Implement color for quadratic bezier curves

shader/bezierQuad.vert

@@ -1,7 +1,9 @@
 #version 430 core
 layout (location = 0) in vec3 position;
 layout (location = 1) in vec4 color;
+layout (location = 2) in float rad;
 out vec4 vColor;
+out float vRad;
 
 uniform vec2 winSize;
 uniform float zoom;
@@ -13,4 +15,5 @@ void main()
 {
   gl_Position = worldMat * vec4(position.xyz,1);
   vColor = color;
+  vRad   = rad;
 }