Maya C++ API Programming Tips

source : http://wanochoi.com/?page_id=1588

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How to handle the multiple outputs of?a DG node

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MStatus MyNode::initialize() { ???MFnNumericAttribute nAttr; ???outputsObj = nAttr.create( "outputs", "outputs", MFnNumericData.kFloat, 0.f ); ???nAttr.setArray( true ); ???addAttribute( outputsObj ); ???... } MStatus MyNode::compute( const MPlug& plug, MDataBlock& data ) { ???if( plug != outputsObj ) { return MS::kUnknownParameter; } ???MArrayDataHandle outputsHnd = data.outputArrayValue( outputsObj ); ???const int nOutputs = (int)outputsHnd.elementCount(); ???for( int i=0; i<100; ++i ) ???{ ??????outputsHnd.jumpToElement( i ); ??????outputsHnd.outputValue().set( i ); ???} ???outputsHnd.setAllClean(); ???return MS::kSuccess;?? }

How to capture the current viewport as an image file

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MImage image; M3dView view = M3dView::active3dView(); view.readColorBuffer( image, true ); image.writeToFile( "snapshot.jpg", "jpg" );

How to save the current frame buffer to a JPG file

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GLint viewport[4]; glGetIntegerv( GL_VIEWPORT, viewport ); int width = viewport[2]; int height = viewport[3]; int depth = 4; unsigned char* pixels = new unsigned int[width*height*depth]; glReadBuffer( GL_FRONT ); glReadPixels( 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels ); MImage image; image.setPixels( pixels, width, height ); image.writeToFile( "snapshot.jopg", "jpg" ); delete[] pixels;

How to set the names of a custom DG node and its parent node

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void myNode::postConstructor() { ???MPxNode::postConstructor(); ???MObject thisMObj = thisMObject(); ???MFnDependencyNode nodeFn; ???nodeFn.setObject( thisMObj ); ???nodeFn.setName( "myNodeShape#" ); }

How to compile my source code conditionally according to the Maya API version

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#if MAYA_API_VERSION >= 201300 ... #elif MAYA_API_VERSION >= 201400 ... #elif MAYA_API_VERSION >= 201500 ... #endif

How to get the current Maya version

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1 2	MString mayaVer = MGlobal::mayaVersion(); int apiVer = MGlobal::apiVersion();

How to avoid the conflict with Cuda

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... #define short2? MAYA_short2 #define short3? MAYA_short3 #define long2?? MAYA_long2 #define long3?? MAYA_long3 #define int2??? MAYA_int2 #define int3??? MAYA_int3 #define float2? MAYA_float2 #define float3? MAYA_float3 #define double2 MAYA_double2 #define double3 MAYA_double3 #define double4 MAYA_double4 #include <cuda.h> ...

How to set the MFloatPoint from a MPoint

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MPoint dp; // double type MFloatPoint fp; // float type fp.setCast( dp );

How to get the pixel values of an image

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MImage img; img.readFromFile( "filePathName" ); // load from a file int w=0, h=0; // image width, height img.getSize( w, h ); int d = img.depth(); // image depth unsigned char* c = (unsigned char*)NULL; if( img.pixelType() == MImage::kByte ) { ???c = img.pixels(); } for( int j=0; j<h; ++j ) for( int i=0; i<w; ++i ) {{ ???int idx = d*(i+j*w); ???unsigned char pixelVal[4]; // RGB(d=3) or RGBA(d=4) ???for( int k=0; k<d; ++k ) ???{ ??????pixelVal[k] = c[idx++]; ???} ???... }}

How to get the DAG path from a node name

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MString nodeName( "nodeName" ); MDagPath dagPath; MSelectionList sList; if( MGlobal::getSelectionListByName( nodeName, sList ) ) { ???sList.getDagPath( 0, dagPath ); }

How to get the DG node object from a node name

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MString nodeName( "nodeName" ); MObject nodeObj; MSelectionList sList; if( MGLobal::getSelectionListByName( nodeName, sList ) ) { ???sList.getDependNode( 0, nodeObj ); }

How to get the DAG path from a DAG node object

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MObject dagNodeObj = ...; MDagPath dagPath; MFnDagNode dagFn( dagNodeObj ); dagFn.getPath( dagPath );

How to get the node name from a node object

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MObject nodeObj = ...; MString nodeName; if( nodeObj.hasFn( MFn::kDagNode ) ) { ???MFnDagNode dagNodeFn( nodeObj ); ???nodeName = dagNode.fullPathName(); } else if( nodeObj.hasFn( MFn::kDependencyNode ) ) { ???MFnDependencyNode dgNodeFn( nodeObj ); ???nodeName = dgNodeFn.name(); }

