Question

我正在使用SFML库在C ++上进行伪绘画（在C ++中接近零体验）。我做了一个单独的功能来编辑图像，“工具0”基本上是一支铅笔。当我尝试将此args传递给我的函数时，它不起作用，但是当我执行同样的操作而不将其传递给drawOnImage函数时，它将正常工作。我在显示的代码中剪掉了多余的部分

我尝试将鼠标位置的x和y作为单独的args传递（不使用Vector），但这无济于事

void drawOnImage(sf::Color color, int tool, sf::Texture canvas, sf::Image image, sf::Vector2i vector);

int main()
{
    sf::Image image;
    image.create(windowWidth, windowHeight, sf::Color::White);
    sf::Texture canvas;
    sf::Color currentColor = sf::Color::Black;  // Color
    int currentTool = 0; // instrument that is currently chosen
    sf::Sprite sprite;
    int mousedown = 0;
    mainWindow.setFramerateLimit(60);
    canvas.loadFromImage(image);
    sprite.setTexture(canvas);
while (mainWindow.isOpen())
    {
        canvas.loadFromImage(image);
        sf::Event event;
        while (mainWindow.pollEvent(event))
        {
            // "close requested" event: we close the window
            if (event.type == sf::Event::Closed)
                mainWindow.close();
            else if ((event.type == sf::Event::MouseMoved) && (mousedown == 1)) 
            {
                canvas.update(mainWindow);
                drawOnImage(currentColor, currentTool, canvas, image, sf::Mouse::getPosition(mainWindow));
            }
            else if (event.type == sf::Event::MouseButtonPressed)
            {
                mousedown = 1;
                drawOnImage(currentColor, currentTool, canvas, image, sf::Mouse::getPosition(mainWindow));
                //image.setPixel(sf::Mouse::getPosition(mainWindow).x, //IT WORKS but drawOnImage does not 
 sf::Mouse::getPosition(mainWindow).y, sf::Color::Black);
}
void drawOnImage(sf::Color color, int tool, sf::Texture canvas, sf::Image image,sf::Vector2i vector) {
    if (tool == 0) {
        image.setPixel(vector.x,vector.y, sf::Color::Black);
    }
}

我敢肯定，我只是不了解某些c ++功能，例如传递对象的地址而不是名称，但我自己无法弄清楚

为什么像素不改变颜色

0 个答案: