PathTracer1_3

float sphereDistance(vec3 point, vec3 sphereOrigin, float sphereRadius) { 
  return length(point - sphereOrigin) - sphereRadius;
}

void main(void) {
      vec3 rayDir = normalize(vPosition - vEyePosition);
      if (sphereDistance(vPosition, vec3(0,1,0), 1.1) > 0.)
          discard;
      gl_FragColor = vec4(rayDir, 1.0);
}