app/main.cpp

   1 #define GST_USE_UNSTABLE_API
   2 #define HAVE_MEMFD_CREATE
   3
   4 #include <string>
   5 #include <iostream>
   6 #include <cstring>
   7 #include <cstdio>
   8 #include <cstdlib>
   9
  10 #include <signal.h>
  11 #include <wayland-client.h>
  12 #include <sys/mman.h>
  13 #include <unistd.h>
  14 #include <fcntl.h>
  15 #include <assert.h>
  16
  17 #include "xdg-shell-client-protocol.h"
  18 #include "agl-shell-desktop-client-protocol.h"
  19 #include "utils.h"
  20
  21 #include <gst/gst.h>
  22
  23 #include <gst/video/videooverlay.h>
  24 #include <gst/wayland/wayland.h>
  25
  26 // these only applies if the window is a dialog/pop-up one
  27 // by default the compositor make the window maximized
  28 #define WINDOW_WIDTH_SIZE       640
  29 #define WINDOW_HEIGHT_SIZE      720
  30
  31 #define WINDOW_WIDTH_POS_X      640
  32 #define WINDOW_WIDTH_POS_Y      180
  33
  34 #define MAX_BUFFER_ALLOC        2
  35
  36 // C++ requires a cast and we in wayland we do the cast implictly
  37 #define WL_ARRAY_FOR_EACH(pos, array, type) \
  38         for (pos = (type)(array)->data; \
  39              (const char *) pos < ((const char *) (array)->data + (array)->size); \
  40              (pos)++)
  41
  42 struct display {
  43         struct wl_display *wl_display;
  44         struct wl_registry *wl_registry;
  45         struct wl_compositor *wl_compositor;
  46         struct wl_output *wl_output;
  47         struct wl_shm *shm;
  48
  49         struct {
  50                 int width;
  51                 int height;
  52         } output_data;
  53
  54         struct xdg_wm_base *wm_base;
  55         struct agl_shell_desktop *agl_shell_desktop;
  56
  57         int has_xrgb;
  58 };
  59
  60 struct buffer {
  61         struct wl_buffer *buffer;
  62         void *shm_data;
  63         int busy;
  64         int width, height;
  65         size_t size;    /* width * 4 * height */
  66         struct wl_list buffer_link; /** window::buffer_list */
  67 };
  68
  69 struct window {
  70         struct display *display;
  71
  72         int x, y;
  73         int width, height;
  74         int init_width;
  75         int init_height;
  76
  77         struct wl_surface *surface;
  78
  79         struct xdg_surface *xdg_surface;
  80         struct xdg_toplevel *xdg_toplevel;
  81         bool wait_for_configure;
  82
  83         int fullscreen, maximized;
  84
  85         struct wl_list buffer_list;
  86         struct wl_callback *callback;
  87         bool needs_update_buffer;
  88 };
  89
  90
  91 struct receiver_data {
  92         struct window *window;
  93
  94         GstElement *pipeline;
  95         GstWaylandVideo *wl_video;
  96         GstVideoOverlay *overlay;
  97 };
  98
  99 static int running = 1;
 100
 101 static void
 102 redraw(void *data, struct wl_callback *callback, uint32_t time);
 103
 104 static struct buffer *
 105 alloc_buffer(struct window *window, int width, int height)
 106 {
 107         struct buffer *buffer = static_cast<struct buffer *>(calloc(1, sizeof(*buffer)));
 108
 109         buffer->width = width;
 110         buffer->height = height;
 111         wl_list_insert(&window->buffer_list, &buffer->buffer_link);
 112
 113         return buffer;
 114 }
 115
 116 static void
 117 destroy_buffer(struct buffer *buffer)
 118 {
 119         if (buffer->buffer)
 120                 wl_buffer_destroy(buffer->buffer);
 121
 122         munmap(buffer->shm_data, buffer->size);
 123         wl_list_remove(&buffer->buffer_link);
 124         free(buffer);
 125 }
 126
 127 static struct buffer *
 128 pick_free_buffer(struct window *window)
 129 {
 130         struct buffer *b;
 131         struct buffer *buffer = NULL;
 132
 133         wl_list_for_each(b, &window->buffer_list, buffer_link) {
 134                 if (!b->busy) {
 135                         buffer = b;
 136                         break;
 137                 }
 138         }
 139
 140         return buffer;
 141 }
 142
 143 static void
 144 prune_old_released_buffers(struct window *window)
 145 {
 146         struct buffer *b, *b_next;
 147
 148         wl_list_for_each_safe(b, b_next,
 149                               &window->buffer_list, buffer_link) {
 150                 if (!b->busy && (b->width != window->width ||
 151                                  b->height != window->height))
 152                         destroy_buffer(b);
 153         }
 154 }
 155
 156 static void
 157 paint_pixels(void *image, int padding, int width, int height, uint32_t time)
 158 {
 159         memset(image, 0x00, width * height * 4);
 160 }
 161
 162 static void
 163 buffer_release(void *data, struct wl_buffer *buffer)
 164 {
 165         struct buffer *mybuf = static_cast<struct buffer *>(data);
 166         mybuf->busy = 0;
 167 }
 168
 169 static const struct wl_buffer_listener buffer_listener = {
 170         buffer_release
 171 };
 172
 173
 174 static int
 175 create_shm_buffer(struct display *display, struct buffer *buffer,
 176                   int width, int height, uint32_t format)
 177 {
 178         struct wl_shm_pool *pool;
 179         int fd, size, stride;
 180         void *data;
 181
 182         stride = width * 4;
 183         size = stride * height;
 184
 185         fd = os_create_anonymous_file(size);
 186         if (fd < 0) {
 187                 fprintf(stderr, "creating a buffer file for %d B failed: %s\n",
 188                                 size, strerror(errno));
 189                 return -1;
 190         }
 191
 192         data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 193         if (data == MAP_FAILED) {
 194                 fprintf(stderr, "mmap failed: %s\n", strerror(errno));
 195                 close(fd);
 196                 return -1;
 197         }
 198
 199         pool = wl_shm_create_pool(display->shm, fd, size);
 200         buffer->buffer = wl_shm_pool_create_buffer(pool, 0, width,
 201                                                    height, stride, format);
 202         wl_buffer_add_listener(buffer->buffer, &buffer_listener, buffer);
 203         wl_shm_pool_destroy(pool);
 204         close(fd);
 205
 206         buffer->shm_data = data;
 207         buffer->size = size;
 208         buffer->width = width;
 209         buffer->height = height;
 210
 211         fprintf(stdout, "Created shm buffer with width %d, height %d\n", width, height);
 212         return 0;
 213 }
 214
 215 static struct buffer *
 216 get_next_buffer(struct window *window)
 217 {
 218         struct buffer *buffer = NULL;
 219         int ret = 0;
 220
 221         if (window->needs_update_buffer) {
 222                 int i;
 223
 224                 for (i = 0; i < MAX_BUFFER_ALLOC; i++)
 225                         alloc_buffer(window, window->width, window->height);
 226
 227                 window->needs_update_buffer = false;
 228         }
 229
 230         buffer = pick_free_buffer(window);
 231         if (!buffer)
 232                 return NULL;
 233
 234
 235         if (!buffer->buffer) {
 236                 ret = create_shm_buffer(window->display, buffer, window->width,
 237                                         window->height, WL_SHM_FORMAT_XRGB8888);
 238
 239                 if (ret < 0)
 240                         return NULL;
 241
 242                 /* paint the padding */
 243                 memset(buffer->shm_data, 0x00, window->width * window->height * 4);
 244         }
 245
 246         return buffer;
 247 }
 248
 249
 250 static const struct wl_callback_listener frame_listener = {
 251         redraw
 252 };
 253
 254 static void
 255 redraw(void *data, struct wl_callback *callback, uint32_t time)
 256 {
 257         struct window *window = static_cast<struct window *>(data);
 258         struct buffer *buffer;
 259
 260         prune_old_released_buffers(window);
 261
 262         buffer = get_next_buffer(window);
 263         if (!buffer) {
 264                 fprintf(stderr,
 265                                 !callback ? "Failed to create the first buffer.\n" :
 266                                 "Both buffers busy at redraw(). Server bug?\n");
 267                 abort();
 268         }
 269
 270         // do the actual painting
