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X11: Pick better system and rgba visuals for GL
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We want to create windows with the default visuals such that we then
have the right visual for GLX when we want to create the paint GL
context for the window.

For instance, (in bug 738670) the default rgba visual we picked for the
NVidia driver had an alpha size of 0 which gave us a BadMatch when later
trying to initialize a gl context on it with a alpha FBConfig.

Instead of just picking what the Xserver likes for the default, and just
picking the first rgba visual we now actually call into GLX to pick
an appropriate visual.
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@alexlarsson
alexlarsson committed Oct 29, 2014
1 parent 8765970 commit dae4477
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Showing 5 changed files with 187 additions and 6 deletions.
2 changes: 2 additions & 0 deletions gdk/x11/gdkdisplay-x11.h
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Original file line number Diff line number Diff line change
Expand Up @@ -139,6 +139,8 @@ struct _GdkX11Display
guint has_glx_video_sync : 1;
guint has_glx_buffer_age : 1;
guint has_glx_sync_control : 1;
guint has_glx_multisample : 1;
guint has_glx_visual_rating : 1;
};

struct _GdkX11DisplayClass
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183 changes: 178 additions & 5 deletions gdk/x11/gdkglcontext-x11.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include "gdkx11screen.h"
#include "gdkx11window.h"
#include "gdkx11visual.h"
#include "gdkvisualprivate.h"

#include "gdkinternals.h"

Expand Down Expand Up @@ -508,10 +509,10 @@ gdk_x11_gl_context_init (GdkX11GLContext *self)
}

gboolean
gdk_x11_display_init_gl (GdkDisplay *display)
gdk_x11_screen_init_gl (GdkScreen *screen)
{
GdkDisplay *display = gdk_screen_get_display (screen);
GdkX11Display *display_x11 = GDK_X11_DISPLAY (display);
GdkScreen *screen;
Display *dpy;
int error_base, event_base;
int screen_num;
Expand All @@ -524,7 +525,6 @@ gdk_x11_display_init_gl (GdkDisplay *display)
if (!glXQueryExtension (dpy, &error_base, &event_base))
return FALSE;

screen = gdk_display_get_default_screen (display);
screen_num = GDK_X11_SCREEN (screen)->screen_num;

display_x11->have_glx = TRUE;
Expand All @@ -545,6 +545,10 @@ gdk_x11_display_init_gl (GdkDisplay *display)
epoxy_has_glx_extension (dpy, screen_num, "GLX_EXT_buffer_age");
display_x11->has_glx_sync_control =
epoxy_has_glx_extension (dpy, screen_num, "GLX_OML_sync_control");
display_x11->has_glx_multisample =
epoxy_has_glx_extension (dpy, screen_num, "GLX_ARB_multisample");
display_x11->has_glx_visual_rating =
epoxy_has_glx_extension (dpy, screen_num, "GLX_EXT_visual_rating");

GDK_NOTE (OPENGL,
g_print ("GLX version %d.%d found\n"
Expand Down Expand Up @@ -702,6 +706,175 @@ create_gl_context (GdkDisplay *display,
True);
}

struct glvisualinfo {
int supports_gl;
int double_buffer;
int stereo;
int alpha_size;
int depth_size;
int stencil_size;
int num_multisample;
int visual_caveat;
};

static gboolean
visual_compatible (const GdkVisual *a, const GdkVisual *b)
{
return a->type == b->type &&
a->depth == b->depth &&
a->red_mask == b->red_mask &&
a->green_mask == b->green_mask &&
a->blue_mask == b->blue_mask &&
a->colormap_size == b->colormap_size &&
a->bits_per_rgb == b->bits_per_rgb;
}

static gboolean
visual_is_rgba (const GdkVisual *visual)
{
return
visual->depth == 32 &&
visual->red_mask == 0xff0000 &&
visual->green_mask == 0x00ff00 &&
visual->blue_mask == 0x0000ff;
}

