mutter/cogl/cogl-sdl.h
Neil Roberts 17c818a9a7 Add an SDL2 winsys
This adds an alternate version of the SDL winsys using the SDL 2 API.
The two versions are mutually exclusive and share the same
CoglWinsysID. Version 2 of SDL fits a little bit better with Cogl
because it supports multiple windows and the video subsystem can be
initialised entirely independently of the rest of the subsystems.

The SDL2 winsys creates an invisible dummy window in order to bind the
GL context after creating the Cogl display. This is similar to how the
X11 winsys's work.

SDL2 seems to support compiling with support for both GL and GLES.
However there doesn't seem to be a way to select between the two
backends outside of SDL. In fact if you do compile them both in it
seems to break down because it will always try to use the window
system functions from the GLES backend because those are filled in
second in the vtable. However when creating the window it will always
prefer to use the GL function to choose a visual. This function gets
confused because the GL backend has not been initialised at that
point. The Cogl backend therefore just leaves it up to SDL to pick a
sensible backend. It will then verify that it picked a GL library
which matches the Cogl driver by checking the string from
glGetString(GL_VERSION).

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 6cb5ab41355e7bfe28f367cf4afa39a7afcfeec2)
2012-08-06 14:27:44 +01:00

199 lines
5.2 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2012 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_SDL_H__
#define __COGL_SDL_H__
#include <cogl/cogl-context.h>
#include <SDL.h>
G_BEGIN_DECLS
/**
* SECTION:cogl-sdl
* @short_description: Integration api for the Simple DirectMedia
* Layer library.
*
* Cogl is a portable graphics api that can either be used standalone
* or alternatively integrated with certain existing frameworks. This
* api enables Cogl to be used in conjunction with the Simple
* DirectMedia Layer library.
*
* Using this API a typical SDL application would look something like
* this:
* |[
* MyAppData data;
* GError *error = NULL;
*
* data.ctx = cogl_sdl_context_new (NULL, SDL_USEREVENT, &error);
* if (!data.ctx)
* {
* fprintf (stderr, "Failed to create context: %s\n",
* error->message);
* return 1;
* }
*
* my_application_setup (&data);
*
* data.redraw_queued = TRUE;
* while (!data.quit)
* {
* while (!data.quit)
* {
* if (!SDL_PollEvent (&event))
* {
* if (data.redraw_queued)
* break;
*
* cogl_sdl_idle (ctx);
* if (!SDL_WaitEvent (&event))
* {
* fprintf (stderr, "Error waiting for SDL events");
* return 1;
* }
* }
*
* handle_event (&data, &event);
* cogl_sdl_handle_event (ctx, &event);
* }
*
* data.redraw_queued = redraw (&data);
* }
* ]|
*/
/**
* cogl_sdl_context_new:
* @type: An SDL user event type between %SDL_USEREVENT and
* %SDL_NUMEVENTS - %1
* @error: A GError return location.
*
* This is a convenience function for creating a new #CoglContext for
* use with SDL and specifying what SDL user event type Cogl can use
* as a way to interrupt SDL_WaitEvent().
*
* This function is equivalent to the following code:
* |[
* CoglRenderer *renderer = cogl_renderer_new ();
* CoglDisplay *display;
*
* cogl_renderer_set_winsys_id (renderer, COGL_WINSYS_ID_SDL);
*
* cogl_sdl_renderer_set_event_type (renderer, type);
*
* if (!cogl_renderer_connect (renderer, error))
* return NULL;
*
* display = cogl_display_new (renderer, NULL);
* if (!cogl_display_setup (display, error))
* return NULL;
*
* return cogl_context_new (display, error);
* ]|
*
* <note>SDL applications are required to either use this API or
* to manually create a #CoglRenderer and call
* cogl_sdl_renderer_set_event_type().</note>
*
* Since: 2.0
* Stability: unstable
*/
CoglContext *
cogl_sdl_context_new (int type, GError **error);
/**
* cogl_sdl_renderer_set_event_type:
* @renderer: A #CoglRenderer
* @type: An SDL user event type between %SDL_USEREVENT and
* %SDL_NUMEVENTS - %1
*
* Tells Cogl what SDL user event type it can use as a way to
* interrupt SDL_WaitEvent() to ensure that cogl_sdl_handle_event()
* will be called in a finite amount of time.
*
* <note>This should only be called on an un-connected
* @renderer.</note>
*
* <note>For convenience most simple applications can use
* cogl_sdl_context_new() if they don't want to manually create
* #CoglRenderer and #CoglDisplay objects during
* initialization.</note>
*
* Since: 2.0
* Stability: unstable
*/
void
cogl_sdl_renderer_set_event_type (CoglRenderer *renderer, int type);
/**
* cogl_sdl_renderer_get_event_type:
* @renderer: A #CoglRenderer
*
* Queries what SDL user event type Cogl is using as a way to
* interrupt SDL_WaitEvent(). This is set either using
* cogl_sdl_context_new or by using
* cogl_sdl_renderer_set_event_type().
*
* Since: 2.0
* Stability: unstable
*/
int
cogl_sdl_renderer_get_event_type (CoglRenderer *renderer);
/**
* cogl_sdl_handle_event:
* @context: A #CoglContext
* @event: An SDL event
*
* Passes control to Cogl so that it may dispatch any internal event
* callbacks in response to the given SDL @event. This function must
* be called for every SDL event.
*
* Since: 2.0
* Stability: unstable
*/
void
cogl_sdl_handle_event (CoglContext *context, SDL_Event *event);
/**
* cogl_sdl_idle:
* @context: A #CoglContext
*
* Notifies Cogl that the application is idle and about to call
* SDL_WaitEvent(). Cogl may use this to run low priority book keeping
* tasks.
*
* Since: 2.0
* Stability: unstable
*/
void
cogl_sdl_idle (CoglContext *context);
G_END_DECLS
#endif /* __COGL_SDL_H__ */