示例#1
0
// Pre-render callback
//
void refreshCompute::preRenderCB(const MString& panelName, void * data)
{
	refreshCompute *thisCompute = (refreshCompute *) data;
	if (!thisCompute)
		return;

	M3dView view;
	MStatus status = M3dView::getM3dViewFromModelPanel(panelName, view);
	if (status != MS::kSuccess)
		return;

	int width = 0, height = 0;
	width = view.portWidth( &status );
	if (status != MS::kSuccess || (width < 2))
		return;
	height = view.portHeight( &status );
	if (status != MS::kSuccess || (height < 2))
		return;

	unsigned int vx,vy,vwidth,vheight;
	vx = 0;
	vy = 0;
	vwidth = width / 2;
	vheight = height / 2;
	status = view.pushViewport (vx, vy, vwidth, vheight);

	if (thisCompute->mBufferOperation != kDrawDepthBuffer)
	{
		M3dView view;
		MStatus status = M3dView::getM3dViewFromModelPanel(panelName, view);
		MPoint origin;
		status = view.drawText( MString("Pre render callback: ") + panelName, origin );
	}
}
MStatus initializePlugin(MObject obj)
{
	MFnPlugin plugin(obj, "David Kouril", "1.0", "Any");

	MStatus status = plugin.registerNode(CustomLocator::typeName,
		CustomLocator::typeId,
		CustomLocator::creator,
		CustomLocator::initialize,
		MPxNode::kLocatorNode); // is this why it didn't work before????????? yep, looks like it

	// register startStreamingCommand command
	status = plugin.registerCommand("startM2CVStreaming", startStreamingCommand::creator);
	status = plugin.registerCommand("endM2CVStreaming", endStreamingCommand::creator);
	status = plugin.registerCommand("showM2CVWindow", showStreamingWindowCommand::creator);

	streamer = new Streamer;

	// add a custom menu with items: Start streaming, Stop streaming
	MGlobal::executeCommand("global string $gMainWindow");
	MGlobal::executeCommand("setParent $gMainWindow");
	MGlobal::executeCommand("menu -label \"MayaToCellVIEW\" mayaToCelViewMenu");

	MGlobal::executeCommand("setParent -menu mayaToCelViewMenu");
	MGlobal::executeCommand("menuItem -label \"Start Streaming\" -command \"startM2CVStreaming\" startStreamingItem");
	MGlobal::executeCommand("menuItem -label \"End Streaming\" -command \"endM2CVStreaming\" -enable false endStreamingItem");
	MGlobal::executeCommand("menuItem -label \"Show Streaming Window\" -command \"showM2CVWindow\" -enable true showWindowItem");

	if (!status)
	{
		status.perror("Failed to register customLocator\n");
		return status;
	}

	std::cout << "initializePlugin successful." << std::endl;

	MStatus status1;
	M3dView viewport = M3dView::active3dView(&status1);
	std::cerr << "viewport dims: " << viewport.portWidth() << ", " << viewport.portHeight() << std::endl;

	// just testing the callbacks:
	MStatus callBackStatus;
	//MCallbackId callBackId = MUiMessage::add3dViewPostRenderMsgCallback(MString("persp"), &simpleCallBackTest, nullptr, &callBackStatus);
	MCallbackId callBackId = MUiMessage::add3dViewPostRenderMsgCallback(MString("modelPanel4"), &simpleCallBackTest, nullptr, &callBackStatus);
	if (callBackId == 0)
	{
		std::cerr << "Something's f****d up" << ", status: " << callBackStatus << std::endl;
	}

	return status;
}
示例#3
0
void xorDraw::beginXorDrawing()
{
	// Save the state of these 3 attribtes and restore them later.
	glGetBooleanv (GL_DEPTH_TEST, depthTest);
	glGetBooleanv (GL_COLOR_LOGIC_OP, colorLogicOp);
	glGetBooleanv (GL_LINE_STIPPLE, lineStipple);

	glDrawBuffer( GL_FRONT );

