const char *volume_box_fs =
  "#version 400\n"
  "precision highp float;\n"
  "\n"
  "in vec3 vWorldPos;\n"
  "\n"
  "out vec4 colorOut;\n"
  "\n"
  "void main()\n"
  "{\n"
  "    // Store world position (will be used for ray marching)\n"
  "    colorOut = vec4(vWorldPos, 1.0);\n"
  "}\n"
  "\n";
