MPxHwShaderNode Class Reference

#include <MPxHwShaderNode.h>

Class Description

Base class for user defined hardware shaders.

MPxHwShaderNode allows the creation of user-defined hardware shaders. A hardware shader allows the plug-in writer to control the on-screen display of an object in Maya.

You must derive a hardware shader node from MPxHwShaderNode for it to have any affect on the on-screen display at all. In addition to their affect on the on-screen display of objects, hardware shaders function as surface shader nodes. This allows you to connect any shading network up to the hardware shader's outColor attribute to handle the shading during a software render.

To create a working hardware shader, derive from this class and override the bind(), unbind(), and geometry() methods. If your hardware shader uses texture coordinates from Maya, you also need to override either texCoordsPerVertex or getTexCoordSetNames(). The other methods of the parent class MPxNode may also be overridden to perform dependency node capabilities.

NOTE: Plug-in hardware shaders are fully supported for polygonal mesh shapes. NURBS surfaces are only supported in the High Quality Interactive viewport and Hardware Renderer if the glBind/glGeometry/glUnbind methods of this class are implemented.

Examples:

Inheritance diagram for MPxHwShaderNode:

Classes
struct	RenderParameters
	Provides information on how to render the image. More...

Public Types
enum	Writeable {   kWriteNone = 0x0000, kWriteVertexArray = 0x0001, kWriteNormalArray = 0x0002, kWriteColorArrays = 0x0004,   kWriteTexCoordArrays = 0x0008, kWriteAll = 0x000f }
	Bit masks used in conjuction with the 'writeable' parameter passed to the geometry() method to determine which arrays the shader is allowed to write to. More...
enum	DirtyMask {   kDirtyNone = 0x0000, kDirtyVertexArray = 0x0001, kDirtyNormalArray = 0x0002, kDirtyColorArrays = 0x0004,   kDirtyTexCoordArrays = 0x0008, kDirtyAll = 0x000f }
	Bit masks used in combination with the return value of the dirtyMask() method to determine which portions of the geometry are dirty. More...
enum	TransparencyOptions { kIsTransparent = 0x0001, kNoTransparencyFrontBackCull = 0x0002, kNoTransparencyPolygonSort = 0x0004 }
	Bit masks to be returned by the shader's transparencyOptions() method. More...
Public Types inherited from MPxNode
enum	Type {   kDependNode, kLocatorNode, kDeformerNode, kManipContainer,   kSurfaceShape, kFieldNode, kEmitterNode, kSpringNode,   kIkSolverNode, kHardwareShader, kHwShaderNode, kTransformNode,   kObjectSet, kFluidEmitterNode, kImagePlaneNode, kParticleAttributeMapperNode,   kCameraSetNode, kConstraintNode, kManipulatorNode, kMotionPathNode,   kClientDeviceNode, kThreadedDeviceNode, kAssembly, kSkinCluster,   kGeometryFilter, kBlendShape, kLast }
	Defines the type of node. More...
enum	SchedulingType {   kParallel, kSerial, kGloballySerial, kUntrusted,   kDefaultScheduling = kSerial }
	Defines the degree of parallelism of a node. More...