	// Turn Line stippling on.
	glLineStipple( 1, 0x5555 );
	glLineWidth( 1.0 );
	glEnable( GL_LINE_STIPPLE );

	// Save the state of the matrix on stack
	glMatrixMode (GL_MODELVIEW);
	glPushMatrix();

	// Setup the Orthographic projection Matrix.
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
    gluOrtho2D(
    			0.0, (GLdouble) fView->portWidth(),
    			0.0, (GLdouble) fView->portHeight()
    );
    glMatrixMode( GL_MODELVIEW );
	glLoadIdentity();
    glTranslatef(0.375, 0.375, 0.0);

	// Set the draw color
	glColor3f(1.0f, 1.0f, 1.0f);

	// Draw the marquee in XOR mode
	
	glDisable (GL_DEPTH_TEST);

	// Enable XOR mode.
	glEnable(GL_COLOR_LOGIC_OP);
	glLogicOp (GL_XOR);
}
示例#4
0
MStatus viewCapture::doIt( const MArgList& args )
{
	MStatus status = MS::kSuccess;

	if ( args.length() != 1 ) {
		// Need the file name argument
		//
		return MS::kFailure;
	}

	MString fileName;
	args.get( 0, fileName );

	// Get the active 3D view
	//
	M3dView view = M3dView::active3dView();

	// Capture the current view
	//
	view.refresh();
	view.beginGL();
 
	// Set the target for our pixel read to be the front buffer.  First, the
	// current state is saved using the glPushAttrib call.  It is important
	// to leave the OpenGL in the same state that we found it.
	//
	glPushAttrib( GL_PIXEL_MODE_BIT ); 

	int width = view.portWidth();
	int height = view.portHeight(); 

	// Allocate buffers for the pixel data
	//
	GLfloat * red   = new GLfloat[width*height];
	GLfloat * green = new GLfloat[width*height];
	GLfloat * blue  = new GLfloat[width*height];

	// Read the values from the OpenGL frame buffer
	//
	glReadBuffer( GL_FRONT );
	glReadPixels( 0, 0, width, height, GL_RED, GL_FLOAT, red );
	glReadPixels( 0, 0, width, height, GL_GREEN, GL_FLOAT, green );
	glReadPixels( 0, 0, width, height, GL_BLUE, GL_FLOAT, blue );
	
	// Put the gl read target back
	//
	glPopAttrib(); 

	view.endGL();

	// Write file as a PPM
	//
	Pic_Pixel * line = PixelAlloc( width );
	int idx;

	Pic * file = PicOpen( fileName.asChar(), (short) width, (short) height );
	if ( NULL != file ) { 
		for ( int row = height - 1; row >= 0; row-- ) {
			// Covert the row of pixels into PPM format
			//
			for ( int col = 0; col < width; col++ ) {
				// Find the array elements for this pixel
				//
				idx = ( row * width ) + ( col );
				line[col].r = (Pic_byte)( red[idx]   * 255.0 );
				line[col].g = (Pic_byte)( green[idx] * 255.0 );
				line[col].b = (Pic_byte)( blue[idx] * 255.0 );
			}
			// Write the line
			//
			if ( !PicWriteLine( file, line ) ) {
				status = MS::kFailure; 
				return MS::kFailure;
			}
		}
		PicClose( file ); 
	}
 
	delete []red;
	delete []green;
	delete []blue;
	PixelFree( line );

	return status;
}
示例#5
0
MStatus marqueeContext::doRelease( MEvent & event )
//
// Selects objects within the marquee box.
{

	MSelectionList			incomingList, marqueeList;

	// Clear the marquee when you release the mouse button

#ifdef USE_SOFTWARE_OVERLAYS

	GLboolean depthTest[1];
	GLboolean colorLogicOp[1];
	GLboolean lineStipple[1];

	event.getPosition( last_x, last_y );

	// Save the state of these 3 attribtes and restore them later.
	glGetBooleanv (GL_DEPTH_TEST, depthTest);
	glGetBooleanv (GL_COLOR_LOGIC_OP, colorLogicOp);
	glGetBooleanv (GL_LINE_STIPPLE, lineStipple);