 271         paint_pixels(buffer->shm_data, 0x0, window->width, window->height, time);
 272
 273         wl_surface_attach(window->surface, buffer->buffer, 0, 0);
 274         wl_surface_damage(window->surface, 0, 0, window->width, window->height);
 275
 276         if (callback)
 277                 wl_callback_destroy(callback);
 278
 279         window->callback = wl_surface_frame(window->surface);
 280         wl_callback_add_listener(window->callback, &frame_listener, window);
 281         wl_surface_commit(window->surface);
 282
 283         buffer->busy = 1;
 284 }
 285
 286 static void
 287 shm_format(void *data, struct wl_shm *wl_shm, uint32_t format)
 288 {
 289         struct display *d = static_cast<struct display *>(data);
 290
 291         if (format == WL_SHM_FORMAT_XRGB8888)
 292                 d->has_xrgb = true;
 293 }
 294
 295 static const struct wl_shm_listener shm_listener = {
 296         shm_format
 297 };
 298
 299 static void
 300 xdg_wm_base_ping(void *data, struct xdg_wm_base *shell, uint32_t serial)
 301 {
 302         xdg_wm_base_pong(shell, serial);
 303 }
 304
 305 static const struct xdg_wm_base_listener xdg_wm_base_listener = {
 306         xdg_wm_base_ping,
 307 };
 308
 309 static void
 310 display_handle_geometry(void *data, struct wl_output *wl_output,
 311                         int x, int y, int physical_width, int physical_height,
 312                         int subpixel, const char *make, const char *model, int transform)
 313 {
 314         (void) data;
 315         (void) wl_output;
 316         (void) x;
 317         (void) y;
 318         (void) physical_width;
 319         (void) physical_height;
 320         (void) subpixel;
 321         (void) make;
 322         (void) model;
 323         (void) transform;
 324 }
 325
 326 static void
 327 display_handle_mode(void *data, struct wl_output *wl_output, uint32_t flags,
 328                     int width, int height, int refresh)
 329 {
 330         struct display *d = static_cast<struct display *>(data);
 331
 332         if (wl_output == d->wl_output && (flags & WL_OUTPUT_MODE_CURRENT)) {
 333                 d->output_data.width = width;
 334                 d->output_data.height = height;
 335
 336                 fprintf(stdout, "Found output with width %d and height %d\n",
 337                                 d->output_data.width, d->output_data.height);
 338         }
 339 }
 340
 341 static void
 342 display_handle_scale(void *data, struct wl_output *wl_output, int scale)
 343 {
 344         (void) data;
 345         (void) wl_output;
 346         (void) scale;
 347 }
 348
 349 static void
 350 display_handle_done(void *data, struct wl_output *wl_output)
 351 {
 352         (void) data;
 353         (void) wl_output;
 354 }
 355
 356 static const struct wl_output_listener output_listener = {
 357         display_handle_geometry,
 358         display_handle_mode,
 359         display_handle_done,
 360         display_handle_scale
 361 };
 362
 363 static void
 364 application_id(void *data, struct agl_shell_desktop *agl_shell_desktop,
 365                 const char *app_id)
 366 {
 367         (void) data;
 368         (void) agl_shell_desktop;
 369         (void) app_id;
 370 }
 371
 372 static void
 373 application_id_state(void *data, struct agl_shell_desktop *agl_shell_desktop,
 374                      const char *app_id, const char *app_data,
 375                      uint32_t app_state, uint32_t app_role)
 376 {
 377         (void) data;
 378         (void) app_data;
 379         (void) agl_shell_desktop;
 380         (void) app_id;
 381         (void) app_state;
 382         (void) app_role;
 383 }
 384
 385 static const struct agl_shell_desktop_listener agl_shell_desktop_listener = {
 386         application_id,
 387         application_id_state,
 388 };
 389
 390 static void
 391 registry_handle_global(void *data, struct wl_registry *registry, uint32_t id,
 392                        const char *interface, uint32_t version)
 393 {
 394         struct display *d = static_cast<struct display *>(data);
 395
 396         if (strcmp(interface, "wl_compositor") == 0) {
