Re: [Maya-Python] MPxLocatorNode and compute troubleshooting (with example code)
In the real plugin, I do declare "Author Name", "Plug Version", etc. The point of my example was to remove all that code (which Maya allows- it gets initialized to default values) to make it clear to myself, and others, what the problem is. Hence I cut out the normal try/except error stuff as well- cleaner examples are nice. *> then In your compute method there is no code to write some value on your output and also no setClean call. * Doesn't matter matter if I set it clean- compute never gets called in my example, so adding in setClean() or any other function call isn't relevant as far as I can tell- it never gets dirtied. *> Your node must also be connected to another node.* Does it always? There are nodes that update on attribute change without being connected. My first example does this. Change 'input' int attribute and compute() gets called, and 'output' updates. The dirty/clean stuff works a charm- I told Maya that attributeAffects(MyNode.aInput, MyNode. aOutput) and boom- input did indeed affect output as advertised! So saying it must be connected is untrue for this case of kInt or KFloat, both of which I've tested. Now if I do attributeAffects(MyNode.aInput, MyNode.aOutput) with aOutput being an MFnTypedAttribute, compute() never gets called. attributeAffects() does not work as described in the API docs (for this simple one node case) and I want to know why. I assume there is a logical, maybe even obvious, explanation; maybe it's an optimization on Maya's part because I haven't actually created an array of data for the aOutput attr yet? *> Do you have any prior experience with the API?* Mostly writing translators, compiling others' c++ nodes to work with my version of maya/environment. Just got into python api stuff though. *> Have you a basic understanding of the concept of hierarchy , connections , attributes and plug ?( DAG versus dependency nodes )* I would say that I definitely have at least basic understanding, but I came here for the people with the advanced understanding. :) Thanks again for your patience. I really want to resolve this simple example before I start porting my code to Maya nodes. -shawn On Friday, June 8, 2012 4:29:55 PM UTC-4, cedric bazillou wrote: > > first In your plugin declaration with the kDoubleArray output I would > rather correct those lines( things can be done in a lot of different ways, > this is how i do it ): > " > > def initializePlugin(mobject): > fnPlugin = omMPx.MFnPlugin(mobject) > fnPlugin.registerNode(nodeType, nodeId, nodeCreator, nodeInitializer) > " > by > " > kPluginNodeName = "spaceSwitch" #<-- replace by your plugin name > > kPluginNodeId = OpenMaya.MTypeId(your_Custom_ID_number here) > def initializePlugin(mobject): > mplugin = OpenMayaMPx.MFnPlugin(mobject, "AuthorName", "VersionNum", > "Any") > mplugin.registerNode( kPluginNodeName, kPluginNodeId, nodeCreator, > nodeInitializer, OpenMayaMPx.MPxNode.kDependNode)# <-- As you can see I use > the type of the node here a dependency node > " > > > then In your compute method there is no code to write some value on your > output and also no setClean call. > Your node must also be connected to another node. just few question bellow, > Are your example the complete code for your nodes? > Do you have an ascii maya file that can be used as an example? > Do you have any prior experience with the API? > Have you a basic understanding of the concept of hierarchy , connections , > attributes and plug ?( DAG versus dependency nodes ) > > Le vendredi 8 juin 2012 19:51:19 UTC+2, WhileRomeBurns a écrit : >> >> Thanks for the quick replies! So he basically tricks Maya into dirtying >> his plug in the draw method? Nice. So in my example, I would query the >> value of a third dummy attribute- something lighter weight than an array >> like a float or int and use that to force the eval? Can do! >> >> >> * > how about writing a node to compute your pointList and plug it to >> your locator that will only draw from * >> Absolutely the way to go, but I thought I would save time and test the >> idea in one node. But then nothing worked :) >> >> >> Additionally, I'm now fighting python just to call compute with * >> MFnTypedAttributes*. Two examples, slightly modified versions of >> Farsheed's skeleton code. The first one has MFnNumericAttribute as the >> output attribute and it calls the compute method as expected. The second >> one is bunk though and I cannot figure out why. Hmm. Take a look: >> >> nodeNumeric.py: >> http://pastebin.ubuntu.com/1030758/
Re: [Maya-Python] MPxLocatorNode and compute troubleshooting (with example code)
