scripted/pyVertexBufferGenerator.py

# Copyright 2015 Autodesk, Inc. All rights reserved.
# 
# Use of this software is subject to the terms of the Autodesk
# license agreement provided at the time of installation or download,
# or which otherwise accompanies this software in either electronic
# or hard copy form.

from ctypes import *
import maya.api.OpenMayaRender as omr
import maya.api.OpenMaya as om

# Example plugin: vertexBufferGenerator.py
#
# This plug-in is an example of a custom MPxVertexBufferGenerator.
# It provides custom vertex streams based on shader requirements coming from 
# an MPxShaderOverride.  The semanticName() in the MVertexBufferDescriptor is used 
# to signify a unique identifier for a custom stream.

# This plugin is meant to be used in conjunction with the d3d11Shader or cgShader plugins.

# The vertexBufferGeneratorGL.cgfx (cgfxShader), vertexBufferGeneratorDX11.fx (dx11Shader) and
# vertexBufferGenerator.ogsfx (glslShader) files accompanying this sample
# The Names of the streams and the stream data generated by this plugin match what is 
# expected from the included effects files.
# This sample use the MyCustomBufferGenerator to create a custom made streams.

# The vertexBufferGenerator2GL.cgfx (cgfxShader), vertexBufferGenerator2DX11.fx (dx11Shader) and
# vertexBufferGenerator2.ogsfx (glslShader) files accompanying this sample
# The Names of the streams and the stream data generated by this plugin match what is 
# expected from the included effects files.
# This sample use the MyCustomBufferGenerator2 to create a custom made streams
# by combining the Position and Normal streams in a single one.

def maya_useNewAPI():
    """
    The presence of this function tells Maya that the plugin produces, and
    expects to be passed, objects created using the Maya Python API 2.0.
    """
    pass


class MyCustomBufferGenerator(omr.MPxVertexBufferGenerator):
    def __init__(self):
        omr.MPxVertexBufferGenerator.__init__(self)

    def getSourceIndexing(self, object, sourceIndexing):
        # get the mesh from the object
        mesh = om.MFnMesh(object)

        # if it is an empty mesh we do nothing.
        numPolys = mesh.numPolygons
        if numPolys == 0:
            return False

        vertToFaceVertIDs = sourceIndexing.indices()
        faceNum = 0

        # for each face
        for i in range(0, numPolys):

            # assign a color ID to all vertices in this face.
            faceColorID = faceNum % 3

            vertexCount = mesh.polygonVertexCount(i)
            for x in range(0, vertexCount):
                # set each face vertex to the face color
                vertToFaceVertIDs.append(faceColorID)

            faceNum += 1

        # assign the source indexing
        sourceIndexing.setComponentType(omr.MComponentDataIndexing.kFaceVertex)

        return False

    def getSourceStreams(self, object, sourceStreams):
        #No source stream needed
        return False

    def createVertexStream(self, object, vertexBuffer, targetIndexing, sharedIndexing, sourceStreams):
        # get the descriptor from the vertex buffer.  
        # It describes the format and layout of the stream.
        descriptor = vertexBuffer.descriptor()
        
        # we are expecting a float stream.
        if descriptor.dataType != omr.MGeometry.kFloat:
            return

        # we are expecting a float2
        if descriptor.dimension != 2:
            return

        # we are expecting a texture channel
        if descriptor.semantic != omr.MGeometry.kTexture:
            return

        # get the mesh from the current path
        # if it is not a mesh we do nothing.
        mesh = om.MFnMesh(object)

        indices = targetIndexing.indices()
            
        vertexCount = len(indices)
        if vertexCount <= 0:
            return

        # fill the data.
        buffer = vertexBuffer.acquire(vertexCount, True)    # writeOnly = True - we don't need the current buffer values

        inc = sizeof(c_float)
        address = buffer

        for i in range(0, vertexCount):
            # Here we are embedding some custom data into the stream.
            # The included effects (vertexBufferGeneratorGL.cgfx and
            # vertexBufferGeneratorDX11.fx) will alternate 
            # red, green, and blue vertex colored triangles based on this input.
            c_float.from_address(address).value = 1.0
            address += inc

            c_float.from_address(address).value = indices[i] # color index
            address += inc

        # commit the buffer to signal completion.
        vertexBuffer.commit(buffer)


class MyCustomBufferGenerator2(omr.MPxVertexBufferGenerator):
    def __init__(self):
        omr.MPxVertexBufferGenerator.__init__(self)

    def getSourceIndexing(self, object, sourceIndexing):
        # get the mesh from the object
        mesh = om.MFnMesh(object)

        (vertexCount, vertexList) = mesh.getVertices()
        vertCount = len(vertexList)

        vertices = sourceIndexing.indices()
        for i in range(0, vertCount):
            vertices.append( vertexList[i] )

        return True

    def getSourceStreams(self, object, sourceStreams):
        sourceStreams.append( "Position" )
        sourceStreams.append( "Normal" )
        return True

    def createVertexStream(self, object, vertexBuffer, targetIndexing, sharedIndexing, sourceStreams):
        # get the descriptor from the vertex buffer.  
        # It describes the format and layout of the stream.
        descriptor = vertexBuffer.descriptor()
        
        # we are expecting a float or int stream.
        dataType = descriptor.dataType
        if dataType != omr.MGeometry.kFloat and dataType != omr.MGeometry.kInt32:
            return

        # we are expecting a dimension of 3 or 4
        dimension = descriptor.dimension
        if dimension != 4 and dimension != 3:
            return