 397                 d->wl_compositor =
 398                         static_cast<struct wl_compositor *>(wl_registry_bind(registry, id,
 399                                                     &wl_compositor_interface, 1));
 400         } else if (strcmp(interface, "xdg_wm_base") == 0) {
 401                 d->wm_base = static_cast<struct xdg_wm_base *>(wl_registry_bind(registry,
 402                                 id, &xdg_wm_base_interface, 1));
 403                 xdg_wm_base_add_listener(d->wm_base, &xdg_wm_base_listener, d);
 404         } else if (strcmp(interface, "wl_shm") == 0) {
 405                 d->shm = static_cast<struct wl_shm *>(wl_registry_bind(registry,
 406                                 id, &wl_shm_interface, 1));
 407                 wl_shm_add_listener(d->shm, &shm_listener, d);
 408         } else if (strcmp(interface, "agl_shell_desktop") == 0) {
 409                 d->agl_shell_desktop = static_cast<struct agl_shell_desktop *>(wl_registry_bind(registry, id,
 410                                                         &agl_shell_desktop_interface, 1));
 411                 /* as an example, show how to register for events from the compositor */
 412                 agl_shell_desktop_add_listener(d->agl_shell_desktop,
 413                                                &agl_shell_desktop_listener, d);
 414         } else if (strcmp(interface, "wl_output") == 0) {
 415                 d->wl_output = static_cast<struct wl_output *>(wl_registry_bind(registry, id,
 416                                              &wl_output_interface, 1));
 417                 wl_output_add_listener(d->wl_output, &output_listener, d);
 418         }
 419 }
 420
 421 static void
 422 registry_handle_global_remove(void *data, struct wl_registry *reg, uint32_t id)
 423 {
 424         (void) data;
 425         (void) reg;
 426         (void) id;
 427 }
 428
 429 static const struct wl_registry_listener registry_listener = {
 430         registry_handle_global,
 431         registry_handle_global_remove,
 432 };
 433
 434
 435 static void
 436 error_cb(GstBus *bus, GstMessage *msg, gpointer user_data)
 437 {
 438         struct receiver_data *d =
 439                 static_cast<struct receiver_data *>(user_data);
 440
 441         gchar *debug = NULL;
 442         GError *err = NULL;
 443
 444         gst_message_parse_error(msg, &err, &debug);
 445
 446         g_print("Error: %s\n", err->message);
 447         g_error_free(err);
 448
 449         if (debug) {
 450                 g_print("Debug details: %s\n", debug);
 451                 g_free(debug);
 452         }
 453
 454         gst_element_set_state(d->pipeline, GST_STATE_NULL);
 455 }
 456
 457 static GstBusSyncReply
 458 bus_sync_handler(GstBus *bus, GstMessage *message, gpointer user_data)
 459 {
 460         struct receiver_data *d =
 461                 static_cast<struct receiver_data *>(user_data);
 462
 463         if (gst_is_wayland_display_handle_need_context_message(message)) {
 464                 GstContext *context;
 465                 struct wl_display *display_handle = d->window->display->wl_display;
 466
 467                 context = gst_wayland_display_handle_context_new(display_handle);
 468                 d->wl_video = GST_WAYLAND_VIDEO(GST_MESSAGE_SRC(message));
 469                 gst_element_set_context(GST_ELEMENT(GST_MESSAGE_SRC(message)), context);
 470
 471                 goto drop;
 472         } else if (gst_is_video_overlay_prepare_window_handle_message(message)) {
 473                 struct wl_surface *window_handle = d->window->surface;
 474
 475                 /* GST_MESSAGE_SRC(message) will be the overlay object that we
 476                  * have to use. This may be waylandsink, but it may also be
 477                  * playbin. In the latter case, we must make sure to use
 478                  * playbin instead of waylandsink, because playbin resets the
 479                  * window handle and render_rectangle after restarting playback
 480                  * and the actual window size is lost */
 481                 d->overlay = GST_VIDEO_OVERLAY(GST_MESSAGE_SRC(message));