Public Member Functions
	MPxHwShaderNode ()
	Class constructor.
virtual	~MPxHwShaderNode ()
	Class destructor.
virtual MPxNode::Type	type () const
	This method returns the type of the node. More...
virtual MStatus	bind (const MDrawRequest &request, M3dView &view)
	This method is invoked for hardware rendering to Maya's 3D view. More...
virtual MStatus	unbind (const MDrawRequest &request, M3dView &view)
	This method is invoked for hardware rendering to Maya's 3D view. More...
virtual MStatus	geometry (const MDrawRequest &request, M3dView &view, int prim, unsigned int writable, int indexCount, const unsigned int *indexArray, int vertexCount, const int *vertexIDs, const float *vertexArray, int normalCount, floatArrayPtr normalArrays, int colorCount, floatArrayPtr colorArrays, int texCoordCount, floatArrayPtr texCoordArrays)
	This method is obsolete. More...
virtual MStatus	geometry (const MDrawRequest &request, M3dView &view, int prim, unsigned int writable, int indexCount, const unsigned int *indexArray, int vertexCount, const int *vertexIDs, const float *vertexArray, int normalCount, floatArrayPtr normalArrays, int colorCount, floatArrayPtr colorArrays, int texCoordCount, floatArrayPtr texCoordArrays, const int *faceIDs, const float *localUVCoord)
	This method is invoked for hardware rendering to Maya's 3D view. More...
virtual MStatus	glBind (const MDagPath &shapePath)
	This method should only be overridden for hardware rendering. More...
virtual MStatus	glUnbind (const MDagPath &shapePath)
	This method should only be overridden for hardware rendering. More...
virtual MStatus	glGeometry (const MDagPath &shapePath, int glPrim, unsigned int writeMask, int indexCount, const unsigned int *indexArray, int vertexCount, const int *vertexIDs, const float *vertexArray, int normalCount, floatArrayPtr normalArrays, int colorCount, floatArrayPtr colorArrays, int texCoordCount, floatArrayPtr texCoordArrays)
	This method is obsolete. More...
virtual MStatus	glGeometry (const MDagPath &shapePath, int glPrim, unsigned int writeMask, int indexCount, const unsigned int *indexArray, int vertexCount, const int *vertexIDs, const float *vertexArray, int normalCount, floatArrayPtr normalArrays, int colorCount, floatArrayPtr colorArrays, int texCoordCount, floatArrayPtr texCoordArrays, const int *faceIDs, const float *localUVCoord)
	This method should only be overridden for hardware rendering. More...
virtual bool	supportsBatching () const
	Specifies whether or not this shader supports batched rendering of shapes. More...
virtual bool	invertTexCoords () const
	Specifies whether this shader requires inverted texture coordinates. More...
const MDagPath &	currentPath () const
	This method returns a reference to the current path that the shader is invoked for. More...
unsigned int	dirtyMask () const
	This method returns a "dirty" mask that indicates which geometry items have changed from the last invocation of the plugin to draw. More...
virtual int	normalsPerVertex ()
	Specifies how many normals per vertex the HW shader would like Maya to provide. More...
virtual int	colorsPerVertex ()
	This method returns the number of color values per vertex that the hw shader node would like to receive from Maya. More...
virtual int	getColorSetNames (MStringArray &names)
	NO SCRIPT SUPPORT. More...
virtual int	texCoordsPerVertex ()
	This method returns the number of texture coordinate values per vertex that the hw shader node would like to receive from Maya. More...
virtual int	getTexCoordSetNames (MStringArray &names)
	NO SCRIPT SUPPORT. More...
virtual bool	hasTransparency ()
	This method returns a boolean value that indicates whether the object will be drawn transparently or not. More...
virtual bool	provideVertexIDs ()
	This method returns a boolean value that indicates whether a map of the vertex IDs will be provided to the geometry method. More...
virtual bool	provideFaceIDs ()
	This method returns a boolean value that indicates whether a map of the face IDs will be provided to the geometry method. More...
virtual bool	provideLocalUVCoord ()
	This method returns a boolean value that indicates whether the local uv coordinates of the subdivided face vertices will be provided to the geometry method. More...
virtual unsigned int	transparencyOptions ()
	This method returns transparency options for usage as hints for Maya's internal draw during a given rendering pass. More...
virtual MStatus	getAvailableImages (const MString &uvSetName, MStringArray &imageNames)
	NO SCRIPT SUPPORT. More...
virtual MStatus	renderImage (const MString &imageName, floatRegion region, int &imageWidth, int &imageHeight)
	NO SCRIPT SUPPORT. More...
virtual MStatus	renderImage (const MString &imageName, floatRegion region, const MPxHwShaderNode::RenderParameters &parameters, int &imageWidth, int &imageHeight)
	NO SCRIPT SUPPORT. More...
virtual MStatus	renderImage (MHWRender::MUIDrawManager &uiDrawManager, const MString &imageName, floatRegion region, const MPxHwShaderNode::RenderParameters &parameters, int &imageWidth, int &imageHeight)
	NO SCRIPT SUPPORT. More...
virtual MStatus	renderSwatchImage (MImage &image)
	If the shader specifies to override swatch rendering, then this method must be overridden in order to draw anything into a swatch. More...
MObject	currentShadingEngine () const
	This method returns an MObject to the shading engine that is currently being rendered. More...
Public Member Functions inherited from MPxNode
	MPxNode ()
	Constructor. More...
virtual	~MPxNode ()
	Destructor.
virtual void	postConstructor ()
	Post constructor. More...
virtual MStatus	compute (const MPlug &plug, MDataBlock &dataBlock)
	This method should be overridden in user defined nodes. More...
virtual bool	getInternalValueInContext (const MPlug &plug, MDataHandle &dataHandle, MDGContext &ctx)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual bool	setInternalValueInContext (const MPlug &plug, const MDataHandle &dataHandle, MDGContext &ctx)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual bool	getInternalValue (const MPlug &plug, MDataHandle &dataHandle)
	This method is obsolete. More...
virtual bool	setInternalValue (const MPlug &plug, const MDataHandle &dataHandle)
	This method is obsolete. More...
virtual int	internalArrayCount (const MPlug &plug, const MDGContext &ctx) const
	This method is overridden by nodes that have internal array attributes which are not stored in Maya's datablock. More...
virtual void	copyInternalData (MPxNode *)
	This method is overridden by nodes that store attribute data in some internal format. More...
virtual MStatus	legalConnection (const MPlug &plug, const MPlug &otherPlug, bool asSrc, bool &isLegal) const
	This method allows you to check for legal connections being made to attributes of this node. More...
virtual MStatus	legalDisconnection (const MPlug &plug, const MPlug &otherPlug, bool asSrc, bool &isLegal) const
	This method allows you to check for legal disconnections being made to attributes of this node. More...
virtual MStatus	setDependentsDirty (const MPlug &plug, MPlugArray &plugArray)
	This method can be overridden in user defined nodes to specify which plugs should be set dirty based upon an input plug {plugBeingDirtied} which Maya is marking dirty. More...
virtual MStatus	preEvaluation (const MDGContext &context, const MEvaluationNode &evaluationNode)
	Prepare a node's internal state for threaded evaluation. More...
virtual MStatus	postEvaluation (const MDGContext &context, const MEvaluationNode &evaluationNode, PostEvaluationType evalType)
	Clean up node's internal state after threaded evaluation. More...
virtual SchedulingType	schedulingType () const
	When overridden this method controls the degree of parallelism supported by the node during threaded evaluation. More...
virtual MStatus	connectionMade (const MPlug &plug, const MPlug &otherPlug, bool asSrc)
	This method gets called when connections are made to attributes of this node. More...
virtual MStatus	connectionBroken (const MPlug &plug, const MPlug &otherPlug, bool asSrc)
	This method gets called when connections are broken with attributes of this node. More...
virtual MStatus	dependsOn (const MPlug &plug, const MPlug &otherPlug, bool &depends) const
	This method may be overridden by the user defined node. More...
virtual bool	isPassiveOutput (const MPlug &plug) const
	This method may be overridden by the user defined node if it wants to provide output attributes which do not prevent value modifications to the destination attribute. More...
virtual MStatus	shouldSave (const MPlug &plug, bool &isSaving)
	This method may be overridden by the user defined node. More...
virtual MPlug	passThroughToOne (const MPlug &plug) const
	This method may be overridden by nodes that have a one-to-one relationship between an input attribute and a corresponding output attribute. More...
virtual bool	passThroughToMany (const MPlug &plug, MPlugArray &plugArray) const
	This method is overridden by nodes that want to control the traversal behavior of some Maya search algorithms which traverse the history/future of shape nodes looking for directly related nodes. More...
virtual bool	isAbstractClass () const
	Override this class to return true if this node is an abstract node. More...
virtual MStringArray	getFilesToArchive (bool shortName=false, bool unresolvedName=false, bool markCouldBeImageSequence=false) const
	Use this method to return all external files used by this node. More...
virtual void	getExternalContent (MExternalContentInfoTable &table) const
	Returns the external content (files) that this node depends on. More...
bool	addExternalContentForFileAttr (MExternalContentInfoTable &table, const MObject &attr) const
	Adds content info to the specified table from a file path attribute. More...
bool	setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &table)
	Sets content info in the specified attribute from the table. More...
virtual void	setExternalContent (const MExternalContentLocationTable &table)
	Changes the location of external content in batch. More...
virtual MTypeId	typeId () const
	Returns the TYPEID of this node. More...
virtual MString	typeName () const
	Returns the type name of this node. More...
virtual MString	name () const
	Returns the name of this particular instance of this class. More...
virtual MObject	thisMObject () const
	Returns the MObject associated with this user defined node. More...
virtual MStatus	setExistWithoutInConnections (bool flag)
	This method specifies whether or not the node can exist without input connections. More...
virtual bool	existWithoutInConnections (MStatus *ReturnStatus=NULL) const
	Determines whether or not this node can exist without input connections. More...
virtual MStatus	setExistWithoutOutConnections (bool flag)
	This method specifies whether or not the node can exist without output connections. More...
virtual bool	existWithoutOutConnections (MStatus *ReturnStatus=NULL) const
	Determines whether or not this node can exist without output connections. More...

