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Public Member Functions | Static Public Member Functions | Static Public Attributes

# MPxFieldNode Class Reference
OpenMayaFX - API module for effects | Proxy classes

This reference page is linked to from the following overview topics: Parent class descriptions, Overview of example plug-ins.

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## Detailed Description

Base class for user defined fields.

MPxFieldNode allows the creation and manipulation of dependency graph nodes representing fields. This is the top level of a hierarchy of field node function sets. It permits manipulation of the attributes common to all types of fields.

Examples:

  dynExprField.h, and torusField.h.

`#include <MPxFieldNode.h>`

Inheritance diagram for MPxFieldNode:
[legend]

List of all members.

## Public Member Functions
| MPxFieldNode ()
| Class constructor.
virtual | ~MPxFieldNode ()
| The class destructor.
virtual MPxNode::Type | type () const
| This method returns the type of the node.
virtual MStatus | compute (const MPlug &plug, MDataBlock &dataBlock)
| This method should be overridden in user defined nodes.
virtual MStatus | getForceAtPoint (const MVectorArray &point, const MVectorArray &velocity, const MDoubleArray &mass, MVectorArray &force, double deltaTime)
| This method is not required to be overridden, it is only necessary for compatibility with the MFnField function set.
virtual MStatus | iconSizeAndOrigin (GLuint &width, GLuint &height, GLuint &xbo, GLuint &ybo)
| Define the size and the origin of the field's icon.
virtual MStatus | iconBitmap (GLubyte *bitmap)
| Define the bitmap for the field's icon.
virtual void | draw (M3dView &view, const MDagPath &path, M3dView::DisplayStyle style, M3dView::DisplayStatus)
| Overriding this method allows the drawing of custom geometry using standard OpenGL calls.
virtual double | falloffCurve (const double param, MStatus *ReturnStatus=NULL)
| Returns the falloff at the given parameter value.
virtual bool | isFalloffCurveConstantOne (MStatus *ReturnStatus=NULL)
| Returns true if the falloffCurve is a constant one (default) or false if not.
## Static Public Member Functions
static const char * | className ()
| Returns the name of this class.
## Static Public Attributes
static MObject | mMagnitude
| magnitude attribute Search for all occurrences
static MObject | mAttenuation
| attenuation attribute Search for all occurrences
static MObject | mMaxDistance
| maximum distance attribute Search for all occurrences
static MObject | mUseMaxDistance
| flag for maximum distance attribute Search for all occurrences
static MObject | mApplyPerVertex
| flag for per vertex attribute Search for all occurrences
static MObject | mInputData
| input attribute compound, multi Search for all occurrences
static MObject | mInputPositions
| child attribute, multi Search for all occurrences
static MObject | mInputVelocities
| child attribute, multi Search for all occurrences
static MObject | mInputMass
| child attribute, multi Search for all occurrences
static MObject | mDeltaTime
| child attribute Search for all occurrences
static MObject | mInputForce
| forces input attribute, multi Search for all occurrences
static MObject | mOutputForce
| forces output attribute, multi Search for all occurrences
static MObject | mOwnerCentroidX
| X component of mOwnerCentroid. Search for all occurrences
static MObject | mOwnerCentroidY
| Y component of mOwnerCentroid. Search for all occurrences
static MObject | mOwnerCentroidZ
| Z component of mOwnerCentroid. Search for all occurrences
static MObject | mOwnerCentroid
| owner centroid attribute Search for all occurrences
static MObject | mOwnerPosData
| owner position attribute, multi Search for all occurrences
static MObject | mOwnerVelData
| owner velocity attribute, multi Search for all occurrences
static MObject | mWorldMatrix
| world matrix attribute Search for all occurrences
static MObject | mInputPPData
| Attribute for input pp data from particleShape. Search for all occurrences
static MObject | mOwnerPPData
| Attribute for input pp data from owner particleShape. Search for all occurrences

## Member Function Documentation

MPxNode::Type type | ( |  | ) | const`[virtual]`

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This method returns the type of the node.

This method should not be overridden by the user. It will return MPxNode::kFieldNode.

Returns:
  The type of node

Status Codes:
  - MS::kSuccess The undo was successful
  - MS::kFailure This method is not undoable

Reimplemented from MPxNode.

MStatus compute | ( | const MPlug & | plug,
|  | MDataBlock & | dataBlock
| ) |  | `[virtual]`

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This method should be overridden in user defined nodes.

Recompute the given output based on the nodes inputs. The plug represents the data value that needs to be recomputed, and the data block holds the storage for all of the node's attributes.

The MDataBlock will provide smart handles for reading and writing this node's attribute values. Only these values should be used when performing computations.

When evaluating the dependency graph, Maya will first call the compute method for this node. If the plug that is provided to the compute indicates that that the attribute was defined by the Maya parent node, the compute method should return MS::kUnknownParameter. When this occurs, Maya will call the internal Maya node from which the user-defined node is derived to compute the plug's value.

This means that a user defined node does not need to be concerned with computing inherited output attributes. However, if desired, these can be safely recomputed by this method to change the behaviour of the node.