 482
 483                 g_print("setting window handle and size (%d x %d) w %d, h %d\n",
 484                                 d->window->x, d->window->y,
 485                                 d->window->width, d->window->height);
 486
 487                 gst_video_overlay_set_window_handle(d->overlay, (guintptr) window_handle);
 488                 gst_video_overlay_set_render_rectangle(d->overlay,
 489                                                        d->window->x, d->window->y,
 490                                                        d->window->width, d->window->height);
 491
 492                 goto drop;
 493         }
 494
 495         return GST_BUS_PASS;
 496
 497 drop:
 498         gst_message_unref(message);
 499         return GST_BUS_DROP;
 500 }
 501
 502 static void
 503 handle_xdg_surface_configure(void *data, struct xdg_surface *surface, uint32_t serial)
 504 {
 505         struct window *window = static_cast<struct window *>(data);
 506
 507         xdg_surface_ack_configure(surface, serial);
 508
 509         if (window->wait_for_configure) {
 510                 redraw(window, NULL, 0);
 511                 window->wait_for_configure = false;
 512         }
 513 }
 514
 515 static const struct xdg_surface_listener xdg_surface_listener = {
 516         handle_xdg_surface_configure,
 517 };
 518
 519 static void
 520 handle_xdg_toplevel_configure(void *data, struct xdg_toplevel *xdg_toplevel,
 521                               int32_t width, int32_t height,
 522                               struct wl_array *states)
 523 {
 524         struct window *window = static_cast<struct window *>(data);
 525         uint32_t *p;
 526
 527         window->fullscreen = 0;
 528         window->maximized = 0;
 529
 530         // use our own macro as C++ can't typecast from (void *) directly
 531         WL_ARRAY_FOR_EACH(p, states, uint32_t *) {
 532                 uint32_t state = *p;
 533                 switch (state) {
 534                 case XDG_TOPLEVEL_STATE_FULLSCREEN:
 535                         window->fullscreen = 1;
 536                         break;
 537                 case XDG_TOPLEVEL_STATE_MAXIMIZED:
 538                         window->maximized = 1;
 539                         break;
 540                 }
 541         }
 542
 543         if (width > 0 && height > 0) {
 544                 if (!window->fullscreen && !window->maximized) {
 545                         window->init_width = width;
 546                         window->init_height = height;
 547                 }
 548                 window->width = width;
 549                 window->height = height;
 550         } else if (!window->fullscreen && !window->maximized) {
 551                 window->width = window->init_width;
 552                 window->height = window->init_height;
 553         }
 554
 555         window->needs_update_buffer = true;
 556
 557 }
 558
 559 static void
 560 handle_xdg_toplevel_close(void *data, struct xdg_toplevel *xdg_toplevel)
 561 {
 562         running = 0;
 563 }
 564
 565 static const struct xdg_toplevel_listener xdg_toplevel_listener = {
 566         handle_xdg_toplevel_configure,
 567         handle_xdg_toplevel_close,
 568 };
 569
 570 static struct window *
 571 create_window(struct display *display, int width, int height, const char *app_id)
 572 {
 573         struct window *window;
 574         int i;
 575
 576         assert(display->wm_base != NULL);
 577
 578         window = static_cast<struct window *>(calloc(1, sizeof(*window)));
 579         if (!window)
 580                 return NULL;
 581
 582         wl_list_init(&window->buffer_list);
 583         window->callback = NULL;
 584         window->display = display;
 585         window->width = width;
 586         window->height = height;
 587         window->surface = wl_compositor_create_surface(display->wl_compositor);
 588
 589         if (display->wm_base) {
 590                 window->xdg_surface =
 591                         xdg_wm_base_get_xdg_surface(display->wm_base, window->surface);
 592                 assert(window->xdg_surface);
 593
