Partially working ellipse shader

shader/circle.vert

@@ -13,7 +13,7 @@ uniform mat4 worldMat;
 
 void main()
 {
-  gl_Position = worldMat * vec4(position.xyz,1);
+  gl_Position = worldMat * vec4(position,1);
   vColor = color;
   vRad = rad;
 }

shader/ellipse.frag

@@ -0,0 +1,26 @@
+#version 430 core
+in vec4 gColor;
+in vec2 gFocusA;
+in vec2 gFocusB;
+in float gRad;
+
+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)
+                          )
+                    );
+  fColor = gColor;
+//  fColor = vec4 (1,1,1,1);
+}
+//note it is the fragdepth that stops this from being square

shader/ellipse.geom

@@ -0,0 +1,45 @@
+#version 430 core
+layout (lines) in;
+layout (triangle_strip, max_vertices = 4) out;
+in vec4 vCol[];
+in float vRad[];
+out vec4 gColor;
+out float gRad;
+out vec2 gFocusA;
+out vec2 gFocusB;
+
+uniform vec2 winSize;
+uniform float zoom;
+
+void main()
+{
+  vec3 focusA = gl_in[0].gl_Position.xyz;
+  vec3 focusB = gl_in[1].gl_Position.xyz;
+  gColor = vCol[0];
+  gRad = vRad[0] * zoom * 2 ;
+
+  gFocusA = vec2 ( (focusA.x + 1) * 0.5 * winSize.x , (focusA.y + 1) * 0.5 * winSize.y);
+//  focusA = vec3 ( 0 , 0, focusA.z);
+  gFocusB = vec2 ( (focusB.x + 1) * 0.5 * winSize.x , (focusB.y + 1) * 0.5 * winSize.y);
+  float am = 0.5;
+
+  gl_Position = vec4 (focusA.x + gRad/winSize.x, focusA.y + gRad/winSize.y, focusA.z , 1);
+//  gl_Position = vec4 (focusA.x + am, focusA.y + am, -1 , 1);
+//  gl_Position = vec4 (focusA , 1);
+  EmitVertex();
+  gl_Position = vec4 (focusA.x - gRad/winSize.x, focusA.y + gRad/winSize.y, focusA.z , 1);
+//  gl_Position = vec4 (focusA.x - am, focusA.y + am, -1 , 1);
+//  gl_Position = vec4 (0 ,0.5 ,-1 , 1);
+//  gl_Position = vec4 (0 + gRad ,0 ,-1 , 1);
+  EmitVertex();
+  gl_Position = vec4 (focusA.x + gRad/winSize.x, focusA.y - gRad/winSize.y, focusA.z , 1);
+//  gl_Position = vec4 (focusA.x + am, focusA.y - am, -1 , 1);
+//  gl_Position = vec4 (0.5 ,0.5 ,-1 , 1);
+  EmitVertex();
+  gl_Position = vec4 (focusA.x - gRad/winSize.x, focusA.y - gRad/winSize.y, focusA.z , 1);
+//  gl_Position = vec4 (focusA.x - am, focusA.y - am, -1 , 1);
+//  gl_Position = vec4 (0.5 ,0 ,-1 , 1);
+  EmitVertex();
+
+  EndPrimitive();
+}

shader/ellipse.vert

@@ -0,0 +1,19 @@
+#version 430 core
+layout (location = 0) in vec3 position;
+layout (location = 1) in vec4 col;
+layout (location = 2) in float rad;
+out vec4 vCol;
+out float vRad;
+
+uniform vec2 winSize;
+uniform float zoom;
+uniform vec2 translation;
+uniform float rotation;
+uniform mat4 worldMat;
+
+void main()
+{
+  gl_Position = worldMat * vec4(position,1);
+  vRad = rad;
+  vCol = col;
+}