History: Geometry Batching

Source of version: 14 (current)

This article intent is to give a practical code demonstrating the usage of [http://www.ogre3d.org/docs/manual/manual_49.html#SEC264|Hardware Buffers] and to be able to understand how the ((PagedGeometry Engine)) works aka [https://ogreaddons.svn.sourceforge.net/svnroot/ogreaddons/trunk/forests/|forests ogreaddon].
This tutorial is not meant to replace the [http://www.ogre3d.org/docs/manual/|Ogre Manual] but to give a practical code to toy with those classes.

As you will notice when you study the ((PagedGeometry)) engine the code below is a rip-off of the engine. I am greatly indebted to ((User:JohnJ|JohnJ)) without his code I wouldn't have grasped the concepts.

{img src="img/wiki_up/Forum_icon_question2.gif" alt="Forum icon question2.gif"} Please, use [http://www.ogre3d.org/forums/viewtopic.php?f=5&t=49028|this forum thread] to discuss problems, suggestions, etc.

{maketoc}

!!What is Geometry Batching?
Batching is the process of rendering sending massive amounts of ((mesh))es by accessing directly the graphics memory. For simple usage using ((Intermediate Tutorial 5|Static Geometry)) is ideal. However sometime you need to be able to use more fundamental methods (such as if you want to create a specific scene manager, have more control on the mesh detail based on ((-LOD)), ...). PagedGeometry is a good example.

!!Vertex & Buffer structure
__TODO__ A nice UML diagram :D

~tc~ BEGIN TABLE ~/tc~
|| Classes | Structure | Explanation
__VertexData__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1VertexData.html|api],%%%[http://www.ogre3d.org/docs/manual/manual_56.html#SEC272|manual]|VertexDeclaration* vertexDeclaration;%%%VertexBufferBinding* vertexBufferBinding; %%%size_t vertexStart; size_t vertexCount; %%%HardwareAnimationDataList hwAnimationDataList; %%%size_t hwAnimationItemUsed; |Collects vertex sources information.%%%''vertexCount'' is the number of vertices. ''hwAnimationDataList'' is usef for morph/pose animation.
__IndexData__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1IndexData.html|api],%%%[ manual]|size_t indexStart;%%%size_t indexCount; |''indexStart'': buffer position to start from during an Operation%%%''indexCount'': number of indexes to use from the buffer
__HardwareVertexBuffer__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1HardwareVertexBuffer.html|api],%%%[http://www.ogre3d.org/docs/manual/manual_55.html#SEC271|manual]|size_t mNumVertices; %%%size_t mVertexSize; |''mVertexSize'': size of a __single__ vertex in this buffer.
__HardwareIndexBuffer__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1HardwareIndexBuffer.html|api],%%%[http://www.ogre3d.org/docs/manual/manual_60.html#SEC279|manual]|enum IndexType;  %%%enum Usage;  %%%enum LockOptions; |...
__VertexBufferBinding__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1VertexBufferBinding.html|api],%%%[http://www.ogre3d.org/docs/manual/manual_58.html#SEC275|manual]| std::map<ushort, %%%HardwareVertexBufferSharedPtr>          VertexBufferBindingMap;  %%% VertexBufferBindingMap mBindingMap;  %%% ushort mHightIndex;|...
__VertexDeclaration__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1VertexDeclaration.html|api],%%%[http://www.ogre3d.org/docs/manual/manual_57.html#SEC273|manual]| typdef std::list<VertexElement>%%%VertexElementList;  %%% VertexElementList mElementList; |''VertexElement'' should be added in a precise order: see below.
__VertexElement__%%%[http://www.ogre3d.org/docs/api/html/classOgre_1_1VertexElement.html|api],%%%[ manual]| ushort mSource;  %%% size_t mOffset;  %%% VertexElementType mType;  %%% VertexElementSemantic mSemantics;  %%% ushort mIndex; %%%|todo||
~tc~ END OF TABLE ~/tc~

Some important points need to be taken in consideration when implementing [http://www.ogre3d.org/docs/api/html/classOgre_1_1VertexDeclaration.html#_details|VertexDeclaration]:
''You should be aware that the ordering and structure of the VertexDeclaration can be very important on DirectX with older cards,so if you want to maintain maximum compatibility with all render systems and all cards you should be careful to follow these rules:''

