OpenSceneGraph/src/osgUtil/SceneView.cpp
Robert Osfield ed43d97ed3 Improved the sort callback support in osgUtil::RenderBin, and removed the
now rendundent DepthSortedBin class.
2002-09-17 15:47:23 +00:00

728 lines
26 KiB
C++

#include <osgUtil/SceneView>
#include <osgUtil/AppVisitor>
#include <osgUtil/DisplayListVisitor>
#include <osg/Notify>
#include <osg/Texture>
#include <osg/AlphaFunc>
#include <osg/TexEnv>
#include <osg/ColorMatrix>
#include <osg/LightModel>
#include <osg/CollectOccludersVisitor>
#include <osg/GLU>
using namespace osg;
using namespace osgUtil;
SceneView::SceneView(DisplaySettings* ds)
{
_displaySettings = ds;
_backgroundColor.set(0.2f, 0.2f, 0.4f, 1.0f);
_computeNearFar = CullVisitor::COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES;
_cullingMode = osg::CullStack::ENABLE_ALL_CULLING;
_LODBias = 1.0f;
_smallFeatureCullingPixelSize = 3.0f;
_fusionDistanceMode = USE_CAMERA_FUSION_DISTANCE;
_fusionDistanceValue = 1.0f;
_lightingMode=HEADLIGHT;
_prioritizeTextures = false;
_viewport = osgNew Viewport;
_initCalled = false;
_cullMask = 0xffffffff;
_cullMaskLeft = 0xffffffff;
_cullMaskRight = 0xffffffff;
}
SceneView::~SceneView()
{
}
void SceneView::setDefaults()
{
_globalState = osgNew osg::StateSet;
_lightingMode=HEADLIGHT;
_light = osgNew osg::Light;
_light->setLightNum(0);
_light->setAmbient(Vec4(0.00f,0.0f,0.00f,1.0f));
_light->setDiffuse(Vec4(0.8f,0.8f,0.8f,1.0f));
_light->setSpecular(Vec4(1.0f,1.0f,1.0f,1.0f));
_state = osgNew State;
_camera = osgNew Camera(_displaySettings.get());
_rendergraph = osgNew RenderGraph;
_renderStage = osgNew RenderStage;
#ifndef __sgi
// sgi's IR graphics has a problem with lighting and display lists, as it seems to store
// lighting state with the display list, and the display list visitor doesn't currently apply
// state before creating display lists. So will disable the init visitor default, this won't
// affect functionality since the display lists will be created as and when needed.
DisplayListVisitor* dlv = osgNew DisplayListVisitor();
dlv->setState(_state.get());
dlv->setNodeMaskOverride(0xffffffff);
_initVisitor = dlv;
#endif
_appVisitor = osgNew AppVisitor;
_cullVisitor = osgNew CullVisitor;
_cullVisitor->setRenderGraph(_rendergraph.get());
_cullVisitor->setRenderStage(_renderStage.get());
_globalState->setGlobalDefaults();
// enable lighting by default.
_globalState->setMode(GL_LIGHTING, osg::StateAttribute::ON);
_globalState->setAssociatedModes(_light.get(),osg::StateAttribute::ON);
// enable depth testing by default.
_globalState->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON);
// set up an alphafunc by default to speed up blending operations.
osg::AlphaFunc* alphafunc = osgNew osg::AlphaFunc;
alphafunc->setFunction(osg::AlphaFunc::GREATER,0.0f);
_globalState->setAttributeAndModes(alphafunc, osg::StateAttribute::ON);
// set up an texture environment by default to speed up blending operations.
