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# Ogre::ProgressiveMesh Class Reference

This class reduces the complexity of the geometry it is given. More...

`#include <OgreProgressiveMesh.h>`

List of all members.

## Public Types
enum | VertexReductionQuota { VRQ_CONSTANT, VRQ_PROPORTIONAL }
| The way to derive the quota of vertices which are reduced at each LOD. More...
typedef std::vector < IndexData * > | LODFaceList
## Public Member Functions
| ProgressiveMesh (const VertexData *vertexData, const IndexData *indexData)
| Constructor, takes the geometry data and index buffer.
virtual | ~ProgressiveMesh ()
virtual void | addExtraVertexPositionBuffer (const VertexData *vertexData)
| Adds an extra vertex position buffer.
virtual void | build (ushort numLevels, LODFaceList *outList, VertexReductionQuota quota=VRQ_PROPORTIONAL, Real reductionValue=0.5f)
| Builds the progressive mesh with the specified number of levels.
## Protected Types
typedef std::vector < PMTriangle > | TriangleList
typedef std::vector < PMFaceVertex > | FaceVertexList
typedef std::vector < PMVertex > | CommonVertexList
typedef std::vector < Real > | WorstCostList
typedef std::vector < PMWorkingData > | WorkingDataList
## Protected Member Functions
void | addWorkingData (const VertexData *vertexData, const IndexData *indexData)
| Internal method for building PMWorkingData from geometry data.
void | initialiseEdgeCollapseCosts (void)
| Internal method for initialising the edge collapse costs.
Real | computeEdgeCollapseCost (PMVertex *src, PMVertex *dest)
| Internal calculation method for deriving a collapse cost from u to v.
Real | computeEdgeCostAtVertexForBuffer (WorkingDataList::iterator idata, size_t vertIndex)
| Internal method evaluates all collapse costs from this vertex and picks the lowest for a single buffer.
void | computeEdgeCostAtVertex (size_t vertIndex)
| Internal method evaluates all collapse costs from this vertex for every buffer and returns the worst.
void | computeAllCosts (void)
| Internal method to compute edge collapse costs for all buffers /.
size_t | getNextCollapser (void)
| Internal method for getting the index of next best vertex to collapse.
void | bakeNewLOD (IndexData *pData)
| Internal method builds an new LOD based on the current state.
void | collapse (PMVertex *collapser)
| Internal method, collapses vertex onto it's saved collapse target.
void | dumpContents (const String &log)
| Internal debugging method.
## Protected Attributes
const VertexData * | mpVertexData
const IndexData * | mpIndexData
size_t | mCurrNumIndexes
size_t | mNumCommonVertices
WorkingDataList | mWorkingData
| Multiple copies, 1 per vertex buffer.
WorstCostList | mWorstCosts
| The worst collapse cost from all vertex buffers for each vertex.
## Classes
class | PMFaceVertex
| A vertex as used by a face. More...
class | PMTriangle
| A triangle in the progressive mesh, holds extra info like face normal. More...
class | PMVertex
| A vertex in the progressive mesh, holds info like collapse cost etc. More...
struct | PMWorkingData
| Data used to calculate the collapse costs. More...

## Detailed Description

This class reduces the complexity of the geometry it is given.

This class is dedicated to reducing the number of triangles in a given mesh taking into account seams in both geometry and texture co-ordinates and meshes which have multiple frames.

  The primary use for this is generating LOD versions of Mesh objects, but it can be used by any geometry provider. The only limitation at the moment is that the provider uses a common vertex buffer for all LODs and one index buffer per LOD. Therefore at the moment this class can only handle indexed geometry.

  NB the interface of this class will certainly change when compiled vertex buffers are supported.

Definition at line 59 of file OgreProgressiveMesh.h.

## Member Typedef Documentation

typedef std::vector<IndexData*> Ogre::ProgressiveMesh::LODFaceList

Definition at line 72 of file OgreProgressiveMesh.h.

typedef std::vector<PMTriangle> Ogre::ProgressiveMesh::TriangleList`[protected]`

Definition at line 185 of file OgreProgressiveMesh.h.

typedef std::vector<PMFaceVertex> Ogre::ProgressiveMesh::FaceVertexList`[protected]`

Definition at line 186 of file OgreProgressiveMesh.h.

typedef std::vector<PMVertex> Ogre::ProgressiveMesh::CommonVertexList`[protected]`

Definition at line 187 of file OgreProgressiveMesh.h.

typedef std::vector<Real> Ogre::ProgressiveMesh::WorstCostList`[protected]`

Definition at line 188 of file OgreProgressiveMesh.h.

typedef std::vector<PMWorkingData> Ogre::ProgressiveMesh::WorkingDataList`[protected]`

Definition at line 198 of file OgreProgressiveMesh.h.

## Member Enumeration Documentation

enum Ogre::ProgressiveMesh::VertexReductionQuota

The way to derive the quota of vertices which are reduced at each LOD.

Enumerator:

  VRQ_CONSTANT | A set number of vertices are removed at each reduction.
  VRQ_PROPORTIONAL | A proportion of the remaining number of vertices are removed at each reduction.

Definition at line 64 of file OgreProgressiveMesh.h.

## Constructor & Destructor Documentation

Ogre::ProgressiveMesh::ProgressiveMesh | ( | const VertexData * | vertexData,
|  | const IndexData * | indexData |
| ) |  |  |

Constructor, takes the geometry data and index buffer.