	// Turn Line stippling on.
	glLineStipple( 1, 0x5555 );
	glLineWidth( 1.0 );
	glEnable( GL_LINE_STIPPLE );

	// Disable GL_DEPTH_TEST
	glDisable (GL_DEPTH_TEST);

	// Enable XOR mode.
	glEnable(GL_COLOR_LOGIC_OP);
	glLogicOp (GL_INVERT);

	// Save the current Matrix onto the stack
	glMatrixMode (GL_MODELVIEW);
	glPushMatrix();

	// Setup the Orthographic projection Matrix.
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
    gluOrtho2D(
    			0.0, (GLdouble) view.portWidth(),
    			0.0, (GLdouble) view.portHeight()
    );
    glMatrixMode( GL_MODELVIEW );
	glLoadIdentity();
    glTranslatef(0.375, 0.375, 0.0);

	// Set the draw color
	glIndexi (2);

	// Redraw the marquee so that it will be cleared from the screen
	// when the mouse is released.
	glBegin( GL_LINE_LOOP );
		glVertex2i( start_x, start_y );
		glVertex2i( p_last_x, start_y );
		glVertex2i( p_last_x, p_last_y );
		glVertex2i( start_x, p_last_y );
	glEnd();
		

#ifndef _WIN32
    glXSwapBuffers( view.display(), view.window() );
#else
	SwapBuffers( view.deviceContext() );
#endif

	// Restore saved Matrix from stack
	glMatrixMode( GL_MODELVIEW );
	glPopMatrix();

	glDisable(GL_COLOR_LOGIC_OP);
	
	// Restore the previous state of these attributes
	if (colorLogicOp[0])
		glEnable (GL_COLOR_LOGIC_OP);
	else
		glDisable (GL_COLOR_LOGIC_OP);

	if (depthTest[0])
		glEnable (GL_DEPTH_TEST);
	else
		glDisable (GL_DEPTH_TEST);

	if (lineStipple[0])
		glEnable( GL_LINE_STIPPLE );
	else
		glDisable( GL_LINE_STIPPLE );

#else
	// If HW overlays enabled, then clear the overlay plane
	// such that the marquee is no longer drawn on screen.
	view.clearOverlayPlane();
	view.endOverlayDrawing();
#endif

	view.endGL();

	// Get the end position of the marquee
	event.getPosition( last_x, last_y );

	// Save the state of the current selections.  The "selectFromSceen"
	// below will alter the active list, and we have to be able to put
	// it back.
	MGlobal::getActiveSelectionList(incomingList);

	// If we have a zero dimension box, just do a point pick
	//
	if ( abs(start_x - last_x) < 2 && abs(start_y - last_y) < 2 ) {
		MGlobal::selectFromScreen( start_x, start_y, MGlobal::kReplaceList );
	} else {
		// Select all the objects or components within the marquee.
		MGlobal::selectFromScreen( start_x, start_y, last_x, last_y,
								   MGlobal::kReplaceList );
	}

	// Get the list of selected items
	MGlobal::getActiveSelectionList(marqueeList);

	// Restore the active selection list to what it was before
	// the "selectFromScreen"
	MGlobal::setActiveSelectionList(incomingList, MGlobal::kReplaceList);

	// Update the selection list as indicated by the modifier keys.
	MGlobal::selectCommand(marqueeList, listAdjustment);
	return MS::kSuccess;		
}
示例#6
0
MStatus marqueeContext::doDrag( MEvent & event )
//
// Drag out the marquee (using OpenGL)
//
{
	
	event.getPosition( last_x, last_y );


#ifdef USE_SOFTWARE_OVERLAYS

	GLboolean depthTest[1];
	GLboolean colorLogicOp[1];
	GLboolean lineStipple[1];

	// Save the state of these 3 attribtes and restore them later.
	glGetBooleanv (GL_DEPTH_TEST, depthTest);
	glGetBooleanv (GL_COLOR_LOGIC_OP, colorLogicOp);
	glGetBooleanv (GL_LINE_STIPPLE, lineStipple);
#endif