Static Public Member Functions
static MPxHwShaderNode *	getHwShaderNodePtr (MObject &object)
	This is a static convenience method to be able to get an MPxHwShaderNode from an MObject provided by a swatch generator class (Class derived from MSwatchRenderRegister). More...
static const char *	className ()
	Returns the name of this class. More...
Static Public Member Functions inherited from MPxNode
static MStatus	addAttribute (const MObject &attr)
	This method adds a new attribute to a user defined node type during the type's initialization. More...
static MStatus	inheritAttributesFrom (const MString &parentClassName)
	This method allows a class of plugin node to inherit all of the attributes of a second class of plugin node. More...
static MStatus	attributeAffects (const MObject &whenChanges, const MObject &isAffected)
	This method specifies that a particular input attribute affects a specific output attribute. More...
static const char *	className ()
	Returns the name of this class. More...

Static Public Attributes
static MObject	outColor
	output color value
static MObject	outColorR
	output color red
static MObject	outColorG
	output color green
static MObject	outColorB
	output color blue
static MObject	outTransparency
	output transparency value
static MObject	outTransparencyR
	output transparency red
static MObject	outTransparencyG
	output transparency green
static MObject	outTransparencyB
	output transparency blue
static MObject	outMatteOpacity
	output matte opacity value
static MObject	outMatteOpacityR
	output matte opacity red
static MObject	outMatteOpacityG
	output matte opacity green
static MObject	outMatteOpacityB
	output matte opacity blue
static MObject	outGlowColor
	output glow color value
static MObject	outGlowColorR
	output glow color red
static MObject	outGlowColorG
	output glow color green
static MObject	outGlowColorB
	output glow color blue
Static Public Attributes inherited from MPxNode
static MObject	message
	message attribute
static MObject	isHistoricallyInteresting
	is historically interesting attribute
static MObject	caching
	caching attribute
static MObject	state
	state attribute
static MObject	frozen
	frozen attribute

Additional Inherited Members
Protected Member Functions inherited from MPxNode
virtual MDataBlock	forceCache (MDGContext &ctx=MDGContext::fsNormal)
	USE _forceCache() IN SCRIPT. More...
virtual void	setMPSafe (bool flag)
	USE _setMPSafe() IN SCRIPT. More...
virtual MStatus	setDoNotWrite (bool flag)
	USE _setDoNotWrite() IN SCRIPT. More...
virtual bool	doNotWrite (MStatus *ReturnStatus=NULL) const
	USE _doNotWrite() IN SCRIPT. More...

Member Enumeration Documentation

enum Writeable

Bit masks used in conjuction with the 'writeable' parameter passed to the geometry() method to determine which arrays the shader is allowed to write to.

Enumerator
kWriteNone
kWriteVertexArray
kWriteNormalArray
kWriteColorArrays
kWriteTexCoordArrays
kWriteAll

enum DirtyMask

Bit masks used in combination with the return value of the dirtyMask() method to determine which portions of the geometry are dirty.

Enumerator
kDirtyNone
kDirtyVertexArray
kDirtyNormalArray
kDirtyColorArrays
kDirtyTexCoordArrays
kDirtyAll

enum TransparencyOptions

Bit masks to be returned by the shader's transparencyOptions() method.

Enumerator
kIsTransparent	Draw as a transparent object. If this bit is not set then the others are ignored.
kNoTransparencyFrontBackCull	Do not use the two-pass front-and-back culling algorithm.
kNoTransparencyPolygonSort	Do not use two-pass drawing of back-to-front sorted polygons.

Member Function Documentation

MPxNode::Type type ( ) const

virtual

This method returns the type of the node.

This method should not be overridden by the user. It will return MPxNode::kHwShaderNode.

Returns

The type of node.

Reimplemented from MPxNode.

MStatus bind ( const MDrawRequest &  request, M3dView &  view  )

virtual

This method is invoked for hardware rendering to Maya's 3D view.

This is the preferred method of interactive feedback and performance. the "gl" version should be used for batch hardware rendering.

This method is called to set up the OpenGL state. It would typically ensure that textures were bound and that any specific OpenGL extensions are enabled. A status code of MS::kSuccess should be returned unless there was a problem during the display, such as insufficient memory or required input data is missing or invalid.

Parameters

[in]	request	the draw request.
[in]	view	the view in which to draw.

Returns

Status code.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus unbind ( const MDrawRequest &  request, M3dView &  view  )

virtual

This method is invoked for hardware rendering to Maya's 3D view.

This is the preferred method of interactive feedback and performance. the "gl" version should be used for batch hardware rendering.

This method is called to restore the OpenGL state. Specifically, it must disable any OpenGL extensions that the matching bind() method may have enabled. This is necessary to ensure that the rest of Maya's drawing code continues to work correctly. A status code of MS::kSuccess should be returned unless there was a problem such as insufficient memory or required input data is missing or invalid.

The arguments passed to this method are the same ones that were passed to the bind() method.

Parameters

[in]	request	the draw request.
[in]	view	the view in which to draw.

Returns

Status code.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus geometry ( const MDrawRequest &  request, M3dView &  view, int  prim, unsigned int  writable, int  indexCount, const unsigned int *  indexArray, int  vertexCount, const int *  vertexIDs, const float *  vertexArray, int  normalCount, floatArrayPtr  normalArrays, int  colorCount, floatArrayPtr  colorArrays, int  texCoordCount, floatArrayPtr  texCoordArrays  )

virtual

This method is obsolete.

Deprecated:

Use the version MPxHwShaderNode::geometry() with the faceIDs argument instead

This method is invoked for hardware rendering to Maya's 3D view.

This is the preferred method of interactive feedback and performance. the "gl" version should be used for batch hardware rendering.

This method does all the actual OpenGL drawing. The arguments contain all the data to successfully call glDrawElements or glDrawRangeElements. It is possible that there will be multiple calls to this method surrounded by a single call to bind() and unbind().

Note 1. The array of vertex IDs returned corresponds to each triangle's vertex. This allows access to associated blind data per vertex. The vertexIDs array allows querying of information such as color per vertex etc.

Note 2. The array of array parameters passed to this method can contain sparse information. Check array positions against NULL to ensure that the array information item is valid.

It is necessary to use the indexArray to access information contained in the data arrays.

