#version 120
// uniform data
uniform sampler2D texture_sampler;
// in
varying vec2 frag_uv;
varying vec3 frag_normal;

void main() {
  if (frag_normal.x > 0.0 || frag_normal.z < 0.0 || frag_normal.y < 0.0) {
    gl_FragColor = texture2D(texture_sampler, frag_uv) * vec4(0.85, 0.85, 0.85, 1.0);
  } else {
    gl_FragColor = texture2D(texture_sampler, frag_uv);
  }
  //gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}