Thanks for the quick replies! So he basically tricks Maya into dirtying his plug in the draw method? Nice. So in my example, I would query the value of a third dummy attribute- something lighter weight than an array like a float or int and use that to force the eval? Can do! * > how about writing a node to compute your pointList and plug it to your locator that will only draw from * Absolutely the way to go, but I thought I would save time and test the idea in one node. But then nothing worked :) Additionally, I'm now fighting python just to call compute with * MFnTypedAttributes*. Two examples, slightly modified versions of Farsheed's skeleton code. The first one has MFnNumericAttribute as the output attribute and it calls the compute method as expected. The second one is bunk though and I cannot figure out why. Hmm. Take a look: nodeNumeric.py: http://pastebin.ubuntu.com/1030758/ Works a charm, compute gets called. nodeTyped.py http://pastebin.ubuntu.com/1030764/ Compute never gets called. Silently fails? Only changed the attr type to TypedAttr and kDoubleArray. Nada. Zilch. Zippo! Did I miss something obvious? Thanks. -shawn -- view archives: http://groups.google.com/group/python_inside_maya change your subscription settings: http://groups.google.com/group/python_inside_maya/subscribe
[Maya-Python] MPxLocatorNode and compute troubleshooting (with example code)
So basically I've got a python node called *simpleLocator* with an attribute called *pointCount *(type *kInt*) which is used to generate some random points. These points can be passed out as an array with the attribute *outPoints *(type *kDoubleArray *for this example). I've setup * attributeAffects*() so that outPoints depends on pointCount, so it should update if the user edits the number of points. This node needs to draw the points every frame with OpenGL as well, but only compute as needed. So far so good. Here's my example code (also attached to this post), stripped to the bare essentials and it almost works: http://hastebin.com/vixiyaruda.py When compute() is called though, plug never equals aOutPoints. Ever, ever. def compute( self, plug, data ): if plug == simpleLocator.aOutPoints: print( 'aOutPoints needs to be computed, but we never get here...' ) return om.MStatus.kSuccess else: return om.MStatus.kUnknownParameter What's normal practice here? Should I just query my simpleLocator.aPointCount every time draw is called and only call generatePoints() if the value of aPointCount has been changed? Should I derive from a node other than MPxLocator and implement my own draw method? Does MPxLocator behave different in C++? Any help, any insight would be greatly appreciated. Thanks. -shawn PS- If you're curious, the real node is generating blue noise for thousands of points and is fairly expensive to calculate. -- view archives: http://groups.google.com/group/python_inside_maya change your subscription settings: http://groups.google.com/group/python_inside_maya/subscribe """ import maya.cmds as mc pluginFile = 'SimpleLocator.py' pluginNode = 'simpleLocator' # unload if mc.pluginInfo( pluginFile, q=True, l=True ): # cleanup nodes first for node in mc.ls( type=pluginNode ): tf = mc.listRelatives( node, p=True )[0] print( 'Deleting node: %s' % node ) mc.delete( node ) mc.delete( tf ) print( 'Unloading plugin: %s' % pluginFile ) mc.unloadPlugin( pluginFile, force=True ) # load print( 'Loading plugin: %s' % pluginFile ) mc.loadPlugin( pluginFile, quiet=True ) print( 'Creating test node: %s' % pluginNode ) mc.createNode( pluginNode ) """ import sys import random import maya.OpenMaya as om import maya.OpenMayaMPx as mpx import maya.OpenMayaRender as mr nodeTypeName = 'simpleLocator' nodeTypeId = om.MTypeId(0x00070) glRenderer = mr.MHardwareRenderer.theRenderer() glFT = glRenderer.glFunctionTable() class simpleLocator( mpx.MPxLocatorNode ): # class variables aPointCount = om.MObject() aOutPoints = om.MObject() def __init__( self ): mpx.MPxLocatorNode.__init__( self ) self.pointCount = 10 self.points = [] self.generatePoints() def generatePoints( self ): random.seed( 1242) self.points = [] for i in xrange( self.pointCount ): self.points.append( (random.uniform(-5,5), random.uniform(-5,5), 0) ) def drawPoints( self ): glFT.glPointSize( 4 ) glFT.glBegin( mr.MGL_POINTS ) for p in self.points: glFT.glVertex3f( p[0], p[1], p[2] ) glFT.glEnd() def compute( self, plug, data ): if plug == simpleLocator.aOutPoints: print( 'aOutPoints needs to be computed.' ) return om.MStatus.kSuccess else: return om.MStatus.kUnknownParameter def draw( self, view, path, style, status ): view.beginGL() self.drawPoints() view.endGL() def nodeCreator(): return mpx.asMPxPtr( simpleLocator() ) def nodeInitializer(): nAttr = om.MFnNumericAttribute() tAttr = om.MFnTypedAttribute() simpleLocator.aPointCount = nAttr.create( 'pointCount', 'ptc', om.MFnNumericData.kInt ) nAttr.setKeyable( True ) nAttr.setDefault( 100 ) simpleLocator.addAttribute( simpleLocator.aPointCount ) simpleLocator.aOutPoints = tAttr.create( 'outPoints', 'opts', om.MFnData.kDoubleArray ) tAttr.setStorable( False ) tAttr.setWritable( False ) tAttr.setReadable( True ) simpleLocator.addAttribute( simpleLocator.aOutPoints ) simpleLocator.attributeAffects( simpleLocator.aPointCount, simpleLocator.aOutPoints ) return om.MStatus.kSuccess def initializePlugin( obj ): plugin = mpx.MFnPlugin( obj ) try: plugin.registerNode( nodeTypeName, nodeTypeId, nodeCreator, nodeInitializer, mpx.MPxNode.kLocatorNode ) except: sys.stderr.write( 'Failed to register node: %s' % nodeTypeName ) raise def uninitializePlugin( obj ): plugin = mpx.MFnPlugin( obj ) try: plugin.deregisterNode( nodeTypeId ) except: sys.stderr.write( 'Failed to deregister node: %s' % nodeTypeName ) raise
