Continue refactoring shaders

shader/ellipse.frag

@@ -1,5 +1,6 @@
 #version 430 core
-in vec4 gColor;
+in vec4 gColorC;
+in vec4 gColorE;
 in vec2 gBoundingBox;
 
 out vec4 fColor;
@@ -7,8 +8,8 @@ out vec4 fColor;
 
 void main()
 {
-  if ( dot(gBoundingBox,gBoundingBox) > 1) { discard; }
-  fColor = gColor;
-//  fColor = vec4 (1,1,1,1);
+  float d = dot(gBoundingBox,gBoundingBox);
+  if ( d > 1) { discard; }
+  fColor = mix (gColorE , gColorC, d);
 }
 //note it is the fragdepth that stops this from being square