/* This picks a compatible (as in has the same X visual details) visual
that has "better" characteristics on the GL side */
static GdkVisual *
pick_better_visual_for_gl (GdkX11Screen *x11_screen,
struct glvisualinfo *gl_info,
GdkVisual *compatible)
{
GdkVisual *visual;
int i;
gboolean want_alpha = visual_is_rgba (compatible);

/* First look for "perfect match", i.e:
* supports gl
* double buffer
* alpha iff visual is an rgba visual
* no unnecessary stuff
*/
for (i = 0; i < x11_screen->nvisuals; i++)
{
visual = x11_screen->visuals[i];
if (visual_compatible (visual, compatible) &&
gl_info[i].supports_gl &&
gl_info[i].double_buffer &&
!gl_info[i].stereo &&
(want_alpha ? (gl_info[i].alpha_size > 0) : (gl_info[i].alpha_size == 0)) &&
(gl_info[i].depth_size == 0) &&
(gl_info[i].stencil_size == 0) &&
(gl_info[i].num_multisample == 0) &&
(gl_info[i].visual_caveat == GLX_NONE_EXT))
return visual;
}

if (!want_alpha)
{
/* Next, allow alpha even if we don't want it: */
for (i = 0; i < x11_screen->nvisuals; i++)
{
visual = x11_screen->visuals[i];
if (visual_compatible (visual, compatible) &&
gl_info[i].supports_gl &&
gl_info[i].double_buffer &&
!gl_info[i].stereo &&
(gl_info[i].depth_size == 0) &&
(gl_info[i].stencil_size == 0) &&
(gl_info[i].num_multisample == 0) &&
(gl_info[i].visual_caveat == GLX_NONE_EXT))
return visual;
}
}

/* Next, allow depth and stencil buffers: */
for (i = 0; i < x11_screen->nvisuals; i++)
{
visual = x11_screen->visuals[i];
if (visual_compatible (visual, compatible) &&
gl_info[i].supports_gl &&
gl_info[i].double_buffer &&
!gl_info[i].stereo &&
(gl_info[i].num_multisample == 0) &&
(gl_info[i].visual_caveat == GLX_NONE_EXT))
return visual;
}

/* Next, allow multisample: */
for (i = 0; i < x11_screen->nvisuals; i++)
{
visual = x11_screen->visuals[i];
if (visual_compatible (visual, compatible) &&
gl_info[i].supports_gl &&
gl_info[i].double_buffer &&
!gl_info[i].stereo &&
(gl_info[i].visual_caveat == GLX_NONE_EXT))
return visual;
}

return compatible;
}

void
_gdk_x11_screen_update_visuals_for_gl (GdkScreen *screen)
{
GdkX11Screen *x11_screen;
GdkDisplay *display;
GdkX11Display *display_x11;
Display *dpy;
struct glvisualinfo *gl_info;
int i;

x11_screen = GDK_X11_SCREEN (screen);
display = x11_screen->display;
display_x11 = GDK_X11_DISPLAY (display);

if (!gdk_x11_screen_init_gl (screen))
return;

dpy = gdk_x11_display_get_xdisplay (display);

gl_info = g_new0 (struct glvisualinfo, x11_screen->nvisuals);

for (i = 0; i < x11_screen->nvisuals; i++)
{
XVisualInfo *visual_list;
XVisualInfo visual_template;
int nxvisuals;

visual_template.screen = x11_screen->screen_num;
visual_template.visualid = gdk_x11_visual_get_xvisual (x11_screen->visuals[i])->visualid;
visual_list = XGetVisualInfo (x11_screen->xdisplay, VisualIDMask| VisualScreenMask, &visual_template, &nxvisuals);

if (visual_list == NULL)
continue;

