v4l2: show v4l captured output in SDL window

spa/meson.build

@@ -3,6 +3,7 @@ project('spa', 'c')
 alsa_dep = dependency('alsa')
 v4l2_dep = dependency('libv4l2')
 xv_dep = dependency('x11')
+sdl_dep = dependency('sdl2')
 dl_lib = find_library('dl', required : true)
 
 inc = include_directories('include')

spa/plugins/v4l2/v4l2-utils.c

@@ -493,13 +493,15 @@ mmap_init (SpaV4l2Source *this)
     b->meta[0].size = sizeof (b->header);
 
     b->data[0].type = SPA_DATA_TYPE_MEMPTR;
-    b->data[0].size = buf.length;
     b->data[0].data = mmap (NULL,
                             buf.length,
                             PROT_READ | PROT_WRITE,
                             MAP_SHARED,
                             state->fd,
                             buf.m.offset);
+    b->data[0].offset = 0;
+    b->data[0].size = buf.length;
+    b->data[0].stride = state->fmt.fmt.pix.bytesperline;
 
     if (b->data[0].data == MAP_FAILED) {
       perror ("mmap");

spa/tests/meson.build

@@ -5,5 +5,5 @@ executable('test-mixer', 'test-mixer.c',
 
 executable('test-v4l2', 'test-v4l2.c',
            include_directories : inc,
-           dependencies : [dl_lib],
+           dependencies : [dl_lib, sdl_dep],
            install : false)

spa/tests/test-v4l2.c

@@ -23,12 +23,17 @@
 #include <unistd.h>
 #include <dlfcn.h>
 
+#include <SDL2/SDL.h>
+
 #include <spa/node.h>
 #include <spa/video/format.h>
 
 typedef struct {
   SpaHandle *source;
   const SpaNode *source_node;
+  SDL_Renderer *renderer;
+  SDL_Window *window;
+  SDL_Texture *texture;
 } AppData;
 
 static SpaResult
@@ -73,6 +78,7 @@ make_node (SpaHandle **handle, const SpaNode **node, const char *lib, const char
   }
   return SPA_RESULT_ERROR;
 }
+#define MIN(a,b) (a < b ? a : b)
 
 static void
 on_source_event (SpaHandle *handle, SpaEvent *event, void *user_data)
@@ -84,10 +90,32 @@ on_source_event (SpaHandle *handle, SpaEvent *event, void *user_data)
     {
       SpaOutputInfo info[1] = { 0, };
       SpaResult res;
+      void *sdata, *ddata;
+      int sstride, dstride;
+      int i;
+      uint8_t *src, *dst;
 
       if ((res = data->source_node->pull_port_output (data->source, 1, info)) < 0)
         printf ("got pull error %d\n", res);
 
+      if (SDL_LockTexture (data->texture, NULL, &ddata, &dstride) < 0) {
+        fprintf (stderr, "Couldn't lock texture: %s\n", SDL_GetError());
+        return;
+      }
+      sdata = info[0].buffer->datas[0].data;
+      sstride = info[0].buffer->datas[0].stride;
+
+      for (i = 0; i < 240; i++) {
+        src = ((uint8_t*)sdata + i * sstride);
+        dst = ((uint8_t*)ddata + i * dstride);
+        memcpy (dst, src, MIN (sstride, dstride));
+      }
+      SDL_UnlockTexture(data->texture);
+
+      SDL_RenderClear (data->renderer);
+      SDL_RenderCopy (data->renderer, data->texture, NULL, NULL);
+      SDL_RenderPresent (data->renderer);
+
       if (info[0].buffer) {
         spa_buffer_unref (info[0].buffer);
       }
@@ -164,13 +192,30 @@ run_async_source (AppData *data)
 {
   SpaResult res;
   SpaCommand cmd;
+  bool done = false;
 
   cmd.type = SPA_COMMAND_START;
   if ((res = data->source_node->send_command (data->source, &cmd)) < 0)
     printf ("got error %d\n", res);
 
-  printf ("sleeping for 10 seconds\n");
-  sleep (10);
+
+  while (!done) {
+    SDL_Event event;
+
+    while (SDL_PollEvent (&event)) {
+      switch (event.type) {
+        case SDL_KEYDOWN:
+          if (event.key.keysym.sym == SDLK_ESCAPE) {
+            done = SDL_TRUE;
+          }
+          break;
+        case SDL_QUIT:
+          done = SDL_TRUE;
+          break;
+      }
+    }
+
+  }
 
   cmd.type = SPA_COMMAND_STOP;
   if ((res = data->source_node->send_command (data->source, &cmd)) < 0)
@@ -183,6 +228,25 @@ main (int argc, char *argv[])
   AppData data;
   SpaResult res;
 
+  if (SDL_Init (SDL_INIT_VIDEO) < 0) {
+    printf ("can't initialize SDL: %s\n", SDL_GetError ());
+    return -1;
+  }
+
+  if (SDL_CreateWindowAndRenderer (320, 240, SDL_WINDOW_RESIZABLE, &data.window, &data.renderer)) {
+    printf ("can't create window: %s\n", SDL_GetError ());
+    return -1;
+  }
+
+  data.texture = SDL_CreateTexture (data.renderer,
+                                    SDL_PIXELFORMAT_YUY2,
+                                    SDL_TEXTUREACCESS_STREAMING,
+                                    320, 240);
+  if (!data.texture) {
+    printf ("can't create texture: %s\n", SDL_GetError ());
+    return -1;
+  }
+
   if ((res = make_nodes (&data)) < 0) {
     printf ("can't make nodes: %d\n", res);
     return -1;
@@ -194,5 +258,7 @@ main (int argc, char *argv[])
 
   run_async_source (&data);
 
+  SDL_DestroyRenderer (data.renderer);
+
   return 0;
 }