fb.c

在linux framebuffer上显示模拟的动态水波效果

#include "fb.h"

int fb_init()
{
	static int fb_inited = 0;
	char *dev, *env;

	if (fb_inited)
		return 0;

	fb = malloc(sizeof(FRAMEBUFFER));
	if (!fb) {
		fprintf(stderr, "malloc: %s\n", strerror(errno));
		exit(1);
	}
	env = getenv("FRAMEBUFFER");
	if (env)
		dev = env;
	else
		dev = DEFAULT_FRAMEBUFFER;
	if ((fb->fbh = open(dev, O_RDWR)) == -1) {
		fprintf(stderr, "open %s: %s\n", dev, strerror(errno));
		exit(1);
	}
	if (ioctl(fb->fbh, FBIOGET_VSCREENINFO, &fb->fbinfo)) {
		fprintf(stderr, "ioctl FBIOGET_VSCREENINFO: %s\n",
				strerror(errno));
		exit(1);
	}
	fb->fbsize =
		fb->fbinfo.xres * fb->fbinfo.yres * fb->fbinfo.bits_per_pixel / 8;
	fb->fbmem =
		mmap(NULL, fb->fbsize, PROT_WRITE | PROT_READ, MAP_SHARED, fb->fbh,
			 0);
	if (fb->fbmem == MAP_FAILED) {
		fprintf(stderr, "mmap: %s\n", strerror(errno));
		exit(1);
	}
	fb->fbclone = malloc(fb->fbsize);
	if (!fb->fbclone) {
		fprintf(stderr, "malloc: %s\n", strerror(errno));
		exit(1);
	}
	fb_inited = 1;

	fb->init=fb_init;
	fb->release=fb_release;
	fb->snap=fb_snap;
	fb->refresh=fb_refresh;
	fb->blit=fb_blit;
	fb->convert=fb_convert;
	fb_clear();
	return 0;
}

void fb_release()
{
	if (fb) {
		munmap(fb->fbmem, fb->fbsize);
		free(fb->fbclone);
		close(fb->fbh);
		free(fb);
	}
}

void fb_snap()
{
	memcpy(fb->fbclone, fb->fbmem, fb->fbsize);
}

void fb_refresh()
{
	memcpy(fb->fbmem, fb->fbclone, fb->fbsize);
}

void fb_clear()
{
	memset(fb->fbclone, 0x0, fb->fbsize);
	memcpy(fb->fbmem, fb->fbclone, fb->fbsize);
}

inline unsigned char make8color(unsigned char r, unsigned char g,
								unsigned char b)
{
	return ((((r >> 5) & 7) << 5) |
			(((g >> 5) & 7) << 2) | ((b >> 6) & 3));
}

inline unsigned short make15color(unsigned char r, unsigned char g,
								  unsigned char b)
{
	return ((((r >> 3) & 31) << 10) |
			(((g >> 3) & 31) << 5) | ((b >> 3) & 31));
}

inline unsigned short make16color(unsigned char r, unsigned char g,
								  unsigned char b)
{
	return ((((r >> 3) & 31) << 11) |
			(((g >> 2) & 63) << 5) | ((b >> 3) & 31));
}


void *fb_convert(unsigned char *rgbbuff, unsigned long count, int bpp)
{
	unsigned long i;
	void *fbbuff = NULL;
	unsigned char *c_fbbuff;
	unsigned short *s_fbbuff;
	unsigned int *i_fbbuff;

	switch (bpp) {

	case 8:
		c_fbbuff = (unsigned char *) malloc(count * sizeof(unsigned char));
		for (i = 0; i < count; i++)
			c_fbbuff[i] =
				make8color(rgbbuff[i * 3], rgbbuff[i * 3 + 1],
						   rgbbuff[i * 3 + 2]);
		fbbuff = (void *) c_fbbuff;
		break;
	case 15:
		s_fbbuff =
			(unsigned short *) malloc(count * sizeof(unsigned short));
		for (i = 0; i < count; i++)
			s_fbbuff[i] =
				make15color(rgbbuff[i * 3], rgbbuff[i * 3 + 1],
							rgbbuff[i * 3 + 2]);
		fbbuff = (void *) s_fbbuff;
		break;
	case 16:
		s_fbbuff =
			(unsigned short *) malloc(count * sizeof(unsigned short));
		for (i = 0; i < count; i++)
			s_fbbuff[i] =
				make16color(rgbbuff[i * 3], rgbbuff[i * 3 + 1],
							rgbbuff[i * 3 + 2]);
		fbbuff = (void *) s_fbbuff;
		break;
	case 24:
	case 32:
		i_fbbuff = (unsigned int *) malloc(count * sizeof(unsigned int));
		for (i = 0; i < count; i++)
			i_fbbuff[i] = ((rgbbuff[i * 3] << 16) & 0xFF0000) |
				((rgbbuff[i * 3 + 1] << 8) & 0xFF00) |
				(rgbbuff[i * 3 + 2] & 0xFF);
		fbbuff = (void *) i_fbbuff;
		break;
	default:
		fprintf(stderr, "Unsupported video mode! You've got: %dbpp\n",
				bpp);
		exit(1);
	}
	return fbbuff;
}

void fb_blit(unsigned char *image, int x, int y, int width, int height)
{
	int i, xc, yc;
	unsigned char *fbptr;
#if 10
	if (!fb)
		return;
	if (fb->fbinfo.xres == width && fb->fbinfo.yres == height) {
		memcpy(fb->fbmem, image, fb->fbsize);
	} else {
		fb_snap();
		xc = (width > fb->fbinfo.xres) ? fb->fbinfo.xres : width;
		yc = (height > fb->fbinfo.yres) ? fb->fbinfo.yres : height;
		fbptr =
			fb->fbclone + (y * fb->fbinfo.xres +
						   x) * fb->fbinfo.bits_per_pixel / 8;
		for (i = 0; i < yc;
			 i++, fbptr +=
			 fb->fbinfo.xres * fb->fbinfo.bits_per_pixel / 8, image +=
			 width * fb->fbinfo.bits_per_pixel / 8)
			memcpy(fbptr, image, xc * fb->fbinfo.bits_per_pixel / 8);
		memcpy(fb->fbmem, fb->fbclone, fb->fbsize);
	}
#endif
}