glXGetConfig (dpy, &visual_list[0], GLX_USE_GL, &gl_info[i].supports_gl);
glXGetConfig (dpy, &visual_list[0], GLX_DOUBLEBUFFER, &gl_info[i].double_buffer);
glXGetConfig (dpy, &visual_list[0], GLX_STEREO, &gl_info[i].stereo);
glXGetConfig (dpy, &visual_list[0], GLX_ALPHA_SIZE, &gl_info[i].alpha_size);
glXGetConfig (dpy, &visual_list[0], GLX_DEPTH_SIZE, &gl_info[i].depth_size);
glXGetConfig (dpy, &visual_list[0], GLX_STENCIL_SIZE, &gl_info[i].stencil_size);

if (display_x11->has_glx_multisample)
glXGetConfig(dpy, &visual_list[0], GLX_SAMPLE_BUFFERS_ARB, &gl_info[i].num_multisample);

if (display_x11->has_glx_visual_rating)
glXGetConfig(dpy, &visual_list[0], GLX_VISUAL_CAVEAT_EXT, &gl_info[i].visual_caveat);
else
gl_info[i].visual_caveat = GLX_NONE_EXT;

XFree (visual_list);
}

x11_screen->system_visual = pick_better_visual_for_gl (x11_screen, gl_info, x11_screen->system_visual);
if (x11_screen->rgba_visual)
x11_screen->rgba_visual = pick_better_visual_for_gl (x11_screen, gl_info, x11_screen->rgba_visual);
}


GdkGLContext *
gdk_x11_window_create_gl_context (GdkWindow *window,
gboolean attached,
Expand All @@ -723,7 +896,7 @@ gdk_x11_window_create_gl_context (GdkWindow *window,

display = gdk_window_get_display (window);

if (!gdk_x11_display_init_gl (display))
if (!gdk_x11_screen_init_gl (gdk_window_get_screen (window)))
{
g_set_error_literal (error, GDK_GL_ERROR,
GDK_GL_ERROR_NOT_AVAILABLE,
Expand Down Expand Up @@ -936,7 +1109,7 @@ gdk_x11_display_get_glx_version (GdkDisplay *display,
if (!GDK_IS_X11_DISPLAY (display))
return FALSE;

if (!gdk_x11_display_init_gl (display))
if (!gdk_x11_screen_init_gl (gdk_display_get_default_screen (display)))
return FALSE;

if (major != NULL)
Expand Down
2 changes: 1 addition & 1 deletion gdk/x11/gdkglcontext-x11.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ struct _GdkX11GLContextClass
GdkGLContextClass parent_class;
};

gboolean gdk_x11_display_init_gl (GdkDisplay *display);
gboolean gdk_x11_screen_init_gl (GdkScreen *screen);
GdkGLContext * gdk_x11_window_create_gl_context (GdkWindow *window,
gboolean attached,
GdkGLProfile profile,
Expand Down
1 change: 1 addition & 0 deletions gdk/x11/gdkscreen-x11.h
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Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,7 @@ GdkScreen * _gdk_x11_screen_new (GdkDisplay *display,
gint screen_number);

void _gdk_x11_screen_setup (GdkScreen *screen);
void _gdk_x11_screen_update_visuals_for_gl (GdkScreen *screen);
void _gdk_x11_screen_window_manager_changed (GdkScreen *screen);
void _gdk_x11_screen_size_changed (GdkScreen *screen,
XEvent *event);
Expand Down
5 changes: 5 additions & 0 deletions gdk/x11/gdkvisual-x11.c
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Original file line number Diff line number Diff line change
Expand Up @@ -341,6 +341,11 @@ _gdk_x11_screen_init_visuals (GdkScreen *screen)

x11_screen->visuals = visuals;
x11_screen->nvisuals = nvisuals;

/* If GL is available we want to pick better default/rgba visuals,
as we care about glx details such as alpha/depth/stencil depth,
stereo and double buffering */
_gdk_x11_screen_update_visuals_for_gl (screen);
}

gint
Expand Down

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