 594                 xdg_surface_add_listener(window->xdg_surface,
 595                                          &xdg_surface_listener, window);
 596                 window->xdg_toplevel = xdg_surface_get_toplevel(window->xdg_surface);
 597                 assert(window->xdg_toplevel);
 598
 599                 xdg_toplevel_add_listener(window->xdg_toplevel,
 600                                           &xdg_toplevel_listener, window);
 601
 602                 xdg_toplevel_set_app_id(window->xdg_toplevel, app_id);
 603
 604                 wl_surface_commit(window->surface);
 605                 window->wait_for_configure = true;
 606         }
 607
 608         for (i = 0; i < MAX_BUFFER_ALLOC; i++)
 609                 alloc_buffer(window, window->width, window->height);
 610
 611         return window;
 612 }
 613
 614
 615 static void
 616 destroy_window(struct window *window)
 617 {
 618         struct buffer *buffer, *buffer_next;
 619
 620         if (window->callback)
 621                 wl_callback_destroy(window->callback);
 622
 623         wl_list_for_each_safe(buffer, buffer_next,
 624                               &window->buffer_list, buffer_link)
 625                 destroy_buffer(buffer);
 626
 627         if (window->xdg_toplevel)
 628                 xdg_toplevel_destroy(window->xdg_toplevel);
 629
 630         if (window->xdg_surface)
 631                 xdg_surface_destroy(window->xdg_surface);
 632
 633         wl_surface_destroy(window->surface);
 634         free(window);
 635 }
 636
 637 static void
 638 signal_int(int sig, siginfo_t *si, void *_unused)
 639 {
 640         running = 0;
 641 }
 642
 643 static struct display *
 644 create_display(int argc, char *argv[])
 645 {
 646         struct display *display;
 647
 648         display = static_cast<struct display *>(calloc(1, sizeof(*display)));
 649         if (display == NULL) {
 650                 fprintf(stderr, "out of memory\n");
 651                 exit(1);
 652         }
 653         display->wl_display = wl_display_connect(NULL);
 654         assert(display->wl_display);
 655
 656         display->has_xrgb = false;
 657         display->wl_registry = wl_display_get_registry(display->wl_display);
 658
 659         wl_registry_add_listener(display->wl_registry, &registry_listener, display);
 660         wl_display_roundtrip(display->wl_display);
 661
 662         if (display->shm == NULL) {
 663                 fprintf(stderr, "No wl_shm global\n");
 664                 return NULL;
 665         }
 666
 667         if (display->agl_shell_desktop == NULL) {
 668                 fprintf(stderr, "No agl_shell extension present\n");
 669                 return NULL;
 670         }
 671
 672         wl_display_roundtrip(display->wl_display);
 673
 674         if (!display->has_xrgb) {
 675                 fprintf(stderr, "WL_SHM_FORMAT_XRGB32 not available\n");
 676                 return NULL;
 677         }
 678
 679         return display;
 680 }
 681
 682 static void
 683 destroy_display(struct display *display)
 684 {
 685         if (display->shm)
 686                 wl_shm_destroy(display->shm);
 687
 688         if (display->wm_base)
 689                 xdg_wm_base_destroy(display->wm_base);
 690
 691         if (display->agl_shell_desktop)
 692                 agl_shell_desktop_destroy(display->agl_shell_desktop);
 693
 694         if (display->wl_compositor)
 695                 wl_compositor_destroy(display->wl_compositor);
 696
 697         wl_registry_destroy(display->wl_registry);
 698         wl_display_flush(display->wl_display);
 699         wl_display_disconnect(display->wl_display);
 700         free(display);
 701 }
 702
 703 int main(int argc, char *argv[])
 704 {
 705         int ret = 0;
 706         struct sigaction sa;
 707         struct receiver_data receiver_data = {};
 708         struct display *display;
 709         struct window *window;
 710         const char *camera_device = NULL;
 711         const char *width_str = NULL;
 712         const char *height_str = NULL;
 713         int width;
 714         int height;
 715
 716         char pipeline_str[1024];