Parameters:

  [in] | plug | plug representing the attribute that needs to be recomputed
  [in] | dataBlock | data block containing storage for the node's attributes

Returns:
  Status code

Status Codes:
  - MS::kSuccess Compute was successful
  - MS::kFailure Compute failed

Reimplemented from MPxNode.

Examples:
  dynExprField.h, and torusField.h.

MStatus getForceAtPoint | ( | const MVectorArray & | point,
|  | const MVectorArray & | velocity,
|  | const MDoubleArray & | mass,
|  | MVectorArray & | force,
|  | double | deltaTime
| ) |  | `[virtual]`

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This method is not required to be overridden, it is only necessary for compatibility with the MFnField function set.

Compute the force of a field on an array of points, given their position, velocity, and mass.

This method uses MVectorArray to represent the positions of a point.

Parameters:

  [in] | point | array of positions for each point.
  [in] | velocity | array of velocities for each point. If the length of the velocity array is 0, a velocity of 0.0 is assumed for all the points. Note the velocity array is a requirement for the Air and Drag fields to compute forces.
  [in] | mass | array of mass values for each point. If the length of the mass array is 0, a mass of 1.0 is assumed for all the points.
  [out] | force | output array of forces applied to each point. If the length of the force array supplied is 0, the array is automatically resized. If the contents of the force array contains data, the computed force is added to the supplied data. This can be useful to accumulate forces of multiple fields.
  [in] | deltaTime | time increment in seconds

Returns:
  Status code

Status Codes:
  - MS::kSuccess The method was successful.
  - MS::kFailure An object error has occurred.

Examples:
  torusField.h.

MStatus iconSizeAndOrigin | ( | GLuint & | width,
|  | GLuint & | height,
|  | GLuint & | xbo,
|  | GLuint & | ybo
| ) |  | `[virtual]`

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Define the size and the origin of the field's icon.

Maya calls this method to determine the size and origin of the icon you wish your field to use. Overriding this method is optional.

The arguments have the same meaning as defined in OpenGL's glBitmap method.

Parameters:

  [out] | width | the width of the icon in pixels. It needs to be a multiple of 32 on windows and a multiple of 16 on any other platform.
  [out] | height | the height of the icon in pixels. It needs to be a multiple of 32 on windows and a multiple of 16 on any other platform.
  [out] | xbo | the origin of the icon in x direction.
  [out] | ybo | the origin of the icon in y direction.

Returns:
  Status code

Status Codes:
  - MS::kSuccess has custom icon.
  - MS::kFailure no custom icon.

Examples:
  dynExprField.h, and torusField.h.

MStatus iconBitmap | ( | GLubyte * | bitmap | ) | `[virtual]`

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Define the bitmap for the field's icon.

Maya calls this method to get the bitmap for the icon you wish your field to use. Overriding this method is optional, but if you do override it then you must also override iconSizeAndOrigin().

Parameters:

  [out] | bitmap | Bitmap for the field's icon, in the format expected by OpenGL's glBitmap() function. The storage pointed to by this parameter will have already been allocated by Maya according to the values returned by iconSizeAndOrigin().

Returns:
  Status code

Status Codes:
  - MS::kSuccess has custom icon.
  - MS::kFailure no custom icon.

Examples:
  dynExprField.h, and torusField.h.

void draw | ( | M3dView & | view,
|  | const MDagPath & | path,
|  | M3dView::DisplayStyle | style,
|  | M3dView::DisplayStatus |
| ) |  | `[virtual]`

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Overriding this method allows the drawing of custom geometry using standard OpenGL calls.

The OpenGL state should be left in the same state that it was in previously. The OpenGL routine glPushAttrib may be used to make this easier.

When this routine is called, the following conditions may be assumed:

- the correct transform matrix will be loaded for the node, so the geometry should be drawn in local space
- the correct default color will be set for wire frame drawing given the object's state (eg active, dormant, etc.)
- the object is not invisible or hidden
- if the object has a bounding box, then the bounding box is at least partially in the frustum

As a convenience, this draw method will also be used by OpenGL's selection mechanism to determine whether this object gets selected by a particular mouse event. The user does not need to write a separate selection routine.

Parameters:

  [in] | view | 3D view that is being drawn into
  [in] | path | to this node in the DAG
  [in] | style | style to draw object in

Examples:
  torusField.h.

double falloffCurve | ( | const double | param,
|  | MStatus * | ReturnStatus = `NULL`
| ) |  | `[virtual]`

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Returns the falloff at the given parameter value.

Parameters:

  [in] | param | Parameter value in the range [0.0, 1.0]
  [out] | ReturnStatus | Status code

Returns:
  The falloff value at the given the param.

Status Codes:
  - MS::kSuccess The method was successful.
  - MS::kFailure An object error has occurred.

bool isFalloffCurveConstantOne | ( | MStatus * | ReturnStatus = `NULL` | ) | `[virtual]`

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Returns true if the falloffCurve is a constant one (default) or false if not.

Parameters:

  [out] | ReturnStatus | Status code

Returns:
  true if the falloff curve is a constant one, false otherwise

Status Codes:
  - MS::kSuccess The method was successful.
  - MS::kFailure An object error has occurred.

const char * className | ( |  | ) | `[static]`

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Returns the name of this class.

Returns:
  The name of this class.

Reimplemented from MPxNode.

MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode
MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode MPxFieldNode