python/api1/py1CircleNode.py

from __future__ import division
#-
# ==========================================================================
# Copyright (C) 1995 - 2006 Autodesk, Inc. and/or its licensors.  All 
# rights reserved.
#
# The coded instructions, statements, computer programs, and/or related 
# material (collectively the "Data") in these files contain unpublished 
# information proprietary to Autodesk, Inc. ("Autodesk") and/or its 
# licensors, which is protected by U.S. and Canadian federal copyright 
# law and by international treaties.
#
# The Data is provided for use exclusively by You. You have the right 
# to use, modify, and incorporate this Data into other products for 
# purposes authorized by the Autodesk software license agreement, 
# without fee.
#
# The copyright notices in the Software and this entire statement, 
# including the above license grant, this restriction and the 
# following disclaimer, must be included in all copies of the 
# Software, in whole or in part, and all derivative works of 
# the Software, unless such copies or derivative works are solely 
# in the form of machine-executable object code generated by a 
# source language processor.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND. 
# AUTODESK DOES NOT MAKE AND HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED 
# WARRANTIES INCLUDING, BUT NOT LIMITED TO, THE WARRANTIES OF 
# NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR 
# PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE, OR 
# TRADE PRACTICE. IN NO EVENT WILL AUTODESK AND/OR ITS LICENSORS 
# BE LIABLE FOR ANY LOST REVENUES, DATA, OR PROFITS, OR SPECIAL, 
# DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES, EVEN IF AUTODESK 
# AND/OR ITS LICENSORS HAS BEEN ADVISED OF THE POSSIBILITY 
# OR PROBABILITY OF SUCH DAMAGES.
#
# ==========================================================================
#+

#
# Autodesk Script File
# MODIFY THIS AT YOUR OWN RISK
#
# Creation Date:   27 September 2006
#

########################################################################
# DESCRIPTION:
#
# Produces the dependency graph node "spCircle".  
#
# This plug-in is an example of a user-defined dependency graph node.
# It takes a number as input (such as time) and generates two output
# numbers. One number describes a sine curve as the input varies and
# the other number generates a cosine curve. If these two are hooked up to
# the x and z translation attributes of an object, the object will describe
# movement through a circle in the xz plane as time is changed.
#
# See circleNodeTest.py for an example of how to use the node. The script will
# create a new "Circle" menu with a single item. Selecting this will build
# a simple model (a sphere which follows a circular path), which can be played back
# by clicking on the "play" icon on the time slider.  
# Note: The circleNode plug-in needs to be loaded before the "Circle" menu item
# can be executed properly.
#
# The node has two additional attributes, which can be changed to affect
# the animation: "scale" that defines the size of the circular path and
# "frames" that defines the number of frames required for a complete circuit
# of the path. Either of these can be hooked up to other nodes, or can
# be simply set using the command "maya.cmds.setAttr" operating on the circle node
# "circleNode1" created by the Python script. For example:
#
#   import maya.cmds as cmds
#   cmds.createNode("spCircle", name="circleNode1")
#   cmds.setAttr("circleNode1.scale", 3)
#   # will change the size of the circle
#   cmds.setAttr("circleNode1.frames", 5)
#   # will cause objects to complete a circle in indicated number of frames.
#
########################################################################

import math, sys

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

kPluginNodeTypeName = "spCircle"
kPluginNodeId = OpenMaya.MTypeId(0x0008004c)


# Node definition
class circle(OpenMayaMPx.MPxNode):
    # class variables
    aInput = OpenMaya.MObject()
    aScale = OpenMaya.MObject()
    aFrames = OpenMaya.MObject()
    aSOutput = OpenMaya.MObject()
    aCOutput = OpenMaya.MObject()


    def __init__(self):
        OpenMayaMPx.MPxNode.__init__(self)


    def compute(self, plug, data):
        # Check that the requested recompute is one of the output values
        if (plug == circle.aSOutput or plug == circle.aCOutput):
            # Read the input values
            inputData = data.inputValue(circle.aInput)
            scaleData = data.inputValue(circle.aScale)
            framesData = data.inputValue(circle.aFrames)

            # Compute the output values
            currentFrame = inputData.asFloat()
            scaleFactor  = scaleData.asFloat()
            framesPerCircle = framesData.asFloat()
            angle = 6.2831853 * (currentFrame/framesPerCircle)
            sinResult = math.sin(angle) * scaleFactor
            cosResult = math.cos(angle) * scaleFactor

            # Store them on the output plugs
            sinHandle = data.outputValue(circle.aSOutput)
            cosHandle = data.outputValue(circle.aCOutput)
            sinHandle.setFloat(sinResult)
            cosHandle.setFloat(cosResult)
            data.setClean(plug)
        else:
            return OpenMaya.kUnknownParameter

        return None


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


# initializer
def nodeInitializer():
    nAttr = OpenMaya.MFnNumericAttribute()

    # Setup the input attributes
    circle.aInput = nAttr.create("input", "in", OpenMaya.MFnNumericData.kFloat, 0.0)
    nAttr.setStorable(True)

    circle.aScale = nAttr.create("scale", "sc", OpenMaya.MFnNumericData.kFloat, 10.0)
    nAttr.setStorable(True)

    circle.aFrames = nAttr.create("frames", "fr", OpenMaya.MFnNumericData.kFloat, 48.0)
    nAttr.setStorable(True)

    # Setup the output attributes
    circle.aSOutput = nAttr.create("sineOutput", "so", OpenMaya.MFnNumericData.kFloat, 0.0)
    nAttr.setWritable(False)
    nAttr.setStorable(False)

    circle.aCOutput = nAttr.create("cosineOutput", "co", OpenMaya.MFnNumericData.kFloat, 0.0,)
    nAttr.setWritable(False)
    nAttr.setStorable(False)

    # Add the attributes to the node
    circle.addAttribute(circle.aInput)
    circle.addAttribute(circle.aScale)
    circle.addAttribute(circle.aFrames)
    circle.addAttribute(circle.aSOutput)
    circle.addAttribute(circle.aCOutput)

    # Set the attribute dependencies
    circle.attributeAffects(circle.aInput, circle.aSOutput)
    circle.attributeAffects(circle.aInput, circle.aCOutput)
    circle.attributeAffects(circle.aScale, circle.aSOutput)
    circle.attributeAffects(circle.aScale, circle.aCOutput)
    circle.attributeAffects(circle.aFrames, circle.aSOutput)
    circle.attributeAffects(circle.aFrames, circle.aCOutput)


# initialize the script plug-in
def initializePlugin(mobject):
    mplugin = OpenMayaMPx.MFnPlugin(mobject, "Autodesk", "1.0", "Any")
    try:
        mplugin.registerNode( kPluginNodeTypeName, kPluginNodeId, 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( kPluginNodeId )
    except:
        sys.stderr.write( "Failed to deregister node: %s" % kPluginNodeTypeName )
        raise