SDL显示内存中的图像

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#include <stdio.h>
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"

void ShowPic(unsigned char *buf, int size, SDL_Surface *screen, int x, int y)
{
    SDL_RWops *src;
    SDL_Surface *image;
    SDL_Rect dest;

    src = SDL_RWFromMem(buf, size);

    /* 将BMP文件加载到一个surface*/
    image = IMG_Load_RW(src, 1);
    if ( image == NULL )
    {
        fprintf(stderr, "无法加载 %s\n", SDL_GetError());
        return;
    }

    /* Blit到屏幕surface。onto the screen surface.
       这时不能锁住surface。
     */
    dest.x = x;
    dest.y = y;
    dest.w = image->w;
    dest.h = image->h;
    SDL_BlitSurface(image, NULL, screen, &dest);

    /* 刷新屏幕的变化部分 */
    SDL_UpdateRects(screen, 1, &dest);
}

int main(int argc, char *argv[])
{
    unsigned char *buf;
    FILE *fp;
    int size, i;

    if (argc != 2)
    {
        fprintf(stderr, "Usage:%s file_name\n", argv[0]);
        exit(1);

    }

    if (SDL_Init(SDL_INIT_AUDIO|SDL_INIT_VIDEO) < 0)
	{
        fprintf(stderr, "无法初始化SDL: %s\n", SDL_GetError());
        exit(1);
    }
    atexit(SDL_Quit);

	SDL_Surface *screen;

    screen = SDL_SetVideoMode(640, 480, 16, SDL_SWSURFACE);
    if (screen == NULL)
	{
        fprintf(stderr, "无法设置640x480的视频模式：%s\n", SDL_GetError());
        exit(1);
    }

    fp = fopen(argv[1], "r");
    if (fp == NULL)
    {
        perror("fopen");
        exit(1);
    }

    fseek(fp, 0L, SEEK_END);
    size = ftell(fp);
    printf("file size:%d\n", size);
    rewind(fp);

    buf = malloc(size);
    if (buf == NULL)
    {
        perror("malloc");
        exit(1);
    }
    memset(buf, 0, size);

    i = fread(buf, size, 1, fp);
    if (i < 0)
    {
        perror("fread");
        exit(1);
    }
    fclose(fp);

    printf("read:%d\n", i);

#if 0
    for (i = 0; i < 100; i++)
    {
        if (i % 10 == 0)
            printf("\n");
        printf("%02X ", buf[i]);
    }
    printf("\n");
#endif
	ShowPic(buf, size, screen, 0, 0);

	printf("please enter Enter to exit....");
	getchar();

	return 0;
}