Parameters

[in]	request	the draw request.
[in]	view	the view in which to draw.
[in]	prim	the type of primitive to draw. This is one of the values accepted by glBegin(). Typically it will be GL_TRIANGLES but it could be any of the others.
[in]	writable	this is a mask which indicates which of the various array arguments can be modified in place. If a bit in writable is set then you can modify corresponding data array (after casting it to a non-const type). If the bit is not set in writable then you must not modify the data since it points to internal Maya storage. You can test the bits in writeable against the values defined by the enum MPxHwShaderNode::Writable.
[in]	indexCount	specifies both the number of indices to draw and the size of the indexArray argument.
[in]	indexArray	the array of index values. This array is in a format suitable for passing as the indices argument to glDrawElements() or glDrawRangeElements(). See the OpenGL documentation for details on calling these routines.
[in]	vertexCount	the number of elements in the vertexArray, the normalArray, each of the colorArrays, and each of the texCoordArrays.
[in]	vertexIDs	the component IDs of the vertices in vertexArray. This array is only provided if it was requested by overriding the provideVertexIDs() method to return true.
[in]	vertexArray	the array of vertex data. Currently, this is always 3 element floating point values. This data is in a format suitable for passing to glVertexPointer(). See the OpenGL documentation for details.
[in]	normalCount	the number of individual "normal" arrays that are being provided in normalArrays. See the description of normalsPerVertex method below for details.
[in]	normalArrays	the normal (and tangent) data suitable. There may be 0, 1, 2, or 3 "normal" arrays. See the description of the normalsPerVertex method below for details.
[in]	colorCount	the number of individual color arrays.
[in]	colorArrays	the arrays of color data. The first set of color data is pointed to by colorArrays[0]. Each color array contains vertexCount color values, each of which is 4 floating point values long and represents the red, green, blue, and alph values on a 0 to 1 scale. Each individual array is suitable for passing to glColorPointer().
[in]	texCoordCount	the number of texture coordinate arrays. Each array contains one set of UV texture coordinates.
[in]	texCoordArrays	the arrays of texture coordinate data. The first set of texture coordinate data is pointed to by texCoordArrays[0]. Each array contains vertexCount coordinate values, each of which is 2 floating point values long. Each individual array is suitable for passing to glTexCoordPointer().

Returns

Status code.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus geometry ( const MDrawRequest &  request, M3dView &  view, int  prim, unsigned int  writable, int  indexCount, const unsigned int *  indexArray, int  vertexCount, const int *  vertexIDs, const float *  vertexArray, int  normalCount, floatArrayPtr  normalArrays, int  colorCount, floatArrayPtr  colorArrays, int  texCoordCount, floatArrayPtr  texCoordArrays, const int *  faceIDs, const float *  localUVCoord  )

virtual

This method is invoked for hardware rendering to Maya's 3D view.

This is the preferred method of interactive feedback and performance. the "gl" version should be used for batch hardware rendering.

This method does all the actual OpenGL drawing. The arguments contain all the data to successfully call glDrawElements or glDrawRangeElements. It is possible that there will be multiple calls to this method surrounded by a single call to bind() and unbind().

Note 1. The array of vertex IDs passed in corresponds to each triangle's vertex. This allows access to associated blind data per vertex. The vertexIDs array allows querying of information such as color per vertex etc.

The array of face IDs passed in can be used to query information at a per face level.

The array of local uv coords passed in stores the local uv of the subdivided face vertices.

Note 2. The array of array parameters passed to this method can contain sparse information. Check array positions against NULL to ensure that the array information item is valid.

It is necessary to use the indexArray to access information contained in the data arrays.

Parameters

[in]	request	the draw request.
[in]	view	the view in which to draw.
[in]	prim	the type of primitive to draw. This is one of the values accepted by glBegin(). Typically it will be GL_TRIANGLES but it could be any of the others.
[in]	writable	this is a mask which indicates which of the various array arguments can be modified in place. If a bit in writable is set then you can modify corresponding data array (after casting it to a non-const type). If the bit is not set in writable then you must not modify the data since it points to internal Maya storage. You can test the bits in writeable against the values defined by the enum MPxHwShaderNode::Writable.
[in]	indexCount	specifies both the number of indices to draw and the size of the indexArray argument.
[in]	indexArray	the array of index values. This array is in a format suitable for passing as the indices argument to glDrawElements() or glDrawRangeElements(). See the OpenGL documentation for details on calling these routines.
[in]	vertexCount	the number of elements in the vertexArray, the normalArray, each of the colorArrays, and each of the texCoordArrays, the vertexID, the faceID and the localUVCoord array. The array length is (vertexCount * the size of the type of data). e.g. vertexCount*3 for vertexArray, and vertexCount*1 for vertexID.
[in]	vertexIDs	the component IDs of the vertices in vertexArray. This array is only provided if it was requested by overriding the provideVertexIDs() method to return true.
[in]	vertexArray	the array of vertex data. Currently, this is always 3 element floating point values. This data is in a format suitable for passing to glVertexPointer(). See the OpenGL documentation for details.
[in]	normalCount	the number of individual "normal" arrays that are being provided in normalArrays. See the description of normalsPerVertex method below for details.
[in]	normalArrays	the normal (and tangent) data suitable. There may be 0, 1, 2, or 3 "normal" arrays. See the description of the normalsPerVertex method below for details.
[in]	colorCount	the number of individual color arrays.
[in]	colorArrays	the arrays of color data. The first set of color data is pointed to by colorArrays[0]. Each color array contains vertexCount color values, each of which is 4 floating point values long and represents the red, green, blue, and alpha values on a 0 to 1 scale. Each individual array is suitable for passing to glColorPointer().
[in]	texCoordCount	the number of texture coordinate arrays. Each array contains one set of UV texture coordinates.
[in]	texCoordArrays	the arrays of texture coordinate data. The first set of texture coordinate data is pointed to by texCoordArrays[0]. Each array contains vertexCount coordinate values, each of which is 2 floating point values long. Each individual array is suitable for passing to glTexCoordPointer().
[in]	faceIDs	the component IDs of the faces in vertexArray. This array is only provided if it was requested by overriding the provideFaceIDs() method to return true.
[in]	localUVCoord	the local uv of the smooth vertices in vertexArray. This array is only provided if it was requested by overriding the provideLocalUVCoord() method to return true.

Returns

Status code.

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

MStatus glBind ( const MDagPath &  shapePath )

virtual

This method should only be overridden for hardware rendering.

The implementation can assume the graphics context and model view projection matrix have already been set.

This method will be invoked once per frame and should be overridden to allocate any resources needed for the draw. For example, binding vertex programs, fragment programs, or allocating textures. A status code of MS::kSuccess should be returned unless there was a problem such as insufficient memory or required input data is missing or invalid.

Parameters

[in]

shapePath

Path to the surface being drawn.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus glUnbind ( const MDagPath &  shapePath )

virtual

This method should only be overridden for hardware rendering.

The implementation can assume the graphics context and model view projection matrix have already been set.

This method will be invoked once per frame and should be overridden to deallocate any resources used to draw. It's important that all resources be released when a batch hardware render has occured because the graphics context will be deleted. It may be desireable to override the other version of bind/unbind to keep track of whether the draw is for the 3D view or the batch hardware renderer. This information could then be used to better track the reuse of resources and optimize performance.

A status code of MS::kSuccess should be returned unless there was a problem.

Parameters

[in]

shapePath

Path to the surface being drawn.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus glGeometry ( const MDagPath &  shapePath, int  prim, unsigned int  writable, int  indexCount, const unsigned int *  indexArray, int  vertexCount, const int *  vertexIDs, const float *  vertexArray, int  normalCount, floatArrayPtr  normalArrays, int  colorCount, floatArrayPtr  colorArrays, int  texCoordCount, floatArrayPtr  texCoordArrays  )

virtual

This method is obsolete.

