diff options
| -rw-r--r-- | src/opengl/qgl_x11.cpp | 69 |
1 files changed, 67 insertions, 2 deletions
diff --git a/src/opengl/qgl_x11.cpp b/src/opengl/qgl_x11.cpp index 8173bec..9fca28c 100644 --- a/src/opengl/qgl_x11.cpp +++ b/src/opengl/qgl_x11.cpp @@ -1132,6 +1132,72 @@ void *QGLContext::getProcAddress(const QString &proc) const return glXGetProcAddressARB(reinterpret_cast<const GLubyte *>(proc.toLatin1().data())); } +// +// This class is used to create a temporary, minimal GL context, which is used +// to retrive GL version and extension info. It's significantly faster to +// construct than a QGLWidget, and it doesn't have the recursive creation +// problem that QGLWidget would have. E.g. creating a temporary QGLWidget to +// retrieve GL info as part of the QGLWidget initialization. +// +class QGLTempContext +{ +public: + QGLTempContext(int screen = 0) : + initialized(false), + old_drawable(0), + old_context(0) + { + int attribs[] = {GLX_RGBA, XNone}; + XVisualInfo *vi = glXChooseVisual(X11->display, screen, attribs); + if (!vi) { + qWarning("QGLTempContext: No GL capable X visuals available."); + return; + } + + int useGL; + glXGetConfig(X11->display, vi, GLX_USE_GL, &useGL); + if (!useGL) { + XFree(vi); + return; + } + + old_drawable = glXGetCurrentDrawable(); + old_context = glXGetCurrentContext(); + + XSetWindowAttributes a; + a.colormap = qt_gl_choose_cmap(X11->display, vi); + drawable = XCreateWindow(X11->display, RootWindow(X11->display, screen), + 0, 0, 1, 1, 0, + vi->depth, InputOutput, vi->visual, + CWColormap, &a); + context = glXCreateContext(X11->display, vi, 0, True); + if (context && glXMakeCurrent(X11->display, drawable, context)) { + initialized = true; + } else { + qWarning("QGLTempContext: Unable to create GL context."); + XDestroyWindow(X11->display, drawable); + } + XFree(vi); + } + + ~QGLTempContext() { + if (initialized) { + glXMakeCurrent(X11->display, 0, 0); + glXDestroyContext(X11->display, context); + XDestroyWindow(X11->display, drawable); + } + if (old_drawable && old_context) + glXMakeCurrent(X11->display, old_drawable, old_context); + } + +private: + bool initialized; + Window drawable; + GLXContext context; + GLXDrawable old_drawable; + GLXContext old_context; +}; + /***************************************************************************** QGLOverlayWidget (Internal overlay class for X11) *****************************************************************************/ @@ -1574,8 +1640,7 @@ void QGLExtensions::init() return; init_done = true; - QGLWidget dmy; - dmy.makeCurrent(); + QGLTempContext context; init_extensions(); // nvidia 9x.xx unix drivers contain a bug which requires us to call glFinish before releasing an fbo |