Implement varying width in bezierQuad

shader/bezierQuad.frag

@@ -8,12 +8,23 @@ float x = gBoundingBox.x;
 float y = gBoundingBox.y;
 float z = gBoundingBox.z;
 
+float w = 0.1;
+
+float f (float a, float b)
+{   
+    float c = 1 / (1 - 2*b) ;
+    return c * (a - 0.5) + 0.5 ;
+}
 void main()
 {
+
   //float d = x - y - 1 + 2* sqrt(y);
   float d = sqrt(x) + sqrt(y) - 1;
-//  if ( d < -0.1 || d > 0.1) { discard; }
+  float e = sqrt(f(x,w)) + sqrt(f(y,w)) - 1;
+  if ( d < 0 || e > 0) { discard; }
   fColor = gColor;
-  if ( d < -z*0.1 || d > z*0.1) { fColor = vec4 (0,1,0,1); }
+//  if ( d < 0) { fColor = vec4 (0,1,0,1); }
-  if ( d < -0.1 || d > 0.1) { fColor = vec4 (0,0,1,1); }
+//  if ( e > 0) { fColor = vec4 (0,0,1,1); }
+//  if ( d < z*z*0.0 || d > z*z*0.1+ 0.5) { fColor = vec4 (0,1,0,1); }
+//  if ( d < -0.1 || d > 0.1) { fColor = vec4 (0,0,1,1); }
 }

shader/bezierQuad.geom

@@ -11,11 +11,14 @@ void main()
   vec3 pb = gl_in[1].gl_Position.xyz;
   vec3 pc = gl_in[2].gl_Position.xyz;
 
+//  vec3 pa = vec3(paa.xy + 0.1 * (paa.xy - pca.xy), paa.z);
+//  vec3 pc = vec3(pca.xy + 0.1 * (pca.xy - paa.xy), pca.z);
+
   gBoundingBox = vec3 (1,0,1);
   gColor = vColor[0];
   gl_Position = vec4 (pa, 1);
   EmitVertex();
-  gBoundingBox = vec3 (0,0,-0.9);
+  gBoundingBox = vec3 (0,0,0);
   gColor = vColor[1];
   gl_Position = vec4 (pb, 1);
   EmitVertex();

src/Dodge/Rendering.hs

@@ -121,7 +121,7 @@ worldPictures w
                 where tst x y sc t = translate x y $ scale sc sc $ color white $ text t
 
 testPic :: World -> [Picture]
-testPic w = [setLayer 1 $ onLayerL [99] $ color red $ bezierQuad (-90,0) (90,-50) (-200,200) ]
+testPic w = [setLayer 1 $ onLayerL [99] $ color red $ bezierQuad (-200,200) (-200,-200) (200,200) ]
 -- $ uncurry translate (mouseWorldPos w)