shader_type canvas_item;

uniform sampler2D gradient_texture;

void vertex() {
	// Called for every vertex the material is visible on.
}

void fragment() {
	vec4 existing_color = texture(TEXTURE, UV);
	float grayscale_value = (existing_color.r + existing_color.g + existing_color.b)/3.0;
	vec4 new_color = texture(gradient_texture, vec2(grayscale_value));
	COLOR.rgb = new_color.rgb;
	COLOR.a = existing_color.a;
}

//void light() {
//	// Called for every pixel for every light affecting the CanvasItem.
//	// Uncomment to replace the default light processing function with this one.
//}