shader_type canvas_item;

// Input textures for source and target palettes.
uniform sampler2D source_palette : source_color;
uniform sampler2D target_palette : source_color;
uniform int color_count = 6; // Default to 6 colors

void fragment() {
    // Get the current pixel color
    vec3 current_color = COLOR.rgb;

    // Find the matching color in the source palette
    bool found = false;
    for (int i = 0; i < color_count; i++) {
        // Sample exact pixel from the palette texture
        // For a 6x1 texture, the centers of the pixels are at x coordinates: 0.5/6, 1.5/6, 2.5/6, etc.
        float x_coord = (float(i) + 0.5) / float(color_count);
        vec3 palette_color = texture(source_palette, vec2(x_coord, 0.5)).rgb;

        // Compare colors (with a small tolerance for floating point precision)
        if (distance(current_color, palette_color) < 0.01) {
            // Get the corresponding color from the target palette at the same position
            vec3 target_color = texture(target_palette, vec2(x_coord, 0.5)).rgb;
            COLOR.rgb = target_color;
        }
    }
}