	// Turn Line stippling on.
	glLineStipple( 1, 0x5555 );
	glLineWidth( 1.0 );
	glEnable( GL_LINE_STIPPLE );

	// Save the state of the matrix on stack
	glMatrixMode (GL_MODELVIEW);
	glPushMatrix();

	// Setup the Orthographic projection Matrix.
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
    gluOrtho2D(
    			0.0, (GLdouble) view.portWidth(),
    			0.0, (GLdouble) view.portHeight()
    );
    glMatrixMode( GL_MODELVIEW );
	glLoadIdentity();
    glTranslatef(0.375, 0.375, 0.0);

	// Set the draw color
	glIndexi (2);

	// If we are using software overlays then we need to draw the marquee
	// in XOR mode

#ifdef USE_SOFTWARE_OVERLAYS
	
	glDisable (GL_DEPTH_TEST);

	// Enable XOR mode.
	glEnable(GL_COLOR_LOGIC_OP);
	glLogicOp (GL_XOR);

	// We erase the previously drawn rubber band on the screen by 
	// redrawing it in XOR OpenGL mode.

	if (fsDrawn)
	{
		
		glBegin( GL_LINE_LOOP );
			glVertex2i( start_x, start_y );
			glVertex2i( p_last_x, start_y );
			glVertex2i( p_last_x, p_last_y );
			glVertex2i( start_x, p_last_y );
		glEnd();
		
	}

	fsDrawn = true;
#else
	// If HW overlays enabled then we will clear the overlay plane 
	// so that the previously drawn marquee does not appear on the screen
	// anymore
	view.clearOverlayPlane();

#endif

	// Draw the rectangular marquee
	//
	glBegin( GL_LINE_LOOP );
		glVertex2i( start_x, start_y );
		glVertex2i( last_x, start_y );
		glVertex2i( last_x, last_y );
		glVertex2i( start_x, last_y );
	glEnd();

#ifdef _WIN32
	SwapBuffers( view.deviceContext() );
#elif defined (OSMac_)
	::aglSwapBuffers(view.display()); 
#else
	glXSwapBuffers( view.display(), view.window() );
#endif

	// Restore the state of the matrix from stack
	glMatrixMode( GL_MODELVIEW );
	glPopMatrix();


#ifdef USE_SOFTWARE_OVERLAYS
	// Store the current x and y coordinates such that in the next iteration
	// we can erase this marquee by redrawing it in XOR mode.
	p_last_x = last_x;
	p_last_y = last_y;

	// Restore the previous state of these attributes
	if (colorLogicOp[0])
		glEnable (GL_COLOR_LOGIC_OP);
	else
		glDisable (GL_COLOR_LOGIC_OP);

	if (depthTest[0])
		glEnable (GL_DEPTH_TEST);
	else
		glDisable (GL_DEPTH_TEST);

	if (lineStipple[0])
		glEnable( GL_LINE_STIPPLE );
	else
		glDisable( GL_LINE_STIPPLE );
#endif

	return MS::kSuccess;		

}
示例#7
0
void ProxyViz::draw( M3dView & view, const MDagPath & path, 
							 M3dView::DisplayStyle style,
							 M3dView::DisplayStatus status )
{
	if(!m_enableCompute) return;
	MObject thisNode = thisMObject();
	updateWorldSpace(thisNode);
	
	MPlug mutxplug( thisNode, axmultiplier);
	MPlug mutyplug( thisNode, aymultiplier);
	MPlug mutzplug( thisNode, azmultiplier);
	setScaleMuliplier(mutxplug.asFloat(), 
						mutyplug.asFloat(),
						mutzplug.asFloat() );	
                        
    MPlug svtPlug(thisNode, adisplayVox);
    setShowVoxLodThresold(svtPlug.asFloat() );
	