# ((-Vertex))Elements should be added in the following order, and the order of the elements within a shared buffer should be as follows: position, blending weights, normals, diffuse colours, specular colours, texture coordinates (in order, with no gaps)
# You must not have unused gaps in your buffers which are not referenced by any VertexElement
# You must not cause the buffer & offset settings of 2 VertexElements to overlap
!!Sample Code Usage
The code below will demonstrate how to make a [http://www.ogre3d.org/docs/api/html/classOgre_1_1MovableObject.html|MovableObject] which uses batched geometry. The code can be compiled as a static lib and used very simply. It will display a simple cube (no texture, no color).
Adding texture and color could be done in a second part.

{CODE(wrap="1", colors="c++")} Ogre::SceneNode* sn = sceneManager->getRootSceneNode()
    ->createChildSceneNode(Ogre::Vector3(0,0,0));
 
 Ogre::BatchedGeometry* object = 
    new Ogre::BatchedGeometry(sceneManager, sn);
 
 object->addObject(Ogre::Vector3::ZERO);
 object->build();
{CODE}
To add your own geometry you need to modify the code between :

{CODE(wrap="1", colors="c++")} // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
{CODE}
__Note__: The code is a bare minimum rip-off from the PagedGeometry Engine source also know as the [https://ogreaddons.svn.sourceforge.net/svnroot/ogreaddons/trunk/forests/|forests ogreaddons].

!!Code Structure
The code is only composed of two classes: BatchedGeometry and Batch.

''BatchedGeometry'' derives from a [http://www.ogre3d.org/docs/api/html/classOgre_1_1MovableObject.html|MovableObject] which means you can easily manipulate it in your scenes. Its purpose is to collect the various sub-part composing the geometry you want to batch.

An very important point to note is that batches should be grouped together to use the hardware at its fullest. This is the reason of the BatchedGeometry::getFormatString() method in the PagedGeometry Engine. I didn't implement this (yet) to keep the code... simple.

''Batch'' derives from a [http://www.ogre3d.org/docs/api/html/classOgre_1_1Renderable.html|Renderable]. This is the class that access the hardware buffer during the rendering phase.

!!Code Source
!!!OgreBatchedGeometry.h
{CODE(wrap="1", colors="c++")} #ifndef __OGE_BATCHEDGEOMETRY_H__
 #define __OGE_BATCHEDGEOMETRY_H__
 
 #include "OgreBatch.h"
 #include "OGRE/OgrePrerequisites.h"
 #include "OGRE/OgreMovableObject.h"
 
 namespace Ogre
 {
     /**
      */
     class BatchedGeometry: public MovableObject
     {
     private:
         Vector3 mCenter;
         Real mRadius;
         AxisAlignedBox mBounds;
         bool mBoundsUndefined;
     
         Real mMinDistanceSquared;
         // Why not using MovableObject::mBeyondFarDistance ?
         bool mWithinFarDistance; 
 
         /// Stores a list of Batchs, using a format string 
         /// (generated with getGeometryFormatString()) as the key value
         typedef std::map<String, Batch*> BatchMap; 
         BatchMap mBatchs;
 
         bool mIsBuilt;
 
         SceneManager* mSceneManager;
         SceneNode* mSceneNode;
         SceneNode* mParentSceneNode;
 
     public:
         typedef Ogre::MapIterator<BatchMap> BatchIterator;
 
     public:
         BatchedGeometry(SceneManager* mgr, SceneNode* parentSceneNode);
         virtual ~BatchedGeometry();
         
         // ---- Abstract method that need to be implemented ----
         const String& getMovableType() const {
             static String s = "BatchedGeometry"; return s; }
         const AxisAlignedBox& getBoundingBox() const { return mBounds; }
         Real getBoundingRadius() const { return mRadius; }
         const Vector3& getCenter() const { return mCenter; }
         const SceneNode* getSceneNode() const { return mSceneNode; }
 
         void _updateRenderQueue(RenderQueue* queue);
         void visitRenderables(Renderable::Visitor* visitor, bool debugRenderables) {}
 
         // ------------------------------------------------------
         void clear();
         void build();
 
         bool isVisible();
 
