/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 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.
*/
#include <stdio.h>
#include <osg/Notify>
#include <osgUtil/Statistics>

#include <osgUtil/RenderStage>


using namespace osg;
using namespace osgUtil;

// register a RenderStage prototype with the RenderBin prototype list.
//RegisterRenderBinProxy<RenderStage> s_registerRenderStageProxy;

RenderStage::RenderStage(SortMode mode):
    RenderBin(mode)
{
    // point RenderBin's _stage to this to ensure that references to
    // stage don't go tempted away to any other stage.
    _stage = this;
    _stageDrawnThisFrame = false;

    _clearMask = GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT;
    _clearColor.set(0.0f,0.0f,0.0f,0.0f);
    _clearAccum.set(0.0f,0.0f,0.0f,0.0f);
    _clearDepth = 1.0;
    _clearStencil = 0;


}

RenderStage::RenderStage(const RenderStage& rhs,const osg::CopyOp& copyop):
        RenderBin(rhs,copyop),
        _stageDrawnThisFrame(false),
        _dependencyList(rhs._dependencyList),
        _viewport(rhs._viewport),
        _clearMask(rhs._clearMask),
        _colorMask(rhs._colorMask),
        _clearColor(rhs._clearColor),
        _clearAccum(rhs._clearAccum),
        _clearDepth(rhs._clearDepth),
        _clearStencil(rhs._clearStencil),
        _renderStageLighting(rhs._renderStageLighting)

{
    _stage = this;
}


RenderStage::~RenderStage()
{
}

void RenderStage::reset()
{
    _dependencyList.clear();
    _stageDrawnThisFrame = false;
    
    if (_renderStageLighting.valid()) _renderStageLighting->reset();

    RenderBin::reset();
}

void RenderStage::addToDependencyList(RenderStage* rs)
{
    if (rs) _dependencyList.push_back(rs);
}

void RenderStage::drawPreRenderStages(osg::State& state,RenderLeaf*& previous)
{
    if (_dependencyList.empty()) return;
    
    //cout << "Drawing prerendering stages "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
    for(DependencyList::iterator itr=_dependencyList.begin();
        itr!=_dependencyList.end();
        ++itr)
    {
        (*itr)->draw(state,previous);
    }
    //cout << "Done Drawing prerendering stages "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
}

void RenderStage::draw(osg::State& state,RenderLeaf*& previous)
{
    if (_stageDrawnThisFrame) return;

    _stageDrawnThisFrame = true;

    // note, SceneView does call to drawPreRenderStages explicitly
    // so there is no need to call it here.
    //drawPreRenderStages(state,previous);

    RenderBin::draw(state,previous);
}

void RenderStage::drawImplementation(osg::State& state,RenderLeaf*& previous)
{
    
    if (!_viewport)
    {
        notify(FATAL) << "Error: cannot draw stage due to undefined viewport."<< std::endl;
        return;
    }
    
    
    // set up the back buffer.
    state.applyAttribute(_viewport.get());

#define USE_SISSOR_TEST
#ifdef USE_SISSOR_TEST
    glScissor( _viewport->x(), _viewport->y(), _viewport->width(), _viewport->height() );
    //cout << "    clearing "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
    
    glEnable( GL_SCISSOR_TEST );
#endif


    // glEnable( GL_DEPTH_TEST );

    // set which color planes to operate on.
    if (_colorMask.valid()) _colorMask->apply(state);
    else glColorMask(GL_TRUE,GL_TRUE,GL_TRUE,GL_TRUE);

    if (_clearMask & GL_COLOR_BUFFER_BIT)
        glClearColor( _clearColor[0], _clearColor[1], _clearColor[2], _clearColor[3]);

    if (_clearMask & GL_DEPTH_BUFFER_BIT)
        glClearDepth( _clearDepth);

    if (_clearMask & GL_STENCIL_BUFFER_BIT)
        glClearStencil( _clearStencil);

    if (_clearMask & GL_ACCUM_BUFFER_BIT)
        glClearAccum( _clearAccum[0], _clearAccum[1], _clearAccum[2], _clearAccum[3]);


    glClear( _clearMask );
    
#ifdef USE_SISSOR_TEST
    glDisable( GL_SCISSOR_TEST );
#endif

    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();

    // apply the lights.
    if (_renderStageLighting.valid()) _renderStageLighting->draw(state,previous);

    // draw the children and local.
    RenderBin::drawImplementation(state,previous);

    // now reset the state so its back in its default state.
    if (previous)
    {
        RenderGraph::moveToRootRenderGraph(state,previous->_parent);
        state.apply();
        previous = NULL;
    }

}
// Statistics features
bool RenderStage::getStats(Statistics* primStats)
{
    if (_renderStageLighting.valid())
    {
        // need to re-implement by checking for lights in the scene
        // by downcasting the positioned attribute list. RO. May 2002.
        //primStats->addLight(_renderStageLighting->_lightList.size());
    }
    return RenderBin::getStats(primStats);
}