cg-virtual-monitor/vnc-client/src/main.c

#include <SDL2/SDL.h>
#include <rfb/rfbclient.h>
#include <fxlink/devices.h>
#include <fxlink/logging.h>
#include <stdio.h>
#include <signal.h>
#include <assert.h>
#include <stdbool.h>

/* Size of the calculator display */
#define CALC_WIDTH 396
#define CALC_HEIGHT 224

/* Application globals */
struct app {
    /* RFB/VNC client to get framebuffers from VNC server */
    rfbClient *client;
    /* SDL globals used to store the framebuffer and show it on-screen */
    SDL_Window *window;
    SDL_Surface *surface;
    /* CLI options */
    bool display_calc;
    bool display_sdl;
    /* Calculator tracking */
    libusb_context *libusb_ctx;
    struct fxlink_device_list devices;
    struct fxlink_device *calc;
    libusb_device *calc_unique_id;
    /* 16-bit framebuffer for the calculator (big endian) */
    uint16_t *fb16_be;
};
static struct app app = { 0 };

/* Cleanup all resources when execution finishes. */
static void cleanup(void)
{
    /* Wait for libusb to settle down */
    while(fxlink_device_list_interrupt(&app.devices))
        libusb_handle_events(app.libusb_ctx);

    if(app.client)
        rfbClientCleanup(app.client);

    if(app.window)
        SDL_DestroyWindow(app.window);
    SDL_Quit();

    /* This device is managed by the device list */
    app.calc = NULL;
    app.calc_unique_id = NULL;

    free(app.fb16_be);

    fxlink_device_list_stop(&app.devices);
    if(app.libusb_ctx)
        libusb_exit(app.libusb_ctx);
}

/* Handle a framebuffer update by displaying to the SDL window and/or sending a
   new 16-bit framebuffer to the calculator. */
static void fb_update(rfbClient *client)
{
    uint32_t *fb = (void *)client->frameBuffer;

    if(app.display_sdl) {
        /* Very crude assumption about the SDL surface format and pitch */
        memcpy(app.surface->pixels, fb, CALC_WIDTH * CALC_HEIGHT * 4);
        SDL_UpdateWindowSurface(app.window);
    }

    if(app.display_calc && app.calc && app.fb16_be) {
        for(int y = 0; y < CALC_HEIGHT; y++)
        for(int x = 0; x < CALC_WIDTH; x++) {
            uint32_t color = fb[CALC_WIDTH * y + x];
            int R = (color >> 16) & 0xff;
            int G = (color >> 8) & 0xff;
            int B = (color & 0xff);

            /* Conversion to RGB565 */
            int c = ((R & 0xf8) << 8) | ((G & 0xfc) << 3) | ((B & 0xf8) >> 3);
            app.fb16_be[CALC_WIDTH * y + x] = (c >> 8) | (c << 8);
        }

        fxlink_device_start_bulk_OUT(app.calc,
            "cgvm", "fb", app.fb16_be, CALC_WIDTH * CALC_HEIGHT * 2, false);
    }
}

/* Convert a gint keycode to an rfbKeySym. This is just for show, the keymap is
   way too basic to be useful. */
static rfbKeySym keycode_to_rfbKeySym(int keycode)
{
    switch(keycode) {
    case 0x91 /* F1     */: return XK_F1;
    case 0x92 /* F2     */: return XK_F2;
    case 0x93 /* F3     */: return XK_F3;
    case 0x94 /* F4     */: return XK_F4;
    case 0x95 /* F5     */: return XK_F5;
    case 0x96 /* F6     */: return XK_F6;

    case 0x81 /* SHIFT  */: return XK_Shift_L;
    case 0x82 /* OPTN   */: return 0;
    case 0x83 /* VARS   */: return XK_Super_L;
    case 0x84 /* MENU   */: return 0;
    case 0x85 /* LEFT   */: return XK_Left;
    case 0x86 /* UP     */: return XK_Up;

    case 0x71 /* ALPHA  */: return XK_Control_L;
    case 0x72 /* SQUARE */: return 0;
    case 0x73 /* POWER  */: return 0;
    case 0x74 /* EXIT   */: return 0;
    case 0x75 /* DOWN   */: return XK_Down;
    case 0x76 /* RIGHT  */: return XK_Right;

