Improve bezier curve rendering

shader/bezierQuad.vert

@@ -1,9 +1,10 @@
 #version 430 core
 layout (location = 0) in vec3 position;
 layout (location = 1) in vec4 color;
-layout (location = 2) in float rad;
+layout (location = 2) in vec3 radVec;
 out vec4 vColor;
-out float vRad;
+out vec2 vPosOff;
+out float vRadMag;
 
 uniform vec2 winSize;
 uniform float zoom;
@@ -14,6 +15,7 @@ uniform mat4 worldMat;
 void main()
 {
   gl_Position = worldMat * vec4(position.xyz,1);
-  vColor = color;
-  vRad   = rad;
+  vColor  = color;
+  vPosOff = ( worldMat * vec4(radVec.xy,0,1) ).xy ;
+  vRadMag = radVec.z ;
 }