         /** Internal method to notify the object of the camera 
          *  to be used for the next rendering operation.
          */
         void _notifyCurrentCamera(Camera* cam);
 
         void addSelfToRenderQueue(RenderQueue* queue, uint8 group);
         inline Real const getMinDistanceSquared() const {
             return mMinDistanceSquared; }
 
         /// Convert from the given global position to the local 
         /// coordinate system of the parent scene node.
         Vector3 convertToLocal(const Vector3& globalVec) const;
 
         BatchIterator getBatchIterator() const;
 
         // The main method of the class!
         void addObject(const Vector3& position,
             const Quaternion& orientation = Quaternion::IDENTITY,
             const Vector3& scale = Vector3::UNIT_SCALE);
 
         ///Generate a format string that uniquely identifies 
         /// this material & vertex/index format
         // TODO String getFormatString(Ogre::SubEntity* ent);
     };
 }
 #endif
{CODE}
!!!OgreBatchedGeometry.cpp


{CODE(wrap="1", colors="c++")} #include "OgreBatchedGeometry.h"
 
 #include "OGRE/OgreCamera.h"
 #include "OGRE/OgreSceneNode.h"
 #include "OGRE/OgreSceneManager.h"
 
 namespace Ogre
 {
     //-----------------------------------------------------------------------------
     BatchedGeometry::BatchedGeometry(SceneManager* mgr, 
         SceneNode* parentSceneNode)
         : mBoundsUndefined(true),
           mMinDistanceSquared(0),
           mWithinFarDistance(false),
           mSceneManager(mgr),
           mSceneNode(0),
           mParentSceneNode(parentSceneNode)
     {
         clear();
         COUT("BatchedGeometry created")
     }
     //-----------------------------------------------------------------------------
     BatchedGeometry::~BatchedGeometry()
     {
         clear();
         COUT("BatchedGeometry destroyed")
     }
     //-----------------------------------------------------------------------------
     void BatchedGeometry::clear()
     {
         // Remove the batch from the scene
         if (mSceneNode)
         {
             mSceneNode->removeAllChildren();
             mSceneManager->destroySceneNode(mSceneNode->getName());
             mSceneNode = 0;
         }
 
         // Reset bounds information
         mBoundsUndefined = true;
         //mBounds = AxisAlignedBox::BOX_NULL; why not?
         mCenter = Vector3::ZERO;
         mRadius = 0;
 
         // Delete each batch
         for (BatchMap::iterator i = mBatchs.begin(); i != mBatchs.end(); ++i)
         {
             delete i->second;
         }
         mBatchs.clear();
 
         mIsBuilt = false;
     }
     //-----------------------------------------------------------------------------
     void BatchedGeometry::build()
     {
         if (mIsBuilt)
             OGRE_EXCEPT(Exception::ERR_DUPLICATE_ITEM, "Invalid call to build() - celestial object is already batched (call clear() first)", "BatchedGeometry::build()");
 
         if (mBatchs.size() != 0)
         {
             // Finish bounds information
             mCenter = mBounds.getCenter();
             //Center the bounding box
             mBounds.setMinimum(mBounds.getMinimum() - mCenter);
             mBounds.setMaximum(mBounds.getMaximum() - mCenter);
             //Calculate BB radius
             mRadius = mBounds.getMaximum().length(); 
 
             // Create scene node
             mSceneNode = mParentSceneNode->createChildSceneNode(mCenter);
 
             // Build each batch
             for (BatchMap::iterator i = mBatchs.begin(); i != mBatchs.end(); ++i)
             {
                 i->second->build();
             }
         }
 
         // Attach the batch to the scene node
         mSceneNode->attachObject(this);
 
         // Debug
         mSceneNode->showBoundingBox(true); // TODO param
 
         mIsBuilt = true;
     }
     //-----------------------------------------------------------------------------
     void BatchedGeometry::_updateRenderQueue(RenderQueue* queue)
     {
         if (isVisible())
         {
             // If appropriate ask each batch to add itself
             // to the render queue 
             for (BatchMap::iterator i = mBatchs.begin(); i != mBatchs.end(); ++i)
             {
                 i->second->addSelfToRenderQueue(queue, 
                     getRenderQueueGroup());
             }
         }
     }
     //-----------------------------------------------------------------------------
     bool BatchedGeometry::isVisible()
     {
         // mVisible is an MovableObject attribute
         return mVisible && mWithinFarDistance;
     }
     //-----------------------------------------------------------------------------
     void BatchedGeometry::_notifyCurrentCamera(Camera* cam)
     {
         if (getRenderingDistance() == 0)
         {
             mWithinFarDistance = true;
         }
         else
         {
             //Calculate camera distance
             Vector3 camVec = convertToLocal(
                 cam->getDerivedPosition()) - mCenter;
             Real centerDistanceSquared = camVec.squaredLength();
             mMinDistanceSquared = std::max(0.0f, 
                 centerDistanceSquared - (mRadius * mRadius));
 
