【昉·星光 2 高性能RISC-V单板计算机体验】使用 SDL2 绘制窗口程序

注意到starfive官方给出了libSDL2-dev的软件包，使用SDL作为中间件可以跨平台适配许多的界面库，使用昉·星光2使用SDL2来绘制一个窗口

之前根据官方文档中的说明，将 libsdl2-dev 软件包安装好

然后编写代码，创建一个窗口并在窗口上显示一个BMP位图，位图和代码如下

• 位图（william hill官网 不能上传bmp，这里给的是jpg，需要手动转为bmp）

  

• 代码

#include <SDL.h>
#include <stdlib.h>
#include <string.h>
int main( int argc, char *argv[] ) {
  
  int x = 720, y = 256, f = 60;
  
  for ( int i = 1; i < argc; i++ ) {
    if        ( strcmp( argv[ i ], "-x" ) == 0 && argc > i + 1 ) {
      x = (int) strtol( argv[ ++i ], NULL, 10 );
    } else if ( strcmp( argv[ i ], "-y" ) == 0 && argc > i + 1 ) {
      y = (int) strtol( argv[ ++i ], NULL, 10 );
    } else if ( strcmp( argv[ i ], "-f" ) == 0 && argc > i + 1 ) {
      f = (int) strtol( argv[ ++i ], NULL, 10 );
    }
  }
  
  SDL_Init( SDL_INIT_VIDEO | SDL_INIT_EVENTS );
  
  SDL_Window *window = SDL_CreateWindow( "Hello World", 
					 SDL_WINDOWPOS_UNDEFINED,
					 SDL_WINDOWPOS_UNDEFINED, 
					 x, y, SDL_WINDOW_SHOWN );
  
  SDL_Surface *surface = SDL_LoadBMP( "logo.bmp" );
  
  SDL_Renderer *renderer = 
    SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED );
    
  SDL_Texture *texture = SDL_CreateTextureFromSurface( renderer, surface );
  
  SDL_FreeSurface( surface );
  
  surface = NULL;
  
  SDL_bool quit = SDL_FALSE;
  
  SDL_Event e = { 0 };
  
  while ( !quit ) {
    
    Uint32 start = SDL_GetTicks();
    
    while ( SDL_PollEvent( &e ) )
      switch ( e.type ) {
	
      case SDL_QUIT: quit = SDL_TRUE; break;
	
      default: break;
      }
    
    
    SDL_RenderClear( renderer );
    
    SDL_RenderCopy( renderer, texture, NULL, NULL );
    
    SDL_RenderPresent( renderer );
    
    Uint32 end = SDL_GetTicks();
    
    int wait_for = 1000 / f - ( end - start );
    
    if ( wait_for > 0 ) {
      SDL_Delay( wait_for );
    }
  }
  
  SDL_DestroyTexture( texture );
  SDL_DestroyRenderer( renderer );
  SDL_DestroyWindow( window );
  SDL_Quit();
  return 0;
}

保存以上代码为 hello.c 文件，使用 g++ 来编译

由于用到了 SDL2 库，所以需要链接到 SDL2，并且包含 SDL2 的 include 目录，编译成可执行文件

g++ hello.c -o hello -lSDL2 -I/usr/local/include/SDL2

将前文的图片保存在相同的文件夹，文件名为 logo.bmp，然后运行这个程序

./hello