	MDagPath cameraPath;
	view.getCamera(cameraPath);
	if(hasView() ) updateViewFrustum(thisNode);
	else updateViewFrustum(cameraPath);
	
	setViewportAspect(view.portWidth(), view.portHeight() );
	
	MPlug actp(thisNode, aactivated);
	if(actp.asBool()) setWireColor(.125f, .1925f, .1725f);
    else setWireColor(.0675f, .0675f, .0675f);

	_viewport = view;
	fHasView = 1;
	
	view.beginGL();
	
	double mm[16];
	matrix_as_array(_worldInverseSpace, mm);
	
	glPushMatrix();
	glMultMatrixd(mm);	
	
	ExampVox * defBox = plantExample(0);
	updateGeomBox(defBox, thisNode);
	drawWireBox(defBox->geomCenterV(), defBox->geomScale() );
	Matrix44F mat;
	mat.setFrontOrientation(Vector3F::YAxis);
	mat.scaleBy(defBox->geomSize() );
    mat.glMatrix(m_transBuf);
	
	drawCircle(m_transBuf);
	
	drawGridBounding();
	// drawGrid();

	if ( style == M3dView::kFlatShaded || 
		    style == M3dView::kGouraudShaded ) {		
		drawPlants();
	}
	else 
		drawWiredPlants();
	
    if(hasView() ) drawViewFrustum();
    
	drawBrush(view);
	drawActivePlants();
	drawGround();
	glPopMatrix();
	view.endGL();
	std::cout<<" viz node draw end";
}
示例#8
0
// Post-render callback
//
void refreshCompute::postRenderCB(const MString& panelName, void * data)
{	
	refreshCompute *thisCompute = (refreshCompute *) data;
	if (!thisCompute)
		return;

	// Get the view if any for the panel
	M3dView view;
	MStatus status = M3dView::getM3dViewFromModelPanel(panelName, view);
	if (status != MS::kSuccess)
		return;

	view.popViewport();

	if (thisCompute->mBufferOperation == kDrawDepthBuffer)
	{
		int width = 0, height = 0;
		width = view.portWidth( &status ) / 2 ;
		if (status != MS::kSuccess || (width < 2))
			return;
		height = view.portHeight( &status ) / 2 ;
		if (status != MS::kSuccess || (height < 2))
			return;

		unsigned int numPixels = width * height;

		float *depthPixels = new float[numPixels];
		if (!depthPixels)
			return;

		unsigned char *colorPixels = new unsigned char[numPixels * 4];
		if (!colorPixels)
		{
			delete depthPixels;
			delete colorPixels;
		}

		// Read into a float buffer
		status = view.readDepthMap( 0,0, width, height, (unsigned char *)depthPixels, M3dView::kDepth_Float );

		if (status != MS::kSuccess)
		{
			delete depthPixels;
			delete colorPixels;
			return;
		}

		// Find depth range and remap normalized depth range (-1 to 1) into 0...255
		// for color.
		float *dPtr = depthPixels;
		unsigned int i = 0;

		float zmin = 100.0f; // *dPtr;
		float zmax = -100.0f; // *dPtr;
		for(i=0; i<numPixels; i++)
		{
			float val = *dPtr; // * 2.0f - 1.0f;
			if(val < zmin) {
				zmin = *dPtr;
			}
			if(val > zmax) {
				zmax = *dPtr;
			}
			dPtr++;
		}
		float zrange = zmax - zmin;
		//printf("depth values = (%g, %g). Range = %g\n", zmin, zmax, zrange);

		unsigned char *cPtr = colorPixels;

		dPtr = depthPixels;
		for(i=0; i < numPixels; i++)
		{
			float val = *dPtr; // * 2.0f - 1.0f;
			//unsigned char depth = (unsigned char)(255.0f * (( (*dPtr)-zmin) / zrange) + zmin );
			unsigned char depth = (unsigned char)(255.0f * (( (val)-zmin) / zrange) );
			//unsigned char depth = (unsigned char)(255.0f * val);
			*cPtr = depth; cPtr++;
			*cPtr = depth; cPtr++;
			*cPtr = depth; cPtr++;
			*cPtr = 0xff;   
			cPtr++;
			dPtr++;
		}

