gtk2/gdk/gdkcairo.h
Alexander Larsson 038aac6275 gdk: Add support for OpenGL
This adds the new type GdkGLContext that wraps an OpenGL context for a
particular native window. It also adds support for the gdk paint
machinery to use OpenGL to draw everything. As soon as anyone creates
a GL context for a native window we create a "paint context" for that
GdkWindow and switch to using GL for painting it.

This commit contains only an implementation for X11 (using GLX).

The way painting works is that all client gl contexts draw into
offscreen buffers rather than directly to the back buffer, and the
way something gets onto the window is by using gdk_cairo_draw_from_gl()
to draw part of that buffer onto the draw cairo context.

As a fallback (if we're doing redirected drawing or some effect like a
cairo_push_group()) we read back the gl buffer into memory and composite
using cairo. This means that GL rendering works in all cases, including
rendering to a PDF. However, this is not particularly fast.

In the *typical* case, where we're drawing directly to the window in
the regular paint loop we hit the fast path. The fast path uses opengl
to draw the buffer to the window back buffer, either by blitting or
texturing. Then we track the region that was drawn, and when the draw
ends we paint the normal cairo surface to the window (using
texture-from-pixmap in the X11 case, or texture from cairo image
otherwise) in the regions where there is no gl painted.

There are some complexities wrt layering of gl and cairo areas though:
* We track via gdk_window_mark_paint_from_clip() whenever gtk is
  painting over a region we previously rendered with opengl
  (flushed_region). This area (needs_blend_region) is blended
  rather than copied at the end of the frame.
* If we're drawing a gl texture with alpha we first copy the current
  cairo_surface inside the target region to the back buffer before
  we blend over it.

These two operations allow us full stacking of transparent gl and cairo
regions.
2014-10-13 10:43:31 -04:00

88 lines
3.6 KiB
C

/* GDK - The GIMP Drawing Kit
* Copyright (C) 2005 Red Hat, Inc.
*
* 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/>.
*/
#ifndef __GDK_CAIRO_H__
#define __GDK_CAIRO_H__
#if !defined (__GDK_H_INSIDE__) && !defined (GDK_COMPILATION)
#error "Only <gdk/gdk.h> can be included directly."
#endif
#include <gdk/gdkversionmacros.h>
#include <gdk/deprecated/gdkcolor.h>
#include <gdk/gdkrgba.h>
#include <gdk/gdkpixbuf.h>
#include <pango/pangocairo.h>
G_BEGIN_DECLS
GDK_AVAILABLE_IN_ALL
cairo_t * gdk_cairo_create (GdkWindow *window);
GDK_AVAILABLE_IN_ALL
gboolean gdk_cairo_get_clip_rectangle (cairo_t *cr,
GdkRectangle *rect);
GDK_AVAILABLE_IN_ALL
void gdk_cairo_set_source_rgba (cairo_t *cr,
const GdkRGBA *rgba);
GDK_AVAILABLE_IN_ALL
void gdk_cairo_set_source_pixbuf (cairo_t *cr,
const GdkPixbuf *pixbuf,
gdouble pixbuf_x,
gdouble pixbuf_y);
GDK_AVAILABLE_IN_ALL
void gdk_cairo_set_source_window (cairo_t *cr,
GdkWindow *window,
gdouble x,
gdouble y);
GDK_AVAILABLE_IN_ALL
void gdk_cairo_rectangle (cairo_t *cr,
const GdkRectangle *rectangle);
GDK_AVAILABLE_IN_ALL
void gdk_cairo_region (cairo_t *cr,
const cairo_region_t *region);
GDK_AVAILABLE_IN_ALL
cairo_region_t *
gdk_cairo_region_create_from_surface
(cairo_surface_t *surface);
GDK_DEPRECATED_IN_3_4_FOR(gdk_cairo_set_source_rgba)
void gdk_cairo_set_source_color (cairo_t *cr,
const GdkColor *color);
GDK_AVAILABLE_IN_3_10
cairo_surface_t * gdk_cairo_surface_create_from_pixbuf (const GdkPixbuf *pixbuf,
int scale,
GdkWindow *for_window);
GDK_AVAILABLE_IN_3_16
void gdk_cairo_draw_from_gl (cairo_t *cr,
GdkWindow *window,
int source,
int source_type,
int buffer_scale,
int x,
int y,
int width,
int height);
G_END_DECLS
#endif /* __GDK_CAIRO_H__ */