osg之黑夜背景地月系显示

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目录

效果

 代码

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效果

 代码

/**
* Lights test. This application is for testing the LightSource support in osgEarth.
* 灯光测试。此应用程序用于测试osgEarth中的光源支持。
*/
#include "stdafx.h"
#include <osgViewer/Viewer>
#include <osgEarth/Notify>
#include <osgEarth/Lighting>
#include <osgEarth/PhongLightingEffect>
#include <osgEarth/NodeUtils>
#include <osgEarthUtil/EarthManipulator>
#include <osgEarthUtil/ExampleResources>
#include <osgEarthUtil/Ephemeris>
#include <osgEarthUtil/Shadowing>#define LC "[lights] "using namespace osgEarth;
using namespace osgEarth::Util;int
usage(const char* name)
{OE_NOTICE<< "\nUsage: " << name << " file.earth" << std::endl<< MapNodeHelper().usage() << std::endl;return 0;
}// converts a double-precision Vec3d to an equivalent single-precision Vec4f position
// as needed for light positions.
// Vec3d转换为Vec4f ，根据光源位置的需要
osg::Vec4
worldToVec4(const osg::Vec3d& ecef)
{osg::Vec4 result(0.0f, 0.0f, 0.0f, 1.0f);osg::Vec3d d = ecef;while (d.length() > 1e6)// 避免光源位置太远？？{d *= 0.1;result.w() *= 0.1;}return osg::Vec4(d.x(), d.y(), d.z(), result.w());
}// 生成随机颜色
osg::Vec4
randomColor()
{float r = (float)rand() / (float)RAND_MAX;float g = (float)rand() / (float)RAND_MAX;float b = (float)rand() / (float)RAND_MAX;return osg::Vec4(r, g, b, 1.0f);
}// 添加光源
osg::Group*
addLights(osg::View* view, osg::Node* root, int lightNum)
{// 获取地理坐标系MapNode* mapNode = MapNode::get(root);const SpatialReference* mapsrs = mapNode->getMapSRS();const SpatialReference* geosrs = mapsrs->getGeographicSRS();osg::Vec3d world;osg::Group* lights = new osg::Group();// Add a directional light that simulates the sun - but skip this if a sky// was already added in the earth file.// 添加模拟太阳的平行光// 但如果地球文件中已经添加了天空，则跳过此操作。if (lightNum == 0){// Ephemeris 星历表类，给出了自然发生的天体天体的位置；// 其中包括太阳和月亮。// 还包括一些相关的实用程序功能。Ephemeris e;DateTime dt(2016, 8, 10, 14.0);// 设置UTC时间CelestialBody sun = e.getSunPosition(dt); // 设置天体相对于地球的位置。world = sun.geocentric;// 太阳的地理位置// 定义太阳光osg::Light* sunLight = new osg::Light(lightNum++);world.normalize();// 归一化sunLight->setPosition(osg::Vec4d(world, 0.0));sunLight->setAmbient(osg::Vec4(0.2, 0.2, 0.2, 1.0));// 环境光照sunLight->setDiffuse(osg::Vec4(1.0, 1.0, 0.9, 1.0));// 漫反射光照// osg::LightSource 用于定义场景中的灯光的叶节点。osg::LightSource* sunLS = new osg::LightSource();sunLS->setLight(sunLight);lights->addChild(sunLS);// 为root节点 投射阴影ShadowCaster* caster = osgEarth::findTopMostNodeOfType<ShadowCaster>(root);if (caster){OE_INFO << "Found a shadow caster!\n";caster->setLight(sunLight);}std::cout << "because no skyNode,so create sunLS" << std::endl;}#if 1	// 这里主要是为测试加载其他光源// A red spot light. A spot light has a real position in space // and points in a specific direciton. The Cutoff and Exponent// properties control the cone angle and sharpness, respectively// 一束红光。拥有真实的位置和光方向。// “Cutoff”和“Exponent”属性分别控制圆锥体角度和锐度{// 定义光照射 地点GeoPoint p(geosrs, -121, 34, 5000000., ALTMODE_ABSOLUTE);p.toWorld(world);// 定义光osg::Light* spot = new osg::Light(lightNum++);spot->setPosition(worldToVec4(world));spot->setAmbient(osg::Vec4(0, 0.2, 0, 1));spot->setDiffuse(osg::Vec4(1, 0, 0, 1));spot->setSpotCutoff(20.0f);spot->setSpotExponent(100.0f);// point straight down at the map:直接指向地图world.normalize();spot->setDirection(-world);// 光源叶子节点osg::LightSource* spotLS = new osg::LightSource();spotLS->setLight(spot);lights->addChild(spotLS);}// A green point light. A Point light lives at a real location in // space and lights equally in all directions.