How to get the parent DAG node object

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MObject parentDagNodeObj; MFnDagNode dagFn( thisMObject() ); MObject obj = dagFn.parent( 0 ); if( !obj.isNull() ) { ???parentDagNodeObj = obj; }

How to get the shape node DAG path from a transform DAG path

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MDagPath xformDagPath = ... MDagPath shapeDagPath = xformDagPath; shapeDagPath.extendToShape();

How to get the DAG paths of selected mesh shape nodes

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MDagPathArray dagPaths; MSelectionList sList; MGlobal::getActiveSelectionList( sList ); MItSelectionList itr( sList, MFn::kMesh ); for( ; !itr.isDone(); itr.next() ) { ???MDagPath dagPath; ???itr.getDagPath( dagPath ); ???MFnDagNode dagFn( dagPath ); ???if( dagFn.isIntermediateObject() ) { continue; } ???dagPaths.append( dagPath ); }

How to get the all of NURBS curve node objects in the current scene

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MObjectArray curveObjs; MItDag itr( MItDag::kDepthFirst, MFn::kNurbsCurve ); for( ; !itr.isDone(); itr.next() ) { ???curveObjs.append( itr.item() ); }

How to get the list of a selected mesh polygons

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MIntArray selectedPolygonList; MSelectionList sList; MGlobal::getActiveSelectionList( sList ); MItSelectionList sItr( sList, MFn::kMeshPolygonComponent ); MDagPath dagPath; MObject componentObj; sItr.getDagPath( dagPath, componentObj ); MFnSingleIndexedComponent sCompFn( componentObj ); sCompFn.getElements( selectedPolygonList );

How to get the all of fields in the current scene

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MItDag itr( MItDag::kDepthFirst, MFn::kField ); for( ; !itr.isDone(); itr.next() ) { ???MFnField fieldFn( itr.item() ); ???... }

How to get the world matrix of the current DAG node

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MObject thisNodeObj = thisMObject(); MFnDependencyNode thisNodeFn( thisNodeObj ); MObject worldMatrixObj = thisNodeFn.attribute( "worldMatrix" ); MPlug worldMatrixPlg( thisNodeObj, worldMatrixObj ); worldMatrixPlg = worldMatrixPlg.elementByLogicalIndex( 0 ); worldMatrixPlg.getValue( worldMatrixObj ); MFnMatrixData worldMatrixData( worldMatrixObj ); Matrix worldMatrix = worldMatrixData.matrix();

How to connect the output plug to the parent automatically when a custom locator node is created

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class MyLocator { ???... ???bool connected; ???... }; MyLocator::MyLocator() { ???connected = false; } void MyLocator::draw( M3dView& view, ...) { ???if( !connected ) ???{ ??????MObject thisNodeObj = thisMObject(); ??????MFnDagNode dagFn( thisNodeObj ); ??????MObject parentNodeObj = dagFn.parent( 0 ); ??????dagFn.setObject( parentNodeObj ); ??????MPlug parentPlg = dagFn.findPlug( "plugName" ); ??????MPlug outputPlg = MPlug( thisNodeObj, outputObj ); ??????if( !outputPlg.isConnected() ) ??????{ ?????????MDGModifier dgMod; ?????????dgMod.connect( outputPlg, parentPlg ); ?????????dgMod.doIt(); ?????????connected = true; ??????} ???} ???... }

How to make a custom locator node un-selectable

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void MyLocator::draw( M3dView& view, ...) { ???if( view.selectMode() ) { return; } ???... }

How to detect which input attribute is changed

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MStatus MyCustomNode::compute( const MPlug& plug, MDataBlock& data ) { ???if( plug != outputObj ) { return MS::kUnknownParameter; } ???bool inputIsChanged = !data.isClean( inputObj ); ???float input = data.inputValue( inputObj ).asFloat(); ???... }

Note) It doesn’t work when inputObj is array type.

How to detect whether the current state is batch mode

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if( MGlobal::mayaState() == MGlobal::kBatch ) { ???... }

How to detect whether the current viewport is Viewport 2.0

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M3dView view = M3dView::active3dView(); if( view.getRendererName() == M3dView::kViewport2Renderer ) { ???... }

How not to draw a custom locator node while mouse interactions (>=2015)

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void MyLocator::draw( M3dView& view, ...) { ???if( MHWRender::MFrameContext::inUserInteraction() ????|| MHWRender::MFrameContext::userChangingViewContext() ) ???{ ??????... ???} }

How to draw a text in draw() of a custom locator node

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void MyLocator::draw( M3dView& view, ...) { ???... ???view.beginGL(); ???view.drawText( MString("text"), MPoint(0,0,0), M3dView::kLeft ); ???view.endGL(); ???... }

