ogre 学习笔记 - Day 7

[Sample_ParticleFX]

粒子效果

    void setupParticles(){ParticleSystem::setDefaultNonVisibleUpdateTimeout(5);  // set nonvisible timeoutParticleSystem* ps;// create some nice fireworks and place it at the originps = mSceneMgr->createParticleSystem("Fireworks", "Examples/Fireworks");mSceneMgr->getRootSceneNode()->attachObject(ps);// create a green nimbus around the ogre headps = mSceneMgr->createParticleSystem("Nimbus", "Examples/GreenyNimbus");mSceneMgr->getRootSceneNode()->attachObject(ps);ps = mSceneMgr->createParticleSystem("Rain", "Examples/Rain");  // create a rainstormps->fastForward(5);   // fast-forward the rain so it looks more naturalmSceneMgr->getRootSceneNode()->createChildSceneNode(Vector3(0, 1000, 0))->attachObject(ps);// create aureola around ogre head perpendicular to the groundps = mSceneMgr->createParticleSystem("Aureola", "Examples/Aureola");mSceneMgr->getRootSceneNode()->attachObject(ps);// create shared pivot node for spinning the fountainsmFountainPivot = mSceneMgr->getRootSceneNode()->createChildSceneNode();ps = mSceneMgr->createParticleSystem("Fountain1", "Examples/PurpleFountain");  // create fountain 1// attach the fountain to a child node of the pivot at a distance and anglemFountainPivot->createChildSceneNode(Vector3(200, -100, 0), Quaternion(Degree(20), Vector3::UNIT_Z))->attachObject(ps);ps = mSceneMgr->createParticleSystem("Fountain2", "Examples/PurpleFountain");  // create fountain 2// attach the fountain to a child node of the pivot at a distance and anglemFountainPivot->createChildSceneNode(Vector3(-200, -100, 0), Quaternion(Degree(-20), Vector3::UNIT_Z))->attachObject(ps);}

ps = mSceneMgr->createParticleSystem(“Fireworks”, “Examples/Fireworks”);

粒子材质

particle_system Examples/Fireworks
{material Examples/Flarepoint_rendering            falseparticle_width             10particle_height            10cull_each                  falsequota                      1000emit_emitter_quota         10billboard_type             point// Emitter that emits multiple Point emitters with name 'explosion'emitter Box{name                    mainEmitteremit_emitter            explosionangle                   30emission_rate           1000time_to_live            3direction               0 1 0velocity                200}// This Point emitter is emitted by the Box emitter and emits billboard particles itselfemitter Point{name                    explosionangle                   180emission_rate           100time_to_live            2direction               0 1 0velocity                80duration                -1repeat_delay_min        2repeat_delay_max        3}// Make em float downwardsaffector LinearForce{force_vector            0 -100 0force_application       add}// Give em some nice coloursaffector ColourInterpolator{time0                   0colour0                 1 1 0time1                   0.5colour1                 1 0 0time2                   0.9colour2                 0 0 1}
}

粒子以及粒子发射器属性配置，暂时不深究

mSceneMgr->getRootSceneNode()->attachObject(ps);
这里有个注意点，创建的所有的ParticleSystem都 attach 到了 RootSceneNode 上。
也就是说相同类型的 object 可以 attach 多个到同一节点上，也就意味着不能通过类型获取到 object。

[Sample_Shadows]

阴影

    if (mRoot->getRenderSystem()->getCapabilities()->hasCapability(RSC_HWSTENCIL)){mSceneMgr->setShadowTechnique(SHADOWTYPE_STENCIL_MODULATIVE);mCurrentShadowTechnique = SHADOWTYPE_STENCIL_MODULATIVE;}else{mSceneMgr->setShadowTechnique(SHADOWTYPE_TEXTURE_MODULATIVE);mCurrentShadowTechnique = SHADOWTYPE_TEXTURE_MODULATIVE;}

启用阴影

pPlaneEnt->setCastShadows(false);

设置是否产生阴影

mSceneMgr->setShadowTextureSettings(1024, 2);

设置基于纹理阴影的纹理属性

mSceneMgr->setShadowColour(ColourValue(0.5, 0.5, 0.5));

设置阴影颜色

mSceneMgr->setShadowTexturePixelFormat(PF_BYTE_RGBA);

设置基于纹理阴影的纹理像素格式

mSceneMgr->setShadowTextureCasterMaterial(themat);

设置阴影的材质

mSceneMgr->setShadowTextureSelfShadow(true);

设置是否启用基于纹理阴影的自阴影

[Sample_SkeletalAnimation]