             // Note: centerDistanceSquared measures the distance 
             // between the camera and the center of the Batch,
             // while minDistanceSquared measures the closest distance
             // between the camera and the closest edge of the
             // geometry's bounding sphere.
 
             //Determine whether the BatchedGeometry is within 
             / the far rendering distance
             mWithinFarDistance = 
                 mMinDistanceSquared <= Math::Sqr(getRenderingDistance());
         }
     }
     //-----------------------------------------------------------------------------
     Ogre::Vector3 BatchedGeometry::convertToLocal(const Vector3& globalVec) const
     {
         assert(mParentSceneNode);
         //Convert from the given global position to 
         // the local coordinate system of the parent scene node.
         return (mParentSceneNode->getOrientation().Inverse() * globalVec);
     }
     //-----------------------------------------------------------------------------
     BatchedGeometry::BatchIterator BatchedGeometry::getBatchIterator() const
     {
         return BatchIterator((BatchMap&)mBatchs);
     }
     //-----------------------------------------------------------------------------
     void BatchedGeometry::addObject(const Vector3& position, 
         const Quaternion& orientation, const Vector3& scale)
     {
         // Create geometry
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         String format = "aa"; // TODO = getFormatString(...)
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         Batch* batch;
 
         /* TODO
         BatchIterator iter = mBatchs.find(format);
         if (iter != mBatchs.end())
             batch = iter->second;
         else
         { */
             batch = new Batch(this);
             mBatchs.insert(std::pair<String, Batch*>(format, batch));
         // }
 
         // cf. PagedGeometry addSubEntity()
         batch->addSub( position, orientation, scale );
 
         // Update the bounding box
         Matrix4 mat(orientation);
         mat.setScale(scale);
         AxisAlignedBox entBounds;
 
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         // entBounds = ent->getBoundingBox();
         entBounds.setMinimum(Vector3(-100,-100,-100));
         entBounds.setMaximum(Vector3( 100, 100, 100));
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         entBounds.transform(mat);
 
         if (mBoundsUndefined)
         {
             mBounds.setMinimum(entBounds.getMinimum() + position);
             mBounds.setMaximum(entBounds.getMaximum() + position);
             mBoundsUndefined = false;
         }
         else
         {
             Vector3 min = mBounds.getMinimum();
             Vector3 max = mBounds.getMaximum();
             min.makeFloor(entBounds.getMinimum() + position);
             max.makeCeil(entBounds.getMaximum() + position);
             mBounds.setMinimum(min);
             mBounds.setMaximum(max);
         }
     }
     //-----------------------------------------------------------------------------
 }
{CODE}
!!!OgreBatch.h


{CODE(wrap="1", colors="c++")} #ifndef __OGRE_BATCH_H__
 #define __OGRE_BATCH_H__
 
 #include "OGRE/OgrePrerequisites.h"
 #include "OGRE/OgreMovableObject.h"
 #include "OGRE/OgreMaterialManager.h"
 
 #define COUT(x) std::cout << x << std::endl; 
 
 namespace Ogre
 {
     // Forward definition
     class BatchedGeometry;
 
     /*
      *
      */
     class Batch : public Renderable
     {
     private:
         bool mIsBuilt;
 
         VertexData* mVertexData;
         IndexData* mIndexData;
 
         BatchedGeometry* mParent;
         MaterialPtr mMaterial;
 
         // NOTE : This should be recalculated every frame
         Technique* mBestTechnique; 
 