		MImage image;
		image.setPixels( colorPixels, width, height );

		// Uncomment next line to test writing buffer to file.
		//image.writeToFile( "C:\\temp\\dumpDepth.iff" );

		// Write all pixels back. The origin of the image (lower left)
		// is used 
		status = view.writeColorBuffer( image, 5, 5 );

		if (depthPixels)
			delete depthPixels;
		if (colorPixels)
			delete colorPixels;
	}

	// Do a simple color invert operation on all pixels
	//
	else if (thisCompute->mBufferOperation == kInvertColorBuffer)
	{
		// Optional to read as RGBA. Note that this will be slower
		// since we must swizzle the bytes around from the default
		// BGRA format.
		bool readAsRGBA = true;

		// Read the RGB values from the color buffer
		MImage image;
		status = view.readColorBuffer( image, readAsRGBA );
		if (status != MS::kSuccess)
			return;

		status = view.writeColorBuffer( image, 5, 5 );

		unsigned char *pixelPtr = (unsigned char*)image.pixels();
		if (pixelPtr)
		{
			unsigned int width, height;
			image.getSize( width, height );

			MImage image2;
			image2.create( width, height );
			unsigned char *pixelPtr2 = (unsigned char*)image2.pixels();

			unsigned int numPixels = width * height;
			for (unsigned int i=0; i < numPixels; i++)
			{
				*pixelPtr2 = (255 - *pixelPtr);	
				pixelPtr2++; pixelPtr++;
				*pixelPtr2 = (255 - *pixelPtr);	
				pixelPtr2++; pixelPtr++;
				*pixelPtr2 = (255 - *pixelPtr);	
				pixelPtr2++; pixelPtr++;
				*pixelPtr2 = 255;	
				pixelPtr2++; pixelPtr++;
			}

			// Write all pixels back. The origin of the image (lower left)
			// is used 
			status = view.writeColorBuffer( image2, 5, short(5+height/2) );
		}
	}
}
示例#9
0
bool SceneShapeUI::snap( MSelectInfo &snapInfo ) const
{
	MStatus s;

	if( snapInfo.displayStatus() != M3dView::kHilite )
	{
		MSelectionMask meshMask( MSelectionMask::kSelectMeshes );
		if( !snapInfo.selectable( meshMask ) )
		{
			return false;
		}
	}

	// early out if we have no scene to draw
	SceneShape *sceneShape = static_cast<SceneShape *>( surfaceShape() );
	const IECore::SceneInterface *sceneInterface = sceneShape->getSceneInterface().get();
	if( !sceneInterface )
	{
		return false;
	}

	IECoreGL::ConstScenePtr scene = sceneShape->glScene();
	if( !scene )
	{
		return false;
	}

	// Get the viewport that the snapping operation is taking place in.
	M3dView view = snapInfo.view();

	// Use an IECoreGL::Selector to find the point in world space that we wish to snap to.
	// We do this by first getting the origin of the selection ray and transforming it into
	// NDC space using the OpenGL projection and transformation matrices. Once we have the
	// point in NDC we can use it to define the viewport that the IECoreGL::Selector will use.

	MPoint localRayOrigin;
	MVector localRayDirection;
	snapInfo.getLocalRay( localRayOrigin, localRayDirection );
	
	Imath::V3d org( localRayOrigin[0], localRayOrigin[1], localRayOrigin[2] );
	MDagPath camera;
	view.getCamera( camera );
	MMatrix localToCamera = snapInfo.selectPath().inclusiveMatrix() * camera.inclusiveMatrix().inverse();
	
	view.beginSelect();
		Imath::M44d projectionMatrix;
		glGetDoublev( GL_PROJECTION_MATRIX, projectionMatrix.getValue() );
	view.endSelect();

