Python Geom.addPrimitive方法代码示例

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def create_hexagon(radius):
    """ Creates a hexagon shape that is centered at (0,0,0) with the corners having a distance of radius to the center and
    the normals pointing in direction (0,-1,0). 
    Returns the tuple (PandaNode, GeomVertexData). """
    format = GeomVertexFormat.getV3n3c4t2()
    vdata=GeomVertexData('hexagon', format, Geom.UHStatic)
    vertex=GeomVertexWriter(vdata, 'vertex')
    normal=GeomVertexWriter(vdata, 'normal')
    # create the vertices
    vertex.addData3f(0,0,0)
    normal.addData3f(0,-1,0)
    # add the other vertices
    for phi in range(0,360,60):
        # right-hand-rule (with middle finger pointing upwards): the y-axis points towards the screen,
        # therefore the hexagon will be created in the x,z plane, with x-axis pointing to the right
        # and the z-axis pointing up
        # get the next vertex coordinates by rotating the point (0,0,radius) in the x,z plane
        x,z = rotate_phi_degrees_counter_clockwise(phi, (0,radius))
        #print (x,z)
        vertex.addData3f(x,0,z) 
        normal.addData3f(0,-1,0) # the normal vector points away from the screen
    # add the vertices to a geometry primitives
    prim = GeomTrifans(Geom.UHStatic)
    for i in range(7):
        prim.addVertex(i)
    prim.addVertex(1)
    prim.closePrimitive()
    geom = Geom(vdata)
    geom.addPrimitive(prim)
    hex_node = GeomNode('')
    hex_node.addGeom(geom)
    return hex_node, vdata

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def create_side(x_z_top_left, x_z_bottom_right, static=True):
    x1, z1 = x_z_top_left
    x2, z2 = x_z_bottom_right
    format = GeomVertexFormat.getV3n3c4t2()
    vdata = GeomVertexData('', format, Geom.UHStatic)
    vertex = GeomVertexWriter(vdata, 'vertex')
    normal = GeomVertexWriter(vdata, 'normal')
    vertex.addData3f(x1, 0, z1) # top left
    vertex.addData3f(x2, 0, z1) # top right
    vertex.addData3f(x2, 0, z2) # bottom right
    vertex.addData3f(x1, 0, z2) # bottom left
    for _i in range(4):
        normal.addData3f(0, - 1, 0)
    if static:
        prim_hint = Geom.UHStatic
    else:
        prim_hint = Geom.UHDynamic
    prim = GeomTristrips(prim_hint)
    prim.addVertices(1, 0, 2, 3)
    prim.closePrimitive()
    geom = Geom(vdata)
    geom.addPrimitive(prim)
    node = GeomNode('')
    node.addGeom(geom)
    return (node, vdata)

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def create_triangle(x_z_left, x_z_top, x_z_right, static=True):
    x1,z1 = x_z_left
    x2,z2 = x_z_top
    x3,z3 = x_z_right
    format = GeomVertexFormat.getV3n3c4t2()
    vdata=GeomVertexData('', format, Geom.UHStatic)
    vertex=GeomVertexWriter(vdata, 'vertex')
    normal=GeomVertexWriter(vdata, 'normal')
    vertex.addData3f(x1, 0, z1) # left
    vertex.addData3f(x2, 0, z2) # top
    vertex.addData3f(x3, 0, z3) # right
    for _i in range(3):
        normal.addData3f(0,-1,0)
    if static:
        prim_hint = Geom.UHStatic
    else:
        prim_hint = Geom.UHDynamic
    prim = GeomTriangles(prim_hint)
    prim.addVertices(0,2,1)
    prim.closePrimitive()
    geom = Geom(vdata)
    geom.addPrimitive(prim)
    node = GeomNode('')
    node.addGeom(geom)
    return node

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
 def draw(self):
     format=GeomVertexFormat.getV3n3cpt2()
     vdata=GeomVertexData('square', format, Geom.UHDynamic)
     vertex=GeomVertexWriter(vdata, 'vertex')
     normal=GeomVertexWriter(vdata, 'normal')
     color=GeomVertexWriter(vdata, 'color')
     circle=Geom(vdata)
     # Create vertices
     vertex.addData3f(self.pos)
     color.addData4f(self.color)
     for v in range(self._EDGES):
         x = self.pos.getX() + (self.size * math.cos((2*math.pi/self._EDGES)*v))
         y = self.pos.getY() + (self.size * math.sin((2*math.pi/self._EDGES)*v))
         z = self.pos.getZ()
         vertex.addData3f(x, y, z)
         color.addData4f(self.color)
     
