Add completed circle shader, add incomplete arc shader

shader/arc.frag

@@ -0,0 +1,19 @@
+#version 430 core
+in vec4 gColor;
+in vec2 cenPosT;
+in float gRad;
+out vec4 fColor;
+out float gl_FragDepth;
+
+uniform vec2 winSize;
+
+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,cenPosT)));
+  //fColor = vec4( 0.5,0,0 , 1 );
+}