【c++|SDL】开始使用之---demo

every blog every motto: You can do more than you think.
https://blog.csdn.net/weixin_39190382?type=blog

0. 前言

SDL 记录

1. hello word

#include

SDL_Window* g_pWindow = 0;
SDL_Renderer* g_pRenderer = 0;

int main(int argc, char* args[])
{
    // initialize SDL
    if(SDL_Init(SDL_INIT_EVERYTHING) >= 0)
    {
        // if succeeded create our window
        g_pWindow = SDL_CreateWindow("Chapter 1: Setting up SDL", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 480,SDL_WINDOW_SHOWN);
        // if the window creation succeeded create our renderer
        if(g_pWindow != 0)
        {
            g_pRenderer = SDL_CreateRenderer(g_pWindow, -1, 0);
        }
    }
    else
    {
        return 1; // sdl could not initialize
    }
    // everything succeeded lets draw the window
    // set to black // This function expects Red, Green, Blue and
    // Alpha as color values
    SDL_SetRenderDrawColor(g_pRenderer, 0, 0, 0, 255);
    // clear the window to black
    SDL_RenderClear(g_pRenderer);
    // show the window
    SDL_RenderPresent(g_pRenderer);
    // set a delay before quitting
    SDL_Delay(5000);
    // clean up SDL
    SDL_Quit();
    return 0;
}

2. 整体框架

将其中一些代码封装到Game类中，main.cpp保持整洁

编译使用：

g++ main.cpp Game.cpp  -o main -lSDL2 

运行

./main

说明： 后续无特别说明与这里相同

main.cpp

#include "Game.h"
// our Game object
Game* g_game = 0;

int main(int argc, char* argv[])
{
    g_game = new Game();
    // g_game->init("Chapter 1", 100, 100, 640, 480, 0);
    // g_game->init("Chapter 1", 100, 100, 640, 580,SDL_WINDOW_FULLSCREEN);
    g_game->init("Chapter 1", 100, 100, 640, 580,false);
    while(g_game->running())
    {
        g_game->handleEvents();
        g_game->update();
        g_game->render();
    }
    g_game->clean();
    return 0;
}

Game.h 声明类和函数

#ifndef __Game__
#define __Game__

#include 
class Game
{

public:
    Game() {};
    ~Game() {};
    // simply set the running variable to true
    bool init(const char* title, int xpos, int ypos,int width, int height, bool fullscreen);
    void render();
    void update();
    void handleEvents();
    void clean();
    // a function to access the private running variable
    bool running() { return m_bRunning; }
private:
    bool m_bRunning;
    SDL_Window* m_pWindow;
    SDL_Renderer* m_pRenderer;
};
#endif /* defined(__Game__) */

Game.cpp 实现类和函数

#include "Game.h"
#include 

using namespace std;

bool Game::init(const char* title, int xpos, int ypos, int width, int height, bool fullscreen)
{   
    int flags = 0;
    if (fullscreen)
    {
        flags = SDL_WINDOW_FULLSCREEN;
    }
    // attempt to initialize SDL
    if(SDL_Init(SDL_INIT_EVERYTHING) == 0)
    {
        std::cout << "SDL init success\n";
        // init the window
        m_pWindow = SDL_CreateWindow(title, xpos, ypos, width, height, flags);
        if(m_pWindow != 0) // window init success
        {
            std::cout << "window creation success\n";
            m_pRenderer = SDL_CreateRenderer(m_pWindow, -1, 0);
            if(m_pRenderer != 0) // renderer init success
            {
                std::cout << "renderer creation success\n";
                SDL_SetRenderDrawColor(m_pRenderer,255,255,255,255);
            }
            else
            {
                std::cout << "renderer init fail\n";
                return false; // renderer init fail
            }
        }
        else
        {
            std::cout << "window init fail\n";
            return false; // window init fail
        }
    }
    else
    {
        std::cout << "SDL init fail\n";
        return false; // SDL init fail
    }
    std::cout << "init success\n";
    m_bRunning = true; // everything inited successfully, start the main loop
    return true;
}

void Game::render()
{
    SDL_RenderClear(m_pRenderer); // clear the renderer to the draw color
    SDL_RenderPresent(m_pRenderer); // draw to the screen
}


void Game::handleEvents()
{
    SDL_Event event;
    if(SDL_PollEvent(&event))
    {
        switch (event.type)
    {
        case SDL_QUIT:
            m_bRunning = false;
        break;

        default:
        break;
    }
    }
}

void Game::clean()
{
    std::cout << "cleaning game\n";
    SDL_DestroyWindow(m_pWindow);
    SDL_DestroyRenderer(m_pRenderer);
    SDL_Quit();
}

void Game::update()
{

}