        # we are expecting a texture channel
        if descriptor.semantic != omr.MGeometry.kTexture:
            return

        # get the mesh from the current path
        # if it is not a mesh we do nothing.
        mesh = om.MFnMesh(object)

        indices = targetIndexing.indices()

        vertexCount = len(indices)
        if vertexCount <= 0:
            return

        positionStream = sourceStreams.getBuffer( "Position" )
        if positionStream == None or positionStream.descriptor().dataType != omr.MGeometry.kFloat:
            return
        positionDimension = positionStream.descriptor().dimension
        if positionDimension != 3 and positionDimension != 4:
            return

        normalStream = sourceStreams.getBuffer( "Normal" )
        if normalStream == None or normalStream.descriptor().dataType != omr.MGeometry.kFloat:
            return
        normalDimension = normalStream.descriptor().dimension
        if normalDimension != 3 and normalDimension != 4:
            return

        positionBuffer = positionStream.map()
        if positionBuffer != 0:
            normalBuffer = normalStream.map()
            if normalBuffer != 0:
                compositeBuffer = vertexBuffer.acquire(vertexCount, True) # writeOnly = True - we don't need the current buffer values
                if compositeBuffer != 0:

                    compaddress = compositeBuffer
                    posaddress = positionBuffer
                    normaddress = normalBuffer

                    floatinc = sizeof(c_float)
                    intinc = sizeof(c_int)

                    if dataType == omr.MGeometry.kFloat:

                        for i in range(0, vertexCount):
                            xcompaddr = compaddress
                            ycompaddr = compaddress+floatinc
                            zcompaddr = compaddress+2*floatinc
                            wcompaddr = compaddress+3*floatinc

                            #xposaddr = posaddress
                            yposaddr = posaddress+floatinc
                            zposaddr = posaddress+2*floatinc

                            xnormaddr = normaddress
                            #ynormaddr = normaddress+floatinc
                            znormaddr = normaddress+2*floatinc

                            c_float.from_address(xcompaddr).value = c_float.from_address(yposaddr).value  # store position.y
                            c_float.from_address(ycompaddr).value = c_float.from_address(zposaddr).value  # store position.z
                            c_float.from_address(zcompaddr).value = c_float.from_address(xnormaddr).value # store normal.x
                            if dimension == 4:
                                c_float.from_address(wcompaddr).value = c_float.from_address(znormaddr).value # store normal.z

                            compaddress += dimension*floatinc
                            posaddress += positionDimension*floatinc
                            normaddress += normalDimension*floatinc

                    elif dataType == omr.MGeometry.kInt32:

                        for i in range(0, vertexCount):
                            xcompaddr = compaddress
                            ycompaddr = compaddress+intinc
                            zcompaddr = compaddress+2*intinc
                            wcompaddr = compaddress+3*intinc

                            #xposaddr = posaddress
                            yposaddr = posaddress+floatinc
                            zposaddr = posaddress+2*floatinc

                            xnormaddr = normaddress
                            #ynormaddr = normaddress+floatinc
                            znormaddr = normaddress+2*floatinc

                            c_int.from_address(xcompaddr).value = c_float.from_address(yposaddr).value * 255  # store position.y
                            c_int.from_address(ycompaddr).value = c_float.from_address(zposaddr).value * 255  # store position.z
                            c_int.from_address(zcompaddr).value = c_float.from_address(xnormaddr).value * 255 # store normal.x
                            if dimension == 4:
                                c_int.from_address(wcompaddr).value = c_float.from_address(znormaddr).value * 255 # store normal.z

                            compaddress += dimension*intinc
                            posaddress += positionDimension*floatinc
                            normaddress += normalDimension*floatinc
                    
                    vertexBuffer.commit(compositeBuffer)

                normalStream.unmap()

            positionStream.unmap()

# This is the buffer generator creation function registered with the DrawRegistry.
# Used to initialize the generator.
def createMyCustomBufferGenerator():
    return MyCustomBufferGenerator()

def createMyCustomBufferGenerator2():
    return MyCustomBufferGenerator2()


def getCustomSemantics():
    if omr.MRenderer.drawAPI() == omr.MRenderer.kDirectX11:
        # register a generator based on a custom semantic for DX11.
        # You can use any name in DX11.
        return ("myCustomStream", "myCustomStreamB")
    if omr.MRenderer.drawAPI() == omr.MRenderer.kOpenGLCoreProfile:
        # register a generator based on a custom semantic for OGSFX.  
        # Pretty limited in OGSFX since it only allows standard semantics.
        # But thanks to the annotations a custom value can be set afterward from glslShader plugin
        return ("myCustomStream", "myCustomStreamB")
    if omr.MRenderer.drawAPI() == omr.MRenderer.kOpenGL:
        # register a generator based on a custom semantic for cg.  
        # Pretty limited in cg so we hook onto the "ATTR" semantics.
        return ("ATTR8", "ATTR7")
    return None


# The following routines are used to register/unregister
# the vertex generators with Maya

def initializePlugin(obj):
    (customSemantic, customSemantic2) = getCustomSemantics()

    omr.MDrawRegistry.registerVertexBufferGenerator(customSemantic, createMyCustomBufferGenerator)
    omr.MDrawRegistry.registerVertexBufferGenerator(customSemantic2, createMyCustomBufferGenerator2)

def uninitializePlugin(obj):
    (customSemantic, customSemantic2) = getCustomSemantics()

    omr.MDrawRegistry.deregisterVertexBufferGenerator(customSemantic)
    omr.MDrawRegistry.deregisterVertexBufferGenerator(customSemantic2)