     # Create triangles
     for t in range(self._EDGES):
         tri = GeomTriangles(Geom.UHDynamic)
         tri.addVertex(0)
         tri.addVertex(t+1)
         if (t+2) > self._EDGES:
             tri.addVertex(1)
         else:
             tri.addVertex(t+2)
         tri.closePrimitive()
         circle.addPrimitive(tri)
     
     gn = GeomNode('Circle')
     gn.addGeom(circle)
     np = NodePath(gn)
     np.setHpr(0, 90, 0)
     return np

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
	def circle (self, radius, axis, offset):	
		
		# since we're doing line segments, just vertices in our geom 
		format = GeomVertexFormat.getV3() 
		
		# build our data structure and get a handle to the vertex column 
		vdata = GeomVertexData ('', format, Geom.UHStatic) 
		vertices = GeomVertexWriter (vdata, 'vertex') 
				
		# build a linestrip vertex buffer 
		lines = GeomLinestrips (Geom.UHStatic) 
		
		for i in range (0, self.subdiv): 
			angle = i / float(self.subdiv) * 2.0 * math.pi 
			ca = math.cos (angle) 
			sa = math.sin (angle) 
			if axis == "x": 
				vertices.addData3f (0, radius * ca, radius * sa + offset) 
			if axis == "y": 
				vertices.addData3f (radius * ca, 0, radius * sa + offset) 
			if axis == "z": 
				vertices.addData3f (radius * ca, radius * sa, offset) 
		
		for i in range (1, self.subdiv): 
			lines.addVertices(i - 1, i) 
		lines.addVertices (self.subdiv - 1, 0) 
			
		lines.closePrimitive() 
		
		geom = Geom (vdata) 
		geom.addPrimitive (lines) 
		# Add our primitive to the geomnode 
		self.gnode.addGeom (geom) 

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
    def __init__(self, width=1, depth=1, height=1, origin=Point3(0, 0, 0)):

        # Create vetex data format
        gvf = GeomVertexFormat.getV3n3()
        gvd = GeomVertexData("vertexData", gvf, Geom.UHStatic)

        # Create vetex writers for each type of data we are going to store
        gvwV = GeomVertexWriter(gvd, "vertex")
        gvwN = GeomVertexWriter(gvd, "normal")

        # Write out all points
        for p in GetPointsForBox(width, depth, height):
            gvwV.addData3f(Point3(p) - origin)

        # Write out all the normals
        for n in ((-1, 0, 0), (1, 0, 0), (0, -1, 0), (0, 1, 0), (0, 0, -1), (0, 0, 1)):
            for i in range(4):
                gvwN.addData3f(n)

        geom = Geom(gvd)
        for i in range(0, gvwV.getWriteRow(), 4):

            # Create and add both triangles
            geom.addPrimitive(GetGeomTriangle(i, i + 1, i + 2))
            geom.addPrimitive(GetGeomTriangle(i, i + 2, i + 3))

        # Init the node path, wrapping the box
        geomNode = GeomNode("box")
        geomNode.addGeom(geom)
        NodePath.__init__(self, geomNode)

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
	def drawSquare(self, x1,y1,z1, x2,y2,z2):
		format=GeomVertexFormat.getV3n3cpt2()
		vdata=GeomVertexData('square', format, Geom.UHStatic)
		
		vertex=GeomVertexWriter(vdata, 'vertex')
		normal=GeomVertexWriter(vdata, 'normal')
		color=GeomVertexWriter(vdata, 'color')
		texcoord=GeomVertexWriter(vdata, 'texcoord')
		
		#make sure we draw the sqaure in the right plane
		#if x1!=x2:
		vertex.addData3f(x1, y1, z1)
		vertex.addData3f(x2, y1, z1)
		vertex.addData3f(x2, y2, z2)
		vertex.addData3f(x1, y2, z2)

		normal.addData3f(self.myNormalize(Vec3(2*x1-1, 2*y1-1, 2*z1-1)))
		normal.addData3f(self.myNormalize(Vec3(2*x2-1, 2*y1-1, 2*z1-1)))
		normal.addData3f(self.myNormalize(Vec3(2*x2-1, 2*y2-1, 2*z2-1)))
		normal.addData3f(self.myNormalize(Vec3(2*x1-1, 2*y2-1, 2*z2-1)))
		
