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win32: Use a dummy window to support delayed stage creation

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The Win32 backend now implements the create_context method which
creates a context and binds it to a 1x1 invisible window. That way
there will always be a context bound and the features can be retrieved
without creating the default stage. This reflects the changes in
1c6ffc8..b245d55 to the GLX backend.
This commit is contained in:
Neil Roberts 2010-01-20 16:41:25 +00:00 committed by Emmanuele Bassi
parent 479fdffc7d
commit ae188d203c
3 changed files with 198 additions and 82 deletions
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192
clutter/win32/clutter-backend-win32.c
View File

@ -156,10 +156,23 @@ clutter_backend_win32_dispose (GObject *gobject)
if (backend_win32->gl_context)
{
wglMakeCurrent (NULL, NULL);
wglDeleteContext (backend_win32->gl_context);
backend_win32->gl_context = NULL;
}
if (backend_win32->dummy_dc)
{
ReleaseDC (backend_win32->dummy_hwnd, backend_win32->dummy_dc);
backend_win32->dummy_dc = NULL;
}
if (backend_win32->dummy_hwnd)
{
DestroyWindow (backend_win32->dummy_hwnd);
backend_win32->dummy_hwnd = NULL;
}
G_OBJECT_CLASS (clutter_backend_win32_parent_class)->dispose (gobject);
}
@ -201,21 +214,20 @@ clutter_backend_win32_get_features (ClutterBackend *backend)
SwapIntervalProc swap_interval;
ClutterBackendWin32 *backend_win32;
/* FIXME: we really need to check if gl context is set */
extensions = (const gchar *) glGetString (GL_EXTENSIONS);
/* this will make sure that the GL context exists and is bound to a
drawable */
backend_win32 = CLUTTER_BACKEND_WIN32 (backend);
g_return_val_if_fail (backend_win32->gl_context != NULL, 0);
g_return_val_if_fail (wglGetCurrentDC () != NULL, 0);
CLUTTER_NOTE (BACKEND, "Checking features\n"
"GL_VENDOR: %s\n"
"GL_RENDERER: %s\n"
"GL_VERSION: %s\n"
"GL_EXTENSIONS: %s\n",
extensions = (const gchar *) glGetString (GL_EXTENSIONS);
CLUTTER_NOTE (BACKEND,
"Checking features\n"
" GL_VENDOR: %s\n"
" GL_RENDERER: %s\n"
" GL_VERSION: %s\n"
" GL_EXTENSIONS: %s\n",
glGetString (GL_VENDOR),
glGetString (GL_RENDERER),
glGetString (GL_VERSION),
@ -261,9 +273,166 @@ clutter_backend_win32_get_features (ClutterBackend *backend)
else
CLUTTER_NOTE (BACKEND, "no use-able vblank mechanism found");
CLUTTER_NOTE (BACKEND, "backend features checked");
return flags;
}
static ATOM
clutter_backend_win32_get_dummy_window_class ()
{
static ATOM klass = 0;
if (klass == 0)
{
WNDCLASSW wndclass;
memset (&wndclass, 0, sizeof (wndclass));
wndclass.lpfnWndProc = DefWindowProc;
wndclass.hInstance = GetModuleHandleW (NULL);
wndclass.lpszClassName = L"ClutterBackendWin32DummyWindow";
klass = RegisterClassW (&wndclass);
}
return klass;
}
static gboolean
clutter_backend_win32_pixel_format_is_better (const PIXELFORMATDESCRIPTOR *pfa,
const PIXELFORMATDESCRIPTOR *pfb)
{
/* Always prefer a format with a stencil buffer */
if (pfa->cStencilBits == 0)
{
if (pfb->cStencilBits > 0)
return TRUE;
}
else if (pfb->cStencilBits == 0)
return FALSE;
/* Prefer a bigger color buffer */
if (pfb->cColorBits > pfa->cColorBits)
return TRUE;
else if (pfb->cColorBits < pfa->cColorBits)
return FALSE;
/* Prefer a bigger depth buffer */
return pfb->cDepthBits > pfa->cDepthBits;
}
static int
clutter_backend_win32_choose_pixel_format (HDC dc, PIXELFORMATDESCRIPTOR *pfd)
{
int i, num_formats, best_pf = 0;
