every blog every motto: You can do more than you think.
https://blog.csdn.net/weixin_39190382?type=blog
0. 前言
读取图片,显示图片,动画
SDL中有两种在屏幕上显示的方法
- SDL_Surface: 使用软件渲染处理
- SDL_Texture: 使用硬件加速渲染处理
1. 在界面上显示图片
修改Game.h
#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;SDL_Window* m_pWindow;SDL_Renderer* m_pRenderer;SDL_Texture* m_pTexture; // the new SDL_Texture variableSDL_Rect m_sourceRectangle; // the first rectangleSDL_Rect m_destinationRectangle; // another rectangle
};#endif /* defined(__Game__) */
修改Game.cpp
修改其中的init和render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";SDL_Surface* pTempSurface = SDL_LoadBMP("assets/rider.bmp");m_pTexture = SDL_CreateTextureFromSurface(m_pRenderer, pTempSurface);SDL_FreeSurface(pTempSurface);SDL_QueryTexture(m_pTexture, NULL, NULL,&m_sourceRectangle.w,&m_sourceRectangle.h); // 获取长宽m_destinationRectangle.x = m_sourceRectangle.x = 0;m_destinationRectangle.y = m_sourceRectangle.y = 0;m_destinationRectangle.w = m_sourceRectangle.w;m_destinationRectangle.h = m_sourceRectangle.h;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_RenderCopy(m_pRenderer, m_pTexture,&m_sourceRectangle,&m_destinationRectangle);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()
{}
2. 显示位置和范围
修改m_sourceRectangle和m_destinationRectangle
具体在Game.cpp SDL_QueryTexture代码下面
Game.cpp init函数代码如下,其他代码相同
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";SDL_Surface* pTempSurface = SDL_LoadBMP("assets/rider.bmp");m_pTexture = SDL_CreateTextureFromSurface(m_pRenderer, pTempSurface);SDL_FreeSurface(pTempSurface);SDL_QueryTexture(m_pTexture, NULL, NULL,&m_sourceRectangle.w,&m_sourceRectangle.h); // 获取长宽m_sourceRectangle.w = 50;m_sourceRectangle.h = 50;m_destinationRectangle.x = 100;m_destinationRectangle.y = 100;m_sourceRectangle.x = 50;m_sourceRectangle.y = 50;// m_destinationRectangle.x = m_sourceRectangle.x = 0;// m_destinationRectangle.y = m_sourceRectangle.y = 0;m_destinationRectangle.w = m_sourceRectangle.w;m_destinationRectangle.h = m_sourceRectangle.h;m_bRunning = true; // everything inited successfully, start the main loopreturn true;
}
3. 动图
有多帧图片,每100ms显示其中一张,可以让图片动起来
#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";// SDL_Surface* pTempSurface = SDL_LoadBMP("assets/rider.bmp");SDL_Surface* pTempSurface = SDL_LoadBMP("assets/animate.bmp");m_pTexture = SDL_CreateTextureFromSurface(m_pRenderer, pTempSurface);SDL_FreeSurface(pTempSurface);SDL_QueryTexture(m_pTexture, NULL, NULL,&m_sourceRectangle.w,&m_sourceRectangle.h); // 获取长宽m_sourceRectangle.x = 0;m_sourceRectangle.y = 0;m_sourceRectangle.w = 128;m_sourceRectangle.h = 82;m_destinationRectangle.x = 0;m_destinationRectangle.y = 0;// m_destinationRectangle.x = m_sourceRectangle.x = 0;// m_destinationRectangle.y = m_sourceRectangle.y = 0;m_destinationRectangle.w = m_sourceRectangle.w;m_destinationRectangle.h = m_sourceRectangle.h;m_bRunning = true; // everything inited successfully, start the main loopreturn true;
}void Game::render()
{SDL_RenderClear(m_pRenderer); // clear the renderer to the draw color// SDL_RenderCopy(m_pRenderer, m_pTexture,0,0);SDL_RenderCopy(m_pRenderer, m_pTexture,&m_sourceRectangle,&m_destinationRectangle);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()
{m_sourceRectangle.x = 128 * int(((SDL_GetTicks() / 100) % 6));}
可以翻转图片
void Game::render()
{SDL_RenderClear(m_pRenderer); // clear the renderer to the draw color// SDL_RenderCopy(m_pRenderer, m_pTexture,0,0);// SDL_RenderCopy(m_pRenderer, m_pTexture,&m_sourceRectangle,&m_destinationRectangle);SDL_RenderCopyEx(m_pRenderer, m_pTexture,&m_sourceRectangle, &m_destinationRectangle,0, 0, SDL_FLIP_HORIZONTAL); // pass in the horizontal flipSDL_RenderPresent(m_pRenderer); // draw to the screen
}
3. SDL_image
前面用的是SDL_LoadBMP只能加载bmp图片,SDL_image可以加载很多格式的图片,包括png,jpg,bmp,tiff,pcx,tif,lbm,xpm,gif,tk和xv等。
Game.h中引入SDL_image
#include <SDL2/SDL_image.h>
修改加载图片代码Game.cpp
SDL_Surface* pTempSurface = IMG_Load("assets/animate.png");
编译修改为:
g++ m14main.cpp Game.cpp -o m14 -lSDL2 -lSDL2_image
Game.cpp代码如下:
#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,255,0,0,255);}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";// SDL_Surface* pTempSurface = SDL_LoadBMP("assets/rider.bmp");// SDL_Surface* pTempSurface = SDL_LoadBMP("assets/animate.bmp");// SDL_Surface* pTempSurface = IMG_Load("assets/animate.png");SDL_Surface* pTempSurface = IMG_Load("assets/animate-alpha.png");m_pTexture = SDL_CreateTextureFromSurface(m_pRenderer, pTempSurface);SDL_FreeSurface(pTempSurface);SDL_QueryTexture(m_pTexture, NULL, NULL,&m_sourceRectangle.w,&m_sourceRectangle.h); // 获取长宽m_sourceRectangle.x = 0;m_sourceRectangle.y = 0;m_sourceRectangle.w = 128;m_sourceRectangle.h = 82;m_destinationRectangle.x = 0;m_destinationRectangle.y = 0;// m_destinationRectangle.x = m_sourceRectangle.x = 0;// m_destinationRectangle.y = m_sourceRectangle.y = 0;m_destinationRectangle.w = m_sourceRectangle.w;m_destinationRectangle.h = m_sourceRectangle.h;m_bRunning = true; // everything inited successfully, start the main loopreturn true;
}void Game::render()
{SDL_RenderClear(m_pRenderer); // clear the renderer to the draw color// SDL_RenderCopy(m_pRenderer, m_pTexture,0,0);// SDL_RenderCopy(m_pRenderer, m_pTexture,&m_sourceRectangle,&m_destinationRectangle);SDL_RenderCopyEx(m_pRenderer, m_pTexture,&m_sourceRectangle, &m_destinationRectangle,0, 0, SDL_FLIP_HORIZONTAL); // pass in the horizontal flipSDL_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()
{m_sourceRectangle.x = 128 * int(((SDL_GetTicks() / 100) % 6));}