How to copy the input mesh to the output mesh in compute() of a custom node

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MStatus MyNode::compute( const MPlug& plug, MDataBlock& data ) { ???... ???MFnMesh newMeshFn; ???MFnMeshData dataCreator; ???MObject newMeshData = dataCreator.create(); ???newMeshFn.copy( data.inputValue( inMeshObj ).asMeshTransformed(), newMeshData ); ???data.outputValue( outMeshObj ).set( newMeshData ); ???... }

How to deform the input mesh in compute() of a custom node like such a deformer

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MStatus MyNode::compute( const MPlug& plug, MDataBlock& data ) { ???... ???MPointArray deformedPoints = ... ???MFnMesh newMeshFn; ???MFnMeshData dataCreator; ???MObject newMeshData = dataCreator.create(); ???newMeshFn.copy( data.inputValue( inMeshObj ).asMeshTransformed(), newMeshData ); ???newMeshFn.setPoints( deformedPoints ); ???data.outputValue( outMeshObj ).set( newMeshData ); ???... }

How to handle array attribute

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class MyCustomNode { ???... ???MObject valuesObj; ???... ???MDoubleArray values; }; MObject MyCustomNode::valuesObj; MStatus MyCustomNode::initialize() { ???... ???valuesObj = tAttr.create( "values", "values", MFnData::kDoubleArray ); ???... } MStatus MyCustomNode::compute( const MPlug& plug, MDataBlock& data ) { ???... ???// get ???MFnDoubleArrayData arrayData; ???MObject dataObj = data.inputValue( valuesObj ).data(); ???arrayData.setObject( dataObj ); ???int numValues = 100; ???// set ???if( arrayData.length() != numValues ) ???{ ??????MDoubleArray array( numValues, 0.0 ); ??????dataObj = arrayData.create( array ); ??????data.outputValue( valuesObj ).set( dataObj ); ???} ???... } // MEL makePaintable -at doubleArray MyCustomNode values; setAttr MyCustomNode1.values -type doubleArray 3 1.0 2.0 3.0;

How to get the value of an attribute anywhere in a custom node

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MObject thisNodeObj = thisMObject(); double? v0 = MPlug( thisNodeObj, attr0Obj ).asDouble(); float?? v1 = MPlug( thisNodeObj, attr1Obj ).asFloat(); int???? v2 = MPlug( thisNodeObj, attr2Obj ).asInt(); short?? v3 = MPlug( thisNodeObj, attr3Obj ).asShort(); bool??? v4 = MPlug( thisNodeObj, attr4Obj ).asBool(); MTime?? v5 = MPlug( thisNodeObj, attr5Obj ).asMTime(); char??? v6 = MPlug( thisNodeObj, attr6Obj ).asChar(); MString v7 = MPlug( thisNodeObj, attr7Obj ).asString(); MColor c; MPlug plg( thisNodeObj, attrObj ); plg.child(0).getValue( c.r ); plg.child(1).getValue( c.g ); plg.child(2).getValue( c.b );

How to get the pointer of the other connected node

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OtherNodeClassName* otherNodePtr = (OtherNodeClassName*)NULL; MObject thisNodeObj = thisMObject(); MFnDependencyNode thisNodeFn( thisNodeObj ); MPlug plg = thisNodeFn.findPlug( inputAttrObj ); MPlugArray connectedPlgs; if( plg.isConnected() ) { ???if( plg.isSource() ) { ??????plg.connectedTo( connectedPlgs, false, true ); ???} else if( plg.isDestination() ) { ??????plg.connectedTo( connectedPlgs, true, false ); ???} ???MFnDependencyNode otherNodeFn( connectedPlgs[0].node() ); ???if( otherNodeFn.typeId() == OtherNodeClassName::id ) ???{ ??????otherNodePtr = (OtherNodeClassName*)otherNodeFn.userNode(); ???} }

How to restore GL states in draw() of a custom locator node

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void MyLocator::draw( M3dView& view, ...) { ???float lastPointSize=0; glGetFloatv( GL_POINT_SIZE, &lastPointSize ); ???float lastLineWidth=0; glGetFloatv( GL_LINE_WIDTH, &lastLineWidth ); ???bool lightingWasOn = glIsEnabled( GL_LIGHTING ) ? true : false; ???if( lightingWasOn ) { glDisable( GL_LIGHTING ); } ???view.beginGL(); ???... ???view.endGL(); ???glPointSize( lastPointSize ); ???glLineWidth( lastLineWidth ); ???if( lightingWasOn ) { glEnable( GL_LIGHTING ); } }

How to call compute() of a custom locator without output connection

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void MyLocator::draw( M3dView& view, ...) { ???MObject thisNodeObj = thisMObject(); ???MObject obj = MPlug( thisNodeObj, outputObj ).asMObject(); ???... }