// 绿灯。点光源位于空间中的真实位置，并在所有方向上均匀发光。{// 定义光照射 地点GeoPoint p(geosrs, -45, -35, 1000000., ALTMODE_ABSOLUTE);p.toWorld(world);// 定义光osg::Light* point = new osg::Light(lightNum++);point->setPosition(worldToVec4(world));point->setAmbient(osg::Vec4(0, 0, 0, 1));point->setDiffuse(osg::Vec4(1.0, 1.0, 0.0, 1));// 光源叶子节点osg::LightSource* pointLS = new osg::LightSource();pointLS->setLight(point);lights->addChild(pointLS);}
#endif// Generate the necessary uniforms for the shaders.// 为着色器生成必要的uniforms。// GenerateGL3LightingUniforms类的作用：遍历图形，查找灯光和材质，//		并为它们生成静态 Uniforms 或动态剔除回调，//		以便它们可以使用核心配置文件着色器。GenerateGL3LightingUniforms gen;lights->accept(gen);return lights;
}int
main(int argc, char** argv)
{osg::ArgumentParser arguments(&argc, argv);// help?if (arguments.read("--help"))return usage(argv[0]);// create a viewer:osgViewer::Viewer viewer(arguments);// Whether to test updating material// 是否测试更新材质bool update = arguments.read("--update");// Tell the database pager to not modify the unref settingsviewer.getDatabasePager()->setUnrefImageDataAfterApplyPolicy(true, false);// install our default manipulator (do this before calling load)viewer.setCameraManipulator(new EarthManipulator(arguments));// disable the small-feature cullingviewer.getCamera()->setSmallFeatureCullingPixelSize(-1.0f);// 在添加光源之前，需要关闭viewer本身的光viewer.setLightingMode(viewer.NO_LIGHT);// load an earth file, and support all or our example command-line optionsosg::ref_ptr<osg::Node> node = MapNodeHelper().load(arguments, &viewer);if (node.valid()){MapNode* mapNode = MapNode::get(node.get());if (!mapNode)return -1;// Example of a custom material for the terrain.// 地形自定义材质示例。osg::ref_ptr< osg::Material > material = 0;if (update)// 开启update属性后，会创建material，进而调用回调方法，随机更改影像颜色{OE_NOTICE << "Custom material" << std::endl;material = new osg::Material;// 材质决定材质颜色material->setDiffuse(osg::Material::FRONT, osg::Vec4(1, 1, 1, 1));//漫反射光照    material->setAmbient(osg::Material::FRONT, osg::Vec4(1, 1, 1, 1));// 环境光照// Attach our StateAttributeCallback so that uniforms are updated.绑定材质回调material->setUpdateCallback(new MaterialCallback());mapNode->getOrCreateStateSet()->setAttributeAndModes(material);}// Does a Sky already exist (loaded from the earth file)?SkyNode* sky = osgEarth::findTopMostNodeOfType<SkyNode>(node.get());if (!sky)// 如果没有深空节点{std::cout << "no skyNode " << std::endl;// Add phong lighting.添加标签照明？？？PhongLightingEffect* phong = new PhongLightingEffect();phong->attach(node->getOrCreateStateSet());}// 添加光源. 当没有sky时，才会采用addLights中，创建光源的方式添加。osg::Group* lights = addLights(&viewer, node.get(), sky ? 1 : 0);mapNode->addChild(lights);viewer.setSceneData(node.get());while (!viewer.done()){if (viewer.getFrameStamp()->getFrameNumber() % 100 == 0){// 每100帧，随机生成一个颜色if (material){material->setDiffuse(osg::Material::FRONT, randomColor());}}viewer.frame();}return 0;}else{return usage(argv[0]);}
}

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