Remarks:
  DO NOT pass write-only, unshadowed buffers to this method! They will not work. Pass only shadowed buffers, or better yet perform mesh reduction as an offline process using DefaultHardwareBufferManager to manage vertex buffers in system memory.

virtual Ogre::ProgressiveMesh::~ProgressiveMesh | ( |  | ) | `[virtual]`

## Member Function Documentation

virtual void Ogre::ProgressiveMesh::addExtraVertexPositionBuffer | ( | const VertexData * | vertexData | ) | `[virtual]`

Adds an extra vertex position buffer.

Remarks:
  As well as the main vertex buffer, the client of this class may add extra versions of the vertex buffer which will also be taken into account when the cost of simplifying the mesh is taken into account. This is because the cost of simplifying an animated mesh cannot be calculated from just the reference position, multiple positions needs to be assessed in order to find the best simplification option.

  DO NOT pass write-only, unshadowed buffers to this method! They will not work. Pass only shadowed buffers, or better yet perform mesh reduction as an offline process using DefaultHardwareBufferManager to manage vertex buffers in system memory.

Parameters:

  | buffer | Pointer to x/y/z buffer with vertex positions. The number of vertices must be the same as in the original GeometryData passed to the constructor.

virtual void Ogre::ProgressiveMesh::build | ( | ushort | numLevels,
|  | LODFaceList * | outList,
|  | VertexReductionQuota | quota = `VRQ_PROPORTIONAL`,
|  | Real | reductionValue = `0.5f` |
| ) |  |  | `[virtual]`

Builds the progressive mesh with the specified number of levels.

Parameters:

  | numLevels | The number of levels to include in the output excluding the full detail version.
  | outList | Pointer to a list of LOD geometry data which will be completed by the application. Each entry is a reduced form of the mesh, in decreasing order of detail.
  | quota | The way to derive the number of vertices removed at each LOD
  | reductionValue | Either the proportion of vertices to remove at each level, or a fixed number of vertices to remove at each level, depending on the value of quota

void Ogre::ProgressiveMesh::addWorkingData | ( | const VertexData * | vertexData,
|  | const IndexData * | indexData |
| ) |  |  | `[protected]`

Internal method for building PMWorkingData from geometry data.

void Ogre::ProgressiveMesh::initialiseEdgeCollapseCosts | ( | void |  | ) | `[protected]`

Internal method for initialising the edge collapse costs.

Real Ogre::ProgressiveMesh::computeEdgeCollapseCost | ( | PMVertex * | src,
|  | PMVertex * | dest |
| ) |  |  | `[protected]`

Internal calculation method for deriving a collapse cost from u to v.

Real Ogre::ProgressiveMesh::computeEdgeCostAtVertexForBuffer | ( | WorkingDataList::iterator | idata,
|  | size_t | vertIndex |
| ) |  |  | `[protected]`

Internal method evaluates all collapse costs from this vertex and picks the lowest for a single buffer.

void Ogre::ProgressiveMesh::computeEdgeCostAtVertex | ( | size_t | vertIndex | ) | `[protected]`

Internal method evaluates all collapse costs from this vertex for every buffer and returns the worst.

void Ogre::ProgressiveMesh::computeAllCosts | ( | void |  | ) | `[protected]`

Internal method to compute edge collapse costs for all buffers /.

size_t Ogre::ProgressiveMesh::getNextCollapser | ( | void |  | ) | `[protected]`

Internal method for getting the index of next best vertex to collapse.

void Ogre::ProgressiveMesh::bakeNewLOD | ( | IndexData * | pData | ) | `[protected]`

Internal method builds an new LOD based on the current state.

void Ogre::ProgressiveMesh::collapse | ( | PMVertex * | collapser | ) | `[protected]`

Internal method, collapses vertex onto it's saved collapse target.

Remarks:
  This updates the working triangle list to drop a triangle and recalculates the edge collapse costs around the collapse target. This also updates all the working vertex lists for the relevant buffer.

void Ogre::ProgressiveMesh::dumpContents | ( | const String & | log | ) | `[protected]`

Internal debugging method.

## Member Data Documentation

const VertexData* Ogre::ProgressiveMesh::mpVertexData`[protected]`

Definition at line 113 of file OgreProgressiveMesh.h.

const IndexData* Ogre::ProgressiveMesh::mpIndexData`[protected]`

Definition at line 114 of file OgreProgressiveMesh.h.

size_t Ogre::ProgressiveMesh::mCurrNumIndexes`[protected]`

Definition at line 116 of file OgreProgressiveMesh.h.

size_t Ogre::ProgressiveMesh::mNumCommonVertices`[protected]`

Definition at line 117 of file OgreProgressiveMesh.h.

WorkingDataList Ogre::ProgressiveMesh::mWorkingData`[protected]`

Multiple copies, 1 per vertex buffer.

Definition at line 200 of file OgreProgressiveMesh.h.

WorstCostList Ogre::ProgressiveMesh::mWorstCosts`[protected]`

The worst collapse cost from all vertex buffers for each vertex.

Definition at line 203 of file OgreProgressiveMesh.h.

The documentation for this class was generated from the following file:

- OgreProgressiveMesh.h

Copyright © 2000-2005 by The OGRE Team
This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License.
Last modified Mon Jun 16 12:51:55 2008