How to get the normal vector of a current camera

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M3dView view = M3dView::active3dView(); MDagPath camDagPath; view.getCamera( camDagPath ); MVector cameraZ = MVector(0,0,1) * camDagPath.inclusiveMatrix();

How to create attributes in initialize() of a custom node

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MStatus MyLocator::initialize() { ???MRampAttribute????? rAttr; ???MFnEnumAttribute??? eAttr; ???MFnUnitAttribute??? uAttr; ???MFnTypedAttribute?? tAttr; ???MFnNumericAttribute nAttr; ???MFnMessageAttribute gAttr; ???timeObj = uAttr.create( "time", "time", MFnUnitAttribute::kTime, 0.0 ); ???addAttribute( timeObj ); ???angleObj = uAttr.create( "angle", "angle", MFnUnitAttribute::kAngle, 0.0 ); ???addAttribute( angleObj ); ???boolObj = nAttr.create( "bool", "bool", MFnNumericData::kBoolean, false ); ???addAttribute( boolObj ); ???intObj = nAttr.create( "int", "int", MFnNumericData::kInt, 0 ); ???addAttribute( intObj ); ???floatObj = nAttr.create( "float", "float", MFnNumericData::kFloat, 0.f ); ???addAttribute( floatObj ); ???doubleObj = nAttr.create( "double", "double", MFnNumericData::kDouble, 0.0 ); ???addAttribute( doubleObj ); ???int2Obj = nAttr.create( "int2", "int2", MFnNumericData::k2Int, 0 ); ???addAttribute( int2Obj ); ???int3Obj = nAttr.create( "int3", "int3", MFnNumericData::k3Int, 0 ); ???addAttribute( int3Obj ); ???float2Obj = nAttr.create( "float2", "float2", MFnNumericData::k2Float, 0.f ); ???addAttribute( float2Obj ); ???float3Obj = nAttr.create( "float3", "float3", MFnNumericData::k3Float, 0.f ); ???addAttribute( float3Obj ); ???double2Obj = nAttr.create( "double2", "double2", MFnNumericData::k2Double, 0.0 ); ???addAttribute( double2Obj ); ???double3Obj = nAttr.create( "double3", "double3", MFnNumericData::k3Double, 0.0 ); ???addAttribute( double3Obj ); ???stringObj = tAttr.create( "string", "string", MFnData::kString, "abc" ); ???addAttribute( stringObj ); ???matrixObj = tAttr.create( "matrix", "matrix", MFnMatrixAttribute::kDouble ); ???addAttribute( matrixObj ); ???curveObj = tAttr.create( "curve", "curve", MFnData::kNurbsCurve ); ???addAttribute( curveObj ); ???meshObj = tAttr.create( "mesh", "mesh", MFnData::kMesh ); ???addAttribute( meshObj ); ???iaObj = tAttr.create( "iArray", "iArray", MFnData::kIntArray ); ???addAttribute( iaObj ); ???faObj = tAttr.create( "fArray", "fArray", MFnData::kFloatArray ); ???addAttribute( faObj ); ???daObj = tAttr.create( "dArray", "dArray", MFnData::kDoubleArray ); ???addAttribute( daObj ); ???paObj = tAttr.create( "pArray", "pArray", MFnData::kPointArray ); ???addAttribute( paObj ); ???vaObj = tAttr.create( "vArray", "vArray", MFnData::kVectorArray ); ???addAttribute( vaObj ); ???saObj = tAttr.create( "sArray", "sArray", MFnData::kStringArray ); ???addAttribute( saObj ); ???msgObj = gAttr.create( "message", "message" ); ???addAttribute( msgObj ); ???clrObj = nAttr.createColor( "color", "color" ); ???addAttribute( clrObj ); ???pntObj = nAttr.createPoint( "point", "point" ); ???addAttribute( pntObj ); ???enumObj = eAttr.create( "enum", "enum" 0 ); ??????eAttr.addField( "A", 0 ); ??????eAttr.addField( "B", 0 ); ???addAttribute( enumObj ); ???crvRmpObj = rAttr.createCurveRampAttr( "crvRamp", "crvRamp" ); ???addAttribute( crvRmpObj ); ???clrRmpObj = rAttr.createColorRampAttr( "clrRamp", "clrRamp" ); ???addAttribute( clrRmpObj ); ???fileNameObj = tAttr.create( "fileName", "fileName", MFnData::kString ); ???tAttr.setUsedAsFilename( true ); ???addAttribute( fileNameObj ); ???... }

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轉載于:https://www.cnblogs.com/yaoyansi/p/5538178.html

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