【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<SDL2/SDL.h>SDL_Window* g_pWindow = 0;
SDL_Renderer* g_pRenderer = 0;int main(int argc, char* args[])
{// initialize SDLif(SDL_Init(SDL_INIT_EVERYTHING) >= 0){// if succeeded create our windowg_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 rendererif(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 valuesSDL_SetRenderDrawColor(g_pRenderer, 0, 0, 0, 255);// clear the window to blackSDL_RenderClear(g_pRenderer);// show the windowSDL_RenderPresent(g_pRenderer);// set a delay before quittingSDL_Delay(5000);// clean up SDLSDL_Quit();return 0;
}

2. 整体框架

在这里插入图片描述

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 <SDL2/SDL.h>
class Game
{public:Game() {};~Game() {};// simply set the running variable to truebool 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 variablebool 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 <iostream>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 SDLif(SDL_Init(SDL_INIT_EVERYTHING) == 0){std::cout << "SDL init success\n";// init the windowm_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 loopreturn true;
}void Game::render()
{SDL_RenderClear(m_pRenderer); // clear the renderer to the draw colorSDL_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()
{}