Implement animCubeNode.py

examples/animCubeNode.py

@@ -0,0 +1,130 @@
+"""
+Produces the dependency graph node "spAnimCube".
+
+This plug-in demonstrates how to take time as an input, and create polygonal
+geometry for output. The compute method of the node constructs a polygonal
+cube whose size depends on the current frame number. The resulting mesh is
+passed to an internal Maya node that displays it and allows
+it to be positioned.
+
+To use this node, execute the python script animCubeNode.py that contains
+the following commands:
+
+  import maya.cmds as cmds
+  cmds.createNode("transform", name="animCube1")
+  cmds.createNode("mesh", name="animCubeShape1", parent="animCube1")
+  cmds.sets("animCubeShape1", add="initialShadingGroup")
+  cmds.createNode("spAnimCube", name="animCubeNode1")
+  cmds.connectAttr("time1.outTime", "animCubeNode1.time")
+  cmds.connectAttr("animCubeNode1.outputMesh", "animCubeShape1.inMesh")
+
+This creates a mesh node under a transform node which is hooked into
+the world for display. It then creates an spAnimCube node, and connects
+its input to the time node, and its output to the mesh node.
+
+A cube will now appear on the screen. If the play button on the time
+slider is pressed, the displayed cube will grow and shrink as the frame
+number changes.
+
+import maya.cmds as cmds
+cmds.createNode("transform", name="animCube1")
+cmds.createNode("mesh", name="animCubeShape1", parent="animCube1")
+cmds.sets("animCubeShape1", add="initialShadingGroup")
+cmds.createNode("spAnimCube", name="animCubeNode1")
+cmds.connectAttr("time1.outTime", "animCubeNode1.time")
+cmds.connectAttr("animCubeNode1.outputMesh", "animCubeShape1.inMesh")
+
+"""
+
+import cmdc
+
+kPluginNodeName = "spAnimCube"
+kPluginNodeId = cmdc.MTypeId(0x8700B)
+
+
+class animCube(cmdc.MPxNode):
+    time = cmdc.MObject()
+    outputMesh = cmdc.MObject()
+
+    @classmethod
+    def nodeCreator(cls):
+        return cmdc.asMPxPtr(cls())
+
+    @classmethod
+    def nodeInitializer(cls):
+        unitAttr = cmdc.MFnUnitAttribute()
+        typedAttr = cmdc.MFnTypedAttribute()
+
+        cls.time = unitAttr.create("time", "tm",
+                                   cmdc.MFnUnitAttribute.kTime, 0.0)
+        cls.outputMesh = typedAttr.create("outputMesh", "out",
+                                          cmdc.MFnData.kMesh)
+
+        cls.addAttribute(cls.time)
+        cls.addAttribute(cls.outputMesh)
+
+        cls.attributeAffects(cls.time, cls.outputMesh)
+
+    def createMesh(self, tempTime, outData):
+        frame = max(0, int(tempTime.asUnits(cmdc.MTime.kFilm)))
+        cubeSize = 0.5 * float(frame % 10)
+
+        points = [
+            cmdc.FloatPoint(-cubeSize, -cubeSize, -cubeSize),
+            cmdc.FloatPoint(cubeSize, -cubeSize, -cubeSize),
+            cmdc.FloatPoint(cubeSize, -cubeSize, cubeSize),
+            cmdc.FloatPoint(-cubeSize, -cubeSize, cubeSize),
+            cmdc.FloatPoint(-cubeSize, cubeSize, -cubeSize),
+            cmdc.FloatPoint(-cubeSize, cubeSize, cubeSize),
+            cmdc.FloatPoint(cubeSize, cubeSize, cubeSize),
+            cmdc.FloatPoint(cubeSize, cubeSize, -cubeSize),
+        ]
+
+        faceConnects = [
+            0, 1, 2, 3, 4, 5, 6, 7, 3, 2, 6, 5,
+            0, 3, 5, 4, 0, 4, 7, 1, 1, 7, 6
+        ]
+
+        faceCounts = [4, 4, 4, 4, 4, 4]
+
+        meshFS = cmdc.MFnMesh()
+        newMesh = meshFS.create(len(points),
+                                len(faceCounts),
+                                points,
+                                faceCounts,
+                                faceConnects,
+                                outData)
+
+        return newMesh
+
+    def compute(self, plug, data):
+        if plug == self.outputMesh:
+            timeData = data.inputValue(self.time)
+            tempTime = timeData.asTime()
+
+            outputHandle = data.outputValue(self.outputMesh)
+
+            dataCreator = cmdc.MFnMeshData()
+            newOutputData = dataCreator.create()
+
+            self.createMesh(tempTime, newOutputData)
+
+            outputHandle.setMObject(newOutputData)
+            data.setClean(plug)
+
+            return cmdc.kSuccess
+
+        return cmdc.kUnknownParameter
+
+
+def initializePlugin(mobject):
+    mplugin = cmdc.MFnPlugin(mobject)
+    mplugin.registerNode(kPluginNodeName,
+                         kPluginNodeId,
+                         animCube.nodeCreator,
+                         animCube.nodeInitializer)
+
+
+def uninitializePlugin(mobject):
+    mplugin = cmdc.MFnPlugin(mobject)
+    mplugin.deregisterNode(kPluginNodeId)