    case 0x61 /* XOT    */: return 'a';
    case 0x62 /* LOG    */: return 'b';
    case 0x63 /* LN     */: return 'c';
    case 0x64 /* SIN    */: return 'd';
    case 0x65 /* COS    */: return 'e';
    case 0x66 /* TAN    */: return 'f';

    case 0x51 /* FRAC   */: return 'g';
    case 0x52 /* FD     */: return 'h';
    case 0x53 /* LEFTP  */: return 'i';
    case 0x54 /* RIGHTP */: return 'j';
    case 0x55 /* COMMA  */: return 'k';
    case 0x56 /* ARROW  */: return 'l';

    case 0x41 /* 7      */: return 'm';
    case 0x42 /* 8      */: return 'n';
    case 0x43 /* 9      */: return 'o';
    case 0x44 /* DEL    */: return XK_BackSpace;

    case 0x31 /* 4      */: return 'p';
    case 0x32 /* 5      */: return 'q';
    case 0x33 /* 6      */: return 'r';
    case 0x34 /* MUL    */: return 's';
    case 0x35 /* DIV    */: return 't';

    case 0x21 /* 1      */: return 'u';
    case 0x22 /* 2      */: return 'v';
    case 0x23 /* 3      */: return 'w';
    case 0x24 /* ADD    */: return 'x';
    case 0x25 /* SUB    */: return 'y';

    case 0x11 /* 0      */: return 'z';
    case 0x12 /* DOT    */: return ' ';
    case 0x13 /* EXP    */: return '"';
    case 0x14 /* NEG    */: return '-';
    case 0x15 /* EXE    */: return XK_Return;

    default: return 0;
    }
}

/* Handle incoming messages from the calculator. */
static void handle_calc_message(struct fxlink_message const *msg)
{
    if(fxlink_message_is_apptype(msg, "cgvm", "pressed-keys")) {
        uint8_t *keys = msg->data;
        for(int i = 0; i < msg->size / 2; i++) {
            int code = keycode_to_rfbKeySym(keys[2*i]);
            int down = keys[2*i+1] ? TRUE : FALSE;
            if(code > 0)
                SendKeyEvent(app.client, code, down);
        }
    }
    else {
        hlog("cgvm");
        log_("got unknown message: application '%.16s', type '%.16s'\n",
            msg->application, msg->type);
    }
}

static void usage(int rc)
{
    fprintf(stderr,
        "usage: cgvm_vnc [--calc] [--sdl]\n"
        "Connects to VNC server 127.0.0.1 and gets raw frames.\n"
        "--calc:  Send frames to a calculator (once one is detected).\n"
        "--sdl:   Show frames on an SDL window.\n");
    exit(rc);
}

static bool init_rfb_client(rfbClient **client, char *server,
    uint32_t *fb)
{
    int argc = 4;
    char *argv[] = { "cgvm_vnc", "-encodings", "raw", server, NULL };

    *client = rfbGetClient(8, 3, 4);
    if(!*client) {
        fprintf(stderr, "rfbGetClient failed\n");
        return false;
    }
    (*client)->FinishedFrameBufferUpdate = fb_update;
    (*client)->width = CALC_WIDTH;
    (*client)->height = CALC_HEIGHT;
    (*client)->frameBuffer = (void *)fb;

    /* Standard 32-bit xRGB */
    (*client)->format.bitsPerPixel = 32;
    (*client)->format.redShift = 16;
    (*client)->format.greenShift = 8;
    (*client)->format.blueShift = 0;
    (*client)->format.redMax = 0xff;
    (*client)->format.greenMax = 0xff;
    (*client)->format.blueMax = 0xff;
    SetFormatAndEncodings(*client);

    if(!rfbInitClient(*client, &argc, argv)) {
        fprintf(stderr, "rfbInitClient failed\n");
        *client = NULL;
        return false;
    }
    return true;
}

int main(int argc, char **argv)
{
    for(int i = 1; i < argc; i++) {
        if(!strcmp(argv[i], "-h") || !strcmp(argv[i], "--help"))
            usage(0);
        else if(!strcmp(argv[i], "--calc"))
            app.display_calc = true;
        else if(!strcmp(argv[i], "--sdl"))
            app.display_sdl = true;
        else {
            fprintf(stderr, "error: unrecognized option '%s'\n", argv[i]);
            return 1;
        }
    }
    if(argc == 1)
        usage(0);
    if(!app.display_calc && !app.display_sdl)
        usage(1);

    atexit(cleanup);
    /* TODO: Sometimes when the calculator disconnects the wait on the RFB
       server loops and can't be killed by SIGINT or SIGTERM? */
    signal(SIGINT, exit);

