Transformations (C++)

group FnXFormUtil
class FnXFormUtil
#include <FnXFormUtil.h>

Provides a number of matrix transform utilities.

Matrix ordering matches the IMath convention:

FnAttribute::DoubleAttribute::array_type m = attr.getNearestSample(0.f);
Imath::M44d(m[0],  m[1],  m[2],  m[3],
            m[4],  m[5],  m[6],  m[7],
            m[8],  m[9],  m[10], m[11],
            m[12], m[13], m[14], m[15]);

or,

Imath::M44d( (double(*)[4]) m.data());

Public Static Functions

static std::pair<FnAttribute::DoubleAttribute, bool> CalcTransformMatrixAtTime(const FnAttribute::GroupAttribute &groupAttr, float time)
Parameters:

  • groupAttr – the FnAttribute::GroupAttribute to calculate the transform from.

  • time – the sample time at which to calculate the transform.

Returns:

(4x4 matrix attr, isAbsolute)

static std::pair<FnAttribute::DoubleAttribute, bool> CalcTransformMatrixAtTimes(const FnAttribute::GroupAttribute &groupAttr, const float *time, int numSamples)

Note

This will do xform interpolation as needed

Parameters:

  • groupAttr – FnAttribute::GroupAttribute containing the transform

  • time – sample time to calculate the transform at.

  • numSamples – number of time samples in time argument.

Returns:

return (4x4 matrix attr, isAbsolute)

static std::pair<FnAttribute::DoubleAttribute, bool> CalcTransformMatrixAtExistingTimes(const FnAttribute::GroupAttribute &groupAttr)

Note

This will do xform interpolation as needed

Parameters:

groupAttr – FnAttribute::GroupAttribute containing the transform

Returns:

return (4x4 matrix attr, isAbsolute)

static FnAttribute::DoubleAttribute CreateBoundsAttr(double xMin, double xMax, double yMin, double yMax, double zMin, double zMax)

Creates a bounds attribute with the following properties:

  • Tuple Size: 2

  • Length: 6,

  • Values: [xMin, xMax, yMin, yMax, zMin, zMax]

Parameters:

  • xMin – x min

  • xMax – x max

  • yMin – y min

  • yMax – y max

  • zMin – z max

  • zMax – z max

Returns:

an FnAttribute::DoubleAttribute instance.

static FnAttribute::DoubleAttribute MergeBounds(const FnAttribute::DoubleAttribute &boundAttr1, const FnAttribute::DoubleAttribute &boundAttr2)

Merge the two bounds attributes. If the boundsAttrs are multi-sampled, the output bounds will be up-sampled to the union of incoming sample times. Bounds data at sample-times not provided (but needed) will be synthesized using fillInterpSample()

Parameters:

  • boundAttr1 – first bounds attribute

  • boundAttr2 – second bounds attribute

Returns:

an instance of FnAttribute::DoubleAttribute containing the merged attributes.

static FnAttribute::DoubleAttribute CalcTransformedBoundsAtExistingTimes(const FnAttribute::Attribute &xform, const FnAttribute::DoubleAttribute &boundAttr)

Calculates a new bounds attribute after baking in the specified coordinate system.

The input transform can either be specified as a 4 x 4 FnAttribute::DoubleAttribute (matrix) or as an unbaked FnAttribute::GroupAttribute xform hierarchy. All other types will result in failure an invalid FnAttribute instance being returned.

The computed bounds attribute will contain time samples at the union of existing samples in the incoming xform and bound attributes.

If a user requires a non-multisampled bound attribute, this call should be followed up with a call to CollapseBoundTimeSamples()

Parameters:

  • xform – the coordinate system

  • boundAttr – the bound attribute to transform

Returns:

the new transformed bound attribute.

static FnAttribute::DoubleAttribute CollapseBoundsTimeSamples(const FnAttribute::DoubleAttribute &boundAttr)

Creates a single sampled attribute with the merged union of the mutlisampled input attribute.

Parameters:

boundAttr – Multisampled bound attribute

Returns:

Single sample merged union of the input bound attribute

static void InitXForm(FnAttribute::GroupBuilder &gb)

This group of function accepting FnAttribute::GroupBuilder references are used to simplify the construction of xform attributes.

For the specified GroupBuilder, set group inherit to false (as all xforms should be) and then do a shallow update with the specified attribute, if provided.

Note that if one’s command sequence utilizes only: 

Init(gb, ...)
PushXXX(...)
PushXXX(...)
PushXXX(...)
etc...

It’s OK to construct the group builder with the GroupBuilder::BuilderModeStrict argument.

Note

All children must be either instances of FnAttribute::DoubleAttributes or FnAttribute::GroupAttribute.

Parameters:

gb – An instance of FnAttribute::GroupBuilder

static void InitXForm(FnAttribute::GroupBuilder &gb, const FnAttribute::Attribute &xform)
static void PushRotateAttr(FnAttribute::GroupBuilder &gb, double angle, double x, double y, double z)
static FnAttribute::Attribute PushRotateAttr(const FnAttribute::Attribute &xform, double angle, double x, double y, double z)
static void PushTranslateAttr(FnAttribute::GroupBuilder &gb, double x, double y, double z)
static FnAttribute::Attribute PushTranslateAttr(const FnAttribute::Attribute &xform, double x, double y, double z)
static void PushScaleAttr(FnAttribute::GroupBuilder &gb, double x, double y, double z)
static FnAttribute::Attribute PushScaleAttr(const FnAttribute::Attribute &xform, double x, double y, double z)
static void PushMatrixAttr(FnAttribute::GroupBuilder &gb, const double *mtx16)
static FnAttribute::Attribute PushMatrixAttr(const FnAttribute::Attribute &xform, const double *mtx16)
static void PushOriginAttr(FnAttribute::GroupBuilder &gb)
static FnAttribute::Attribute PushOriginAttr(const FnAttribute::Attribute &xform)