Improve ellipses

shader/ellipse.frag

@@ -1,25 +1,13 @@
 #version 430 core
 in vec4 gColor;
-in vec2 gFocusA;
-in vec2 gFocusB;
-in float gRad;
+in vec2 gBoundingBox;
 
 out vec4 fColor;
 //out float gl_FragDepth;
 
 void main()
 {
-  vec2 pos = gl_FragCoord.xy;
- // fColor = vec4( gColor.xyz , 0 );
- // fColor = vec4( gColor.xyz , 1 - step(distance(pos,cenPos.xy),gRad) );
- // fColor = vec4( gColor.xyz , distance(pos,cenPos.xy)/gRad );
-//  fColor = vec4( gColor.rgb, gColor.a * (1-step(gRad/2,distance(pos,cenPosT))) );
-  gl_FragDepth = max( gl_FragCoord.z 
-                    , step(gRad/2
-                          , distance(pos,gFocusA) + distance(gFocusA,gFocusB)
-                            //+ distance(pos,gFocusB)
-                          )
-                    );
+  if ( dot(gBoundingBox,gBoundingBox) > 1) { discard; }
   fColor = gColor;
 //  fColor = vec4 (1,1,1,1);
 }