Deprecated:

Use the version MPxHwShaderNode::glGeometry() with the faceIDs argument instead

This method should only be overridden for hardware rendering.

The implementation can assume graphics context and model view projection matrix have already been set.

This method does all the actual OpenGL drawing. The arguments contain all the data to successfully call glDrawElements or glDrawRangeElements. It is possible that there will be multiple calls to this method surrounded by a single call to bind() and unbind().

Note 1. The array of vertex IDs returned corresponds to each triangle's vertex. This allows access to associated blind data per vertex. The vertexIDs array allows querying of information such as color per vertex etc.

Note 2. The array of array parameters passed to this method can contain sparse information. Check array positions against NULL to ensure that the array information item is valid.

It is necessary to use the indexArray to access information contained in the data arrays.

Parameters

[in]	shapePath	Path to the surface being drawn.
[in]	prim	the type of GL primitive is supplied as it would be used for glBegin() or glDrawElements(). Typically it will be GL_TRIANGLES or GL_TRIANGLE_STRIP for drawing polygonal or nurb surfaces respectively.
[in]	writable	this is a mask which indicates which of the various array arguments can be modified in place. If a bit in writable is set then you can modify corresponding data array (after casting it to a non-const type). If the bit is not set in writable then you must not modify the data since it points to internal Maya storage. You can test the bits in writeable against the values defined by the enum MPxHwShaderNode::Writable.
[in]	indexCount	specifies both the number of indices to draw and the size of the indexArray argument.
[in]	indexArray	the array of index values. This array is in a format suitable for passing as the indices argument to glDrawElements() or glDrawRangeElements(). See the OpenGL documentation for details on calling these routines.
[in]	vertexCount	the number of elements in the vertexArray, the normalArray, each of the colorArrays, and each of the texCoordArrays.
[in]	vertexIDs	the component IDs of the vertices in vertexArray. This array is only provided if it was requested by overriding the provideVertexIDs() method to return true.
[in]	vertexArray	the array of vertex data. Currently, this is always 3 element floating point values. This data is in a format suitable for passing to glVertexPointer(). See the OpenGL documentation for details.
[in]	normalCount	the number of individual "normal" arrays that are being provided in normalArrays. See the description of normalsPerVertex method below for details.
[in]	normalArrays	the normal (and tangent) data suitable. There may be 0, 1, 2, or 3 "normal" arrays. See the description of the normalsPerVertex method below for details.
[in]	colorCount	the number of individual color arrays.
[in]	colorArrays	the arrays of color data. The first set of color data is pointed to by colorArrays[0]. Each color array contains vertexCount color values, each of which is 4 floating point values long and represents the red, green, blue, and alpha values on a 0 to 1 scale. The 3D view and hardware renderer handle missing color data differently. The 3D view will create an array and pass black colors for each vertex, whereas the hardware renderer will supply a NULL pointer to indicate that color per-vertex data is unavailable.
[in]	texCoordCount	the number of texture coordinate arrays. Each array contains one set of UV texture coordinates.
[in]	texCoordArrays	the arrays of texture coordinate data. The first set of texture coordinate data is pointed to by texCoordArrays[0]. Each array contains vertexCount coordinate values, each of which is 2 floating point values long. Each individual array is suitable for passing to glTexCoordPointer(). The 3D view and hardware renderer handle missing texture coordinates differently. The 3D view will create an array of [0,0] texture coordinates for each vertex, whereas the hardware renderer will supply a NULL pointer to indicate that uv-set data is unavailable.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus glGeometry ( const MDagPath &  shapePath, int  prim, unsigned int  writable, int  indexCount, const unsigned int *  indexArray, int  vertexCount, const int *  vertexIDs, const float *  vertexArray, int  normalCount, floatArrayPtr  normalArrays, int  colorCount, floatArrayPtr  colorArrays, int  texCoordCount, floatArrayPtr  texCoordArrays, const int *  faceIDs, const float *  localUVCoord  )

virtual

This method should only be overridden for hardware rendering.

The implementation can assume graphics context and model view projection matrix have already been set.

This method does all the actual OpenGL drawing. The arguments contain all the data to successfully call glDrawElements or glDrawRangeElements. It is possible that there will be multiple calls to this method surrounded by a single call to bind() and unbind().

Note 1. The array of vertex IDs passed in corresponds to each triangle's vertex. This allows access to associated blind data per vertex. The vertexIDs array allows querying of information such as color per vertex etc.

The array of face IDs passed in can be used to query information at a per face level.

The array of local uv coords passed in stores the local uv of the subdivided face vertices.

Note 2. The array of array parameters passed to this method can contain sparse information. Check array positions against NULL to ensure that the array information item is valid.

It is necessary to use the indexArray to access information contained in the data arrays.

Parameters

[in]	shapePath	Path to the surface being drawn.
[in]	prim	the type of GL primitive is supplied as it would be used for glBegin() or glDrawElements(). Typically it will be GL_TRIANGLES or GL_TRIANGLE_STRIP for drawing polygonal or nurb surfaces respectively.
[in]	writable	this is a mask which indicates which of the various array arguments can be modified in place. If a bit in writable is set then you can modify corresponding data array (after casting it to a non-const type). If the bit is not set in writable then you must not modify the data since it points to internal Maya storage. You can test the bits in writeable against the values defined by the enum MPxHwShaderNode::Writable.
[in]	indexCount	specifies both the number of indices to draw and the size of the indexArray argument.
[in]	indexArray	the array of index values. This array is in a format suitable for passing as the indices argument to glDrawElements() or glDrawRangeElements(). See the OpenGL documentation for details on calling these routines.
[in]	vertexCount	the number of elements in the vertexArray, the normalArray, each of the colorArrays, each of the texCoordArrays, the vertexID, the faceID and the localUVCoord array. The array length is (vertexCount * the size of the type of data). e.g. vertexCount*3 for vertexArray, and vertexCount*1 for vertexID.
[in]	vertexIDs	the component IDs of the vertices in vertexArray. This array is only provided if it was requested by overriding the provideVertexIDs() method to return true.
[in]	vertexArray	the array of vertex data. Currently, this is always 3 element floating point values. This data is in a format suitable for passing to glVertexPointer(). See the OpenGL documentation for details.
[in]	normalCount	the number of individual "normal" arrays that are being provided in normalArrays. See the description of normalsPerVertex method below for details.
[in]	normalArrays	the normal (and tangent) data suitable. There may be 0, 1, 2, or 3 "normal" arrays. See the description of the normalsPerVertex method below for details.
[in]	colorCount	the number of individual color arrays.
[in]	colorArrays	the arrays of color data. The first set of color data is pointed to by colorArrays[0]. Each color array contains vertexCount color values, each of which is 4 floating point values long and represents the red, green, blue, and alpha values on a 0 to 1 scale. The 3D view and hardware renderer handle missing color data differently. The 3D view will create an array and pass black colors for each vertex, whereas the hardware renderer will supply a NULL pointer to indicate that color per-vertex data is unavailable.
[in]	texCoordCount	the number of texture coordinate arrays. Each array contains one set of UV texture coordinates.
[in]	texCoordArrays	the arrays of texture coordinate data. The first set of texture coordinate data is pointed to by texCoordArrays[0]. Each array contains vertexCount coordinate values, each of which is 2 floating point values long. Each individual array is suitable for passing to glTexCoordPointer(). The 3D view and hardware renderer handle missing texture coordinates differently. The 3D view will create an array of [0,0] texture coordinates for each vertex, whereas the hardware renderer will supply a NULL pointer to indicate that uv-set data is unavailable.
[in]	faceIDs	the component IDs of the faces in vertexArray. This array is only provided if it was requested by overriding the provideFaceIDs() method to return true.
[in]	localUVCoord	the local uv of the smooth vertices in vertexArray. This array is only provided if it was requested by overriding the provideLocalUVCoord() method to return true.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

