mutter/examples/cogl-sdl-hello.c
Neil Roberts 6731569c18 Update all of the examples to use cogl_poll_get_info
The aim is that it should be a requirement that all Cogl applications
hook their mainloops into Cogl so we should lead by examples. Most of
the examples now just call cogl_poll_get_info and then g_poll with a
zero timeout so that they can continue to constantly redraw.

The SDL example is a bit special because SDL makes it very difficult
to wait on either a timeout or any file descriptors. The SDL winsys is
documented not to require blocking on any file descriptors so we can
ignore that. It implements the timeout by adding an SDL timer which
pushes an event to the queue to wake up SDL_GetEvent.

The Cogland example was already using the glib main loop so that one
has been updated to add the CoglGLibSource to it.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2012-01-05 13:41:00 +00:00

192 lines
4.3 KiB
C

#include <cogl/cogl.h>
#include <glib.h>
#include <stdio.h>
#include <SDL.h>
/* This short example is just to demonstrate mixing SDL with Cogl as a
simple way to get portable support for events */
typedef struct Data
{
CoglColor black;
CoglPrimitive *triangle;
float center_x, center_y;
CoglFramebuffer *fb;
gboolean quit;
} Data;
static void
redraw (Data *data)
{
cogl_clear (&data->black, COGL_BUFFER_BIT_COLOR);
cogl_push_matrix ();
cogl_translate (data->center_x, -data->center_y, 0.0f);
cogl_primitive_draw (data->triangle);
cogl_pop_matrix ();
cogl_framebuffer_swap_buffers (data->fb);
}
static void
handle_event (Data *data, SDL_Event *event)
{
switch (event->type)
{
case SDL_VIDEOEXPOSE:
redraw (data);
break;
case SDL_MOUSEMOTION:
{
int width =
cogl_framebuffer_get_width (COGL_FRAMEBUFFER (data->fb));
int height =
cogl_framebuffer_get_height (COGL_FRAMEBUFFER (data->fb));
data->center_x = event->motion.x * 2.0f / width - 1.0f;
data->center_y = event->motion.y * 2.0f / height - 1.0f;
redraw (data);
}
break;
case SDL_QUIT:
data->quit = TRUE;
break;
}
}
static Uint32
timer_handler (Uint32 interval, void *user_data)
{
static const SDL_UserEvent dummy_event =
{
SDL_USEREVENT
};
/* Post an event to wake up from SDL_WaitEvent */
SDL_PushEvent ((SDL_Event *) &dummy_event);
return 0;
}
static gboolean
wait_event_with_timeout (Data *data, SDL_Event *event, gint64 timeout)
{
if (timeout == -1)
{
if (SDL_WaitEvent (event))
return TRUE;
else
{
data->quit = TRUE;
return FALSE;
}
}
else if (timeout == 0)
return SDL_PollEvent (event);
else
{
gboolean ret;
/* Add a timer so that we can wake up the event loop */
SDL_TimerID timer_id =
SDL_AddTimer (timeout / 1000, timer_handler, data);
if (SDL_WaitEvent (event))
ret = TRUE;
else
{
data->quit = TRUE;
ret = FALSE;
}
SDL_RemoveTimer (timer_id);
return ret;
}
}
int
main (int argc, char **argv)
{
CoglRenderer *renderer;
CoglDisplay *display;
CoglContext *ctx;
CoglOnscreen *onscreen;
GError *error = NULL;
CoglVertexP2C4 triangle_vertices[] = {
{0, 0.7, 0xff, 0x00, 0x00, 0x80},
{-0.7, -0.7, 0x00, 0xff, 0x00, 0xff},
{0.7, -0.7, 0x00, 0x00, 0xff, 0xff}
};
Data data;
SDL_Event event;
/* Force the SDL winsys */
renderer = cogl_renderer_new ();
cogl_renderer_set_winsys_id (renderer, COGL_WINSYS_ID_SDL);
display = cogl_display_new (renderer, NULL);
ctx = cogl_context_new (display, &error);
if (!ctx)
{
fprintf (stderr, "Failed to create context: %s\n", error->message);
return 1;
}
SDL_InitSubSystem (SDL_INIT_TIMER);
onscreen = cogl_onscreen_new (ctx, 800, 600);
/* Eventually there will be an implicit allocate on first use so this
* will become optional... */
data.fb = COGL_FRAMEBUFFER (onscreen);
if (!cogl_framebuffer_allocate (data.fb, &error))
{
fprintf (stderr, "Failed to allocate framebuffer: %s\n",
error->message);
return 1;
}
cogl_color_set_from_4ub (&data.black, 0, 0, 0, 255);
data.center_x = 0.0f;
data.center_y = 0.0f;
data.quit = FALSE;
cogl_onscreen_show (onscreen);
cogl_push_framebuffer (data.fb);
data.triangle = cogl_primitive_new_p2c4 (COGL_VERTICES_MODE_TRIANGLES,
3, triangle_vertices);
while (!data.quit)
{
CoglPollFD *poll_fds;
int n_poll_fds;
gint64 timeout;
cogl_poll_get_info (ctx, &poll_fds, &n_poll_fds, &timeout);
/* It's difficult to wait for file descriptors using the SDL
event mechanism, but it the SDL winsys is documented that it
will never require this so we can assert that there are no
fds */
g_assert (n_poll_fds == 0);
if (wait_event_with_timeout (&data, &event, timeout))
do
handle_event (&data, &event);
while (SDL_PollEvent (&event));
cogl_poll_dispatch (ctx, poll_fds, n_poll_fds);
}
cogl_pop_framebuffer ();
cogl_object_unref (ctx);
cogl_object_unref (display);
cogl_object_unref (renderer);
return 0;
}