ZipIt Framebuffer Example
Revision as of 13:42, 17 November 2008 by FransMeulenbroeks (talk | contribs) (removed ref to nonexisting page)
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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; }