bool supportsBatching ( ) const

virtual

Specifies whether or not this shader supports batched rendering of shapes.

In normal rendering, a shader is invoked using bind/geometry/unbind (or glBind/glGeometry/glUnbind) once for each shape being rendered. When a shader is used in batched rendering mode however, bind is called once, a series of geometry calls are made for each shape being rendered, followed by a single call to unbind (and similarly for glBind, glGeometry and glUnbind). As shader binding/unbinding can be expensive, batched rendering can significantly improve rendering performance. The more (particularly expensive) operations that can be moved out of the geometry/glGeometry methods the greater the performance improvement is. Ideally, only shape specific operations (such as binding geometry arrays and shape matrices) should be left in the geometry methods.

It is important to note that your shader can only use batched rendering mode if there is no shape (i.e. dag path) specific code in bind, glBind, unbind, or glUnbind. If any of these methods perform shape specific processing, this code must either be moved into geometry/glGeometry, or you must return false in this method to indicate batching should be disabled for this shader.

By default, this method will return false to ensure compatibility with existing shader code.

Returns

true if this shader supports batched rendering, false otherwise

Examples:

bool invertTexCoords ( ) const

virtual

Specifies whether this shader requires inverted texture coordinates.

(i.e. where the top-left hand corner of UV space is (0,0) instead of the bottom-left corner).

By default, this method will return false to ensure compatibility with existing shader code.

Returns

true if inverted texture coordinates are required, false otherwise

Examples:

const MDagPath & currentPath

(

)

const

This method returns a reference to the current path that the shader is invoked for.

The path is only valid before a call to any of the attribute specifying routines:

• normalsPerVertex()
• colorsPerVertex()
• getColorSetNames()
• texCoordsPerVertex()
• getTexCoordSetNames()
• hasTransparency()
• provideVertexIDs()

The path is not guaranteed to be valid at any other time.

This method allows the plugin to return attribute queries which are relative to a specific path or object.

For example, the plugin can retrieve the MObject from the path, then use the MFnMesh class on the MObject, assuming the object is a polygonal surface. Through MFnMesh the code can query the actual number of texture coordinate sets on the surface and return appropriate values for the getTexCoordSetNames() routine.

The [gl]bind(), [gl]unbind() and [gl]geometry() routines already have access to a dag path which is the same path as the one which can be retrieved via this method.

For performance reasons, it is recommended that for those methods the MDagPath passed in as an argument should be used.

Returns

An MDagPath. Note that this path can be invalid Use MDagPath::isValid() to confirm the validity of the path.

unsigned int dirtyMask

(

)

const

This method returns a "dirty" mask that indicates which geometry items have changed from the last invocation of the plugin to draw.

The mask is valid at the time that geometry() or glGeometry() is called and at no other time.

Note that this mask is relative to the geometry for the current object (path) being drawn by the shader. The current path is the MDagPath argument passed in via the geometry routines.

In general the mask will mark the geometry as not being dirty.

Scenarios where the geometry will be marked dirty include:

• Whenever a geometry attribute changes. For example positions or normals are modified.
• Whenever the attributes being requested changes from the previous invocation of the shader. For example, if in the previous invocation the plugin asks for position only, and in the current invocation asks for position and normals, then the geometry attributes returned will have changed and thus be marked "dirty".

Returns

The dirty mask which can be bit 'AND'ed against the MPxHwShaderNode::DirtyMask enum.

int normalsPerVertex ( )

virtual

Specifies how many normals per vertex the HW shader would like Maya to provide.

This can range from 0 to 3. The first normal is the surface normal. The second "normal" is the primary tangent (generally the "u" direction). The third "normal" is the secondary tangent or the binormal (generally the "v" direction). Together, the normal, tangent and binormal form an orthogonal basis frequently named "tangent space basis".

The tangent and binormal vectors are guaranteed to be normalized and orthogonal to the surface normal. Please note that extracting the tangent and/or binormal requires expensive calculations, that will slow down refresh time substantially. In a future version, Maya may cache the resulting tangent space basis; in the meantime, only ask for more than one normal per vertex if they are absolutely required.

Also note that the tangent and binormal calculation requires a uv map. Currently, they are always computed from the first available uv map; if there is no uv mapping on the surface, Maya will only provide surface normals in the geometry call, regardless of the value returned by normalsPerVertex().

If you do not override this method, Maya will provide 1 normal per vertex.

Maya will automatically and silently clamp the result of this function to the [0,3] range.

COMPATIBILITY NOTE: Automatic tangent space basis calculation is only supported starting with Maya 4.0.1. Maya 4.0 supported a different scheme that was much more complicated and no longer supported.

Returns

The number of normal values desired. (0 = none, 1 = surface normal only, 2 = surface normal + tangent, 3 = surface normal + tangent + binormal)

Examples:

int colorsPerVertex ( )

virtual

This method returns the number of color values per vertex that the hw shader node would like to receive from Maya.

Maya will attempt to provide all the color data that the shader would like but it will never provide more data that is actually available in the shape. The color sets returned by getColorSetNames() will override the number of color sets specified by colorsPerVertex(). If you do not override this method or getColorSetNames(), Maya will provide no colors per vertex.

Returns

The number of color values desired

Examples:

int getColorSetNames ( MStringArray &  names )

virtual

NO SCRIPT SUPPORT.

This method returns an array of color per vertex set names.

Maya will attempt to provide color per vertex data from these maps in the corresponding array element in the colorArrays argument to the geometry method. For example, if the names[2] is "cpv56" then colorArrays[2] will be the array of values from cpv56, or NULL if the shape being rendered does not have a color set of that name. If this method is not overridden an empty list of names will be returned, and Maya will use colorsPerVertex() to determine how many color sets to provide.

Parameters

[in]

names

a string array holding the names of the color per vertex sets from which color data should be extracted.

Returns

The number of elements in the names array.

