OSG 中 常用的 Uniforms

osg中的 Uniforms主要存在两个地方，一个是SceneView中，void SceneView::updateUniforms()

void SceneView::updateUniforms(){    if (!_localStateSet)    {        _localStateSet = new osg::StateSet;    }    if (!_localStateSet) return;        if ((_activeUniforms & FRAME_NUMBER_UNIFORM) && _frameStamp.valid())    {        osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_FrameNumber",osg::Uniform::UNSIGNED_INT);        uniform->set(_frameStamp->getFrameNumber());            }        if ((_activeUniforms & FRAME_TIME_UNIFORM) && _frameStamp.valid())    {        osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_FrameTime",osg::Uniform::FLOAT);        uniform->set(static_cast<float>(_frameStamp->getReferenceTime()));    }        if ((_activeUniforms & DELTA_FRAME_TIME_UNIFORM) && _frameStamp.valid())    {        float delta_frame_time = (_previousFrameTime != 0.0) ? static_cast<float>(_frameStamp->getReferenceTime()-_previousFrameTime) : 0.0f;        _previousFrameTime = _frameStamp->getReferenceTime();                osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_DeltaFrameTime",osg::Uniform::FLOAT);        uniform->set(delta_frame_time);    }        if ((_activeUniforms & SIMULATION_TIME_UNIFORM) && _frameStamp.valid())    {        osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_SimulationTime",osg::Uniform::FLOAT);        uniform->set(static_cast<float>(_frameStamp->getSimulationTime()));    }        if ((_activeUniforms & DELTA_SIMULATION_TIME_UNIFORM) && _frameStamp.valid())    {        float delta_simulation_time = (_previousSimulationTime != 0.0) ? static_cast<float>(_frameStamp->getSimulationTime()-_previousSimulationTime) : 0.0f;        _previousSimulationTime = _frameStamp->getSimulationTime();                osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_DeltaSimulationTime",osg::Uniform::FLOAT);        uniform->set(delta_simulation_time);    }        if (_activeUniforms & VIEW_MATRIX_UNIFORM)    {        osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_ViewMatrix",osg::Uniform::FLOAT_MAT4);        uniform->set(getViewMatrix());    }    if (_activeUniforms & VIEW_MATRIX_INVERSE_UNIFORM)    {        osg::Uniform* uniform = _localStateSet->getOrCreateUniform("osg_ViewMatrixInverse",osg::Uniform::FLOAT_MAT4);        uniform->set(osg::Matrix::inverse(getViewMatrix()));    }}

不过默认的是： DEFAULT_UNIFORMS

       enum ActiveUniforms        {            FRAME_NUMBER_UNIFORM            = 1,            FRAME_TIME_UNIFORM              = 2,            DELTA_FRAME_TIME_UNIFORM        = 4,            SIMULATION_TIME_UNIFORM         = 8,            DELTA_SIMULATION_TIME_UNIFORM   = 16,            VIEW_MATRIX_UNIFORM             = 32,            VIEW_MATRIX_INVERSE_UNIFORM     = 64,            DEFAULT_UNIFORMS                = FRAME_NUMBER_UNIFORM |                                              FRAME_TIME_UNIFORM |                                              DELTA_FRAME_TIME_UNIFORM |                                              SIMULATION_TIME_UNIFORM |                                              DELTA_SIMULATION_TIME_UNIFORM |                                              VIEW_MATRIX_UNIFORM |                                              VIEW_MATRIX_INVERSE_UNIFORM,            ALL_UNIFORMS                    = 0x7FFFFFFF        };

另一个是在osg::State中，

    _modelViewMatrixUniform = new Uniform(Uniform::FLOAT_MAT4,"osg_ModelViewMatrix");    _projectionMatrixUniform = new Uniform(Uniform::FLOAT_MAT4,"osg_ProjectionMatrix");    _modelViewProjectionMatrixUniform = new Uniform(Uniform::FLOAT_MAT4,"osg_ModelViewProjectionMatrix");    _normalMatrixUniform = new Uniform(Uniform::FLOAT_MAT3,"osg_NormalMatrix");

要使用这些Uniforms，需要：

viewer->realize();osg::State* state = viewer->getCamera()->getGraphicsContext()->getState();state->setUseModelViewAndProjectionUniforms(true);