SDL 窗口未出现答案

【问题标题】：SDL Window Not AppearingSDL 窗口未出现
【发布时间】：2016-05-11 22:34:41
【问题描述】：

我正在尝试显示一个 SDL 窗口，但它似乎不起作用。程序将运行，显示窗口的功能将正常运行，但我的屏幕上没有任何显示。我在 Dock 中只有一个图标，表示程序没有响应。这是我的代码：

int main(int argc, const char * argv[]) {

    MainComponent mainComponent;
    mainComponent.init();

    char myVar;

    cout << "Enter any key to quit...";
    cin >> myVar;

    return 0;
}

void MainComponent::init() {
    //Initialize SDL
    SDL_Init(SDL_INIT_EVERYTHING);

    window = SDL_CreateWindow("My Game Window", 100, 100, 100, 100, SDL_WINDOW_SHOWN);

    cout << screenWidth << " " << screenHeight << endl;

    if(window == nullptr) {
        cout << "Error could not create window" << SDL_GetError() << endl;
    }

    SDL_Delay(5000);

}

这是 Dock 上图标的屏幕截图https://www.dropbox.com/s/vc01iqp0z07zs25/Screenshot%202016-02-02%2017.26.44.png?dl=0 如果我做错了什么，请告诉我，谢谢！

【问题讨论】：

标签： c++ sdl

【解决方案1】：

SDL_Renderer 应该被初始化来处理渲染。这在What is a SDL renderer? 有详细解释。

这是上面修改后的代码，带有初始化的渲染器；

#include <SDL2/SDL.h>
#include <iostream>

using namespace std;

class MainComponent
{
 public:
    void init();
    ~MainComponent();

 private:
    SDL_Window *window;
    SDL_Renderer* renderer;
};

MainComponent::~MainComponent()
{
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
}

void MainComponent::init() {
    //Initialize SDL
    SDL_Init(SDL_INIT_EVERYTHING);

    int screenWidth = 400;
    int screenHeight = 300;

    window = SDL_CreateWindow("My Game Window", 100, 100, screenWidth, screenHeight, SDL_WINDOW_SHOWN);
    renderer = SDL_CreateRenderer(window, -1, 0);

    cout << screenWidth << " " << screenHeight << endl;

    if(window == nullptr) {
        cout << "Error could not create window" << SDL_GetError() << endl;
    }

    //change the background color
    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);

    // Clear the entire screen to our selected color.
    SDL_RenderClear(renderer);

    // Up until now everything was drawn behind the scenes.
    // This will show the new, red contents of the window.
    SDL_RenderPresent(renderer);


    SDL_Delay(5000);

}


int main(int argc, const char * argv[]) {

    MainComponent mainComponent;
    mainComponent.init();

    char myVar;

    cout << "Enter any key to quit...";
    cin >> myVar;

    SDL_Quit();
    return 0;
}

这应该可以正确编译和运行。希望对您有所帮助。

【讨论】：