Function ThreadMain

test/browser/gl_only_in_pthread.c:24–58

_Atomic int threadRunning = 0;

void *ThreadMain(void *arg)
{
  printf("Thread started. You should see the WebGL canvas fade from black to red.\n");
  EmscriptenWebGLContextAttributes attr;
  emscripten_webgl_init_context_attributes(&attr);
  attr.explicitSwapControl = true;
  ctx = emscripten_webgl_create_context("#canvas", &attr);
  emscripten_webgl_make_context_current(ctx);

  double color = 0;
  for(int i = 0; i < 100; ++i)
  {
    color += 0.01;
    glClearColor(color, 0, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);
    EMSCRIPTEN_RESULT r = emscripten_webgl_commit_frame();
    assert(r == EMSCRIPTEN_RESULT_SUCCESS);

    double now = emscripten_get_now();
    while(emscripten_get_now() - now < 16) /*no-op*/;
  }

#if 0 // TODO: this doesn't work yet for some reason
  unsigned char data[64];
  glReadPixels(0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, data);
  assert(glGetError() == 0);
  printf("%d %d %d %d\n", data[0], data[1], data[2], data[3]);
#endif

  emscripten_webgl_make_context_current(0);
  emscripten_webgl_destroy_context(ctx);
  threadRunning = 0;
  printf("Thread quit\n");
  pthread_exit(0);
}

void CreateThread()
{