OSG中uniform变量

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);

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OSG中uniform变量

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