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ZipIt Framebuffer Example

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UPDATE: This code is incomplete, and doesn't work 100% correctly. If you're interested in drawing graphics on a ZipIt, Albert Santoni has provided Zipit Gfx, a small library that provides some basic graphics drawing capabilities. zipitgfx can be found here. (More information is available in the README posted here.)

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From bomberman0's post...

Here's sample code for writing to the ZipIt's screen. (I've tested it and it works fine on my ZipIt.) If you know C or C++ at all, it shouldn't be very hard to figure out how to draw other stuff with this.


#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>

int main()
{
int fbfd = 0;
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
long int screensize = 0;
char *fbp = 0;
int x = 0, y = 0;
long int location = 0;

/* Open the file for reading and writing */
fbfd = open("/dev/fb0", O_RDWR);
if (!fbfd) {
printf("Error: cannot open framebuffer device.\n");
exit(1);
}
printf("The framebuffer device was opened successfully.\n");

/* Get fixed screen information */
if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
printf("Error reading fixed information.\n");
exit(2);
}

/* Get variable screen information */
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
printf("Error reading variable information.\n");
exit(3);
}

/* Figure out the size of the screen in bytes */
screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;

/* Map the device to memory */
fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE,
MAP_SHARED, fbfd, 0);
if ((int)fbp == -1) {
printf("Error: failed to map framebuffer device to memory.\n");
exit(4);
}
printf("The framebuffer device was mapped to memory successfully.\n");

for (y = 0; y < 240; y++)
{
for (x = 0; x < 320; x++)
{
//x = 100; y = 100; /* Where we are going to put the pixel */

/* Figure out where in memory to put the pixel */
location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/4) +
(y+vinfo.yoffset) * finfo.line_length;

*(fbp + location) = 255; //Paint a black pixel.
}
}
munmap(fbp, screensize);
close(fbfd);
return 0;
}