Examples:

int texCoordsPerVertex ( )

virtual

This method returns the number of texture coordinate values per vertex that the hw shader node would like to receive from Maya.

Maya will attempt to provide all the texture coordinate data that the shader would like but it will never provide more data than is actually available in the shape. The uv sets returned by getTexCoordSetNames() will override the number of uv sets specified by texCoordsPerVertex(). If you do not override this method or getTexCoordSetNames(), Maya will provide no texture coordinates per vertex.

Note

Currently, Maya only retains 2 dimensional texture coordinate data but this may change in a future release.

Returns

The number of texture coordinate values desired

Examples:

int getTexCoordSetNames ( MStringArray &  names )

virtual

NO SCRIPT SUPPORT.

This method returns an array of texture coordinate set names.

Maya will attempt to provide texture coordinates from these maps in the corresponding array element in the texCoordArrays argument to the geometry method. For example, if the names[2] is "uvSet3" then texCoordArrays[2] will be the array of values from uvSet3. If this method is not overridden an empty list of names will be returned, and Maya will use texCoordsPerVertex() to determine how many uv sets to provide.

Parameters

[in]

names

a string array holding the names of the uvSets from which texture coordinate data should be extracted.

Returns

The number of elements in the names array.

Examples:

bool hasTransparency ( )

virtual

This method returns a boolean value that indicates whether the object will be drawn transparently or not.

Transparent objects must be drawn after all the opaque objects in the scene or they will not display correctly. Maya uses the return value to determine when it can draw this shape.

Note : The functionality in this method has been subsumed by the transparencyOptions() method. It is recommended that shader node writers use this newer method as it provides greater control over how transparency is interpreted by Maya's refresh mechanism.

For backward compatibility, if this method is specified and returns a "true" value, it will override the transparencyOptions() method.

Returns

true if the object will be transparent or false if it will not.

Examples:

bool provideVertexIDs ( )

virtual

This method returns a boolean value that indicates whether a map of the vertex IDs will be provided to the geometry method.

Returns

true if vertex IDs should be provided to the geometry method.

Examples:

bool provideFaceIDs ( )

virtual

This method returns a boolean value that indicates whether a map of the face IDs will be provided to the geometry method.

Returns

true if face IDs should be provided to the geometry method.

Examples:

bool provideLocalUVCoord ( )

virtual

This method returns a boolean value that indicates whether the local uv coordinates of the subdivided face vertices will be provided to the geometry method.

Returns

true if the local uv coordinates should be provided to the geometry method.

Examples:

unsigned int transparencyOptions ( )

virtual

This method returns transparency options for usage as hints for Maya's internal draw during a given rendering pass.

Parameters are returned via an integer containing masked out bits. By default the mask is set to 0, meaning that the drawing should be treated as regular opaque object drawing. This will generally mean one call per draw pass.

Options to control transparency are specified by returning one or more masks specified by the TransparencyOptions enumeration :

• kIsTransparent : Draw as a transparent object. If no transparency overrides are specified, then control of how to draw during a given pass is determined internally by Maya's refresh algorithm, and options the user can set per modelling viewport.
• kNoTransparencyFrontBackCull : When kisTransparent is set and this flag is set, do not perform transparency drawing using the internal 2-pass front-face + back-face culling algorithm.
• kNoTransparencyPolygonSort : When kisTransparent is set and this flag is set, do not perform transparency drawing using the internal 2-pass drawing of back-to-front sorted triangles.

Note : Setting the "hasTransparency()" method to true will override this method. This is for backward compatibility with behaviour on existing hardware shader nodes. It is recommended that shaders use the "transparencyOptions()" override, and not longer use the older "hasTransparency()" override from their shader classes.

Returns

Integer containing the appropriate options set via masks.

Examples:

MStatus getAvailableImages ( const MString &  uvSetName, MStringArray &  imageNames  )

virtual

NO SCRIPT SUPPORT.

Maya will call this method to get your shader's list of images which are available for use in the UV editor for the UV set specified.

Typically, this list will include one entry for each texture using the specified UV set, however, your shader is free to return as many images as you wish (for example, blending between two textures, texture alpha masks, artificially shaded views of bump/normal maps, etc). Your shader's renderImage() method will be used to render the images themselves.

Parameters

[in]	uvSetName	Name of a UV set the channel list should be filtered against.
[out]	imageNames	Array in which to return the names of the images this shader defines which are valid for the uvSetName specified.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.
• MS::kNotImplemented Use the default behaviour.

Examples:

MStatus renderImage ( const MString &  imageName, floatRegion  region, int &  imageWidth, int &  imageHeight  )

virtual

NO SCRIPT SUPPORT.

This method is obsolete.

Deprecated:

Use renderImage() that provides RenderParameters instead.

This method allows you to to render the background image used for this shader in the UV editor. The image requested will be one of the image names returned by your shader's getAvailableImages() method.

The implementation must return the dimensions of the image in the 'imageWidth' and 'imageHeight' parameters so that Maya can perform pixel snapping and other resolution-dependent operations.

The implementation can assume OpenGL context, model view projection matrix, and texture transformations have already been set. A default color of white will be set, however you are free to change this. The magnification filter will be set to either point or bilinear based on user configuration and should not be modified. The values of GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T are undefined on entry, and your implementation is responsible for setting them to appropriate values (e.g. GL_REPEAT).

The arguments contain the name of the image to render, and the vertex and texture coordinate values to use at each corner of the rectangular image being rendered. Your implementation is responsible for restoring the original the value of any OpenGL state that is modified.

For example:

glPushAttrib( <GL bits your shader modifies> );
glPushClientAttrib( GL_CLIENT_VERTEX_ARRAY_BIT);

... setup material here ...

glBegin( GL_QUADS);
glTexCoord2f(region[0][0], region[0][1]);
glVertex2f(region[0][0], region[0][1]);
glTexCoord2f(region[0][0], region[1][1]);
glVertex2f(region[0][0], region[1][1]);
glTexCoord2f(region[1][0], region[1][1]);
glVertex2f(region[1][0], region[1][1]);
glTexCoord2f(region[1][0], region[0][1]);
glVertex2f(region[1][0], region[0][1]);
glEnd();

glPopAttrib();
glPopClientAttrib();

Parameters

[in]	imageName	Name of the image to render. This corresponds to one of the image names returned by your shader's getAvailableImages() method.
[in]	region	Rectangular region to be rendered. The values of this parameter should be used to populate the vertex and texture coordinates of the rectangle being rendered.
[out]	imageWidth	Native width (e.g. texture pixel width) of the image. This should be for the entire image, not just the portion within 'region'.
[out]	imageHeight	Native height (e.g. texture pixel height) of the image. This should be for the entire image, not just the portion within 'region'.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

Examples:

MStatus renderImage ( const MString &  imageName, floatRegion  region, const MPxHwShaderNode::RenderParameters &  parameters, int &  imageWidth, int &  imageHeight  )

virtual

NO SCRIPT SUPPORT.

