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# circleNode.py

    #-
    # ==========================================================================
    # 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    # material (collectively the "Data") in these files contain unpublished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
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    # AND/OR ITS LICENSORS HAS BEEN ADVISED OF THE POSSIBILITY
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    #+

    #
    # Autodesk Script File
    # MODIFY THIS AT YOUR OWN RISK
    #
    # Creation Date:   27 September 2006
    #
    # Example Plugin: circleNode.py
    #
    # 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 which describes a sine curve as the input varies and
    # one that generates a cosine curve. If these two are hooked up to
    # the x and z translation attributes of an object the object will describe
    # move 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
    # plugin 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" which defines the size of the circular path, and
    # "frames" which 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 via the command "maya.cmds.setAttr" operating on the circle node
    # "circleNode1" created by the Python script. For example:
    #
    #   import maya.cmds as cmds
    #   cmds.setAttr("circleNode1.scale", #)
    #
    # will change the size of the circle and:
    #
    #   cmds.setAttr("circleNode1.frames", #)
    #
    # 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(0x87005)

    # 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.MStatus.kUnknownParameter

            return OpenMaya.MStatus.kSuccess

    # 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