PIXELFORMATDESCRIPTOR best_pfd;
num_formats = DescribePixelFormat (dc, 0, sizeof (best_pfd), NULL);
for (i = 1; i <= num_formats; i++)
{
memset (pfd, 0, sizeof (*pfd));
if (DescribePixelFormat (dc, i, sizeof (best_pfd), pfd)
/* Check whether this format is useable by Clutter */
&& ((pfd->dwFlags & (PFD_SUPPORT_OPENGL
| PFD_DRAW_TO_WINDOW
| PFD_DOUBLEBUFFER
| PFD_GENERIC_FORMAT))
== (PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_DRAW_TO_WINDOW))
&& pfd->iPixelType == PFD_TYPE_RGBA
&& pfd->cColorBits >= 16 && pfd->cColorBits <= 32
&& pfd->cDepthBits >= 16 && pfd->cDepthBits <= 32
/* Check whether this is a better format than one we've
already found */
&& (best_pf == 0
|| clutter_backend_win32_pixel_format_is_better (&best_pfd, pfd)))
{
best_pf = i;
best_pfd = *pfd;
}
}
*pfd = best_pfd;
return best_pf;
}
static gboolean
clutter_backend_win32_create_context (ClutterBackend *backend,
GError **error)
{
ClutterBackendWin32 *backend_win32 = CLUTTER_BACKEND_WIN32 (backend);
/* COGL assumes that there is always a GL context selected; in order
* to make sure that a WGL context exists and is made current, we
* use a small dummy window that never gets shown to which we can
* always fall back if no stage is available
*/
if (backend_win32->dummy_hwnd == NULL)
{
ATOM window_class = clutter_backend_win32_get_dummy_window_class ();
if (window_class == 0)
{
g_critical ("Unable to register window class");
return FALSE;
}
backend_win32->dummy_hwnd =
CreateWindowW ((LPWSTR) MAKEINTATOM (window_class),
L".",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
1, 1,
NULL, NULL,
GetModuleHandle (NULL),
NULL);
if (backend_win32->dummy_hwnd == NULL)
{
g_critical ("Unable to create dummy window");
return FALSE;
}
}
if (backend_win32->dummy_dc == NULL)
{
PIXELFORMATDESCRIPTOR pfd;
int pf;
backend_win32->dummy_dc = GetDC (backend_win32->dummy_hwnd);
pf = clutter_backend_win32_choose_pixel_format (backend_win32->dummy_dc,
&pfd);
if (pf == 0 || !SetPixelFormat (backend_win32->dummy_dc, pf, &pfd))
{
g_critical ("Unable to find suitable GL pixel format");
ReleaseDC (backend_win32->dummy_hwnd, backend_win32->dummy_dc);
backend_win32->dummy_dc = NULL;
return FALSE;
}
}
if (backend_win32->gl_context == NULL)
{
backend_win32->gl_context = wglCreateContext (backend_win32->dummy_dc);
if (backend_win32->gl_context == NULL)
{
g_critical ("Unable to create suitable GL context");
return FALSE;
}
}
CLUTTER_NOTE (BACKEND, "Selecting dummy 0x%x for the WGL context",
(unsigned int) backend_win32->dummy_hwnd);
wglMakeCurrent (backend_win32->dummy_dc, backend_win32->gl_context);
return TRUE;
}
static void
clutter_backend_win32_ensure_context (ClutterBackend *backend,
ClutterStage *stage)
@ -304,6 +473,10 @@ clutter_backend_win32_ensure_context (ClutterBackend *backend,
CLUTTER_NOTE (MULTISTAGE,
"Received a stale stage, clearing all context");
if (backend_win32->dummy_dc != NULL)
wglMakeCurrent (backend_win32->dummy_dc,
backend_win32->gl_context);
else
wglMakeCurrent (NULL, NULL);
}
else
@ -380,6 +553,7 @@ clutter_backend_win32_class_init (ClutterBackendWin32Class *klass)
backend_class->add_options = clutter_backend_win32_add_options;
backend_class->get_features = clutter_backend_win32_get_features;
backend_class->redraw = clutter_backend_win32_redraw;
backend_class->create_context = clutter_backend_win32_create_context;
backend_class->ensure_context = clutter_backend_win32_ensure_context;
}

