用Ogre生成天龙八部的lightmap和minimap的简单方法

自从在一家创业小公司当了客户端主程以后，就忙的没有时间写博客了，整个公司没有一个人有完整的项目经验，所有一切都在摸索中前进，但初生牛犊不怕虎，项目还算进展顺利。但我始终认为，安静下来总结整理一下工作心得是必要的，可惜这个愿望恐怕得等到这个项目忙完以后。

 

周末有点时间，还是可以抽空随便写点东西。

 

lightmap的重要性不用多说，没必要所有阴影都动态去渲染，那些一辈子也不会动的静态物体，贴一张lightmap就行了，可惜Ogre只提供动态阴影给我们，帮人也不帮到底。

 

如何生成天龙八部一样lightmap，如果你去百度一下，他们会告诉你各种方法，什么光线追踪，shader，之类

 

以上都是告诉你，自己去产生一个阴影。但是Ogre已经帮我们产生了动态阴影，我们就没必要再自己去生成阴影，

 

只要用动态阴影的渲染一张静态阴影图，保存下来不就行了么。

 

那么如何用Ogre的动态阴影去产生一张静态的阴影图呢？

 

1）先学会渲染一张minimap的缩略图，缩略图大家都应该会吧，创建一个垂直俯瞰的摄像机，平行投影拍一张就是

 

2）改进minimap，让垂直俯瞰的摄像机的视口只渲染地形队列。不渲染其他队列

这样拍出来的minimap就只有阴影和地形纹理混合后效果了

   Ogre::RenderQueueInvocationSequence* rqis =
    Ogre::Root::getSingleton().createRenderQueueInvocationSequence("Lightmap maker");
   Ogre::RenderQueueInvocation* rqi =
    rqis->add(Ogre::RENDER_QUEUE_WORLD_GEOMETRY_1, "World Geometry");
   viewport->setRenderQueueInvocationSequenceName("Lightmap maker");

 

3）再改进一下，把地形材质设置为BaseWhite，全白，那么minimap就变成了lightmap了。

 

4）Ogre的阴影并不好用，所以你需要优化，怎么优化，或者用shader实现，以后再写。

 

//////////这是动态阴影的图片、、、、、、、、、、、、、、、、、、、、、、、、、、

 

//////////////////////////这是贴上lightmap的图片

./////////////这是阴影图、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、

 

