How to achieve rain and snow effects in osgearth3.7.2

[Joinjun0088]

When I used the old version of osgear, I used osgArticle to achieve the rain and snow effect. However, I compiled the latest version of osgear and built GL3, which does not define OSG_GL-MATRICESAVALABLE. It will be skipped in PrecipitationAffectDraw. How to solve this problem, or how to achieve the rain and snow effect now.

void PrecipitationEffect::PrecipitationDrawable::drawImplementation(osg::RenderInfo& renderInfo) const
{
#if defined(OSG_GL_MATRICES_AVAILABLE)

if (!_geometry) return;


    const osg::GLExtensions* extensions = renderInfo.getState()->get<osg::GLExtensions>();

    // save OpenGL matrices
    glPushMatrix();

    if (_requiresPreviousMatrix)
    {
        renderInfo.getState()->setActiveTextureUnit(0);
        glMatrixMode( GL_TEXTURE );
        glPushMatrix();
    }

    typedef std::vector<const CellMatrixMap::value_type*> DepthMatrixStartTimeVector;
    DepthMatrixStartTimeVector orderedEntries;
    orderedEntries.reserve(_currentCellMatrixMap.size());

    for(CellMatrixMap::const_iterator citr = _currentCellMatrixMap.begin();
        citr != _currentCellMatrixMap.end();
        ++citr)
    {
        orderedEntries.push_back(&(*citr));
    }

    std::sort(orderedEntries.begin(),orderedEntries.end(),LessFunctor());

    for(DepthMatrixStartTimeVector::reverse_iterator itr = orderedEntries.rbegin();
        itr != orderedEntries.rend();
        ++itr)
    {
        extensions->glMultiTexCoord1f(GL_TEXTURE0+1, (*itr)->second.startTime);

        // load cells current modelview matrix
        if (_requiresPreviousMatrix)
        {
            glMatrixMode( GL_MODELVIEW );
            glLoadMatrix((*itr)->second.modelview.ptr());

            CellMatrixMap::const_iterator pitr = _previousCellMatrixMap.find((*itr)->first);
            if (pitr != _previousCellMatrixMap.end())
            {
                // load previous frame modelview matrix for motion blurr effect
                glMatrixMode( GL_TEXTURE );
                glLoadMatrix(pitr->second.modelview.ptr());
            }
            else
            {
                // use current modelview matrix as "previous" frame value, cancelling motion blurr effect
                glMatrixMode( GL_TEXTURE );
                glLoadMatrix((*itr)->second.modelview.ptr());
            }
        }
        else
        {
            glLoadMatrix((*itr)->second.modelview.ptr());
        }

        _geometry->draw(renderInfo);

        unsigned int numVertices = osg::minimum(_geometry->getVertexArray()->getNumElements(), _numberOfVertices);
        glDrawArrays(_drawType, 0, numVertices);
    }

    // restore OpenGL matrices
    if (_requiresPreviousMatrix)
    {
        glPopMatrix();
        glMatrixMode( GL_MODELVIEW );
    }

    glPopMatrix();
#else
    OSG_NOTICE<<"Warning: ParticleEffect::drawImplementation(..) not fully implemented."<<std::endl;
#endif
}

[gwaldron]

When you built with GL3 you disabled the FFP (fixed-function pipeline), which includes calls like glPushMatrix etc.

So your options are to either build OpenSceneGraph in legacy GL2 mode and hope for the best; or to rewrite the old PrecipitationEffect code to use modern GL.