    //---
    // Initialise the RFB client
    //---

    uint32_t *fb = malloc(CALC_WIDTH * CALC_HEIGHT * 4);
    assert(fb && "out of memory");

    if(!init_rfb_client(&app.client, "127.0.0.1", fb))
        return 1;

    /* Create the SDL window if SDL display is requested */
    if(app.display_sdl) {
        SDL_Init(SDL_INIT_VIDEO);
        app.window = SDL_CreateWindow("CG Virtual Monitor test VNC client",
            SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
            CALC_WIDTH, CALC_HEIGHT, 0);
        app.surface = SDL_GetWindowSurface(app.window);

        /* Surely this is gonna be the default everywhere, like surely */
        assert(app.surface->format->BytesPerPixel == 4);
        assert(app.surface->format->format == SDL_PIXELFORMAT_RGB888);
    }

    if(app.display_calc) {
        int rc;
        if((rc = libusb_init(&app.libusb_ctx)))
            return elog_libusb(rc, "error initializing libusb");

        libusb_set_option(app.libusb_ctx, LIBUSB_OPTION_LOG_LEVEL,
            LIBUSB_LOG_LEVEL_WARNING);
        fxlink_log_grab_libusb_logs();

        /* Track the list of connected calculators. */
        fxlink_device_list_track(&app.devices, app.libusb_ctx);
        app.fb16_be = malloc(CALC_WIDTH * CALC_HEIGHT * 2);
    }

    while(1) {
        if(app.display_sdl) {
            SDL_Event e;
            while(SDL_PollEvent(&e)) {
                if(e.type == SDL_QUIT) {
                    fprintf(stderr, "SDL_QUIT: Exiting...\n");
                    exit(0);
                }
            }
        }

        int i = WaitForMessage(app.client, 100);
        if(i < 0) {
            fprintf(stderr, "WaitForMessage() select: %d\n", i);
            continue;
        }
        else if(i > 0 && !HandleRFBServerMessage(app.client)) {
            fprintf(stderr, "HandleRFBServerMessage() failed\n");
            continue;
        }

        /* Run libusb's event loop */
        struct timeval zero_tv = { 0 };
        libusb_handle_events_timeout(app.libusb_ctx, &zero_tv);
        fxlink_device_list_refresh(&app.devices);

        /* Check if the calculator disconnected */
        if(app.calc) {
            bool still_here = false;
            for(int i = 0; i < app.devices.count; i++) {
                still_here |= app.devices.devices[i].dp == app.calc_unique_id;
            }
            if(!still_here) {
                hlog("cgvm");
                log_("calculator disconnected!\n");
                app.calc = NULL;
                app.calc_unique_id = NULL;
            }
        }

        /* Check for devices ready to connect to */
        if(!app.calc) {
            for(int i = 0; i < app.devices.count; i++) {
                struct fxlink_device *fdev = &app.devices.devices[i];
                char const *id = fxlink_device_id(fdev);

                if(fdev->status != FXLINK_FDEV_STATUS_IDLE || !fdev->comm)
                    continue;
                if(fdev->comm->ep_bulk_IN == 0xff) {
                    hlog("cgvm");
                    log_("ignoring %s: no fxlink interface\n", id);
                    continue;
                }
                if(!fxlink_device_claim_fxlink(fdev))
                    continue;

                hlog("cgvm");
                log_("starting virtual monitor on %s\n", id);
                app.calc = fdev;
                app.calc_unique_id = fdev->dp;
                fxlink_device_start_bulk_IN(fdev);
            }
        }

        /* Handle incoming transfers from the calc */
        if(app.calc) {
            struct fxlink_message *msg = fxlink_device_finish_bulk_IN(app.calc);
            if(msg) {
                handle_calc_message(msg);
                fxlink_message_free(msg, true);
                fxlink_device_start_bulk_IN(app.calc);
            }
        }
    }
    return 0;
}