kwin/glxbackend.h

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/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2012 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#ifndef KWIN_GLX_BACKEND_H
#define KWIN_GLX_BACKEND_H
#include "scene_opengl.h"
namespace KWin
{
class FBConfigInfo
{
public:
GLXFBConfig fbconfig;
int bind_texture_format;
int texture_targets;
int y_inverted;
int mipmap;
};
/**
* @brief OpenGL Backend using GLX over an X overlay window.
**/
class GlxBackend : public OpenGLBackend
{
public:
GlxBackend();
virtual ~GlxBackend();
virtual void screenGeometryChanged(const QSize &size);
virtual SceneOpenGL::TexturePrivate *createBackendTexture(SceneOpenGL::Texture *texture);
virtual QRegion prepareRenderingFrame();
virtual void endRenderingFrame(const QRegion &damage, const QRegion &damagedRegion);
Better handling for making the compositing OpenGL context current With QtQuick2 it's possible that the scene graph rendering context either lives in an own thread or uses the main GUI thread. In the latter case it's the same thread as our compositing OpenGL context lives in. This means our basic assumption that between two rendering passes the context stays current does not hold. The code already ensured that before we start a rendering pass the context is made current, but there are many more possible cases. If we use OpenGL in areas not triggered by the rendering loop but in response to other events the context needs to be made current. This includes the loading and unloading of effects (some effects use OpenGL in the static effect check, in the ctor and dtor), background loading of texture data, lazy loading after first usage invoked by shortcut, etc. etc. To properly handle these cases new methods are added to EffectsHandler to make the compositing OpenGL context current. These calls delegate down into the scene. On non-OpenGL scenes they are noop, but on OpenGL they go into the backend and make the context current. In addition they ensure that Qt doesn't think that it's QOpenGLContext is current by calling doneCurrent() on the QOpenGLContext::currentContext(). This unfortunately causes an additional call to makeCurrent with a null context, but there is no other way to tell Qt - it doesn't notice when a different context is made current with low level API calls. In the multi-threaded architecture this doesn't matter as ::currentContext() returns null. A short evaluation showed that a transition to QOpenGLContext doesn't seem feasible. Qt only supports either GLX or EGL while KWin supports both and when entering the transition phase for Wayland, it would become extremely tricky if our native platform is X11, but we want a Wayland EGL context. A future solution might be to have a "KWin-QPA plugin" which uses either xcb or Wayland and hides everything from Qt. The API documentation is extended to describe when the effects-framework ensures that an OpenGL context is current. The effects are changed to make the context current in cases where it's not guaranteed. This has been done by looking for creation or deletion of GLTextures and Shaders. If there are other OpenGL usages outside the rendering loop, ctor/dtor this needs to be changed, too.
2013-11-22 14:05:36 +00:00
virtual bool makeCurrent() override;
virtual void doneCurrent() override;
virtual OverlayWindow* overlayWindow() override;
virtual bool usesOverlayWindow() const override;
protected:
virtual void present();
private:
void init();
bool initBuffer();
bool initDrawableConfigs();
void waitSync();
bool initRenderingContext();
bool initFbConfig();
void setSwapInterval(int interval);
/**
* @brief The OverlayWindow used by this Backend.
**/
OverlayWindow *m_overlayWindow;
Window window;
FBConfigInfo fbcdrawableinfo[ 32 + 1 ];
GLXFBConfig fbconfig;
GLXWindow glxWindow;
GLXContext ctx;
int m_bufferAge;
bool m_haveMESACopySubBuffer;
bool m_haveMESASwapControl;
bool m_haveEXTSwapControl;
bool m_haveSGISwapControl;
bool haveSwapInterval, haveWaitSync;
friend class GlxTexture;
};
/**
* @brief Texture using an GLXPixmap.
**/
class GlxTexture : public SceneOpenGL::TexturePrivate
{
public:
virtual ~GlxTexture();
virtual void onDamage();
virtual void findTarget();
virtual bool loadTexture(xcb_pixmap_t pix, const QSize &size, int depth);
virtual OpenGLBackend *backend();
private:
friend class GlxBackend;
GlxTexture(SceneOpenGL::Texture *texture, GlxBackend *backend);
SceneOpenGL::Texture *q;
GlxBackend *m_backend;
GLXPixmap m_glxpixmap; // the glx pixmap the texture is bound to
};
} // namespace
#endif // KWIN_GLX_BACKEND_H