shader_type canvas_item;

#define pow2(x) (x * x)
#define iResolution 1.0/SCREEN_PIXEL_SIZE

uniform sampler2D data_texture;
uniform vec2 data_texture_size;
uniform sampler2D texture_low : filter_nearest, repeat_enable;
uniform float texture_low_threshold : hint_range(0, 1) = 0.3;
uniform sampler2D texture_medium : filter_nearest, repeat_enable;
uniform sampler2D texture_high : filter_nearest, repeat_enable;
uniform float texture_high_threshold : hint_range(0, 1) = 0.7;

uniform int dimension;
uniform vec2 texture_size = vec2(100,100);

uniform float smooth_change_range = 0.15;

varying vec2 vert;

void vertex() {
	vert = VERTEX;
}

void fragment() {
	vec4 pixel_color = texture(data_texture, vert/data_texture_size);
	float value = pixel_color.x;
	if (dimension == 1) value = pixel_color.y;
	if (dimension == 2) value = pixel_color.z;

	vec4 color = texture(texture_medium, vert/texture_size);

	if (value < texture_low_threshold)
		color =
			min(
				(texture_low_threshold - value) / smooth_change_range,
				1.0
			) * texture(texture_low, vert/texture_size)
			+ (1.0 - min(
					(texture_low_threshold - value) / smooth_change_range,
					1.0
				)
			) * texture(texture_medium, vert/texture_size);
	if (value > texture_high_threshold)
		color =
			min(
				(value - texture_high_threshold) / smooth_change_range,
				1.0
			) * texture(texture_high, vert/texture_size)
			+ (1.0 - min(
					(value - texture_high_threshold) / smooth_change_range,
					1.0
				)
			) * texture(texture_medium, vert/texture_size);

	COLOR = color;
}