[SFML] Animowanie Wody - Shadery

class Water
    : public sf::Drawable
    , public sf::Transformable
{
public:
    int width, height;
    sf::Vector2i coords;
   
    sf::VertexArray vertexes;
    sf::Texture waterset;
   
    std::vector < int > waters;
   
    Water( int x, int y, int width, int height ) {
       
        coords.x = x;
        coords.y = y;
       
        this->width = width;
        this->height = height;
       
        waterset = sf::Texture();
        waterset = * getTexture( "floors/0_floorset" )->texture;
       
        vertexes.setPrimitiveType( sf::Triangles );
        vertexes.resize( width * height * 6 ); // widthMap * heightMap * TwoTrianglesVertices
       
        waters.resize( width * height );
       
        int coord_x, coord_y;
       
        for( int y = 0; y < height; y++ )
        for( int x = 0; x < width; x++ ) {
           
            sf::Vertex * triangles = & vertexes[( y * width + x ) * 6 ];
           
            coord_x =( coords.x + x );
            coord_y =( coords.y + y );
           
            triangles[ 0 ].position = sf::Vector2f( coord_x * tileSide, coord_y * tileSide );
            triangles[ 1 ].position = sf::Vector2f(( coord_x + 1 ) * tileSide, coord_y * tileSide );
            triangles[ 2 ].position = sf::Vector2f( coord_x * tileSide,( coord_y + 1 ) * tileSide );
            triangles[ 3 ].position = sf::Vector2f( coord_x * tileSide,( coord_y + 1 ) * tileSide );
            triangles[ 4 ].position = sf::Vector2f(( coord_x + 1 ) * tileSide, coord_y * tileSide );
            triangles[ 5 ].position = sf::Vector2f(( coord_x + 1 ) * tileSide,( coord_y + 1 ) * tileSide );
           
            edit( x, y, 0 );
        }
       
       
    }
   
    void edit( int x, int y, int value ) {
       
        if( x < 0 || x >= width || y < 0 || y >= height )
             return;
       
        if( value > 3 || value < 0 )
             return;
       
        waters[ y * width + x ] = value;
       
        int global_x = coords.x + x;
        int global_y = coords.y + y;
       
        sf::Vertex * triangles = & vertexes[( y * width + x ) * 6 ];
       
        int tu =( int( global_x * tileSide ) % 64 ) +( value * 64 );
        int tv =( int( global_y * tileSide ) % 64 );
       
        //cout << "tu: " << tu << ", tv: " << tv << "\n";
       
        triangles[ 0 ].texCoords = sf::Vector2f( tu, tv );
        triangles[ 1 ].texCoords = sf::Vector2f( tu + tileSide, tv );
        triangles[ 2 ].texCoords = sf::Vector2f( tu, tv + tileSide );
        triangles[ 3 ].texCoords = sf::Vector2f( tu, tv + tileSide );
        triangles[ 4 ].texCoords = sf::Vector2f( tu + tileSide, tv );
        triangles[ 5 ].texCoords = sf::Vector2f( tu + tileSide, tv + tileSide );
    }