/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * 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 
 * OpenSceneGraph Public License for more details.
*/

/* Note, elements of PixelBufferX11 have used Prodcer/RenderSurface_X11.cpp as both
 * a guide to use of X11/GLX and copiying directly in the case of setBorder().
 * These elements are license under OSGPL as above, with Copyright (C) 2001-2004  Don Burns.
 */

#include <osgViewer/api/X11/PixelBufferX11>
#include <osgViewer/api/X11/GraphicsWindowX11>

#include <X11/Xlib.h>

#include <unistd.h>

using namespace osgViewer;

static GLXFBConfig getFBConfigFromVisual(::Display* dpy, XVisualInfo* visualInfo)
{
#if defined(__APPLE__) || defined(_AIX)
    int screen = visualInfo->screen;
    int nelements;
    GLXFBConfig *configs = glXGetFBConfigs(dpy, screen, &nelements);
    for( int i = 0; i < nelements; i++ )
    {
        int visual_id;
        if( glXGetFBConfigAttrib( dpy, configs[i], GLX_VISUAL_ID, &visual_id ) == 0 )
        {
            if( (unsigned int)visual_id == visualInfo->visualid )
                return configs[i];
        }
    }
    return NULL;
#else
    return glXGetFBConfigFromVisualSGIX( dpy, visualInfo );
#endif
}

PixelBufferX11::~PixelBufferX11()
{
    close(true);
}

bool PixelBufferX11::createVisualInfo()
{
    typedef std::vector<int> Attributes;
    Attributes attributes;
    
    attributes.push_back(GLX_USE_GL);
    
    attributes.push_back(GLX_RGBA);
    
    if (_traits->doubleBuffer) attributes.push_back(GLX_DOUBLEBUFFER);
    
    attributes.push_back(GLX_RED_SIZE); attributes.push_back(_traits->red);
    attributes.push_back(GLX_GREEN_SIZE); attributes.push_back(_traits->green);
    attributes.push_back(GLX_BLUE_SIZE); attributes.push_back(_traits->blue);
    attributes.push_back(GLX_DEPTH_SIZE); attributes.push_back(_traits->depth);
    
    if (_traits->alpha) { attributes.push_back(GLX_ALPHA_SIZE); attributes.push_back(_traits->alpha); }
    
    if (_traits->stencil) { attributes.push_back(GLX_STENCIL_SIZE); attributes.push_back(_traits->stencil); }

#if defined(GLX_SAMPLE_BUFFERS) && defined (GLX_SAMPLES)

    if (_traits->sampleBuffers) { attributes.push_back(GLX_SAMPLE_BUFFERS); attributes.push_back(_traits->sampleBuffers); }
    if (_traits->sampleBuffers) { attributes.push_back(GLX_SAMPLES); attributes.push_back(_traits->samples); }

#endif
    // TODO
    //  GLX_AUX_BUFFERS
    //  GLX_ACCUM_RED_SIZE
    //  GLX_ACCUM_GREEN_SIZE
    
    attributes.push_back(None);
    
    _visualInfo = glXChooseVisual( _display, _traits->screenNum, &(attributes.front()) );

    return _visualInfo != 0;
}

void PixelBufferX11::init()
{
    if (_initialized) return;

#ifdef GLX_VERSION_1_3

    if (!_traits)
    {
        _valid = false;
        return;
    }
    
    if (_traits->target != 0)
    {
        // we don't support Pbuffer render to texture under GLX.
        _valid = false;
        return;
    }


    _display = XOpenDisplay(_traits->displayName().c_str());
    
    unsigned int screen = _traits->screenNum;

    if (!_display)
    {
        osg::notify(osg::NOTICE)<<"Error: Unable to open display \"" << XDisplayName(_traits->displayName().c_str()) << "\"."<<std::endl;
        _valid = false;
        return;
    }

     // Query for GLX extension
    int errorBase, eventBase;
    if( glXQueryExtension( _display, &errorBase, &eventBase)  == False )
    {
        osg::notify(osg::NOTICE)<<"Error: " << XDisplayName(_traits->displayName().c_str()) <<" has no GLX extension." << std::endl;

        XCloseDisplay( _display );
        _display = 0;
        _valid = false;
        return;
    }
    
    // osg::notify(osg::NOTICE)<<"GLX extension, errorBase="<<errorBase<<" eventBase="<<eventBase<<std::endl;

    if (!createVisualInfo())
    {
        _traits->red /= 2; 
        _traits->green /= 2; 
        _traits->blue /= 2; 
        _traits->alpha /= 2; 
        _traits->depth /= 2; 
        
        osg::notify(osg::INFO)<<"Relaxing traits"<<std::endl;

        if (!createVisualInfo())
        {
            osg::notify(osg::NOTICE)<<"Error: Not able to create requested visual." << std::endl;
            XCloseDisplay( _display );
            _display = 0;
            _valid = false;
            return;
        }    
    }
    
    GLXContext sharedContextGLX = NULL;

    // get any shared GLX contexts    
    GraphicsWindowX11* graphicsWindowX11 = dynamic_cast<GraphicsWindowX11*>(_traits->sharedContext);
    if (graphicsWindowX11) 
    {
        sharedContextGLX = graphicsWindowX11->getGLXContext();
    }
    else
    {
        PixelBufferX11* pixelBufferX11 = dynamic_cast<PixelBufferX11*>(_traits->sharedContext);
        if (pixelBufferX11)
        {
            sharedContextGLX = pixelBufferX11->getGLXContext();
        }
    }
    