骨骼动画

void setupContent()
{mShaderGenerator->invalidateScheme(Ogre::RTShader::ShaderGenerator::DEFAULT_SCHEME_NAME);mViewport->setMaterialScheme(RTShader::ShaderGenerator::DEFAULT_SCHEME_NAME);//Add the hardware skinning to the shader generator default render statemSrsHardwareSkinning = mShaderGenerator->createSubRenderState<RTShader::HardwareSkinning>();Ogre::RTShader::RenderState* renderState = mShaderGenerator->getRenderState(Ogre::RTShader::ShaderGenerator::DEFAULT_SCHEME_NAME);renderState->addTemplateSubRenderState(mSrsHardwareSkinning);
}

设置RTSystem属性，并启用硬件蒙皮

SkeletonPtr skel = static_pointer_cast<Skeleton>(SkeletonManager::getSingleton().load("jaiqua.skeleton",ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME));

加载骨骼

void setupModels()
{tweakSneakAnim();SceneNode* sn = NULL;Entity* ent = NULL;AnimationState* as = NULL;// make sure we can get the buffers for bbox calculationsMeshManager::getSingleton().load("jaiqua.mesh",ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY,HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY, true, true);auto& controllerMgr = ControllerManager::getSingleton();for (int i = 0; i < NUM_MODELS; i++){// create scene nodes for the models at regular angular intervalssn = mSceneMgr->getRootSceneNode()->createChildSceneNode();sn->yaw(Radian(Math::TWO_PI * (float)i / (float)NUM_MODELS));sn->translate(0, 0, -20, Node::TS_LOCAL);mModelNodes.push_back(sn);// create and attach a jaiqua entityent = mSceneMgr->createEntity("Jaiqua" + StringConverter::toString(i + 1), "jaiqua.mesh");ent->setMaterialName("jaiqua");sn->attachObject(ent);// enable the entity's sneaking animation at a random speed and loop it manually since translation is involvedas = ent->getAnimationState("Sneak");as->setEnabled(true);as->setLoop(false);controllerMgr.createController(controllerMgr.getFrameTimeSource(),AnimationStateControllerValue::create(as, true),ScaleControllerFunction::create(Math::RangeRandom(0.5, 1.5)));mAnimStates.push_back(as);}// create name and value for skinning modeStringVector names;names.push_back("Help");names.push_back("Skinning");names.push_back(mBoneBoundingBoxesItemName);// create a params panel to display the help and skinning modemStatusPanel = mTrayMgr->createParamsPanel(TL_TOPLEFT, "HelpMessage", 200, names);mStatusPanel->setParamValue("Help", "H / F1");String value = "Software";enableBoneBoundingBoxMode( false );  // update status panel entry// change the value if hardware skinning is enabledMaterialPtr entityMaterial = ent->getSubEntity(0)->getMaterial();if(entityMaterial){Technique* bestTechnique = entityMaterial->getBestTechnique();if(bestTechnique){Pass* pass = bestTechnique->getPass(0);if (pass && pass->hasVertexProgram() && pass->getVertexProgram()->isSkeletalAnimationIncluded()) {value = "Hardware";}}}mStatusPanel->setParamValue("Skinning", value);
}

tweakSneakAnim();
从代码可以看出来，动画是在.skeleton里的。调整骨骼动画，通常这一步不需要的，动画通常由动画师制作好，程序不需要去修改。不在此对这一操作深入。想深入，需要对骨骼动画有所了解。现在这个阶段，可以不看。
加载 mesh，确保可以获得用于bbox计算的缓冲区? 这个操作有点奇怪，先记住。HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY 硬件可写。硬件读写状态，从硬件读取数据会非常耗时。
创建动画控制器
```
auto& controllerMgr = ControllerManager::getSingleton();for (int i = 0; i < NUM_MODELS; i++)
{// create scene nodes for the models at regular angular intervalssn = mSceneMgr->getRootSceneNode()->createChildSceneNode();sn->yaw(Radian(Math::TWO_PI * (float)i / (float)NUM_MODELS));sn->translate(0, 0, -20, Node::TS_LOCAL);mModelNodes.push_back(sn);// create and attach a jaiqua entityent = mSceneMgr->createEntity("Jaiqua" + StringConverter::toString(i + 1), "jaiqua.mesh");ent->setMaterialName("jaiqua");sn->attachObject(ent);// enable the entity's sneaking animation at a random speed and loop it manually since translation is involvedas = ent->getAnimationState("Sneak");as->setEnabled(true);as->setLoop(false);controllerMgr.createController(controllerMgr.getFrameTimeSource(),AnimationStateControllerValue::create(as, true),ScaleControllerFunction::create(Math::RangeRandom(0.5, 1.5)));mAnimStates.push_back(as);
}
```
从上面的操作，只创建了一个mesh Entity，并没有绑定骨骼。然后就开始获取AnimationState。因为动画在skeleton里，能获取就说明绑定了，什么时候绑定的？
看看 Entity的代码，发现里面有 Mesh，Mesh里有skeleton，通过调试，发现，在 read Mesh的时候，有一个 M_MESH_SKELETON_LINK。也就是说在读取mesh的时候就绑定了骨骼。
- 调试过程
  找到Mesh 中有String mSkeletonName; SkeletonPtr mSkeleton; 之后，搜索 "mSkeletonName = " 赋值的地方，发现只有3个，每个地方下一个断点。调试，走到了 Mesh::setSkeletonName。查看调用堆栈，找到了 readMesh -> readSkeletonLink.
```
Controller<Real>* ControllerManager::createController(const ControllerValueRealPtr& src,const ControllerValueRealPtr& dest, const ControllerFunctionRealPtr& func);
```
创建动画控制器，该函数没有详细的说明。看看 Controller 类。这个类很简单，除了一个get,set，只有一个Updata
```
void update(void)
{if(mEnabled)mDest->setValue(mFunc->calculate(mSource->getValue()));
}
```
AnimationStateControllerValue::create(as, true)，通过entity获取到的AnimationState创建一个ControllerValue，该ControllerValue应该是绑定在该Entity的AnimationState上。
通过第三个参数func，与第一个参数计算当前的值，设置给Dest。
按照这个猜测，上面应该是获取ControllerManager最后一帧的时间，给获取到的AnimationState 随机加 [0.5 - 1.5] 的时间。