         // Should those be part of a struct?
         Vector3 mPosition;
         Quaternion mOrientation;
         Vector3 mScale;
         ColourValue mColour;
 
     public:
         Batch(BatchedGeometry* parent); //, SubEntity* ent);
         ~Batch();
 
         void build();
         void clear();
 
         void setMaterial(MaterialPtr& mat) { mMaterial = mat; }
         void setMaterialName(const String& mat) { 
             mMaterial = MaterialManager::getSingleton().getByName(mat); }
         inline String getMaterialName() const {
             return mMaterial->getName(); }
         const MaterialPtr& getMaterial() const { return mMaterial; }
 
         Technique* getTechnique() const { return mBestTechnique; }
 
         void getWorldTransforms(Matrix4* xform) const;
         const Quaternion& getWorldOrientation() const;
         const Vector3& getWorldPosition() const;
 
         bool castsShadows() const;
         const LightList& getLights() const;
 
         void addSelfToRenderQueue(RenderQueue* queue, uint8 group);
         void getRenderOperation(RenderOperation& operation);
         Real getSquaredViewDepth(const Camera* cam) const;
 
         /**
         * This function is used to make a unique clone of materials,
         * since the materials will be modified by the batch system
         * (and it wouldn't be good to modify the original materials
         * that the user may be using somewhere else).
         */
         Material* getMaterialClone(Material* material);
 
         // cf. PagedGeometry method:
         // void BatchedGeometry::SubBatch::addSubEntity(
         //     SubEntity *ent,  ....);
         void addSub(const Vector3& position, 
             const Quaternion& orientation, const Vector3& scale, 
             const ColourValue& color = ColourValue::White);
     };
 }
 #endif
{CODE}
!!!OgreBatch.cpp


{CODE(wrap="1", colors="c++")} #include "OgreBatch.h"
 #include "OgreBatchedGeometry.h"
 
 #include "OGRE/OgreCamera.h"
 #include "OGRE/OgreSceneNode.h"
 #include "OGRE/OgreHardwareBufferManager.h"
 #include "OGRE/OgreTechnique.h"
 #include "OGRE/OgreRoot.h"
 #include "OGRE/OgreRenderSystem.h"
 #include "OGRE/OgreColourValue.h"
 
 namespace Ogre
 {
     //-----------------------------------------------------------------------------
     Batch::Batch(BatchedGeometry* parent) :
         mParent(parent)
     {
         mIsBuilt = false;
 
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         // See PagedGeometry BatchedGeometry::SubBatch::SubBatch()
         //    Material *origMat = 
         //      ((MaterialPtr)MaterialManager::getSingleton().getByName(
         //         ent->getMaterialName())).getPointer();
         //    mMaterial = 
         //       MaterialManager::getSingleton().getByName(
         //          getMaterialClone(origMat)->getName());
         //    mMaterial = MaterialManager::getSingleton().create(
         //       "Test/ColourTest", 
         //       ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
         mMaterial->getTechnique(0)->getPass(0)
             ->setVertexColourTracking(TVC_AMBIENT);
 
         mMaterial->getTechnique(0)->getPass(0)->setSpecular(0,0,0,1);
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         // See PagedGeometry to see how to clone PARTS of the entity data
         mVertexData = new VertexData();
         mIndexData = new IndexData();
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         // Reset vertex/index count
         mVertexData->vertexStart = 0;
         mVertexData->vertexCount = 0;
         mIndexData->indexStart = 0;
         mIndexData->indexCount = 0;
     }
     //-----------------------------------------------------------------------------
     Batch::~Batch()
     {
         clear();
         delete mVertexData;
         delete mIndexData;
     }
     //-----------------------------------------------------------------------------
     void Batch::addSelfToRenderQueue(RenderQueue* queue, uint8 group)
     {
         if (mIsBuilt)
         {
             // Update material technique based on camera distance
             assert(!mMaterial.isNull());
             mBestTechnique = mMaterial->getBestTechnique(
                 mMaterial->getLodIndexSquaredDepth(
                     mParent->getMinDistanceSquared()));
             queue->addRenderable(this, group);
         }
     }
     //-----------------------------------------------------------------------------
     bool Batch::castsShadows() const
     {
         return mParent->getCastShadows();
     }
     //-----------------------------------------------------------------------------
     void Batch::clear()
     {
         // If built, delete it
         if (mIsBuilt)
         {
                    //Delete buffers
                    mIndexData->indexBuffer.setNull();
                    mVertexData->vertexBufferBinding->unsetAllBindings();
 
