varying vec2 uv, uv1, uv2;
uniform sampler2D textures[3];
uniform vec4 sprite1;
uniform vec4 sprite2;
uniform float fade;

vec4 alphaBlend(vec4 dest, vec4 src) {
	float alpha = src.a + (dest.a * (1.0 - src.a));
	return vec4( ((src.rgb * src.a) + (dest.rgb * dest.a * (1.0 - src.a))) / alpha, alpha);
}

void main() {
	vec4 result = texture2D(textures[0],uv);
	result.rgb *= gl_Color.rgb;

	vec4 icon1 = texture2D(textures[1], mix(sprite1.xy, sprite1.zw, uv1));
	icon1.rgb = (fade * icon1.rgb) + ((1.0 - fade) * gl_Color.rgb);
	if(all(bvec4( greaterThanEqual(uv1, vec2(0.0)), lessThanEqual(uv1, vec2(1.0)))))
		result = alphaBlend( result, icon1 );
	
	vec4 icon2 = texture2D(textures[2], mix(sprite2.xy, sprite2.zw, uv2));
	icon2.a *= fade;
	if(all(bvec4( greaterThanEqual(uv2, vec2(0.0)), lessThanEqual(uv2, vec2(1.0)))))
		result = alphaBlend( result, icon2 );
	
	result.a *= gl_Color.a;
	gl_FragColor = result;
}