main.c

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/fb.h>

#define ANSI_COLOR_RED     "\x1b[31m"
#define ANSI_COLOR_GREEN   "\x1b[32m"
#define ANSI_COLOR_YELLOW  "\x1b[33m"
#define ANSI_COLOR_BLUE    "\x1b[34m"
#define ANSI_COLOR_MAGENTA "\x1b[35m"
#define ANSI_COLOR_CYAN    "\x1b[36m"
#define ANSI_COLOR_RESET   "\x1b[0m"


struct fb_fix_screeninfo finfo;
struct fb_var_screeninfo vinfo;

uint32_t pixel_color(uint8_t r, uint8_t g, uint8_t b, struct fb_var_screeninfo *vinfo)
{
	return (r << vinfo->red.offset) | (g << vinfo->green.offset) | (b << vinfo->blue.offset); 
}

int main()
{
	printf(ANSI_COLOR_GREEN "Framebeffer." ANSI_COLOR_RESET "\n");
	
	int fb_fd = open("/dev/fb0", O_RDWR);
	if(fb_fd == -1){
		printf("Can't open \"/dev/fb0\"\n");
		exit(1);
	}

	//get variable screen information
	ioctl(fb_fd, FBIOGET_VSCREENINFO, &vinfo);
	vinfo.grayscale=0;
	vinfo.bits_per_pixel=32;
	ioctl(fb_fd, FBIOPUT_VSCREENINFO, &vinfo);
	ioctl(fb_fd, FBIOGET_VSCREENINFO, &vinfo);

	ioctl(fb_fd, FBIOGET_VSCREENINFO, &finfo);	
	
	long screensize = vinfo.yres_virtual * finfo.line_length;

	printf("Screen size: %ld\n", screensize);

	uint8_t *fbp = mmap(NULL, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fb_fd, 0);

	//location where we want to draw pizel
	long x;
	long y;

	// The pixel we want to draw at location
	uint32_t pixel;
	
	printf("x resolution: %d\n", vinfo.xres);
	printf("y resolution: %d\n", vinfo.yres);

	for(x = 0; x < vinfo.xres; x++)
	{
		for(y = 0; y < vinfo.yres; y++)
		{
			long location = (x + vinfo.xoffset) * (vinfo.bits_per_pixel / 8) + (y + vinfo.yoffset) * finfo.line_length;
			//printf("%ld\n", location);
			
			uint32_t pix = pixel_color(0xFF, 0x00, 0xFF, &vinfo);
			*((uint32_t*)(fbp + location)) = pix;  //вот тут сегфол бля
		}
	}
	close(fb_fd);
	return 0;
}