shader_type canvas_item;

uniform bool use_pallete;
uniform sampler2D pallete_texture;
uniform vec4 tint_color : hint_color = vec4(1.0);
uniform float tint_factor : hint_range(0, 1);

const float from_u = 0.25;
const float to_u = 0.75;
const float pal_size = 16f;
const float threshold = 0.001;

void fragment() {
	vec4 source_color = texture(TEXTURE , UV.xy);
	vec3 final_color = source_color.rgb;
	
	if (use_pallete){
		for (float i = 0f; i < pal_size; i++) {
			vec4 from_color = texture(pallete_texture , vec2(from_u, i/pal_size));
			vec4 to_color = texture(pallete_texture , vec2(to_u, i/pal_size));
			if(abs(length(source_color.rgb - from_color.rgb)) < threshold) final_color = to_color.rgb;
		}
	}

	COLOR.rgb = mix(final_color, tint_color.rgb, tint_factor);
	COLOR.a = source_color.a;
}