GTKGLContext.cpp

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// ****************************************************************************
// Filename:  GTKGLContext.cpp
// Author:    Florian Hecht
// Date:      2009
// ****************************************************************************


#include "GTKGLContext.h"

#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include <gdk/gdkx.h>

CGTKGLContext::CGTKGLContext(CGTKGLContext *shared_context)
: initialized(false), xdisplay(NULL)
{
        if (glXQueryExtension(GDK_DISPLAY(), NULL, NULL) == FALSE)
        {
                printf("CGTKGLContext: no OpenGL support.\n");
                return;
        }
        
        xdisplay = GDK_DISPLAY();

        int attrlist[] = {GLX_RGBA, GLX_DOUBLEBUFFER, GLX_DEPTH_SIZE, 16, None};
        
        XVisualInfo *vi = glXChooseVisual(xdisplay, DefaultScreen(xdisplay), attrlist);
        if (!vi)
        {
                printf("CGTKGLContext: couldn't find suitable VisualInfo for the GL context. (%d)\n", (size_t) xdisplay);
                return;
        }

        if (shared_context)
                glxcontext = glXCreateContext(xdisplay, vi, shared_context->glxcontext, True);
        else
                glxcontext = glXCreateContext(xdisplay, vi, 0, True);
        
        if (glxcontext == NULL)
        {
                printf("CGTKGLContext: creation of GL context failed.\n");
                XFree(vi);
                return;
        }
        
        visual = gdkx_visual_get(vi->visualid);
        XFree(vi);
        
        initialized = true;
}

CGTKGLContext::~CGTKGLContext()
{
        if (!initialized)
                return;
  
        if (glxcontext == glXGetCurrentContext())
                glXMakeCurrent(xdisplay, None, NULL);

        glXDestroyContext(xdisplay, glxcontext);
}

bool CGTKGLContext::IsInitialized()
{
        return initialized;
}

void CGTKGLContext::MakeCurrent(GdkDrawable *drawable)
{
        if (!initialized)
                return;
        
        if (drawable)
        {
                if (glXMakeCurrent(xdisplay, GDK_WINDOW_XWINDOW(drawable), glxcontext) == False)
                {
                        printf("GTKGLContext: make current failed\n");
                }
        }
}

void CGTKGLContext::SwapBuffers(GdkDrawable *drawable)
{
        if (!initialized)
                return;
        
        glXSwapBuffers(GDK_WINDOW_XDISPLAY(drawable), GDK_WINDOW_XWINDOW(drawable));
}

void CGTKGLContext::DoneCurrent()
{
        if (!initialized)
                return;
                
        glXMakeCurrent(xdisplay, None, NULL);
}