shader_type spatial;
render_mode unshaded, cull_disabled;

// uniforms: detail_strength, scroll_speed, fire_height, fire_shape,
// fire_thickness, fire_sharpness, intensity
// noise parameters: noise_octaves, noise_lacunarity, noise_gain,
// noise_amplitude, noise_frequency

//float hash(vec2 p) { /* ... */ }
//float noise(vec2 x) { /* ... */ }
//float fbm(vec2 p) { /* ...mix octaves...*/ }

void fragment() {
    vec2 uv = UV;
    vec2 muv = -uv;
    muv.x = mod(muv.x, 1.0) - 0.5;
    muv.y += 0.84;

    float scroll = scroll_speed * detail_strength * TIME;
    float n = fbm(detail_strength * muv - vec2(0.0, scroll));

    float fire_intensity = intensity - 16.0 * fire_sharpness * pow(
        max(0.0,
            length(
                muv * vec2((1.0/fire_thickness) + muv.y * fire_shape, 1.0/fire_height)
            ) - n * max(0.0, muv.y + 0.25)
        ), 1.2
    );

    float fi1 = clamp(n * fire_intensity * (1.5 - pow(uv.y, 14.0)), 0.0, 1.0);

    vec3 col = vec3(
        1.5 * fi1,
        1.5 * pow(fi1, 3.0),
        pow(fi1, 6.0)
    );

    float alpha = fire_intensity * (1.0 - pow(uv.y, 3.0));
    vec4 final = vec4(mix(vec3(0.0), col, alpha), alpha);

    ALBEDO = final.rgb;
    ALPHA = final.a;
}