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RtWing
[Basic Geometry]


Data Structures
struct   RtWingEdge
struct   RtWingFace
struct   RtWings
struct   RtWingVertex

Enumerations
enum   RtWingEdgeNeighborRelation { rtWINGEDGENULL = 0, rtWINGEDGECREASE, rtWINGEDGECONTINUOUS, rtWINGEDGEFORCEENUMSIZEINT = RWFORCEENUMSIZEINT }
enum   RtWingEdgePartitioning { rtWINGEDGEPARTITIONFAN = 0, rtWINGEDGEPARTITIONTACK, rtWINGEDGEPARTITIONEAR, rtWINGEDGEPARTITIONFORCEENUMSIZEINT = RWFORCEENUMSIZEINT }
enum   RtWingDecimationApproach { rtWINGEDGEDECIMATIONFEW = 0, rtWINGEDGEDECIMATIONSMALL, rtWINGEDGEDECIMATIONFORCEENUMSIZEINT = RWFORCEENUMSIZEINT }

Functions
RtWingFace *  RtWingFaceForAllEdges (RtWingFace *wingFace, RtWingEdgeCallBack callBack, void *userData)
RtWingFace *  RtWingFaceForAllFaces (RtWingFace *wingFace, RtWingFaceCallBack callBack, void *userData)
RtWingVertex *  RtWingVertexForAllEdges (RtWingVertex *wingVertex, RtWingEdgeCallBack callBack, void *userData)
RtWingVertex *  RtWingVertexForAllFaces (RtWingVertex *wingVertex, RtWingFaceCallBack callBack, void *userData)
void  RtWingEdgeDecimation (RtWings *wings, RtGCondGeometryList *geometryList)
void  RtWingConvexPartitioning (RtWings *wings, RtGCondGeometryList *geometryList, RtWingEdgePartitioning how)
void  RtWingPartitionPolygon (RtWings *wings, RtWingFace *face, RtGCondGeometryList *geometryList, RtWingEdgePartitioning how, RwInt32 ctr)
void  RtWingDestroy (RtWings *wings)
void  RtWingCreate (RtWings *wings, RtGCondGeometryList *geometryList)
void  RtWingUpdateInternalRepresentation (RtWingFace *face, RtWingEdge *edge, RtWingVertex *vertex)

Detailed Description

Winged edge/half-edge toolkit for RenderWare Graphics.

RtWing Toolkit Overview

Requirements

Overview

The functions in this toolkit implement, maintain and operate on polygons using a modified wing/half-edge data structure. The wing representation allows efficient querying (typically O(1)) and modification of geometry. (Internally, the geometry takes a RtGCond form.)

Enumeration Type Documentation

enum RtWingDecimationApproach
 

RtWingDecimationApproach

An enumeration that provides a value for edge decimation. Note, this is only a tie-breaker and should not be considered a high control priority.

Enumeration values:
rtWINGEDGEDECIMATIONFEW  Polygon is partitioned to reduce triangles
rtWINGEDGEDECIMATIONSMALL  Polygon is partitioned to reduce size
enum RtWingEdgeNeighborRelation
 

RtWingEdgeNeighborRelation

An enumeration that tags an edge with neighbor information to help queries and filter operations.

Enumeration values:
rtWINGEDGENULL  The edge has no neighbor
rtWINGEDGECREASE  The edge has a neighbor with mismatching attributes, e.g. face normal or material
rtWINGEDGECONTINUOUS  The edge has a neighbor with matching attributes
enum RtWingEdgePartitioning
 

RtWingEdgePartitioning

An enumeration that provides a value for the convex partitioner.

Enumeration values:
rtWINGEDGEPARTITIONFAN  Polygon is partitioned to help tri-fanning
rtWINGEDGEPARTITIONTACK  Polygon is partitioned to help tri-stripping
rtWINGEDGEPARTITIONEAR  Polygon is partitioned successfully if concave

Function Documentation

void RtWingConvexPartitioning (  RtWings *    wings,
RtGCondGeometryList *    geometryList,
RtWingEdgePartitioning    how
) 
 

RtWingConvexPartitioning partitions every polygon into triangles.

Note:
It is a critial assumption that the wings have enough unused edges and faces, identified by negative value fields, to store the addition geometry!
Parameters:
wings  a pointer to the occupied winged edge data structure
geometryList  a pointer to the list of geometry
how  one of rtWINGEDGEPARTITIONFAN, rtWINGEDGEPARTITIONTACK, rtWINGEDGEPARTITIONEAR, specifying whether partitioning is done by fanning, tacking, or by progressive 'ear' partitioning. This is a platform-specific preference.
See also:
RtWingPartitionPolygon
void RtWingCreate (  RtWings *    wings,
RtGCondGeometryList *    geometryList
) 
 

RtWingCreate takes a geometry list and turns it into a winged edge representation. The wings hold connectivity information as well as pointers to the original data in the geometry list.

