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＃i nclude <stdio.h>
＃i nclude <stdlib.h>
＃i nclude <string.h>
＃i nclude <SDL.h>
＃i nclude <windows.h>
/*
PLEASE NOTE: the program will require SDL.dll which is located in
dev-c++'s dll directory. You have to copy it to you
program's home directory or the path.
*/
/* The screen surface */
SDL_Surface *screen = NULL;//屏幕表面
void display_bmp(char *file_name);
/* This function draws to the screen; replace this with your own code! */
//绘制屏幕
static void
draw ()
{
static int direction = 0;
static int value = 0;
static int which = 0;
SDL_Rect rect;//定义一个矩形区域
Uint32 color;
/* Create a black background */
//创建黑色背景
color = SDL_MapRGB (screen->format, 0, 0, 0);//映射一个颜色值为像素
SDL_FillRect (screen, NULL, color);//使用某种颜色快速填充指定矩形
/* Determine which color the layer should have */
if (direction == 0)
{
value += 2;
if (value >= 256)
{
value = 255;
direction = 1;
}
}
else
{
value -= 2;
if (value <= 5)
{
value = 0;
direction = 0;
which++;
if (which == 5)
which = 0;
}
}
/* Draw a layer with variable color */
//使用指定颜色在层上显示
switch (which)
{
case 0:
color = SDL_MapRGB (screen->format, value, 0, 0);
break;
case 1:
color = SDL_MapRGB (screen->format, 0, value, 0);
break;
case 2:
color = SDL_MapRGB (screen->format, 0, 0, value);
break;
case 3:
color = SDL_MapRGB (screen->format, value, value, value);
break;
case 4:
color = SDL_MapRGB (screen->format, value, 0, value);
break;
}
rect.w = screen->w / 2;
rect.h = screen->h / 2;
rect.x = (screen->w / 2) - (rect.w / 2);
rect.y = (screen->h / 2) - (rect.h / 2);
SDL_FillRect (screen, &rect, color);
/* Make sure everything is displayed on screen */
//翻转屏幕,要翻转必须在设置视频模式时加上SDL_DOUBLEBUF选项
SDL_Flip (screen);
/* Don't run too fast */
//延迟1毫秒
SDL_Delay (1);
}
int
main (int argc, char *argv[])//必须要加参数
{
char *msg;
int done;
/* Initialize SDL */
if (SDL_Init (SDL_INIT_VIDEO) < 0)//初始化SDL
{
sprintf (msg, "Couldn't initialize SDL: %s\n", SDL_GetError ());
MessageBox (0, msg, "Error", MB_ICONHAND);
free (msg);
exit (1);
}
atexit (SDL_Quit);//释放
/* Set 640x480 16-bits video mode */
//设置视频模式640*480
screen = SDL_SetVideoMode (640, 480, 16, SDL_SWSURFACE | SDL_DOUBLEBUF | SDL_FULLSCREEN);
if (screen == NULL)
{
sprintf (msg, "Couldn't set 640x480x16 video mode: %s\n",
SDL_GetError ());
MessageBox (0, msg, "Error", MB_ICONHAND);
free (msg);
exit (2);
}
//设置窗口标题
SDL_WM_SetCaption ("SDL MultiMedia Application", NULL);
//通过这种方式设置全屏方式在win32下出现错误.建议使用在setvideomode中使用sdl_fullscreen参数
//if(SDL_WM_ToggleFullScreen(screen)==0)
// MessageBox(NULL,"设置全屏错误!","设置全屏错误!",0);
//事件循环
done = 0;
while (!done)
{
SDL_Event event;
/* Check for events */
//检测事件
while (SDL_PollEvent (&event))
{
switch (event.type)
{
case SDL_KEYDOWN:
break;
case SDL_QUIT:
done = 1;
break;
default:
break;
}
}
/* Draw to screen */
//绘制屏幕
//draw ();//绘制不同色彩的矩形
display_bmp("123.bmp");//显示图片
}
return 0;
}
void display_bmp(char *file_name)
{
SDL_Surface *image;
/* Load the BMP file into a surface */
//加载位图至屏幕表面
image = SDL_LoadBMP(file_name);
if (image == NULL) {
fprintf(stderr, "Couldn't load %s: %s\n", file_name, SDL_GetError());
return;
}
/*
* Palettized screen modes will have a default palette (a standard
* 8*8*4 colour cube), but if the image is palettized as well we can
* use that palette for a nicer colour matching
*/
//如果图像调色板与屏幕调色板一致的话,设置屏幕的一部分色彩为图像的色彩
if (image->format->palette && screen->format->palette) {
SDL_SetColors(screen, image->format->palette->colors, 0,
image->format->palette->ncolors);
}
/* Blit onto the screen surface */
//迅速传输image表面至于screen表面
if(SDL_BlitSurface(image, NULL, screen, NULL) < 0)
fprintf(stderr, "BlitSurface error: %s\n", SDL_GetError());
//更新指定区域
SDL_UpdateRect(screen, 0, 0, image->w, image->h);
/* Free the allocated BMP surface */
//清除所分配的bmp表面
SDL_FreeSurface(image);
//翻页
SDL_Flip(screen);
}
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