                    // NOTE: If you are adding the elements each time
                    //       you must remove the previous one before
                    // mVertexData->vertexDeclaration->removeAllElements();
 
                    //Reset vertex/index count
                    mVertexData->vertexStart = 0;
                    mVertexData->vertexCount = 0;
                    mIndexData->indexStart = 0;
                    mIndexData->indexCount = 0;
         }
         mIsBuilt = false;
     }
     //-----------------------------------------------------------------------------
     Material* Batch::getMaterialClone(Material* material)
     {
         String name = material->getName() + "_Batch";
         MaterialPtr clone = 
             MaterialManager::getSingleton().getByName( name );
 
         if (clone.isNull())
             clone = material->clone(name);
         return clone.getPointer();
     }
     //-----------------------------------------------------------------------------
     void Batch::getRenderOperation(RenderOperation& operation)
     {
         operation.operationType = RenderOperation::OT_TRIANGLE_LIST;
         operation.srcRenderable = this;
         operation.useIndexes = true;
         operation.vertexData = mVertexData;
         operation.indexData = mIndexData;
 
         /* debug
         COUT(" 1 " << mVertexData->vertexCount)
         COUT(" 1 " << mVertexData->vertexCount)
         COUT(" 2 " << mVertexData->vertexDeclaration->getElementCount())
         COUT(" 3 " << mVertexData->vertexDeclaration->getVertexSize(0))
         COUT(" 4 " << mVertexData->vertexDeclaration->getElement(1)->getIndex())
         COUT(" 5 " << mVertexData->vertexDeclaration->getElement(1)->getSource())
         COUT(" 5 " << mIndexData->indexCount)
         COUT(" 6 " << mIndexData->indexBuffer->getIndexSize())
         COUT(" 7 " << mIndexData->indexBuffer->getNumIndexes())
         */
     }
     //-----------------------------------------------------------------------------
     Real Batch::getSquaredViewDepth(const Camera *camera) const
     {
         Vector3 pos = mParent->convertToLocal(
             camera->getDerivedPosition()) - mParent->getCenter();
 
         return pos.squaredLength();
     }
     //-----------------------------------------------------------------------------
     const LightList& Batch::getLights() const
     {
         return mParent->queryLights();
     }
     //-----------------------------------------------------------------------------
     void Batch::getWorldTransforms(Matrix4* xform) const
     {
         *xform = mParent->_getParentNodeFullTransform();
     }
     //-----------------------------------------------------------------------------
     const Quaternion& Batch::getWorldOrientation() const
     {
         return mParent->getSceneNode()->_getDerivedOrientation();
     }
     //-----------------------------------------------------------------------------
     const Vector3& Batch::getWorldPosition() const
     {
         return mParent->getSceneNode()->_getDerivedPosition();
     }
     //-----------------------------------------------------------------------------
     void Batch::addSub(const Vector3& position, const Quaternion& orientation, 
         const Vector3& scale, const ColourValue& color)
     {
         assert(!mIsBuilt);
         
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         // Use a geometry data struct to pass the data
         mVertexData->vertexCount = 8;
         mIndexData->indexCount = 36;
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         mPosition = position;
         mOrientation = orientation;
         mScale = scale;
         mColour = color;
 
         VertexElementType format = Root::getSingleton().getRenderSystem()
            ->getColourVertexElementType();
 
         switch (format)
         {
             case VET_COLOUR_ARGB:
                 std::swap(mColour.r, mColour.b);
                 break;
             case VET_COLOUR_ABGR:
                 break;
             default:
                 OGRE_EXCEPT(0, "Unknown RenderSystem color format", "Batch::addSub()");
                 break;
         }
     }
     //-----------------------------------------------------------------------------
     void Batch::build()
     {
         assert(!mIsBuilt);
 
         Vector3 batchCenter = mParent->getCenter();
 
         // See PagedGeometry::BatchedGeometry for how to set IT_32BIT
         // If I understand it correctly this is dependent 
         // on the number of vertices you want to batch
         HardwareIndexBuffer::IndexType destIndexType;
         destIndexType = HardwareIndexBuffer::IT_16BIT;
 