2
clutter/win32/clutter-backend-win32.h
View File

@ -46,6 +46,8 @@ struct _ClutterBackendWin32
ClutterBackend parent_instance;
HGLRC gl_context;
HWND dummy_hwnd;
HDC dummy_dc;
gboolean no_event_retrieval;
HCURSOR invisible_cursor;

86
clutter/win32/clutter-stage-win32.c
View File

@ -385,66 +385,6 @@ clutter_stage_win32_get_window_class ()
return klass;
}
static gboolean
clutter_stage_win32_pixel_format_is_better (const PIXELFORMATDESCRIPTOR *pfa,
const PIXELFORMATDESCRIPTOR *pfb)
{
/* Always prefer a format with a stencil buffer */
if (pfa->cStencilBits == 0)
{
if (pfb->cStencilBits > 0)
return TRUE;
}
else if (pfb->cStencilBits == 0)
return FALSE;
/* Prefer a bigger color buffer */
if (pfb->cColorBits > pfa->cColorBits)
return TRUE;
else if (pfb->cColorBits < pfa->cColorBits)
return FALSE;
/* Prefer a bigger depth buffer */
return pfb->cDepthBits > pfa->cDepthBits;
}
static int
clutter_stage_win32_choose_pixel_format (HDC dc, PIXELFORMATDESCRIPTOR *pfd)
{
int i, num_formats, best_pf = 0;
PIXELFORMATDESCRIPTOR best_pfd;
num_formats = DescribePixelFormat (dc, 0, sizeof (best_pfd), NULL);
for (i = 1; i <= num_formats; i++)
{
memset (pfd, 0, sizeof (*pfd));
if (DescribePixelFormat (dc, i, sizeof (best_pfd), pfd)
/* Check whether this format is useable by Clutter */
&& ((pfd->dwFlags & (PFD_SUPPORT_OPENGL
| PFD_DRAW_TO_WINDOW
| PFD_DOUBLEBUFFER
| PFD_GENERIC_FORMAT))
== (PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_DRAW_TO_WINDOW))
&& pfd->iPixelType == PFD_TYPE_RGBA
&& pfd->cColorBits >= 16 && pfd->cColorBits <= 32
&& pfd->cDepthBits >= 16 && pfd->cDepthBits <= 32
/* Check whether this is a better format than one we've
already found */
&& (best_pf == 0
|| clutter_stage_win32_pixel_format_is_better (&best_pfd, pfd)))
{
best_pf = i;
best_pfd = *pfd;
}
}
*pfd = best_pfd;
return best_pf;
}
static gboolean
clutter_stage_win32_realize (ClutterStageWindow *stage_window)
{
@ -452,6 +392,7 @@ clutter_stage_win32_realize (ClutterStageWindow *stage_window)
ClutterBackendWin32 *backend_win32;
PIXELFORMATDESCRIPTOR pfd;
int pf;
GError *error = NULL;
CLUTTER_NOTE (MISC, "Realizing main stage");
@ -518,25 +459,24 @@ clutter_stage_win32_realize (ClutterStageWindow *stage_window)
stage_win32->client_dc = GetDC (stage_win32->hwnd);
pf = clutter_stage_win32_choose_pixel_format (stage_win32->client_dc, &pfd);
/* Create a context. This will be a no-op if we already have one */
if (!_clutter_backend_create_context (CLUTTER_BACKEND (backend_win32),
&error))
{
g_critical ("Unable to realize stage: %s", error->message);
g_error_free (error);
goto fail;
}
if (pf == 0 || !SetPixelFormat (stage_win32->client_dc, pf, &pfd))
/* Use the same pixel format as the dummy DC */
pf = GetPixelFormat (backend_win32->dummy_dc);
DescribePixelFormat (backend_win32->dummy_dc, pf, sizeof (pfd), &pfd);
if (!SetPixelFormat (stage_win32->client_dc, pf, &pfd))
{
g_critical ("Unable to find suitable GL pixel format");
goto fail;
}
if (backend_win32->gl_context == NULL)
{
backend_win32->gl_context = wglCreateContext (stage_win32->client_dc);
if (backend_win32->gl_context == NULL)
{
g_critical ("Unable to create suitable GL context");
goto fail;
}
}
CLUTTER_NOTE (BACKEND, "Successfully realized stage");
return TRUE;