附上代码，看看思路就好！

/*@filename WXLightMapMaker.h @creator LuoYinan@data 2010.6.14@remarks 创建场景光照图*/#ifndef __WX_LIGHTMAP_MAKER_H__#define __WX_LIGHTMAP_MAKER_H__#include "SceneManipulator.h"namespace WX{class LightMapMaker{public:LightMapMaker(SceneManipulator* manipulator);~LightMapMaker(void);// 初始化，包括创建render texture，camera等void initial(void);// 销毁render texturevoid destroy(void);// 保存光照图到文件// 格式 "emei.lightmap.png",也支持全路径,比如../../Data/Scene/emei.lightmap.png"void outputTexture(const Ogre::String& fileName);protected:SceneManipulator* mSceneManipulator;Ogre::RenderTexture* mRenderTexture;};}#endif #include "WXLightMapMaker.h"#include "GameScene/TerrainData.h"#include "GameScene/WXScene.h"#include "GameScene/WXSceneInfo.h"#include "GameScene/WXStaticEntityObject.h"#include "GameScene/WXModelObject.h"namespace WX{//----------------------------------------------------------------------------------LightMapMaker::LightMapMaker(SceneManipulator* manipulator): mSceneManipulator(manipulator), mRenderTexture(0){}//--------------------------------------------------------------------------------LightMapMaker::~LightMapMaker(void){}//--------------------------------------------------------------------------------void LightMapMaker::initial(void){// 确保地形已经载入TerrainData* data = mSceneManipulator->getTerrainData();assert(data && "TerrainData* == NULL");// 创建lightmap摄像机,垂直俯瞰整个地图Ogre::SceneManager* mSceneManager = mSceneManipulator->getSceneManager();//if (mSceneManipulator->getTerrainData()->mLightmapImage == NULL){static const String msLightmapMaker("Lightmap maker");Ogre::Camera* camera = 0;try{camera = mSceneManager->getCamera(msLightmapMaker);}catch (const Ogre::Exception& e){// 只提示异常,而不退出程序if (e.getNumber() == e.ERR_ITEM_NOT_FOUND){//MessageBox(NULL, e.what(), "An exception has occured!", MB_OK | MB_ICONERROR | MB_TASKMODAL);}else{throw;}}if (!camera){camera = mSceneManager->createCamera(msLightmapMaker);camera->setAutoAspectRatio(true);camera->setProjectionType(Ogre::PT_ORTHOGRAPHIC); // 平行投影// 在Ogre1.6版本中,平行投影的大小改为setOrthoWindowWidth和setOrthoWindowHeight来决定,// 而不是以前版本用的FOV和近截面,so...camera->setFOVy(Ogre::Degree(90));camera->setOrthoWindowWidth(mSceneManipulator->getTerrainData()->getXSize()*mSceneManipulator->getBaseScale());camera->setOrthoWindowHeight(mSceneManipulator->getTerrainData()->getZSize()*mSceneManipulator->getBaseScale());Ogre::Quaternion orientation;orientation.FromAxes(Ogre::Vector3::UNIT_X, Ogre::Vector3::NEGATIVE_UNIT_Z, Ogre::Vector3::UNIT_Y);camera->setOrientation(orientation);}// 计算所有对象包围盒,以此来决定摄像机的参数Ogre::AxisAlignedBox aabb;Ogre::SceneManager::MovableObjectIterator itm =mSceneManager->getMovableObjectIterator(Ogre::EntityFactory::FACTORY_TYPE_NAME);while (itm.hasMoreElements()){Ogre::MovableObject* movable = itm.getNext();aabb.merge(movable->getWorldBoundingBox(true));}camera->setNearClipDistance(32 * mSceneManipulator->getBaseScale() / 2); camera->setFarClipDistance(camera->getNearClipDistance() + aabb.getMaximum().y - aabb.getMinimum().y);camera->setPosition(0, camera->getNearClipDistance() + aabb.getMaximum().y, 0);// 调整阴影参数Ogre::Real distance = camera->getNearClipDistance() * Ogre::Math::Sqrt(1 + Ogre::Math::Sqr(camera->getAspectRatio()));mSceneManager->setShadowFarDistance(distance);Ogre::Real camHeight = camera->getPosition().y;mSceneManager->setShadowDirLightTextureOffset(camHeight / distance);// 创建lightmap的Rtt纹理,和天龙一样,设为地形大小的8倍Ogre::TexturePtr pTexture = (Ogre::TexturePtr)Ogre::TextureManager::getSingleton().getByName("LightmapRttTex");if (pTexture.isNull()){size_t width = data->getXSize() * 8;size_t height = data->getZSize() * 8;pTexture = Ogre::TextureManager::getSingleton().createManual("LightmapRttTex", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,Ogre::TEX_TYPE_2D,width, height, 1, 0, Ogre::PF_BYTE_RGB,Ogre::TU_RENDERTARGET, 0);}Ogre::HardwarePixelBufferSharedPtr pBuffer = pTexture->getBuffer(0, 0);mRenderTexture = pBuffer->getRenderTarget(0); // 创建lightmap的视口Ogre::Viewport* viewport = mRenderTexture->addViewport(mSceneManipulator->getSceneManager()->getCamera("Lightmap maker"));viewport->setOverlaysEnabled(false);viewport->setSkiesEnabled(false);viewport->setShadowsEnabled(true);// 自定义一个渲染队列调用组,只渲染地形队列,这是关键,我们只要阴影,不要其他的.