osg::TexEnv* texenv = osgNew osg::TexEnv;
texenv->setMode(osg::TexEnv::MODULATE);
_globalState->setTextureAttributeAndModes(0,texenv, osg::StateAttribute::ON);
osg::LightModel* lightmodel = osgNew osg::LightModel;
lightmodel->setAmbientIntensity(osg::Vec4(0.1f,0.1f,0.1f,1.0f));
_globalState->setAttributeAndModes(lightmodel, osg::StateAttribute::ON);
_backgroundColor.set(0.2f, 0.2f, 0.4f, 1.0f);
_cullMask = 0xffffffff;
_cullMaskLeft = 0xffffffff;
_cullMaskRight = 0xffffffff;
}
void SceneView::init()
{
_initCalled = true;
if (_sceneData.valid() && _initVisitor.valid())
{
_initVisitor->reset();
_initVisitor->setFrameStamp(_frameStamp.get());
if (_frameStamp.valid())
{
_initVisitor->setTraversalNumber(_frameStamp->getFrameNumber());
}
_sceneData->accept(*_initVisitor.get());
}
}
void SceneView::app()
{
if (!_initCalled) init();
#ifdef OSG_USE_MEMORY_MANAGER
m_validateAllAllocUnits();
#endif
//std::cout<<std::endl;
//std::cout<<std::endl;
//std::cout<<"*************************** New frame ************"<<std::endl;
if (_sceneData.valid() && _appVisitor.valid())
{
_appVisitor->reset();
_appVisitor->setFrameStamp(_frameStamp.get());
// use the frame number for the traversal number.
if (_frameStamp.valid())
{
_appVisitor->setTraversalNumber(_frameStamp->getFrameNumber());
}
_sceneData->accept(*_appVisitor.get());
}
}
void SceneView::cull()
{
if (!_state)
{
osg::notify(osg::INFO) << "Warning: no valid osgUtil::SceneView::_state attached, creating a default state automatically."<< std::endl;
// note the constructor for osg::State will set ContextID to 0 which will be fine to single context graphics
// applications which is ok for most apps, but not multiple context/pipe applications.
_state = osgNew osg::State;
}
if (!_globalState)
{
osg::notify(osg::INFO) << "Warning: no valid osgUtil::SceneView::_globalState attached, creating a default global stateset automatically."<< std::endl;
_globalState = osgNew osg::StateSet;
_globalState->setGlobalDefaults();
}
// we in theory should be able to be able to bypass reset, but we'll call it just incase.
_state->reset();
_state->setFrameStamp(_frameStamp.get());
_state->setDisplaySettings(_displaySettings.get());
osg::ref_ptr<osg::Matrix> projection = _projectionMatrix.get();
osg::ref_ptr<osg::Matrix> modelview = _modelviewMatrix.get();
if (_camera.valid())
{
_camera->adjustAspectRatio(_viewport->aspectRatio());
if (_displaySettings.valid())
_camera->setScreenDistance(_displaySettings->getScreenDistance());
if (!projection) projection = osgNew osg::Matrix(_camera->getProjectionMatrix());
if (!modelview) modelview = osgNew osg::Matrix(_camera->getModelViewMatrix());
//cout <<"fovx="<<_camera->calc_fovx()<<endl;
}
if (!projection) projection = osgNew osg::Matrix();
if (!modelview) modelview = osgNew osg::Matrix();
if (_displaySettings.valid() && _displaySettings->getStereo())
{
float fusionDistance = _displaySettings->getScreenDistance();
switch(_fusionDistanceMode)
{
case(USE_CAMERA_FUSION_DISTANCE):
if (_camera.valid())
{
fusionDistance = _camera->getFusionDistance();
}
break;
case(USE_FUSION_DISTANCE_VALUE):
fusionDistance = _fusionDistanceValue;
break;
case(PROPORTIONAL_TO_SCREEN_DISTANCE):
fusionDistance *= _fusionDistanceValue;
break;
}
float iod = _displaySettings->getEyeSeparation();
float sd = _displaySettings->getScreenDistance();
float es = 0.5f*iod*(fusionDistance/sd);
if (!_cullVisitorLeft.valid()) _cullVisitorLeft = dynamic_cast<CullVisitor*>(_cullVisitor->cloneType());
if (!_rendergraphLeft.valid()) _rendergraphLeft = dynamic_cast<RenderGraph*>(_rendergraph->cloneType());
if (!_renderStageLeft.valid()) _renderStageLeft = dynamic_cast<RenderStage*>(_renderStage->clone(osg::CopyOp::DEEP_COPY_ALL));
if (!_cullVisitorRight.valid()) _cullVisitorRight = dynamic_cast<CullVisitor*>(_cullVisitor->cloneType());
if (!_rendergraphRight.valid()) _rendergraphRight = dynamic_cast<RenderGraph*>(_rendergraph->cloneType());
if (!_renderStageRight.valid()) _renderStageRight = dynamic_cast<RenderStage*>(_renderStage->clone(osg::CopyOp::DEEP_COPY_ALL));
// set up the left eye.
osg::ref_ptr<osg::Matrix> projectionLeft = osgNew osg::Matrix(osg::Matrix(1.0f,0.0f,0.0f,0.0f,
0.0f,1.0f,0.0f,0.0f,
iod/(2.0f*sd),0.0f,1.0f,0.0f,
0.0f,0.0f,0.0f,1.0f)*
(*projection));
osg::ref_ptr<osg::Matrix> modelviewLeft = osgNew osg::Matrix( (*modelview) *
osg::Matrix(1.0f,0.0f,0.0f,0.0f,
0.0f,1.0f,0.0f,0.0f,
0.0f,0.0f,1.0f,0.0f,
es,0.0f,0.0f,1.0f));
_cullVisitorLeft->setTraversalMask(_cullMaskLeft);
cullStage(projectionLeft.get(),modelviewLeft.get(),_cullVisitorLeft.get(),_rendergraphLeft.get(),_renderStageLeft.get());
// set up the right eye.
osg::ref_ptr<osg::Matrix> projectionRight = osgNew osg::Matrix(osg::Matrix(1.0f,0.0f,0.0f,0.0f,
0.0f,1.0f,0.0f,0.0f,
-iod/(2.0f*sd),0.0f,1.0f,0.0f,
0.0f,0.0f,0.0f,1.0f)*
(*projection));
osg::ref_ptr<osg::Matrix> modelviewRight = osgNew osg::Matrix( (*modelview) *
osg::Matrix(1.0f,0.0f,0.0f,0.0f,
0.0f,1.0f,0.0f,0.0f,
0.0f,0.0f,1.0f,0.0f,
-es,0.0f,0.0f,1.0f));
_cullVisitorRight->setTraversalMask(_cullMaskRight);
cullStage(projectionRight.get(),modelviewRight.get(),_cullVisitorRight.get(),_rendergraphRight.get(),_renderStageRight.get());
if (_camera.valid() && _computeNearFar != CullVisitor::DO_NOT_COMPUTE_NEAR_FAR)
{
// clamp the camera to the near/far computed in cull traversal.
_camera->setNearFar(_cullVisitorRight->getCalculatedNearPlane(),_cullVisitorRight->getCalculatedFarPlane());
}
}
else
{
if (!_cullVisitor)
{
osg::notify(osg::INFO) << "Warning: no valid osgUtil::SceneView:: attached, creating a default CullVisitor automatically."<< std::endl;
_cullVisitor = osgNew CullVisitor;
}
if (!_rendergraph)
{
osg::notify(osg::INFO) << "Warning: no valid osgUtil::SceneView:: attached, creating a global default RenderGraph automatically."<< std::endl;
_rendergraph = osgNew RenderGraph;
}
if (!_renderStage)
{
osg::notify(osg::INFO) << "Warning: no valid osgUtil::SceneView::_renderStage attached, creating a default RenderStage automatically."<< std::endl;
_renderStage = osgNew RenderStage;
}
_cullVisitor->setTraversalMask(_cullMask);
cullStage(projection.get(),modelview.get(),_cullVisitor.get(),_rendergraph.get(),_renderStage.get());
if (_camera.valid() && _computeNearFar != CullVisitor::DO_NOT_COMPUTE_NEAR_FAR)
{
// clamp the camera to the near/far computed in cull traversal.
_camera->setNearFar(_cullVisitor->getCalculatedNearPlane(),_cullVisitor->getCalculatedFarPlane());
}
}
}
void SceneView::cullStage(osg::Matrix* projection,osg::Matrix* modelview,osgUtil::CullVisitor* cullVisitor, osgUtil::RenderGraph* rendergraph, osgUtil::RenderStage* renderStage)
{
if (!_sceneData || !_viewport->valid()) return;
if (!_initCalled) init();
// collect any occluder in the view frustum.
if (_sceneData->containsOccluderNodes())
{
//std::cout << "Scene graph contains occluder nodes, searching for them"<<std::endl;
osg::CollectOccludersVisitor cov;
cov.setFrameStamp(_frameStamp.get());
// use the frame number for the traversal number.
if (_frameStamp.valid())
{
cov.setTraversalNumber(_frameStamp->getFrameNumber());
}
cov.pushViewport(_viewport.get());
cov.pushProjectionMatrix(projection);
cov.pushModelViewMatrix(modelview);
// traverse the scene graph to search for occluder in there new positions.