This method allows you to to render the background image used for this shader in the UV editor.

The image requested will be one of the image names returned by your shader's getAvailableImages() method.

The implementation must return the dimensions of the image in the 'imageWidth' and 'imageHeight' parameters so that Maya can perform pixel snapping and other resolution-dependent operations.

The implementation can assume OpenGL context, model view projection matrix, and texture transformations have already been set. A default color of white will be set, however you are free to change this. The magnification filter will be set to either point or bilinear based on user configuration and should not be modified. The values of GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T are undefined on entry, and your implementation is responsible for setting them to appropriate values (e.g. GL_REPEAT).

The arguments contain the name of the image to render, and the vertex and texture coordinate values to use at each corner of the rectangular image being rendered. Your implementation is responsible for restoring the original the value of any OpenGL state that is modified.

For example:

glPushAttrib( <GL bits your shader modifies> );
glPushClientAttrib( GL_CLIENT_VERTEX_ARRAY_BIT);

... setup material here ...

glBegin( GL_QUADS);
glTexCoord2f(region[0][0], region[0][1]);
glVertex2f(region[0][0], region[0][1]);
glTexCoord2f(region[0][0], region[1][1]);
glVertex2f(region[0][0], region[1][1]);
glTexCoord2f(region[1][0], region[1][1]);
glVertex2f(region[1][0], region[1][1]);
glTexCoord2f(region[1][0], region[0][1]);
glVertex2f(region[1][0], region[0][1]);
glEnd();

glPopAttrib();
glPopClientAttrib();

Parameters

[in]	imageName	Name of the image to render. This corresponds to one of the image names returned by your shader's getAvailableImages() method.
[in]	region	Rectangular region to be rendered. The values of this parameter should be used to populate the vertex and texture coordinates of the rectangle being rendered.
[in]	parameters	Additional parameters on how to render the image. The values reflect the image settings of the UV editor.
[out]	imageWidth	Native width (e.g. texture pixel width) of the image. This should be for the entire image, not just the portion within 'region'.
[out]	imageHeight	Native height (e.g. texture pixel height) of the image. This should be for the entire image, not just the portion within 'region'.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

MStatus renderImage ( MHWRender::MUIDrawManager &  uiDrawManager, const MString &  imageName, floatRegion  region, const MPxHwShaderNode::RenderParameters &  parameters, int &  imageWidth, int &  imageHeight  )

virtual

NO SCRIPT SUPPORT.

This method allows you to to render the background image used for this shader in the UV editor in viewport 2.0.

The image requested will be one of the image names returned by your shader's getAvailableImages() method.

The implementation must return the dimensions of the image in the 'imageWidth' and 'imageHeight' parameters so that Maya can perform pixel snapping and other resolution-dependent operations.

Parameters

[in]	uiDrawManager	The UI draw manager, it can be used to draw some simple geometry
[in]	imageName	Name of the image to render. This corresponds to one of the image names returned by your shader's getAvailableImages() method.
[in]	region	Rectangular region to be rendered. The values of this parameter should be used to populate the vertex and texture coordinates of the rectangle being rendered.
[in]	parameters	Additional parameters on how to render the image. The values reflect the image settings of the UV editor.
[out]	imageWidth	Native width (e.g. texture pixel width) of the image. This should be for the entire image, not just the portion within 'region'.
[out]	imageHeight	Native height (e.g. texture pixel height) of the image. This should be for the entire image, not just the portion within 'region'.

Returns

Status code

Status Codes:

• MS::kSuccess The method was successful.
• MS::kFailure An error has occurred.

MStatus renderSwatchImage ( MImage &  image )

virtual

If the shader specifies to override swatch rendering, then this method must be overridden in order to draw anything into a swatch.

The shader will only draw a swatch if it has been registered to do so, by providing a valid classification during MFnPlugin::registerNode(). The shader should provide a classification that defines a swatch rendering node such as : "shader/surface/utility/:drawdb/shader/surface/myCustomShader:swatch/myCustomShaderSwatchGenerator" and have "myCustomShaderSwatchGenerator" registered has a swatch renderer : MSwatchRenderRegister::registerSwatchRender("myCustomShaderSwatchGenerator", MHWShaderSwatchGenerator::createObj );

The default implementation is to draw nothing. The basic logic to draw a swatch is as follows:

• Determine the size of the swatch required. This is the dimensions of the MImage passed in as an argument. The pixels for the MImage will have been pre-allocated. The format of the pixels is 32-bit R,G,B,A, with 8-bits per channel.
• Either use an offscreen "swatch context" provided to you or use your own offscreen context. The provided context is available via the MHardwareRenderer class method makeSwatchContextCurrent(). Note that the swatch context may be smaller than the desired image size. In this case the rendering dimensions will be clamped.
• Either use swatch geometry provided to you, or use your own swatch geometry. The provided geometry is available via the method MHardwareRenderer::referenceDefaultGeometry(). The possible "default" geometries are either a sphere, cube or plane.
• Either use the provided "default" light and "default" camera or set up your own. Use the methods (getSwatchOrthoCameraSetting(), getSwatchLightDirection()) on MHardwareRenderer to get these defaults.
• Read back the swatch context into the provided MImage. The convenience method MHardwareRenderer::readSwatchContextPixels() can be used. By default the format of the MImage and the swatch context are the same, so the user does not need to worry about this. The context will read into the pre-allocated MImage pixels.
• Unreference any swatch geometry used for rendering using MHardwareRenderer::dereferenceGeometry().

Parameters

[in,out]

image

Image object to which this method must write the rendered swatch. On input the image's dimensions are already set and pixel storage already allocated.

Returns

Status code

Status Codes:

• MS::kNotImplemented : No rendering will occur.

Examples:

MPxHwShaderNode * getHwShaderNodePtr ( MObject &  object )

static

This is a static convenience method to be able to get an MPxHwShaderNode from an MObject provided by a swatch generator class (Class derived from MSwatchRenderRegister).

Parameters

[in]

object

The object to examine.

Returns

A pointer to an MPxHwShaderNode. If the method failed for any reason then a 0 (null) will be returned.

Examples:

MObject currentShadingEngine

(

)

const

This method returns an MObject to the shading engine that is currently being rendered.

This method will only return a valid MObject during the following calls:

• normalsPerVertex()
• colorsPerVertex()
• getColorSetNames()
• texCoordsPerVertex()
• getTexCoordSetNames()
• hasTransparency()
• provideVertexIDs()
• getAvailableImages()
• bind(), glBind()
• geometry(), glGeometry()
• unbind(), glUnbind()

Returns

The shading engine currently being rendered.

const char * className ( )

static

Returns the name of this class.

Returns

The name of this class.

---

The documentation for this class was generated from the following files:

• MPxHwShaderNode.h
• MPxHwShaderNode.cpp