SDL学习笔记一图片和字体显示

偶然得知SDL这个游戏库，赶忙迫不及待的学习了一下，正好最近在学习DELPHI，于是下了DELPHI版的。可以在http://www.libsdl.org http://www.delphi-jedi.org/这两个站点了解到相关的信息。

SDL库设计的十分的简洁，非常容易使用。我的代码实例，实现了BMP、PNG、JPG三种图片格式的加载显示，并加入了TTF字体的显示，都是库使用的例子，代码不难，发出来共享。以下是截图：

下面是代码：
//Program: A simple delphi sdl demo
//Author: shaoyun
//Mail: shaoyun at yeah.net (please use '@' instead of 'at')
program SDLDemo;
uses SysUtils, Windows, SDL, SDL_Image, SDL_TTF;
var
   screen: PSDL_Surface;
   event: TSDL_Event;
   isOver:boolean=false;

//*******************定义显示位图的函数draw_bmp()*************************
//BMP格式的图片通常都上MB了，谁会用这种格式做游戏
procedure draw_bmp(surface:PSDL_Surface; img_path:PChar; x_pos:integer; y_pos:integer );
var
   image : PSDL_Surface;
   dest:TSDL_Rect;
begin
   image := SDL_LoadBMP(img_path);
if ( image = nil ) then
begin
   MessageBox(0, PChar(Format( ' Error:%s! ' #9, [SDL_GetError])), ' Error ' , MB_OK or MB_ICONHAND);
   exit;
end;
if (image.format.palette<>nil) then
begin
SDL_SetColors(surface, @image.format.palette.colors[0], 0, image.format.palette.ncolors);
end;
dest.x:=x_pos;
dest.y:=y_pos;
dest.w:=0;
dest.h:=0;
if (SDL_BlitSurface(image, nil, surface, @dest) < 0) then
MessageBox(0, PChar(Format( ' BlitSurface error : %s ' , [SDL_GetError])), ' Error ' , MB_OK or MB_ICONHAND);
  SDL_UpdateRect(surface, 0, 0, image.w, image.h);
SDL_FreeSurface(image);
end;

//*******************定义显示图片的函数draw_img()*************************
//这个函数的调用须有SDL_Image.dll、jpeg.dll、libpng1.dll的支持，可以显示bmp、jpg、png三种格式
//文档指明显示png格式需要zlib.dll和libpng1.dll
procedure draw_img(surface:PSDL_Surface; img_path:PChar; x_pos:integer; y_pos:integer);
var
image : PSDL_Surface;
dest:TSDL_Rect;

begin
  image:=IMG_Load(img_path);
   if image=nil then begin 
     MessageBox(0, PChar(Format( ' Error:%s! ' #9, [SDL_GetError])), ' Error ' , MB_OK or MB_ICONHAND); 
    exit; 
  end; 
  dest.x:=x_pos; 
  dest.y:=y_pos; 
  dest.w:=0;
  dest.h:=0; 
  SDL_BlitSurface ( image, nil, surface, @Dest );
  SDL_FreeSurface ( image );
end;

//*******************定义显示TTF字体的函数draw_text()*************************
//不能显示中文，不过网上有人实现了中文的显示
procedure draw_text(surface:PSDL_Surface; words:PChar; x_pos:integer; y_pos:integer );
var 
  text : PSDL_Surface; 
  font : PTTF_Font;
  dest: TSDL_Rect; 
  textColor : TSDL_Color;
 begin 
  textcolor.r:=$00;
  textcolor.g:=$FF;
  textcolor.b:=$00;
  textcolor.unused:=0; 
  font:= TTF_OpenFont( ' simhei.ttf ' ,20);
if font=nil then
begin 
   MessageBox(0, PChar(Format( ' Error:%s! ' #9, [SDL_GetError])), ' Error ' , MB_OK or MB_ICONHAND); 
   exit;
end; 
   text:= TTF_RenderText_Blended(font,words, textColor); 
   dest.x:=x_pos; 
   dest.y:=y_pos; 
   SDL_BlitSurface ( text, nil, surface, @Dest ); 
   SDL_Flip(screen); 
   SDL_FreeSurface ( text ); 
   TTF_CloseFont( font );
end;
//*****************************Main***************************// 
begin
   if ( SDL_Init( SDL_INIT_VIDEO ) < 0 ) then 
   begin 
    exit; 
   end;
   SDL_WM_SetCaption( ' Delphi SDL Simple Demo ' , nil ); 
   screen:= SDL_SetVideoMode( 640,480,32, SDL_SWSURFACE );//设置分辨率 
   if ( screen = nil ) then 
   begin 
    SDL_Quit; 
    exit; 
   end;
    //draw_bmp(screen,'bg.bmp',0,0);
   draw_img(screen, ' bg.jpg ' ,0,0); 
   //TTF初始化 
   if TTF_Init()<0 then
   begin 
     MessageBox(0, PChar(Format( ' Error:%s! ' #9, [SDL_GetError])), ' Error ' , MB_OK or MB_ICONHAND);
     exit;
   end;
   draw_text(screen, ' A Delphi SDL Simple Demo ' ,30,30);
   draw_text(screen, ' By shaoyun ' ,380,400); draw_text(screen, ' E-mail: [email protected] ' ,380,430); 
   //销毁TTF 
   TTF_Quit(); 
   while not isOver do 
   begin 
     while (SDL_PollEvent(@event)<>0) do //处理键盘按键 
     begin
       case of 
         SDL_QUITEV: isOver:=true; 
         SDL_KEYDOWN: 
         begin 
            case event.key.keysym.sym of 
               SDLK_ESCAPE: isOver:= True;
            end; 
         end;
       end;
     end;
   end; 
   SDL_Quit; 
end.

SDL学习笔记一 图片和字体显示