 717         GError *error = NULL;
 718         const char *app_id = "camera-gstreamer";
 719
 720         sa.sa_sigaction = signal_int;
 721         sigemptyset(&sa.sa_mask);
 722         sa.sa_flags = SA_RESETHAND | SA_SIGINFO;
 723         sigaction(SIGINT, &sa, NULL);
 724
 725         int gargc = 2;
 726         char **gargv = static_cast<char **>(calloc(2, sizeof(char *)));
 727
 728         gargv[0] = strdup(argv[0]);
 729         gargv[1] = strdup("--gst-debug-level=2");
 730
 731         camera_device = getenv("DEFAULT_V4L2_DEVICE");
 732         if (!camera_device)
 733                 camera_device = get_first_camera_device();
 734         width_str = getenv("DEFAULT_V4L2_DEVICE_WIDTH");
 735         if (!width_str)
 736                 width = WINDOW_WIDTH_SIZE;
 737         else
 738                 width = atoi(width_str);
 739
 740         height_str = getenv("DEFAULT_V4L2_DEVICE_HEIGHT");
 741         if (!height_str)
 742                 height = WINDOW_HEIGHT_SIZE;
 743         else
 744                 height = atoi(height_str);
 745
 746         memset(pipeline_str, 0, sizeof(pipeline_str));
 747         snprintf(pipeline_str, sizeof(pipeline_str), "v4l2src device=%s ! video/x-raw,width=%d,height=%d ! waylandsink",
 748                 camera_device, width, height);
 749         gst_init(&gargc, &gargv);
 750
 751         setbuf(stdout, NULL);
 752
 753         fprintf(stdout, "Using pipeline: %s\n", pipeline_str);
 754
 755         GstElement *pipeline = gst_parse_launch(pipeline_str, &error);
 756         if (error || !pipeline) {
 757                 fprintf(stderr, "gstreamer pipeline construction failed!\n");
 758                 free(gargv);
 759                 return EXIT_FAILURE;
 760         }
 761
 762         receiver_data.pipeline = pipeline;
 763
 764         display = create_display(argc, argv);
 765         if (!display)
 766                 return -1;
 767
 768         // if you'd want to place the video in a pop-up/dialog type of window:
 769         // agl_shell_desktop_set_app_property(display->agl_shell_desktop, app_id,
 770         //                                 AGL_SHELL_DESKTOP_APP_ROLE_POPUP,
 771         //                                 WINDOW_WIDTH_POS_X, WINDOW_WIDTH_POS_Y,
 772         //                                 0, 0, WINDOW_WIDTH_SIZE, WINDOW_HEIGHT_SIZE,
 773         //                                 display->wl_output);
 774
 775         // we use the role to set a correspondence between the top level
 776         // surface and our application, with the previous call letting the
 777         // compositor know that we're one and the same
 778         window = create_window(display, WINDOW_WIDTH_SIZE, WINDOW_HEIGHT_SIZE, app_id);
 779
 780         if (!window) {
 781                 free(gargv);
 782                 return EXIT_FAILURE;
 783         }
 784
 785         window->display = display;
 786         receiver_data.window = window;
 787
 788         /* Initialise damage to full surface, so the padding gets painted */
 789         wl_surface_damage(window->surface, 0, 0,
 790                           window->width, window->height);
 791
 792         if (!window->wait_for_configure) {
 793                 redraw(window, NULL, 0);
 794         }
 795
 796         GstBus *bus = gst_element_get_bus(pipeline);
 797         gst_bus_add_signal_watch(bus);
 798
 799         g_signal_connect(bus, "message::error", G_CALLBACK(error_cb), &receiver_data);
 800         gst_bus_set_sync_handler(bus, bus_sync_handler, &receiver_data, NULL);
 801         gst_object_unref(bus);
 802
 803         gst_element_set_state(pipeline, GST_STATE_PLAYING);
 804         fprintf(stdout, "gstreamer pipeline running\n");
 805
 806         // run the application
 807         while (running && ret != -1)
 808                 ret = wl_display_dispatch(display->wl_display);
 809
 810         gst_element_set_state(pipeline, GST_STATE_NULL);
 811         gst_object_unref(pipeline);
 812
 813         destroy_window(window);
 814         destroy_display(display);
 815         free(gargv);
 816
 817         return ret;
 818 }