[Terrain]

地形

void setupContent()
{//! [terrain_create]mTerrainGroup = new Ogre::TerrainGroup(mSceneMgr, Ogre::Terrain::ALIGN_X_Z, TERRAIN_SIZE, TERRAIN_WORLD_SIZE);mTerrainGroup->setFilenameConvention(TERRAIN_FILE_PREFIX, TERRAIN_FILE_SUFFIX);mTerrainGroup->setOrigin(mTerrainPos);//! [terrain_create]configureTerrainDefaults(l);
#ifdef PAGING// Paging setupmPageManager = OGRE_NEW PageManager();// Since we're not loading any pages from .page files, we need a way just// to say we've loaded them without them actually being loadedmPageManager->setPageProvider(&mDummyPageProvider);mPageManager->addCamera(mCamera);mTerrainPaging = OGRE_NEW TerrainPaging(mPageManager);PagedWorld* world = mPageManager->createWorld();mTerrainPaging->createWorldSection(world, mTerrainGroup, 2000, 3000,TERRAIN_PAGE_MIN_X, TERRAIN_PAGE_MIN_Y,TERRAIN_PAGE_MAX_X, TERRAIN_PAGE_MAX_Y);
#else//! [define_loop]for (long x = TERRAIN_PAGE_MIN_X; x <= TERRAIN_PAGE_MAX_X; ++x)for (long y = TERRAIN_PAGE_MIN_Y; y <= TERRAIN_PAGE_MAX_Y; ++y)defineTerrain(x, y);// sync load since we want everything in place when we startmTerrainGroup->loadAllTerrains(true);//! [define_loop]
#endif
//! [init_blend]if (mTerrainsImported){for (const auto& ti : mTerrainGroup->getTerrainSlots()){initBlendMaps(ti.second->instance);}}mTerrainGroup->freeTemporaryResources();//! [init_blend]
}

先创建一个 TreeainGroup, 指定场景；对齐方式（指定一个平面），这里是XZ平面(水平面)；地形大小（顶点数）；在世界当中的大小

TerrainGroup::TerrainGroup(SceneManager* sm, Terrain::Alignment align, uint16 terrainSize, Real terrainWorldSize)
{}

mTerrainGroup->setFilenameConvention 设置命名约定？
mTerrainGroup->defineTerrain(x, y, 0.0f); 定义一个指定位置的固定高度

       String filename = mTerrainGroup->generateFilename(x, y);if (ResourceGroupManager::getSingleton().resourceExists(mTerrainGroup->getResourceGroup(), filename)){mTerrainGroup->defineTerrain(x, y);}else{Image img;getTerrainImage(x % 2 != 0, y % 2 != 0, img);mTerrainGroup->defineTerrain(x, y, &img);mTerrainsImported = true;}

按照定义生成一个dat文件

mTerrainGroup->loadAllTerrains(true);

导入地形，参数：是否异步。

从这两天对几个特定sample的学习，发现ogre在每个功能的基本使用上都挺简单的。

但是，随着时间的推移，一步步深入，越来越多的东西没有理解，都只能去按照注释简单的翻译，无法知道它的具体作用。终归为对ogre的实现都没有深入的去看。

毕竟这是一个学习过程。

所以到这里，把引擎最基本的功能(Material, Mesh, Scene, Light, Skybox, Particle, Skybox, Shadow, Animation， Terrain)稍微过了一遍之后，剩下的sample就暂时不看了，那些sample基本都是一些高级应用，看了也无法真正理解(说难听点，就是看也看不懂)。

接下来去看这些基本功能的代码，去分析理解代码。