		#adding different colors to the vertex for visibility
		color.addData4f(0.0,0.5,0.0,0.5)
		color.addData4f(0.0,0.5,0.0,0.5)
		color.addData4f(0.0,0.5,0.0,0.5)
		color.addData4f(0.0,0.5,0.0,0.5)
		
		texcoord.addData2f(0.0, 1.0)
		texcoord.addData2f(0.0, 0.0)
		texcoord.addData2f(1.0, 0.0)
		texcoord.addData2f(1.0, 1.0)

		#quads arent directly supported by the Geom interface
		#you might be interested in the CardMaker class if you are
		#interested in rectangle though
		tri1=GeomTriangles(Geom.UHStatic)
		tri2=GeomTriangles(Geom.UHStatic)
		
		tri1.addVertex(0)
		tri1.addVertex(1)
		tri1.addVertex(3)
		
		tri2.addConsecutiveVertices(1,3)
		
		tri1.closePrimitive()
		tri2.closePrimitive()
		
		square=Geom(vdata)
		square.addPrimitive(tri1)
		square.addPrimitive(tri2)
		#square.setIntoCollideMask(BitMask32.bit(1))
		
		squareNP = NodePath(GeomNode('square gnode')) 
		squareNP.node().addGeom(square)
		squareNP.setTransparency(1) 
		squareNP.setAlphaScale(.5) 
		squareNP.setTwoSided(True)
		squareNP.setCollideMask(BitMask32.bit(1))
		return squareNP

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
    def createPitchLineOld(self,points=[0.5,0.25,-0.25,-0.5],
                            tick=0.00,colour=None):
        """ create a line to hint at the pitch of the aircraft on the hud """
        if colour is None:
            colour = self.colour

        l = LineNodePath(aspect2d,'pitchline',4,Vec4(colour[0],colour[1],
                                                       colour[2],colour[3]))

        plist = []
        for p in points:
            plist.append((p,0.0,0.0))
        plist.insert(0,(points[0],0.0,tick))
        plist.append((points[3],0.0,tick))

        linelist = []
        linelist = [[plist[p],plist[p+1]] for p in range(len(plist)-1)]
        linelist.pop(2)
        l.drawLines(linelist)
        l.create()

        # These lines are drawn from scratch rather than using a graphic file

        format = GeomVertexFormat.getV3()
        vdata = GeomVertexData("vertices",format,Geom.UHStatic)

        # create vertices to add to use in creating lines
        vertexWriter=GeomVertexWriter(vdata,"vertex")
        # here we define enough positions to create two separated lines
        for p in points:
            vertexWriter.addData3f(p,0.0,0.0)
        # and another two positions for the 'ticks' at the line ends
        vertexWriter.addData3f(points[0],0.0,tick)
        vertexWriter.addData3f(points[3],0.0,tick)

        # create the primitives
        line = GeomLines(Geom.UHStatic)
        line.addVertices(4,0) # the tick part
        line.addVertices(0,1) # part of the horizontal line
        line.closePrimitive()
        line2 = GeomLines(Geom.UHStatic)
        line2.addVertices(2,3) # other part of the horizontal line
        line2.addVertices(3,5) # second tick
        line2.closePrimitive()

        # add the lines to a geom object
        lineGeom = Geom(vdata)
        lineGeom.addPrimitive(line)
        lineGeom.addPrimitive(line2)

        # create the node..
        lineGN=GeomNode("splitline")
        lineGN.addGeom(lineGeom)

        # and parent the node to aspect2d
        lineNP = aspect2d.attachNewNode(lineGN)
        return lineNP

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
class SphereNode( GeomNode ):
    def __init__(self,subdivides=3,scale=1.0):
        super(SphereNode,self).__init__('sphere')
        uniform = True
        # see if scale is a tuple
        try:
            xs,ys,zs = scale
            uniform = False
        except TypeError:
            # no, it's a scalar
            xs,ys,zs = scale,scale,scale
               
        north = (0.0,1.0,0.0)
        g = Octahedron()
        
        for i in range(subdivides):
            g.UniformSubdivide( midpointdisplace = NormalizeVert )
            
