shader RibbonBackgroundShader : SpriteBase
{
    stage float3 Top;
    stage float3 Bottom;
    stage float WidthFactor;
    stage float DeltaTime;
    stage float Frequency;
    stage float Amplitude;
    stage float Speed;
    stage float Intensity;

    // Shading of the sprite
    stage override float4 Shading()
    {
        float2 uv = streams.TexCoord.xy;
        float3 color = float3(lerp(Top, Bottom, uv.x * uv.y * 1.1));
        color = color + CalcSine(uv, Speed * 0.2f, Frequency * 0.20f, Amplitude * 0.2f, 0.0f, 0.5f, float3(0.3f, 0.3f, 0.3f), 0.1f, 15.0f,false);
        color = color + CalcSine(uv, Speed * 0.4f, Frequency * 0.40f, Amplitude * 0.15f, 0.0f, 0.5f, float3(0.3f, 0.3f, 0.3f), 0.1f, 17.0f,false);
        color = color + CalcSine(uv, Speed * 0.3f, Frequency * 0.60f, Amplitude * 0.15f, 0.0f, 0.5f, float3(0.3f, 0.3f, 0.3f), 0.05f, 23.0f,false);

        color = color + CalcSine(uv, Speed * 0.1f, Frequency * 0.26f, Amplitude * 0.07f, 0.0f, 0.3f, float3(0.3f, 0.3f, 0.3f), 0.1f, 17.0f,true);
        color = color + CalcSine(uv, Speed * 0.3f, Frequency * 0.36f, Amplitude * 0.07f, 0.0f, 0.3f, float3(0.3f, 0.3f, 0.3f), 0.1f, 17.0f,true);
        color = color + CalcSine(uv, Speed * 0.5f, Frequency * 0.46f, Amplitude * 0.07f, 0.0f, 0.3f, float3(0.3f, 0.3f, 0.3f), 0.05f, 23.0f,true);
        color = color + CalcSine(uv, Speed * 0.2f, Frequency * 0.58f, Amplitude * 0.05f, 0.0f, 0.3f, float3(0.3f, 0.3f, 0.3f), 0.2f, 15.0f,true);
        
        return float4(color.x, color.y, color.z, 0.5f) * Intensity;
    }

    stage float3 CalcSine(float2 uv, float speed, float frequency, float amplitude, float shift, float offset, float3 color, float width, float exponent, bool dir)
    {
        float angle = DeltaTime * speed * frequency * -1.0f + (shift + uv.x) * 2.0f;
    
        float y = sin(angle) * amplitude + offset;
        float clampY = clamp(0.0f, y, y);
        float diffY = y - uv.y;
        
        float dsqr = distance(y, uv.y);
        float scale = 1.0f;
        
        if(dir && diffY > 0.0f)
        {
            dsqr = dsqr * 4.0f;
        }
        else if(!dir && diffY < 0.0f)
        {
            dsqr = dsqr * 4.0f;
        }
        
        scale = pow(smoothstep(width * WidthFactor, 0.0f, dsqr), exponent);
        
        return min(color * scale, color);
    }
};