Question

在我的代码中，我有这些东西可以检查我的代码是否在创建SDL窗口时出错，初始化GLEW等等。他们会离开，我的程序仍然会工作，在the guide I'm following，没有任何错误发生。有人能告诉我我做错了吗？

此外，glClearColor()似乎无效。我认为它与上述错误有关。

我的代码：

// g++ `pkg-config --cflags glew sdl2` main.cpp `pkg-config --libs glew sdl2`
#include <GL/glew.h>
#include <SDL.h>
#include <iostream>
#include <string>

enum class GameState { PLAY, EXIT };

class MainGame
{
public:
    MainGame();
    ~MainGame();

    void run();

private:
    void initSystems();
    void gameLoop();
    void processInput();
    void drawGame();

    SDL_Window* _window;
    int _screenWidth;
    int _screenHeight;

    int _errorCount;

    GameState _gameState;
};

//Function To Display A Error Message When Something Doesnt Work As Inteded/Properly.
void fatalError(std::string errorMsg)
{
    std::cout << errorMsg << std::endl;
}

//When Called, Inits Most Of The Important Vars, Sets Game State And Does An Error Check
MainGame::MainGame()
{
    _errorCount = 0;
    _window = nullptr;
    _screenWidth = 1024;
    _screenHeight = 768;
    _gameState = GameState::PLAY;

    if (_window == nullptr) {
        fatalError("SDL Window Could Not Be Created.");
        _errorCount += 1;
    }

    SDL_GLContext glContext = SDL_GL_CreateContext(_window);

    if (glContext == nullptr) {
        fatalError("SDL_GL Context Could Not Be Created.");
        _errorCount += 1;
    }

    GLenum error = glewInit();

    if (error != GLEW_OK) {
        fatalError("Could Not Initialize Glew.");
        _errorCount += 1;
    }

    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

    glClearColor(0.0f, 1.0f, 1.0f, 1.0f);
}

MainGame::~MainGame()
{
}

void MainGame::run()
{
    initSystems();
    gameLoop();
}

// Initializes The SDL Window.
void MainGame::initSystems()
{
    SDL_Init(SDL_INIT_EVERYTHING);
    _window = SDL_CreateWindow("Game Engine", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, _screenWidth, _screenHeight, SDL_WINDOW_OPENGL);
}

void MainGame::gameLoop()
{
    while (_gameState != GameState::EXIT) {
        processInput();
        drawGame();
    }
}

void MainGame::processInput()
{
    SDL_Event evnt;
    while (SDL_PollEvent(&evnt) == true) {
        switch (evnt.type) {
        case SDL_QUIT:
            _gameState = GameState::EXIT;
            break;
        case  SDL_MOUSEMOTION:
            std::cout << evnt.motion.x << ", " << evnt.motion.y << "\n";
            break;
        }
    }
}

void MainGame::drawGame()
{
    glClearDepth(1.0);
    glClear(GL_COLOR_BUFFER_BIT);
    glClear(GL_DEPTH_BUFFER_BIT);

    SDL_GL_SwapWindow(_window);
}

int main(int argc, char** argv)
{
    MainGame mainGame;
    mainGame.run();

    return 0;
}

Answer 1

不要使用NULL指针调用SDL_GL_CreateContext()。
在创建窗口后不要调用SDL_GL_SetAttribute() ，不会做任何有用的事情。

清理窗户＆amp;析构函数中的GL上下文。

每次通过绘图功能设置清晰的颜色以保持理智。

您可以通过一次通话清除颜色和深度平面。

“致命”错误通常应该尽快杀死程序。我在这里使用了exit()，但throw也可以使用。

所有在一起：

// g++ `pkg-config --cflags sdl2` main.cpp `pkg-config --libs glew sdl2` #include <GL/glew.h> #include <SDL.h> #include <iostream> #include <string> #include <cstdlib> enum class GameState { PLAY, EXIT }; class MainGame { public: MainGame(); ~MainGame(); void run(); private: void processInput(); void drawGame(); SDL_Window* _window; SDL_GLContext _context; int _screenWidth; int _screenHeight; int _errorCount; GameState _gameState; }; //Function To Display A Error Message When Something Doesnt Work As Inteded/Properly. void fatalError(std::string errorMsg) { std::cout << errorMsg << std::endl; exit( EXIT_FAILURE ); } //When Called, Inits Most Of The Important Vars, Sets Game State And Does An Error Check MainGame::MainGame() { _errorCount = 0; _window = nullptr; _screenWidth = 1024; _screenHeight = 768; _gameState = GameState::PLAY; SDL_Init(SDL_INIT_EVERYTHING); SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); _window = SDL_CreateWindow("Game Engine", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, _screenWidth, _screenHeight, SDL_WINDOW_OPENGL); if (_window == nullptr) { fatalError("SDL Window Could Not Be Created."); _errorCount += 1; } _context = SDL_GL_CreateContext(_window); if (_context == nullptr) { fatalError("SDL_GL Context Could Not Be Created."); _errorCount += 1; } GLenum error = glewInit(); if (error != GLEW_OK) { fatalError("Could Not Initialize Glew."); _errorCount += 1; } } MainGame::~MainGame() { SDL_GL_DeleteContext( _context ); SDL_DestroyWindow( _window ); } void MainGame::run() { while (_gameState != GameState::EXIT) { processInput(); drawGame(); } } void MainGame::processInput() { SDL_Event evnt; while (SDL_PollEvent(&evnt) == true) { switch (evnt.type) { case SDL_QUIT: _gameState = GameState::EXIT; break; case SDL_MOUSEMOTION: std::cout << evnt.motion.x << ", " << evnt.motion.y << "\n"; break; } } } void MainGame::drawGame() { glClearColor(0.0f, 1.0f, 1.0f, 1.0f); glClearDepth(1.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); SDL_GL_SwapWindow(_window); } int main(int argc, char** argv) { MainGame mainGame; mainGame.run(); return EXIT_SUCCESS; }

SDL窗口出错？

1 个答案: