C++ TileNode::getStateSet方法代码示例

bool
TileNode::inheritState(EngineContext* context)
{
    // Find the parent node. It will only be null if this is a "first LOD" tile.
    TileNode* parent = getNumParents() > 0 ? dynamic_cast<TileNode*>(getParent(0)) : 0L;

    bool changesMade = false;

    // which quadrant is this tile in?
    unsigned quadrant = getTileKey().getQuadrant();

    // default inheritance of the elevation data for bounding purposes:
    osg::ref_ptr<const osg::Image> elevRaster;
    osg::Matrixf                   elevMatrix;
    if ( parent )
    {
        elevRaster = parent->getElevationRaster();
        elevMatrix = parent->getElevationMatrix();
        elevMatrix.preMult( scaleBias[quadrant] );
    }

    // Find all the sampler matrix uniforms and scale/bias them to the current quadrant.
    // This will inherit textures and use the proper sub-quadrant until new data arrives (later).
    for( RenderBindings::const_iterator binding = context->getRenderBindings().begin(); binding != context->getRenderBindings().end(); ++binding )
    {
        if ( binding->usage().isSetTo(binding->COLOR) )
        {
            if ( parent && parent->getStateSet() )
            {
                MPTexture* parentMPTex = parent->getMPTexture();
                _mptex->inheritState( parentMPTex, scaleBias[quadrant] );
                changesMade = true;
            }
        }

        else if ( binding->usage().isSetTo(binding->COLOR_PARENT) )
        {
            //nop -- this is handled as part of the COLOR binding
        }

        else
        {
            osg::StateAttribute* sa = getStateSet()->getTextureAttribute(binding->unit(), osg::StateAttribute::TEXTURE);        

            // If the attribute isn't present, that means we are inheriting it from above.
            // So construct a new scale/bias matrix.
            if ( sa == 0L )
            {
                osg::Matrixf matrix;

                // Find the parent's matrix and scale/bias it to this quadrant:
                if ( parent && parent->getStateSet() )
                {
                    const osg::Uniform* matrixUniform = parent->getStateSet()->getUniform( binding->matrixName() );
                    if ( matrixUniform )
                    {
                        matrixUniform->get( matrix );
                        matrix.preMult( scaleBias[quadrant] );
                    }
                }

                // Add a new uniform with the scale/bias'd matrix:
                osg::StateSet* stateSet = getOrCreateStateSet();
                stateSet->removeUniform( binding->matrixName() );
                stateSet->addUniform( context->getOrCreateMatrixUniform(binding->matrixName(), matrix) );
                changesMade = true;
            }

            // If this is elevation data, record the new raster so we can apply it to the node.
            else if ( binding->usage().isSetTo(binding->ELEVATION) )
            {
                osg::Texture* t = static_cast<osg::Texture*>(sa);
                elevRaster = t->getImage(0);
                elevMatrix = osg::Matrixf::identity();
            }
        }
    }

    // If we found one, communicate it to the node and its children.
    if (elevRaster.valid())
    {
        if (elevRaster.get() != getElevationRaster() || elevMatrix != getElevationMatrix() )
        {
            setElevationRaster( elevRaster.get(), elevMatrix );
            changesMade = true;
        }
    }

    // finally, update the uniforms for terrain morphing
    updateTileUniforms( context->getSelectionInfo() );

    if ( !changesMade )
    {
        OE_INFO << LC << _key.str() << ", good, no changes :)\n";
    }
    else
    {
        dirtyBound();
    }

//.........这里部分代码省略.........