uniform sampler2D DiffuseTexture, Palette;

uniform bool EnableDepthPreview;
uniform float DepthTextureScale;

varying vec4 vTexCoord;
varying vec2 vTexMetadata;
varying vec4 vChannelMask;
varying vec4 vDepthMask;

void main()
{
	vec4 x = texture2D(DiffuseTexture, vTexCoord.st);
	vec2 p = vec2(dot(x, vChannelMask), vTexMetadata.s);
	vec4 c = texture2D(Palette, p);

	// Discard any transparent fragments (both color and depth)
	if (c.a == 0.0)
		discard;

	float depth = gl_FragCoord.z;
	if (length(vDepthMask) > 0.0)
	{
		vec4 y = texture2D(DiffuseTexture, vTexCoord.pq);
		depth = depth + DepthTextureScale * dot(y, vDepthMask);
	}

	// Convert to window coords
	gl_FragDepth = 0.5 * depth + 0.5;

	if (EnableDepthPreview)
	{
		// Front of the depth buffer is at 0, but we want to render it as bright
		gl_FragColor = vec4(vec3(1.0 - gl_FragDepth), 1.0);
	}
	else
		gl_FragColor = c;
}