[SFML 3.0.2] Shadery a pamięć

sf::Sprite sprite(( _state == ButtonState::Idle ) ? * _texture->_texture
    : * _hoverTexture->_texture );
sprite.setPosition( sf::Vector2f( _rect.position ) );
sf::RenderStates rs;
sf::Shader sh;
sh.loadFromMemory( palette_shader_source, sf::Shader::Type::Fragment );

sh.setUniform( "iTime", float( currentTime.asSeconds() ) );

const sf::Texture & tex =( _state == ButtonState::Idle ) ? * _texture->_texture
    : * _hoverTexture->_texture;
sf::IntRect r = sprite.getTextureRect(); // px w atlasie
sf::Vector2u ts = tex.getSize(); // rozmiar atlasu

sf::Glsl::Vec4 texRectUV(
float( r.position.x ) / ts.x,
float( r.position.y ) / ts.y,
float( r.position.x + r.size.x ) / ts.x,
float( r.position.y + r.size.y ) / ts.y
);

sh.setUniform( "texRectUV", texRectUV );
rs.shader = & sh;
window->draw( sprite, rs );