ogre学习笔记-Intermediate Tutorial 567

Intermediate Tutorial 5         Static Geometry

1、

Creating the Mesh

constfloat width =25;constfloat height =30;
Ogre::ManualObject mo("GrassObject");
 
Ogre::Vector3 vec(width/2,0,0);
Ogre::Quaternion rot;
rot.FromAngleAxis(Ogre::Degree(60), Ogre::Vector3::UNIT_Y);

mo.begin("Examples/GrassBlades", Ogre::RenderOperation::OT_TRIANGLE_LIST);
for(int i =0; i <3;++i){

mo.position(-vec.x, height,-vec.z);
        mo.textureCoord(0,0);
 
        mo.position(vec.x, height, vec.z);
        mo.textureCoord(1,0);
 
        mo.position(-vec.x,0,-vec.z);
        mo.textureCoord(0,1);
 
        mo.position(vec.x,0, vec.z);
        mo.textureCoord(1,1);

  

int offset = i *4;
        mo.triangle(offset, offset+3, offset+1);
        mo.triangle(offset, offset+2, offset+3);

vec = rot * vec;}
mo.end();

  

mo.convertToMesh("GrassBladesMesh");

// Do not add to the code!
        Ogre::MeshPtr        ptr = mo.convertToMesh("GrassBladesMesh");
        Ogre::MeshSerializer ser;
        ser.exportMesh(ptr.getPointer(),"grass.mesh");

2、

Adding Static Geometry

Ogre::Entity*grass = mSceneMgr->createEntity("grass","GrassBladesMesh");
        Ogre::StaticGeometry*sg = mSceneMgr->createStaticGeometry("GrassArea");
 
        constint size =375;constint amount =20;

  

sg->setRegionDimensions(Ogre::Vector3(size, size, size));
sg->setOrigin(Ogre::Vector3(-size/2,0,-size/2));

// Do not add to the project!
sg->setOrigin(Vector3(-size/2,-size/2,-size/2)+ Vector3(x, y, z));

for(int x =-size/2; x < size/2; x +=(size/amount))
{
    for(int z =-size/2; z < size/2; z +=(size/amount))
    {
                Ogre::Real r = size /(float)amount /2;
                Ogre::Vector3 pos(x + Ogre::Math::RangeRandom(-r, r),
                        0, z + Ogre::Math::RangeRandom(-r, r));
                Ogre::Vector3 scale(1, Ogre::Math::RangeRandom(0.9,1.1),1);
                Ogre::Quaternion orientation;
                orientation.FromAngleAxis(Ogre::Degree(Ogre::Math::RangeRandom(0,359)),
                         Ogre::Vector3::UNIT_Y);
 
                sg->addEntity(grass, pos, orientation, scale);
    }
}

sg->build();

3、其它：

Conclusion

Modifying the StaticGeometry Object

Once the StaticGeometry is created, you are not supposed to do too much with it, since that would mostly defeat the purpose. You can, however, do things like wave the grass with the wind. If you are interested in how to do this, take a look at the grass demo which comes with Ogre. The GrassListener::waveGrass function modifies the grass to perform a wave-like motion.

Advanced Object Batching

This is, of course, just the beginnings of object batching. You should use StaticGeometry any time you have objects that are grouped together and will not move. If you are trying to create something as intensive or as expansive as a forest or trying to add grass to a huge amount of terrain, you should take a look at one of the more advanced batching techniques, like thePagedGeometry Engine.

Intermediate Tutorial 6          Projective Decals 投影贴花

Frustums

mDecalFrustum = new Ogre::Frustum();
mProjectorNode = mSceneMgr->getRootSceneNode()->
                    createChildSceneNode("DecalProjectorNode");
mProjectorNode->attachObject(mDecalFrustum);
mProjectorNode->setPosition(0,5,0);

// Do not add this to the project
mDecalFrustum->setProjectionType(Ogre::PT_ORTHOGRAPHIC);
mDecalFrustum->setOrthoWindowHeight(100);

Modifying the Material

Ogre::MaterialPtr mat =(Ogre::MaterialPtr)Ogre::MaterialManager::getSingleton()
                        .getByName(matName);
Ogre::Pass*pass = mat->getTechnique(0)->createPass();

pass->setSceneBlending(Ogre::SBT_TRANSPARENT_ALPHA);
pass->setDepthBias(1);
pass->setLightingEnabled(false);

Ogre::TextureUnitState*texState = pass->createTextureUnitState("decal.png");
texState->setProjectiveTexturing(true, mDecalFrustum);
texState->setTextureAddressingMode(Ogre::TextureUnitState::TAM_CLAMP);
texState->setTextureFiltering(Ogre::FO_POINT, Ogre::FO_LINEAR, Ogre::FO_NONE);

Getting Rid of the Back Projection

Modifying the Projector

mFilterFrustum = new Ogre::Frustum();
mFilterFrustum->setProjectionType(Ogre::PT_ORTHOGRAPHIC);
Ogre::SceneNode*filterNode = mProjectorNode
                    ->createChildSceneNode("DecalFilterNode");
filterNode->attachObject(mFilterFrustum);
filterNode->setOrientation(Ogre::Quaternion(Ogre::Degree(90),Ogre::Vector3::UNIT_Y));

Modifying the Material

texState = pass->createTextureUnitState("decal_filter.png");
texState->setProjectiveTexturing(true, mFilterFrustum);
texState->setTextureAddressingMode(Ogre::TextureUnitState::TAM_CLAMP);
texState->setTextureFiltering(Ogre::TFO_NONE);

PS:有时间看看 Ogre::Frustum的相关函数的文档

Intermediate Tutorial 7          Render to texture (RTT)

1、创建纹理

Ogre::TexturePtr rtt_texture = Ogre::TextureManager::getSingleton()             .createManual("RttTex", 
 Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,  Ogre::TEX_TYPE_2D, 

mWindow->getWidth(), mWindow->getHeight(),0, Ogre::PF_R8G8B8, Ogre::TU_RENDERTARGET);

Ogre::RenderTexture*renderTexture = rtt_texture->getBuffer()->getRenderTarget();
 
renderTexture->addViewport(mCamera);
renderTexture->getViewport(0)->setClearEveryFrame(true);
renderTexture->getViewport(0)->setBackgroundColour(Ogre::ColourValue::Black);
renderTexture->getViewport(0)->setOverlaysEnabled(false);

renderTexture->update();

2、 Creating a material from scratch

Ogre::MaterialPtr renderMaterial = Ogre::MaterialManager::getSingleton()
                    .create("RttMat",
                    Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
renderMaterial->getTechnique(0)->getPass(0)->setLightingEnabled(false);
renderMaterial->getTechnique(0)->getPass(0)->createTextureUnitState("RttTex");

mMiniScreen->setMaterial("RttMat");

3、 Implementing a RenderTargetListener

继承 ：

public Ogre::RenderTargetListener

    virtual void preRenderTargetUpdate(const Ogre::RenderTargetEvent& evt);
    virtual void postRenderTargetUpdate(const Ogre::RenderTargetEvent& evt);

用于 在渲染纹理时，是小窗口隐藏，渲染好后再显示。