	double v[4][4];
	localToCamera.get( v ); 
	Imath::M44d cam( v );
	Imath::V3d ndcPt3d = ( (org * cam ) * projectionMatrix + Imath::V3d( 1. ) ) * Imath::V3d( .5 );
	Imath::V2d ndcPt( std::max( std::min( ndcPt3d[0], 1. ), 0. ), 1. - std::max( std::min( ndcPt3d[1], 1. ), 0. ) );

	view.beginGL();
	
		glMatrixMode( GL_PROJECTION );
		glLoadMatrixd( projectionMatrix.getValue() );
		
		float radius = .001; // The radius of the selection area in NDC.
		double aspect = double( view.portWidth() ) / view.portHeight();
		Imath::V2f selectionWH( radius, radius * aspect );
		
		std::vector<IECoreGL::HitRecord> hits;
		{
			IECoreGL::Selector selector( Imath::Box2f( ndcPt - selectionWH, ndcPt + selectionWH ), IECoreGL::Selector::IDRender, hits );
				
			IECoreGL::State::bindBaseState();
			selector.baseState()->bind();
			scene->render( selector.baseState() );			
		}
				
	view.endGL();

	if( hits.empty() )
	{
		return false;
	}

	// Get the closest mesh hit.	
	float depthMin = std::numeric_limits<float>::max();
	int depthMinIndex = -1;
	for( unsigned int i=0, e = hits.size(); i < e; i++ )
	{		
		if( hits[i].depthMin < depthMin )
		{
			depthMin = hits[i].depthMin;
			depthMinIndex = i;
		}
	}

	// Get the absolute path of the hit object.
	IECore::SceneInterface::Path objPath;
	std::string objPathStr;
	sceneInterface->path( objPath );
	IECore::SceneInterface::pathToString( objPath, objPathStr );
	
	objPathStr += IECoreGL::NameStateComponent::nameFromGLName( hits[depthMinIndex].name );
	IECore::SceneInterface::stringToPath( objPathStr, objPath );

	// Validate the hit selection.
	IECore::ConstSceneInterfacePtr childInterface;
	try
	{
		childInterface = sceneInterface->scene( objPath );
	}
	catch(...)
	{
		return false;
	}

	if( !childInterface )
	{
		return false;
	}
	
	if( !childInterface->hasObject() )
	{
		return false;
	}

	// Get the mesh primitive so that we can query it's vertices.
	double time = sceneShape->time();
	IECore::ConstObjectPtr object = childInterface->readObject( time );
	IECore::ConstMeshPrimitivePtr meshPtr = IECore::runTimeCast<const IECore::MeshPrimitive>( object.get() );
	
	if ( !meshPtr )
	{
		return false;
	}
	
	// Calculate the snap point in object space.
	MPoint worldIntersectionPoint;
	selectionRayToWorldSpacePoint( camera, snapInfo, depthMin, worldIntersectionPoint );
	Imath::V3f pt( worldIntersectionPoint[0], worldIntersectionPoint[1], worldIntersectionPoint[2] );
	Imath::M44f objToWorld( worldTransform( childInterface.get(), time ) );
	pt = pt * objToWorld.inverse();

	// Get the list of vertices in the mesh.
	IECore::V3fVectorData::ConstPtr pointData( meshPtr->variableData<IECore::V3fVectorData>( "P", IECore::PrimitiveVariable::Vertex ) ); 
	const std::vector<Imath::V3f> &vertices( pointData->readable() ); 
	
	// Find the vertex that is closest to the snap point.
	Imath::V3d closestVertex;
	float closestDistance = std::numeric_limits<float>::max(); 
	
	for( std::vector<Imath::V3f>::const_iterator it( vertices.begin() ); it != vertices.end(); ++it )
	{
		Imath::V3d vert( *it );
		float d( ( pt - vert ).length() ); // Calculate the distance between the vertex and the snap point.
		if( d < closestDistance )
		{
			closestDistance = d;
			closestVertex = vert;
		}
	}

	// Snap to the vertex.
	closestVertex *= objToWorld;
	snapInfo.setSnapPoint( MPoint( closestVertex[0], closestVertex[1], closestVertex[2] ) );
	return true;
}