FLDget_node_data_veclen

Synopsis

get/set the number of subcomponents within one Node_Data component

int FLDget_node_data_veclen (
OMobj_id field,
int comp,
int *veclen);

int FLDset_node_data_veclen (
OMobj_id field,
int comp,
int veclen);

Description

These routines set and get the veclen (number of subcomponents) within a single Node_Data Data_Array component. For example, an RGB image's veclen would be 3.

This veclen can be used to calculate the second index into the values[nvals][veclen] data array.

Note: Do not use this for Grids. Use FLDget_nspace instead.

Note: veclens are often set as part of the omnibus FLDset_node_data_comp routine rather than with FLDset_node_data_veclen.

Parameters

OMobj_id field

The OMobj_id of a field that contains a Node_Data subobject.

int comp

An integer that specifies which component [0-n] of the Node_Data to use.

int *veclen
int veclen

In FLDget_node_data_veclen, *veclen is a pointer to an integer in which the veclen (number of subcomponents) will be returned.

In FLDset_node_data_veclen, veclen is an integer that sets the number of subcomponents.

veclens are numbered from 1-n. Whether you actually need to set veclen if veclen=1 depends on how your functions are coded. AVS/Express modules and functions that manipulate Node_Data either assume veclen=1 or require that veclen be set.

Example

This example, a fragment from modules/stream.c, shows streamlines retrieving the veclen from its input field object, then checking to see that it is at least two long:

• •      int FUNCstream (in, probe, order, forward, nseg, max_seg, min_vel,
  stream_comp, ribbons, rib_width, rib_angle, out)
  OMobj_id in, probe, out;
  float min_vel;
  int order, forward, nseg, max_seg, stream_comp, ribbons;
  float rib_width, rib_angle;
  ...
  {
  ...
  int ndim, size, veclen, n, nprobes, i;
  ...
  if (FLDget_node_data_veclen(in, stream_comp, &veclen)!= 1) {
  ERR_RETURN("Error getting veclen");
  }
  if (veclen < 2) {
  ERR_RETURN("cannot create streamlines for scalar");
  }
  ...

This example, a fragment from modules/rd_geom.c shows read geometry (which reads an AVS.geom format file) setting the output veclens of the normals, colors, uv, and uvw components:

• •      FUNCread_geom(filename, out)
  char *filename;
  OMobj_id out;
  {
  ...
  int
  geoms_to_field(num_geoms, geom, out)
  int num_geoms;
  GEOMobj *geom[];
  OMobj_id out;
  {
  ...
  int normal_comp = -1;
  int color_comp = -1;
  int uv_comp = -1, uvw_comp = -1;
  int ncomps= 0;
  ...
  if (normal_comp!= -1)
  {
  if (FLDset_node_data_id(out, normal_comp, GD_NORMAL_NODE_DATA_ID)!= 1)
  ERR_RETURN("Error setting comp id");
  if (FLDset_node_data_veclen(out, normal_comp, 3)!= 1)
  ERR_RETURN("Error setting comp veclen");
  }
  if (color_comp!= -1)
  {
  if (FLDset_node_data_id(out, color_comp, GD_COLOR_NODE_DATA_ID)!=1)
  ERR_RETURN("Error setting comp id");
  if (FLDset_node_data_veclen(out, color_comp, 3)!= 1)
  ERR_RETURN("Error setting comp veclen");
  }
  if (uv_comp!= -1)
  {
  if (FLDset_node_data_id(out, uv_comp, GD_UV_NODE_DATA_ID)!= 1)
  ERR_RETURN("Error setting comp id");
  if (FLDset_node_data_veclen(out, uv_comp, 2)!= 1)
  ERR_RETURN("Error setting comp veclen");
  }
  else if (uvw_comp!= -1)
  {
  if (FLDset_node_data_id(out, uvw_comp, GD_UV_NODE_DATA_ID)!= 1)
  ERR_RETURN("Error setting comp id");
  if (FLDset_node_data_veclen(out, uvw_comp, 3)!= 1)
  ERR_RETURN("Error setting comp veclen");
  }
  ...

Related routines

• •      FLDset_node_data_comp
• •      FLDget_nspace

 




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