[SFML] Obliczanie wartości dla ::glScissor

//sf::RectangleShape area;
::glScissor( area.getPosition().x, area.getPosition().y + area.getSize().y, area.getSize().x, area.getSize().y );

Vector2f RenderTarget::convertCoords( const Vector2i & point, const View & view ) const
{
    // First, convert from viewport coordinates to homogeneous coordinates
    Vector2f coords;
    IntRect viewport = getViewport( view );
    coords.x = - 1.f + 2.f *( point.x - viewport.left ) / viewport.width;
    coords.y = 1.f - 2.f *( point.y - viewport.top ) / viewport.height;
   
    // Then transform by the inverse of the view matrix
    return view.getInverseTransform().transformPoint( coords );
}

const Transform & View::getTransform() const
{
    // Recompute the matrix if needed
    if( !m_transformUpdated )
    {
        // Rotation components
        float angle = m_rotation * 3.141592654f / 180.f;
        float cosine = static_cast < float >( std::cos( angle ) );
        float sine = static_cast < float >( std::sin( angle ) );
        float tx = - m_center.x * cosine - m_center.y * sine + m_center.x;
        float ty = m_center.x * sine - m_center.y * cosine + m_center.y;
       
        // Projection components
        float a = 2.f / m_size.x;
        float b = - 2.f / m_size.y;
        float c = - a * m_center.x;
        float d = - b * m_center.y;
       
        // Rebuild the projection matrix
        m_transform = Transform( a * cosine, a * sine, a * tx + c,
        - b * sine, b * cosine, b * ty + d,
        0.f, 0.f, 1.f );
        m_transformUpdated = true;
    }
   
    return m_transform;
}


////////////////////////////////////////////////////////////
const Transform & View::getInverseTransform() const
{
    // Recompute the matrix if needed
    if( !m_invTransformUpdated )
    {
        m_inverseTransform = getTransform().getInverse();
        m_invTransformUpdated = true;
    }
   
    return m_inverseTransform;
}

Vector2f konwertuj( CRenderWindow & view, const Vector2f & coords )
{
    return view.getTransform().transformPoint( coords );
}