         // The vertex data at last
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         VertexBufferBinding *vertBinding =
             mVertexData->vertexBufferBinding;
         VertexDeclaration *vertDecl = mVertexData->vertexDeclaration;
 
         //Allocate & lock the vertex buffers
         HardwareVertexBufferSharedPtr buffer = 
             HardwareBufferManager::getSingleton()
             .createVertexBuffer(24, 8, 
                    HardwareBuffer::HBU_STATIC_WRITE_ONLY);
 
         vertBinding->setBinding(0, buffer);
 
         float* destPtr = static_cast<float*>
            (buffer->lock(HardwareBuffer::HBL_DISCARD));
 
         // See Ogre Samples/CubeMapping/include/CubeMapping.h !
         VertexDeclaration* dec = mVertexData->vertexDeclaration;
         size_t offset = 0;
         dec->addElement(0, offset, VET_FLOAT3, VES_POSITION);
         offset += VertexElement::getTypeSize(VET_FLOAT3);
         dec->addElement(0, offset, VET_FLOAT3, VES_NORMAL);
 
         const float sqrt13 = 0.577350269f;
 
         *destPtr++ = -100; *destPtr++ = 100; *destPtr++ = -100; 
         *destPtr++ = -sqrt13; *destPtr++ = sqrt13; *destPtr++ = -sqrt13;
         *destPtr++ = 100; *destPtr++ = 100; *destPtr++ = -100; 
         *destPtr++ = sqrt13; *destPtr++ = sqrt13; *destPtr++ = -sqrt13;
         *destPtr++ = 100; *destPtr++ = -100; *destPtr++ = -100; 
         *destPtr++ = sqrt13; *destPtr++ = -sqrt13; *destPtr++ = -sqrt13;
         *destPtr++ = -100; *destPtr++ = -100; *destPtr++ = -100; 
         *destPtr++ = -sqrt13; *destPtr++ = -sqrt13; *destPtr++ = -sqrt13;
         *destPtr++ = -100; *destPtr++ = 100; *destPtr++ = 100; 
         *destPtr++ = -sqrt13; *destPtr++ = sqrt13; *destPtr++ = sqrt13;
         *destPtr++ = 100; *destPtr++ = 100; *destPtr++ = 100; 
         *destPtr++ = sqrt13; *destPtr++ = sqrt13; *destPtr++ = sqrt13;
         *destPtr++ = 100; *destPtr++ = -100; *destPtr++ = 100; 
         *destPtr++ = sqrt13; *destPtr++ = -sqrt13; *destPtr++ = sqrt13;
         *destPtr++ = -100; *destPtr++ = -100; *destPtr++ = 100; 
         *destPtr++ = -sqrt13; *destPtr++ = -sqrt13; *destPtr++ = sqrt13;
 
 
         //Allocate the index buffer
         mIndexData->indexBuffer = HardwareBufferManager::getSingleton()
             .createIndexBuffer(HardwareIndexBuffer::IT_16BIT, 36,
                HardwareBuffer::HBU_STATIC_WRITE_ONLY);
 
         // As an alternative you can lock the buffer your self
         // and copy the data "manually"
         //uint16* indexBuffer16 = static_cast<uint16*>
         //   (mIndexData->indexBuffer->lock(HardwareBuffer::HBL_DISCARD));
 
         uint16 faces[36] = {
                 0,2,3,   0,1,2,   1,6,2,   1,5,6,
                 4,6,5,   4,7,6,   0,7,4,   0,3,7,
                 0,5,1,   0,4,5,   2,7,3,   2,6,7
         };
 
         //for (int i=0; i<36; ++i)
         //{
         //    *indexBuffer16++ = static_cast<uint16>(faces[i]);
         //}
         
         COUT(mIndexData->indexBuffer->getSizeInBytes());
         COUT(sizeof(faces));
         mIndexData->indexBuffer->writeData(
            0, mIndexData->indexBuffer->getSizeInBytes(), faces, true);
         // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
         //mIndexData->indexBuffer->unlock();
         buffer->unlock();
 
         mMaterial->load(); // TODO Not sure about this
         mIsBuilt = true;
     }
 //-----------------------------------------------------------------------------
 }
{CODE}
That's all folks.

--((User:Steven|Steven)) 04:32, 2 April 2009 (UTC)


---
Alias: (alias(Geometry_Batching))
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