// 如果你全部都渲染了,那就变成了minimap,缩略图了.Ogre::RenderQueueInvocationSequence* rqis =Ogre::Root::getSingleton().createRenderQueueInvocationSequence("Lightmap maker");Ogre::RenderQueueInvocation* rqi =rqis->add(Ogre::RENDER_QUEUE_WORLD_GEOMETRY_1, "World Geometry");viewport->setRenderQueueInvocationSequenceName("Lightmap maker");}}//--------------------------------------------------------------------------------void LightMapMaker::destroy(void){if (mRenderTexture){mSceneManipulator->getSceneManager()->destroyCamera("Lightmap maker");mRenderTexture->removeAllViewports();Ogre::TextureManager::getSingleton().remove("LightmapRttTex");mRenderTexture = NULL;}}//--------------------------------------------------------------------------------void LightMapMaker::outputTexture(const Ogre::String& fileName){// 如果已经有lightmap了,跳过if (mSceneManipulator->getTerrainData()->mLightmapImage) {// 需要提示么?return;}// 让所有静态物体都可以投射阴影,来制作lightmapScene::ObjectsByTypeRange objests = mSceneManipulator->getSceneInfo()->findObjectsByType(StaticEntityObject::msType);for (Scene::ObjectsByTypeIterator it = objests.first; it != objests.second; ++ it){ObjectPtr object = (*it);object->setPropertyAsString("cast shadows", "true");//object->setPropertyAsString("receive shadows", "true");}objests = mSceneManipulator->getSceneInfo()->findObjectsByType(ModelObject::msType);for (Scene::ObjectsByTypeIterator it = objests.first; it != objests.second; ++ it){ObjectPtr object = (*it);object->setPropertyAsString("cast shadows", "true");//object->setPropertyAsString("receive shadows", "true");}// 用BaseWhite代替原来的地形材质,并重构地形TerrainData::MaterialTemplates& materials = mSceneManipulator->getTerrainData()->mMaterialTemplates;TerrainData::MaterialTemplates materialsCopy(materials);materials["OneLayer"] = "BaseWhite";materials["OneLayerLightmap"] = "BaseWhite";materials["TwoLayer"] = "BaseWhite";materials["TwoLayerLightmap"] = "BaseWhite";mSceneManipulator->getTerrain()->buildGeometry(mSceneManipulator->getBaseSceneNode(), true);// 更新//mSceneManipulator->getSceneManager()->_updateSceneGraph(mSceneManipulator->getSceneManager()->getCamera("Lightmap maker")); mRenderTexture->update();// 保存lightmap到文件Ogre::String LightmapFileName(fileName);String baseName, path, outExtention;if (fileName.empty()){WX::TerrainData* data = mSceneManipulator->getTerrainData();Ogre::StringUtil::splitBaseFilename(data->mHeightmapFilename, baseName, outExtention);LightmapFileName = baseName + ".lightmap.png";}mRenderTexture->writeContentsToFile(LightmapFileName);// 载入lightmapstatic const String TEMP_GROUP_NAME = "#TEMP#"; // 临时资源组Ogre::StringUtil::splitFilename(LightmapFileName, baseName, path);mSceneManipulator->getTerrainData()->mLightmapFilename = baseName;Ogre::ResourceGroupManager& rgm = Ogre::ResourceGroupManager::getSingleton();rgm.addResourceLocation(path, "FileSystem", TEMP_GROUP_NAME, false);// 这个函数本来是protected,以后最好还是重新载入整个地形,而不是单独载入lightmapmSceneManipulator->getTerrainData()->_loadLightmap(baseName, "image", TEMP_GROUP_NAME); // 换回原来的地形材质,并重构地形std::swap(materials, materialsCopy);mSceneManipulator->getTerrain()->buildGeometry(mSceneManipulator->getBaseSceneNode(), true);// 所有静态物体不再需要投射阴影了,因为我们有lightmapobjests = mSceneManipulator->getSceneInfo()->findObjectsByType(StaticEntityObject::msType);for (Scene::ObjectsByTypeIterator it = objests.first; it != objests.second; ++ it){ObjectPtr object = (*it);object->setPropertyAsString("cast shadows", "false");//object->setPropertyAsString("receive shadows", "true");}objests = mSceneManipulator->getSceneInfo()->findObjectsByType(ModelObject::msType);for (Scene::ObjectsByTypeIterator it = objests.first; it != objests.second; ++ it){ObjectPtr object = (*it);object->setPropertyAsString("cast shadows", "false");//object->setPropertyAsString("receive shadows", "true");}// 销毁临时资源组rgm.destroyResourceGroup(TEMP_GROUP_NAME);}}

 

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