_sceneData->accept(cov);
cov.popModelViewMatrix();
cov.popProjectionMatrix();
cov.popViewport();
// sort the occluder from largest occluder volume to smallest.
cov.removeOccludedOccluders();
//std::cout << "finished searching for occluder - found "<<cov.getCollectedOccluderSet().size()<<std::endl;
cullVisitor->getOccluderList().clear();
std::copy(cov.getCollectedOccluderSet().begin(),cov.getCollectedOccluderSet().end(), std::back_insert_iterator<CullStack::OccluderList>(cullVisitor->getOccluderList()));
}
cullVisitor->reset();
cullVisitor->setFrameStamp(_frameStamp.get());
// use the frame number for the traversal number.
if (_frameStamp.valid())
{
cullVisitor->setTraversalNumber(_frameStamp->getFrameNumber());
}
cullVisitor->setCullingMode(_cullingMode);
cullVisitor->setComputeNearFarMode(_computeNearFar);
cullVisitor->setLODBias(_LODBias);
cullVisitor->setSmallFeatureCullingPixelSize(_smallFeatureCullingPixelSize);
cullVisitor->setClearNode(NULL); // reset earth sky on each frame.
cullVisitor->setRenderGraph(rendergraph);
cullVisitor->setRenderStage(renderStage);
cullVisitor->setState( _state.get() );
renderStage->reset();
// comment out reset of rendergraph since clean is more efficient.
// rendergraph->reset();
// use clean of the rendergraph rather than reset, as it is able to
// reuse the structure on the rendergraph in the next frame. This
// achieves a certain amount of frame cohereancy of memory allocation.
rendergraph->clean();
renderStage->setViewport(_viewport.get());
renderStage->setClearColor(_backgroundColor);
switch(_lightingMode)
{
case(HEADLIGHT):
if (_light.valid()) renderStage->addPositionedAttribute(NULL,_light.get());
else osg::notify(osg::WARN)<<"Warning: no osg::Light attached to ogUtil::SceneView to provide head light.*/"<<std::endl;
break;
case(SKY_LIGHT):
if (_light.valid()) renderStage->addPositionedAttribute(modelview,_light.get());
else osg::notify(osg::WARN)<<"Warning: no osg::Light attached to ogUtil::SceneView to provide sky light.*/"<<std::endl;
break;
case(NO_SCENEVIEW_LIGHT):
break;
}
if (_globalState.valid()) cullVisitor->pushStateSet(_globalState.get());
cullVisitor->pushViewport(_viewport.get());
cullVisitor->pushProjectionMatrix(projection);
cullVisitor->pushModelViewMatrix(modelview);
// traverse the scene graph to generate the rendergraph.
_sceneData->accept(*cullVisitor);
cullVisitor->popModelViewMatrix();
cullVisitor->popProjectionMatrix();
cullVisitor->popViewport();
if (_globalState.valid()) cullVisitor->popStateSet();
const osg::ClearNode* clearNode = cullVisitor->getClearNode();
if (clearNode)
{
if (clearNode->getRequiresClear())
{
renderStage->setClearColor(clearNode->getClearColor());
renderStage->setClearMask(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
// really should set clear mask here, but what to? Need
// to consider the stencil and accumulation buffers..
// will defer to later. Robert Osfield. October 2001.
}
else
{
// we have an earth sky implementation to do the work for use
// so we don't need to clear.
renderStage->setClearMask(0);
}
}
renderStage->sort();
// prune out any empty RenderGraph children.
// note, this would be not required if the rendergraph had been
// reset at the start of each frame (see top of this method) but
// a clean has been used instead to try to minimize the amount of
// allocation and deleteing of the RenderGraph nodes.
rendergraph->prune();
}
void SceneView::draw()
{
if (_displaySettings.valid() && _displaySettings->getStereo())
{
switch(_displaySettings->getStereoMode())
{
case(osg::DisplaySettings::QUAD_BUFFER):
{
_globalState->setAttribute(_viewport.get());
glDrawBuffer(GL_BACK_LEFT);
drawStage(_renderStageLeft.get());
glDrawBuffer(GL_BACK_RIGHT);
drawStage(_renderStageRight.get());
}
break;
case(osg::DisplaySettings::ANAGLYPHIC):
{
_globalState->setAttribute(_viewport.get());
// draw left eye.
osg::ref_ptr<osg::ColorMask> red = osgNew osg::ColorMask;
red->setMask(true,false,false,true);
_globalState->setAttribute(red.get());
_renderStageLeft->setColorMask(red.get());
drawStage(_renderStageLeft.get());
// draw right eye.
osg::ref_ptr<osg::ColorMask> green = osgNew osg::ColorMask;
green->setMask(false,true,true,true);
_globalState->setAttribute(green.get());
_renderStageRight->setColorMask(green.get());
drawStage(_renderStageRight.get());
}
break;
case(osg::DisplaySettings::HORIZONTAL_SPLIT):
{
int separation = _displaySettings->getSplitStereoHorizontalSeparation();
int left_half_width = (_viewport->width()-separation)/2;
int right_half_begin = (_viewport->width()+separation)/2;
int right_half_width = _viewport->width()-right_half_begin;
osg::ref_ptr<osg::Viewport> viewportLeft = osgNew osg::Viewport;
viewportLeft->setViewport(_viewport->x(),_viewport->y(),left_half_width,_viewport->height());
osg::ref_ptr<osg::Viewport> viewportRight = osgNew osg::Viewport;
viewportRight->setViewport(_viewport->x()+right_half_begin,_viewport->y(),right_half_width,_viewport->height());
clearArea(_viewport->x()+left_half_width,_viewport->y(),separation,_viewport->height(),_renderStageLeft->getClearColor());
if (_displaySettings->getSplitStereoHorizontalEyeMapping()==osg::DisplaySettings::LEFT_EYE_LEFT_VIEWPORT)
{
_globalState->setAttribute(viewportLeft.get());
_renderStageLeft->setViewport(viewportLeft.get());
drawStage(_renderStageLeft.get());
_globalState->setAttribute(viewportRight.get());
_renderStageRight->setViewport(viewportRight.get());
drawStage(_renderStageRight.get());
}
else
{
_globalState->setAttribute(viewportRight.get());
_renderStageLeft->setViewport(viewportRight.get());
drawStage(_renderStageLeft.get());
_globalState->setAttribute(viewportLeft.get());
_renderStageRight->setViewport(viewportLeft.get());
drawStage(_renderStageRight.get());
}
}
break;
case(osg::DisplaySettings::VERTICAL_SPLIT):
{
int separation = _displaySettings->getSplitStereoVerticalSeparation();
int bottom_half_height = (_viewport->height()-separation)/2;
int top_half_begin = (_viewport->height()+separation)/2;
int top_half_height = _viewport->height()-top_half_begin;
osg::ref_ptr<osg::Viewport> viewportTop = osgNew osg::Viewport;
viewportTop->setViewport(_viewport->x(),_viewport->y()+top_half_begin,_viewport->width(),top_half_height);
osg::ref_ptr<osg::Viewport> viewportBottom = osgNew osg::Viewport;
viewportBottom->setViewport(_viewport->x(),_viewport->y(),_viewport->width(),bottom_half_height);
clearArea(_viewport->x(),_viewport->y()+bottom_half_height,_viewport->width(),separation,_renderStageLeft->getClearColor());
if (_displaySettings->getSplitStereoVerticalEyeMapping()==osg::DisplaySettings::LEFT_EYE_TOP_VIEWPORT)
{
_globalState->setAttribute(viewportTop.get());
_renderStageLeft->setViewport(viewportTop.get());
drawStage(_renderStageLeft.get());
_globalState->setAttribute(viewportBottom.get());
_renderStageRight->setViewport(viewportBottom.get());
drawStage(_renderStageRight.get());
}
else
{
_globalState->setAttribute(viewportBottom.get());
_renderStageLeft->setViewport(viewportBottom.get());
drawStage(_renderStageLeft.get());
_globalState->setAttribute(viewportTop.get());
_renderStageRight->setViewport(viewportTop.get());
drawStage(_renderStageRight.get());
}
}
break;
default:
{
osg::notify(osg::NOTICE)<<"Warning: stereo camera mode not implemented yet."<< std::endl;
_globalState->setAttribute(_viewport.get());
drawStage(_renderStageLeft.get());
}
break;
}
}
else
{
_globalState->setAttribute(_viewport.get());
osg::ref_ptr<osg::ColorMask> cmask = osgNew osg::ColorMask;
cmask->setMask(true,true,true,true);
_globalState->setAttribute(cmask.get());
// bog standard draw.
