OpenIGTLink/ProtocolV2/Type/PolyData

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Summary

POLYDATA is used to transfer 3D polygonal data. The message format is designed based on the POLY DATA format defined in VTK file format and equivalent to VTK's vtkPolyData class. The message also supports dataset attribute field in VTK, including scalars, calar_scalars, vectors, vectors, normals, texture coordinates and tensor, but not lookup table.

Message Types

POLYDATA

Data	Type	Description
NPOINTS	uint32	Number of points
NVERTICES	uint32	Number of vertices
SIZE_VERTICES	uint32	Total size of vertices data
NLINES	uint32	Number of lines
SIZE_LINES	uint32	Total size of line data
NPOLYGONS	uint32	Number of polygons
SIZE_POLYGONS	uint32	Total size of polygon data
NTRIANGLE_STRIPS	uint32	Number of triangle strips
SIZE_TRIANGLE_STRIPS	uint32	Total size of triangle strips data
NATTRIBUTES	uint32	Number of dataset attributes
POINTS	float32 * NPOINTS * 3	Coordinates of points (P0x, P0y, P0z, P1x, P1y, P1z, ... P(n-1)x, P(n-1)y, P(n-1)z
VERTICES	uint32 * ((NPOINTS_0+1) + (NPOINTS_1+1) + (NPOINTS_(N-1)+1))	array of vertices ((NPOINTS_0, index_0_0, index_0_1, ....), (NPOINTS_1, index_1_0, index_1_1, ....), ..., (NPOINTS_(N-1), index_(N-1)_0, index_(N-1)_1, ....))
LINES	uint32 * ((NPOINTS_0+1) + (NPOINTS_1+1) + (NPOINTS_(N-1)+1))	array of vertices ((NPOINTS_0, index_0_0, index_0_1, ....), (NPOINTS_1, index_1_0, index_1_1, ....), ..., (NPOINTS_(N-1), index_(N-1)_0, index_(N-1)_1, ....))
POLYGONS	uint32 * ((NPOINTS_0+1) + (NPOINTS_1+1) + (NPOINTS_(N-1)+1))	array of vertices ((NPOINTS_0, index_0_0, index_0_1, ....), (NPOINTS_1, index_1_0, index_1_1, ....), ..., (NPOINTS_(N-1), index_(N-1)_0, index_(N-1)_1, ....))
TRIANGLE_STRIPS	uint32 * ((NPOINTS_0+1) + (NPOINTS_1+1) + (NPOINTS_(N-1)+1))	array of vertices ((NPOINTS_0, index_0_0, index_0_1, ....), (NPOINTS_1, index_1_0, index_1_1, ....), ..., (NPOINTS_(N-1), index_(N-1)_0, index_(N-1)_1, ....))
TYPE_ATTRIBUTE0	uint16	Type of dataset attribute 0 (including number of components for scalar type)
NATTRIBUTE0	uint32	Number of data for attribute 0
TYPE_ATTRIBUTE1	uint16	Type of dataset attribute 1 (including number of components for scalar type)
NATTRIBUTE1	uint32	Number of data for attribute1
...	...	...
TYPE_ATTRIBUTE(NATTRIBUTES-1)	uint16	Type of dataset attribute 1 (including number of components for scalar type)
NATTRIBUTE(NATTRIBUTES-1)	uint32	Number of data for attribute2
NAME_ATTRIBUTE0	char * (name length)	Name of attribute 0
(null)	char	(null)
NAME_ATTRIBUTE1	char * (name length)	Name of attribute 1
(null)	char	(null)
...	...	...
NAME_ATTRIBUTE(NATTRIBUTES-1)	char * (name length)	Name of attribute (NATTRIBUTES-1)
(null)	char	(null)
(Padding)	char or 0	Padding (inserted if (NAMESIZE_ATTRIBUTE0+1+NAMESIZE_ATTRIBUTE1+1+...NAMESIZE_ATTRIBUTE(NATTRIBUTES-1)+1) % 2 == 1)
ATTRIBUTE0	SIZE_ATTRIBUTE0 * (number of components) * (float32)	Actual attribute data
ATTRIBUTE1	NATTRIBUTE0 * (number of components) * (float32)	Actual attribute data
...	...	...
ATTRIBUTE(NATTRIBUTES-1)	NATTRIBUTE(NATTRIBUTES-1) * (number of components) * (float32)	Actual attribute data

2/17 change the order of the field to make implementation easier

• Values for TYPE_ATTRIBUTE (16-bit)
  • 0-7 bit: Attribute Type:
    • 0x00: POINT_DATA / Scalars
    • 0x01: POINT_DATA / Vectors
    • 0x02: POINT_DATA / Normals
    • 0x03: POINT_DATA / Tensors
    • 0x04: POINT_DATA / RGBA
    • 0x10: CELL_DATA / Scalars
    • 0x11: CELL_DATA / Vectors
    • 0x12: CELL_DATA / Normals
    • 0x13: CELL_DATA / Tensors
    • 0x14: CELL_DATA / RGBA
  • 8-15 bit: Number of components -- must be 3 for Vectors and Normal, 9 for Tensor, 4 for RGBA.

• Maximum length for attribute name is 255
• If there are a pair of scalar and RGBA data with the same name and type (either POINT or CELL), those are used as scalar values and a look up table.
  • elements in RGBA data must be in the rage of [0.0, 1.0]

GET_POLYDATA

Data

Type

Description

STT_POLYDATA

Data

Type

Description

or

Data	Type	Description
RESOL	uint64	Minimum interval between message (ns). Same format as TimeStamp

STP_POLYDATA

Data

Type

Description

RTS_POLYDATA

Data	Type	Description
Status	8 bit unsigned	0: Success 1: Error

Implementations

The NDARRAY message type is implemented in the following source code.

Contributors

Junichi Tokuda