    _glxContext = glXCreateContext( _display, _visualInfo, sharedContextGLX, True );

    if (!_glxContext)
    {
        osg::notify(osg::NOTICE)<<"Error: Unable to create OpenGL graphics context."<<std::endl;
        XCloseDisplay( _display );
        _display = 0;
        _valid = false;
        return;
    }
    
    _parent = RootWindow( _display, screen );

    XWindowAttributes watt;
    XGetWindowAttributes( _display, _parent, &watt );
    // unsigned int parentWindowHeight = watt.height;

    XSetWindowAttributes swatt;
    swatt.colormap = XCreateColormap( _display, _parent, _visualInfo->visual, AllocNone);
    //swatt.colormap = DefaultColormap( _dpy, 10 );
    swatt.background_pixel = 0;
    swatt.border_pixel = 0;
    swatt.event_mask =  0;
    unsigned long mask = CWBackPixel | CWBorderPixel | CWEventMask | CWColormap;

    bool overrideRedirect = false;
    if (overrideRedirect)
    {
        swatt.override_redirect = true;
        mask |= CWOverrideRedirect;
    }

    GLXFBConfig fbconfig = getFBConfigFromVisual( _display, _visualInfo );

    typedef std::vector <int> AttributeList;

    AttributeList attributes;
    attributes.push_back( GLX_PBUFFER_WIDTH );
    attributes.push_back( _traits->width );
    attributes.push_back( GLX_PBUFFER_HEIGHT );
    attributes.push_back( _traits->height );
    attributes.push_back( 0L );

    _pbuffer = glXCreatePbuffer(_display, fbconfig, &attributes.front() );
                             
    if (!_pbuffer)
    {
        osg::notify(osg::NOTICE)<<"Error: Unable to create Window."<<std::endl;
        XCloseDisplay( _display );
        _display = 0;
        _glxContext = 0;
        _valid = false;
        return;
    }


    XFlush( _display );
    XSync( _display, 0 );

    _valid = true;
    _initialized = true;
#else    
    _valid = false;
    _initialized = true;
    return;
#endif
}

bool PixelBufferX11::realizeImplementation()
{
    if (_realized)
    {
        osg::notify(osg::NOTICE)<<"PixelBufferX11::realizeImplementation() Already realized"<<std::endl;
        return true;
    }

    if (!_initialized) init();
    
    if (!_initialized) return false;

    _realized = true;

    return true;
}

bool PixelBufferX11::makeCurrentImplementation()
{
    if (!_realized)
    {
        osg::notify(osg::NOTICE)<<"Warning: GraphicsWindow not realized, cannot do makeCurrent."<<std::endl;
        return false;
    }

    // osg::notify(osg::NOTICE)<<"PixelBufferX11::makeCurrentImplementation "<<this<<" "<<OpenThreads::Thread::CurrentThread()<<std::endl;
    // osg::notify(osg::NOTICE)<<"   glXMakeCurrent ("<<_display<<","<<_pbuffer<<","<<_glxContext<<std::endl;

    return glXMakeCurrent( _display, _pbuffer, _glxContext )==True;
}

bool PixelBufferX11::makeContextCurrentImplementation(osg::GraphicsContext* readContext)
{
    // osg::notify(osg::NOTICE)<<"PixelBufferX11::makeContextCurrentImplementation() not implementation yet."<<std::endl;
    return makeCurrentImplementation();
}


bool PixelBufferX11::releaseContextImplementation()
{
    if (!_realized)
    {
        osg::notify(osg::NOTICE)<<"Warning: GraphicsWindow not realized, cannot do makeCurrent."<<std::endl;
        return false;
    }

    // osg::notify(osg::NOTICE)<<"PixelBufferX11::releaseContextImplementation() "<<this<<" "<<OpenThreads::Thread::CurrentThread()<<std::endl;
    // osg::notify(osg::NOTICE)<<"   glXMakeCurrent ("<<_display<<std::endl;

    return glXMakeCurrent( _display, None, NULL )==True;
}


void PixelBufferX11::bindPBufferToTextureImplementation(GLenum buffer)
{
    osg::notify(osg::NOTICE)<<"PixelBufferX11::bindPBufferToTextureImplementation() not implementation yet."<<std::endl;
}


void PixelBufferX11::closeImplementation()
{
    // osg::notify(osg::NOTICE)<<"Closing PixelBufferX11"<<std::endl;
    if (_display)
    {
        if (_glxContext)
        {
            glXDestroyContext(_display, _glxContext );
        }
    
        if (_pbuffer)
        {
#ifdef GLX_VERSION_1_3
            glXDestroyPbuffer(_display, _pbuffer);
#endif
        }

        XFlush( _display );
        XSync( _display,0 );

    }
    
    _pbuffer = 0;
    _parent = 0;
    _glxContext = 0;

    if (_visualInfo)
    {
        XFree(_visualInfo);
        _visualInfo = 0;
    }

    if (_display)
    {
        XCloseDisplay( _display );
        _display = 0;
    }

    _initialized = false;
    _realized = false;
    _valid = false;
}

void PixelBufferX11::swapBuffersImplementation()
{
    if (!_realized) return;

    // osg::notify(osg::NOTICE)<<"PixelBufferX11::swapBuffersImplementation "<<this<<" "<<OpenThreads::Thread::CurrentThread()<<std::endl;

    glXSwapBuffers(_display, _pbuffer); 
}