Note:
Any operation on the wing edge representation actions the original data to be concurrently updated to reflect modification in the wing relations!
Parameters:
wings  a pointer to the unoccupied winged edge data structure
geometryList  a pointer to the list of geometry
void RtWingDestroy (  RtWings *    wings ) 
 

RtWingDestroy destroy the winged edge representation.

Parameters:
wings  a pointer to the unoccupied winged edge data structure
void RtWingEdgeDecimation (  RtWings *    wings,
RtGCondGeometryList *    geometryList
) 
 

RtWingEdgeDecimation performs a sophisticated edge decimation algorithm to reduced triangles into fewer, larger polygons, removing colinears and coplanars.

Note:
The geometry must have been fixed and filtered before this stage is called, as slivers and other special-case geometry can lead to improper decimation, and in worst-cases, non-terminating loops.
Parameters:
wings  a pointer to the occupied winged edge data structure
geometryList  a pointer to the list of geometry
See also:
RtWingPartitionPolygon , RtGCondRemoveCollapsedFacesAndUnusedVertices , RtGCondCullZeroAreaPolygons , RtGCondRemapVertices , RtGCondLimitUVs
RtWingFace* RtWingFaceForAllEdges (  RtWingFace *    wingFace,
RtWingEdgeCallBack    callBack,
void *    userData
) 
 

RtWingFaceForAllEdges iterates over all edges belonging to the given face. For each, it calls the given callback.

Parameters:
wingFace  a pointer to the face
callBack  the callback
userData  pointer to void for unknown-type userdata
Returns:
the face on success, otherwise NULL
See also:
RtWingFaceForAllFaces , RtWingVertexForAllEdges , RtWingVertexForAllFaces
RtWingFace* RtWingFaceForAllFaces (  RtWingFace *    wingFace,
RtWingFaceCallBack    callBack,
void *    userData
) 
 

RtWingFaceForAllFaces iterates over all faces neighboring the given face. For each, it calls the given callback.

Parameters:
wingFace  a pointer to the face
callBack  the callback
userData  pointer to void for unknown-type userdata
Returns:
the face on success, otherwise NULL
See also:
RtWingFaceForAllEdges , RtWingVertexForAllEdges , RtWingVertexForAllFaces
void RtWingPartitionPolygon (  RtWings *    wings,
RtWingFace *    face,
RtGCondGeometryList *    geometryList,
RtWingEdgePartitioning    how,
RwInt32    ctr
) 
 

RtWingPartitionPolygon partitions a polygon into triangles.

Note:
It is a critial assumption that the wings have enough unused edges and faces, identified by negative value fields, to store the addition geometry!
Parameters:
wings  a pointer to the occupied winged edge data structure
face  a pointer to the face to be partitioned
geometryList  a pointer to the list of geometry
how  one of rtWINGEDGEPARTITIONFAN, rtWINGEDGEPARTITIONTACK, rtWINGEDGEPARTITIONEAR, specifying whether partitioning is done by fanning, tacking, or by progressive 'ear' partitioning. This is a platform-specific preference.
ctr  an iteration counter that can be used to alter the effects of the partitioning approaches. Default zero.
See also:
RtWingConvexPartitioning
void RtWingUpdateInternalRepresentation (  RtWingFace *    face,
RtWingEdge *    edge,
RtWingVertex *    vertex
) 
 

RtWingUpdateInternalRepresentation recalculates the internal geometry (RtGCondPolygon) after edges have been reordered. It should be called after any modification to a face, to maintain a valid internal representation.

Parameters:
face  A pointer to the face.
edge  A pointer an edge of the face, this will be the first edge in the internal representation.
vertex  A pointer to a vertex of the face, usually face->vertex.
RtWingVertex* RtWingVertexForAllEdges (  RtWingVertex *    wingVertex,
RtWingEdgeCallBack    callBack,
void *    userData
) 
 

RtWingVertexForAllEdges iterates over all edges belonging to the given vertex. For each, it calls the given callback.

Parameters:
wingVertex  a pointer to the vertex
callBack  the callback
userData  pointer to void for unknown-type userdata
Returns:
the vertex on success, otherwise NULL
See also:
RtWingFaceForAllEdges , RtWingFaceForAllFaces , RtWingVertexForAllFaces
RtWingVertex* RtWingVertexForAllFaces (  RtWingVertex *    wingVertex,
RtWingFaceCallBack    callBack,
void *    userData
) 
 

RtWingVertexForAllFaces iterates over all faces belonging to the given vertex. For each, it calls the given callback.

Parameters:
wingVertex  a pointer to the vertex
callBack  the callback
userData  pointer to void for unknown-type userdata
Returns:
the vertex on success, otherwise NULL
See also:
RtWingFaceForAllEdges , RtWingFaceForAllFaces , RtWingVertexForAllEdges
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