152 lines
4 KiB
C
152 lines
4 KiB
C
#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <linux/fb.h>
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#include <sys/mman.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#define UDP_PORT 5005 // the port users will be connecting to
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#define DISCOVER_PORT 5006 // the port on which the server will broadcast its details
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static void die(char *msg)
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{
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fprintf(stderr, "%s\n", msg);
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exit(EXIT_FAILURE);
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}
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static int get_udp_socket(int port)
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{
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int sock_fd;
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struct sockaddr_in6 addr;
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memset(&addr, 0, sizeof(addr));
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if ( ( sock_fd = socket(PF_INET6, SOCK_DGRAM,0) ) < 0 )
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die("could not create socket");
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addr.sin6_port = htons(port);
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addr.sin6_family = AF_INET6;
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addr.sin6_addr = in6addr_any;
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if ( bind(sock_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0 )
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die("could not bind to UDP");
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return sock_fd;
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}
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static ssize_t get_udp_packet(int sock_fd, char *packet, size_t size)
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{
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ssize_t n_read;
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while ((n_read = recv(sock_fd, packet, size, 0)) < 0 );
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return n_read;
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}
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// PixelVloed C version
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// application entry point
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int main(int argc, char* argv[])
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{
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int fbfd = 0;
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struct fb_var_screeninfo orig_vinfo;
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struct fb_var_screeninfo vinfo;
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struct fb_fix_screeninfo finfo;
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long int screensize = 0;
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char *fbp = 0;
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char packet[1120];
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ssize_t packet_size;
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int sock_fd = get_udp_socket(UDP_PORT);
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// Open the file for reading and writing
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fbfd = open("/dev/fb0", O_RDWR);
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if (!fbfd) {
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die("Error: cannot open framebuffer device.\n");
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}
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printf("The framebuffer device was opened successfully.\n");
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// Get variable screen information
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if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
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printf("Error reading variable information.\n");
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}
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printf("Original %dx%d, %dbpp\n", vinfo.xres, vinfo.yres,
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vinfo.bits_per_pixel );
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// Store for reset (copy vinfo to vinfo_orig)
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memcpy(&orig_vinfo, &vinfo, sizeof(struct fb_var_screeninfo));
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// Change variable info
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vinfo.bits_per_pixel = 24;
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if (ioctl(fbfd, FBIOPUT_VSCREENINFO, &vinfo)) {
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printf("Error setting variable information.\n");
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}
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// Get fixed screen information
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if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
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printf("Error reading fixed information.\n");
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}
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// map fb to user mem
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screensize = finfo.smem_len;
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fbp = (char*)mmap(0,
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screensize,
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PROT_READ | PROT_WRITE,
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MAP_SHARED,
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fbfd,
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0);
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if ((long)fbp == -1) {
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die("Failed to mmap.\n");
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}
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else {
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// draw...
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int x, y, pixelcount;
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unsigned int color = 0;
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int pixeloffset = 2;
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int pixellength = 0;
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unsigned int pix_offset;
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unsigned bpp = vinfo.bits_per_pixel / 8;
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while( (packet_size = get_udp_packet(sock_fd, packet, sizeof(packet))) >= 0 ) {
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if((uint8_t)packet[0] == 1){
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pixellength = 8;
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} else {
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pixellength = 7;
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}
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// how many pixels
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pixelcount = (packet_size-1)/pixellength;
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//printf("%d pixels in packet of size: %d using a pixel size of: %d \n", pixelcount, packet_size, pixellength);
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// fetch a pixel from the udp socket
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int i = 0;
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for(i=pixeloffset; // skip pixeloffset
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i<packet_size-(pixellength-1); // walk trough all bytes untill we get to the end minus one package length
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i+=pixellength){
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x = (uint8_t)packet[i ] + (((uint8_t)packet[i+1])<<8);
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y = (uint8_t)packet[i+2] + (((uint8_t)packet[i+3])<<8);
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//printf("%d %d %d %d %d %d\n", x, y, packet[i ], packet[i+1], packet[i+2], packet[i+3]);
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if(x < vinfo.xres && y < vinfo.yres){
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pix_offset = bpp * x + y * finfo.line_length;
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fbp[pix_offset++] = packet[i+6];
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fbp[pix_offset++] = packet[i+5];
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fbp[pix_offset] = packet[i+4];
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}
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}
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}
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}
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// cleanup
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munmap((void *)fbp, screensize);
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if (ioctl(fbfd, FBIOPUT_VSCREENINFO, &orig_vinfo)) {
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printf("Error re-setting variable information.\n");
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}
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close(fbfd);
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return 0;
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}
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