scripted/sineNode.py

#-
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#+

########################################################################
# DESCRIPTION:
#
# Produces the dependency graph node "spSineNode".
#
# This plug-in is an example of a user-defined dependency graph node. It takes
# a single input value and outputs the sine of this multiplied by 10. It is a
# simple example of creating a procedural animation. The number describes a sine
# curve as the input varies. If this number is hooked up to the x translation
# attributes of an object, the object will describe the movement along the x-axis
# as time changes. 
#
########################################################################

# import maya
# maya.cmds.loadPlugin("sineNode.py")
# maya.cmds.createNode("spSineNode")
# maya.cmds.getAttr("spSineNode1.output")

import math, sys

import maya.OpenMaya as OpenMaya
import maya.OpenMayaMPx as OpenMayaMPx

kPluginNodeTypeName = "spSineNode"

sineNodeId = OpenMaya.MTypeId(0x87000)

# Node definition
class sineNode(OpenMayaMPx.MPxNode):
    # class variables
    input = OpenMaya.MObject()
    output = OpenMaya.MObject()
    def __init__(self):
        OpenMayaMPx.MPxNode.__init__(self)
    def compute(self,plug,dataBlock):
        if ( plug == sineNode.output ):
            dataHandle = dataBlock.inputValue( sineNode.input )
            
            inputFloat = dataHandle.asFloat()
            result = math.sin( inputFloat ) * 10.0
            outputHandle = dataBlock.outputValue( sineNode.output )
            outputHandle.setFloat( result )
            dataBlock.setClean( plug )

        return OpenMaya.kUnknownParameter

# creator
def nodeCreator():
    return OpenMayaMPx.asMPxPtr( sineNode() )

# initializer
def nodeInitializer():
    # input
    nAttr = OpenMaya.MFnNumericAttribute()
    sineNode.input = nAttr.create( "input", "in", OpenMaya.MFnNumericData.kFloat, 0.0 )
    nAttr.setStorable(1)
    # output
    nAttr = OpenMaya.MFnNumericAttribute()
    sineNode.output = nAttr.create( "output", "out", OpenMaya.MFnNumericData.kFloat, 0.0 )
    nAttr.setStorable(1)
    nAttr.setWritable(1)
    # add attributes
    sineNode.addAttribute( sineNode.input )
    sineNode.addAttribute( sineNode.output )
    sineNode.attributeAffects( sineNode.input, sineNode.output )
    
# initialize the script plug-in
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.registerNode( kPluginNodeTypeName, sineNodeId, nodeCreator, nodeInitializer )
    except:
        sys.stderr.write( "Failed to register node: %s" % kPluginNodeTypeName )
        raise

# uninitialize the script plug-in
def uninitializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject)
    try:
        mplugin.deregisterNode( sineNodeId )
    except:
        sys.stderr.write( "Failed to deregister node: %s" % kPluginNodeTypeName )
        raise