPos;
+    vec2 tposr = texPos;
+    vec2 tposb = texPos;
+    vec2 tposg = texPos;
     for(int i = 0; i < n; ++i)
     {
     float x = 1 - min(1, sqrt(distance(distmask[i],vec2(0,0))));
-    tpos += x * pinch[i];
+    tposr += x * pinchr[i];
+    tposg += x * pinchg[i];
+    tposb += x * pinchb[i];
     }
-    fColor = texture(screenTexture, tpos);
-    //fColor = texture(screenTexture
-    //        , (texPos + x * pinch[0] 
-    //            + y * pinch[1]
-    //            ));
+    fColor.r = texture(screenTexture, tposr).r;
+    fColor.b = texture(screenTexture, tposb).b;
+    fColor.g = texture(screenTexture, tposg).g;
 }
 //    fColor = vec4
 //        ( toRGB(vec3(  toYUV(texture(screenTexture, texPos).rgb).r