渲染节点

1、渲染节点

案例位置：examples/Cuda/QtGUI/Qt_GLVisualNode

功能介绍：案例展示了渲染节点的使用。PeriDyno引擎中包括多种类型的渲染节点，例如粒子渲染、三角面片渲染、线条渲染等。相关渲染节点请参考 Module模块 。

案例说明：由粒子系统组成的水体，在重力的作用下向下运动，粒子颜色随速度的变化而发生改变。用户可以通过双击NodeEditor中的节点，修改节点中模块的属性。

2、程序实现

接下来介绍案例的实现过程：

创建场景图及边界:

	std::shared_ptr<SceneGraph> scn = std::make_shared<SceneGraph>();
	scn->setUpperBound(Vec3f(1.5, 1, 1.5));
	scn->setLowerBound(Vec3f(-0.5, 0, -0.5));

创建基于矩形，并将其转化为流体粒子:

	//Create a cube
	auto cube = scn->addNode(std::make_shared<CubeModel<DataType3f>>());
	cube->varLocation()->setValue(Vec3f(0.6, 0.85, 0.5));
	cube->varLength()->setValue(Vec3f(0.1, 0.65, 0.1));
	cube->graphicsPipeline()->disable();

	//Create a sampler
	auto sampler = scn->addNode(std::make_shared<CubeSampler<DataType3f>>());
	sampler->varSamplingDistance()->setValue(0.005);
	sampler->graphicsPipeline()->disable();

	cube->outCube()->connect(sampler->inCube());

	auto initialParticles = scn->addNode(std::make_shared<MakeParticleSystem<DataType3f>>());

	sampler->statePointSet()->promoteOuput()->connect(initialParticles->inPoints());

	auto fluid = scn->addNode(std::make_shared<ParticleFluid<DataType3f>>());
	//fluid->loadParticles(Vec3f(0.5, 0.2, 0.4), Vec3f(0.7, 1.5, 0.6), 0.005);
	initialParticles->connect(fluid->importInitialStates());

创建边界及渲染节点:

	//Create a boundary
	auto boundary = scn->addNode(std::make_shared<StaticBoundary<DataType3f>>()); ;
	boundary->loadCube(Vec3f(-0.5, 0, -0.5), Vec3f(1.5, 2, 1.5), 0.02, true);
	boundary->loadSDF(getAssetPath() + "bowl/bowl.sdf", false);
	fluid->connect(boundary->importParticleSystems());

	auto calculateNorm = std::make_shared<CalculateNorm<DataType3f>>();
	fluid->stateVelocity()->connect(calculateNorm->inVec());
	fluid->graphicsPipeline()->pushModule(calculateNorm);

	auto colorMapper = std::make_shared<ColorMapping<DataType3f>>();
	colorMapper->varMax()->setValue(5.0f);
	calculateNorm->outNorm()->connect(colorMapper->inScalar());
	fluid->graphicsPipeline()->pushModule(colorMapper);

	auto ptRender = std::make_shared<GLPointVisualModule>();
	ptRender->setColor(Vec3f(1, 0, 0));
	ptRender->setColorMapMode(GLPointVisualModule::PER_VERTEX_SHADER);

	fluid->statePointSet()->connect(ptRender->inPointSet());
	colorMapper->outColor()->connect(ptRender->inColor());

	fluid->graphicsPipeline()->pushModule(ptRender);

	// A simple color bar widget for node
	auto colorBar = std::make_shared<ImColorbar>();
	colorBar->varMax()->setValue(5.0f);
	colorBar->varFieldName()->setValue("Velocity");
	calculateNorm->outNorm()->connect(colorBar->inScalar());
	// add the widget to app
	fluid->graphicsPipeline()->pushModule(colorBar);