gistfile1.glsl

uniform sampler2D texture;
uniform vec3 tint;
varying vec2 texCoord;

void main() {
	vec4 texel = texture2D(texture, texCoord);

  if (texel.a < 0.5) {
      discard;
  }

	float fogStart = 1.0;
	float fogEnd = 50.0;

	float fogDistance = gl_FragCoord.z / gl_FragCoord.w;
	float fogAmount = (fogDistance - fogStart) / (fogEnd - fogStart);

	texel.xyz = mix(texel.xyz, vec3(0.0), clamp(fogAmount, 0.0, 1.0));
	gl_FragColor = texel;
}