drawStage(_renderStage.get());
}
// const osg::Polytope& polytope = _state->getViewFrustum();
// const osg::Polytope::PlaneList& pl = polytope.getPlaneList();
// std::cout <<"draw frustum"<<std::endl;
// for(osg::Polytope::PlaneList::const_iterator pl_itr=pl.begin();
// pl_itr!=pl.end();
// ++pl_itr)
// {
// std::cout << " plane "<<*pl_itr<<std::endl;
// }
}
void SceneView::drawStage(osgUtil::RenderStage* renderStage)
{
if (!_sceneData || !_viewport->valid()) return;
// note, to support multi-pipe systems the deletion of OpenGL display list
// and texture objects is deferred until the OpenGL context is the correct
// context for when the object were originally created. Here we know what
// context we are in so can flush the appropriate caches.
osg::Drawable::flushDeletedDisplayLists(_state->getContextID());
osg::Texture::flushDeletedTextureObjects(_state->getContextID());
RenderLeaf* previous = NULL;
renderStage->draw(*_state,previous);
GLenum errorNo = glGetError();
if (errorNo!=GL_NO_ERROR)
{
osg::notify(WARN)<<"Warning: detected OpenGL error '"<<gluErrorString(errorNo)<<"'"<< std::endl;
}
}
/** Calculate, via glUnProject, the object coordinates of a window point.
Note, current implementation requires that SceneView::draw() has been previously called
for projectWindowIntoObject to produce valid values. As per OpenGL
windows coordinates are calculated relative to the bottom left of the window.*/
bool SceneView::projectWindowIntoObject(const osg::Vec3& window,osg::Vec3& object) const
{
osg::Matrix inverseMVPW;
inverseMVPW.invert(computeMVPW());
object = window*inverseMVPW;
return true;
}
/** Calculate, via glUnProject, the object coordinates of a window x,y
when projected onto the near and far planes.
Note, current implementation requires that SceneView::draw() has been previously called
for projectWindowIntoObject to produce valid values. As per OpenGL
windows coordinates are calculated relative to the bottom left of the window.*/
bool SceneView::projectWindowXYIntoObject(int x,int y,osg::Vec3& near_point,osg::Vec3& far_point) const
{
osg::Matrix inverseMVPW;
inverseMVPW.invert(computeMVPW());
near_point = osg::Vec3(x,y,0.0f)*inverseMVPW;
far_point = osg::Vec3(x,y,1.0f)*inverseMVPW;
return true;
}
/** Calculate, via glProject, the object coordinates of a window.
Note, current implementation requires that SceneView::draw() has been previously called
for projectWindowIntoObject to produce valid values. As per OpenGL
windows coordinates are calculated relative to the bottom left of the window.*/
bool SceneView::projectObjectIntoWindow(const osg::Vec3& object,osg::Vec3& window) const
{
window = object*computeMVPW();
return true;
}
const osg::Matrix SceneView::computeMVPW() const
{
osg::Matrix matrix;
if (_modelviewMatrix.valid())
matrix = (*_modelviewMatrix);
else if (_camera.valid())
matrix = _camera->getModelViewMatrix();
if (_projectionMatrix.valid())
matrix.postMult(*_projectionMatrix);
else if (_camera.valid())
matrix.postMult(_camera->getProjectionMatrix());
if (_viewport.valid())
matrix.postMult(_viewport->computeWindowMatrix());
else
osg::notify(osg::WARN)<<"osg::Matrix SceneView::computeMVPW() - error no viewport attached to SceneView, coords will be computed inccorectly."<<std::endl;
return matrix;
}
void SceneView::clearArea(int x,int y,int width,int height,const osg::Vec4& color)
{
osg::ref_ptr<osg::Viewport> viewport = osgNew osg::Viewport;
viewport->setViewport(x,y,width,height);
_state->applyAttribute(viewport.get());
glScissor( x, y, width, height );
glEnable( GL_SCISSOR_TEST );
glColorMask(GL_TRUE,GL_TRUE,GL_TRUE,GL_TRUE);
glClearColor( color[0], color[1], color[2], color[3]);
glClear( GL_COLOR_BUFFER_BIT);
glDisable( GL_SCISSOR_TEST );
}