        #print "%d faces per sphere"%len(g.faces)
        
        # okay, we're gonna use setShaderInput to set constants for 
        # surface coverages and planetary seed, so all we need per 
        # vertex is position and normal
        # and we kind of don't need normal for a unit sphere, but 
        # we want to use the same shader for other thangs
        format=GeomVertexFormat.getV3n3()
        vdata=GeomVertexData('sphere', format, Geom.UHDynamic)

        vertex=GeomVertexWriter(vdata, 'vertex')
        normal=GeomVertexWriter(vdata, 'normal')


        for (x,y,z) in g.verts:
            vertex.addData3f( x*xs, y*ys, z*zs )
            if uniform:            
                normal.addData3f( x, y, z )
            else:
                n = NormalizeVert( (x/(xs*xs),y/(ys*ys),z/(zs*zs)) )
                normal.addData3f( n[0], n[1], n[2] )  
            
        trilist=GeomTriangles(Geom.UHDynamic)
        
        for (a,b,c) in g.faces:
            trilist.addVertex(a)
            trilist.addVertex(b)
            trilist.addVertex(c)
        
        trilist.closePrimitive()
        self.geom = Geom(vdata)
        self.geom.addPrimitive( trilist )
        
        self.addGeom( self.geom )

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
class PointCloudNode(GeomNode):
    def __init__(self, name, points, color=(1.0,1.0,1.0,1.0), colors=None):
        GeomNode.__init__(self, name)
        self._points = points
        self._color = color
        self._colors = colors

        self._create_vertex_data()
        self._create_geom_primitives()
        self._create_geoms()

        # set visualisation parameters
        #if self._wireframe:
        #    self.setAttrib(RenderModeAttrib.make(RenderModeAttrib.MWireframe, 2, 1))
        #self.setAttrib(CullFaceAttrib.make(CullFaceAttrib.MCullNone))
        self.setAttrib(RenderModeAttrib.make(RenderModeAttrib.MWireframe, 2, 0))

    def _create_vertex_data(self):
        """Creates and fills the vertex data store."""
        format = GeomVertexFormat.getV3c4()
        vdata = GeomVertexData('cloud', format, Geom.UHDynamic)

        vertex = GeomVertexWriter(vdata, 'vertex')
        color = GeomVertexWriter(vdata, 'color')

        for index, point in enumerate(self._points):
            vertex.addData3f(*point[0:3])
            if self._colors != None:
                color.addData4f(*self._colors[index])
            else:
                color.addData4f(*self._color)

        self._vdata = vdata

    def _create_geom_primitives(self):
        """Creates and fill a GeomTriangles with vertex indices."""
        pts = GeomPoints(Geom.UHDynamic)
        pts.addNextVertices(len(self._points))
        pts.closePrimitive()
        self._geom_primitives = [pts, ]

    def _create_geoms(self):
        """Creates a Geom attached to self and adds the current primitives."""
        self._geom = Geom(self._vdata)
        for primitive in self._geom_primitives:
            self._geom.addPrimitive(primitive)
        self.addGeom(self._geom)

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
    def createCentreMarkOld(self,colour=None):
        """ create a line to hint at the pitch of the aircraft on the hud """
        if colour is None:
            colour = self.colour

        # These lines are drawn from scratch rather than using a graphic file

        format = GeomVertexFormat.getV3()
        vdata = GeomVertexData("vertices",format,Geom.UHStatic)

        # create vertices to add to use in creating lines
        vertexWriter=GeomVertexWriter(vdata,"vertex")
        # essentially I am trying to create a line that gives an idea of
        #       where the forward vector of the plane is pointing which
        #       helps indicate the pitch
        # the bends in the line could be used to indicate a few angles but
        #       I am not sure how useful this really is.
        vertexWriter.addData3f(0.15,0.0,0.0)
        vertexWriter.addData3f(0.10,0.0,0.0)
        vertexWriter.addData3f(0.05,0.0,-0.025)
        vertexWriter.addData3f(0.00,0.0,0.025)
        vertexWriter.addData3f(-0.05,0.0,-0.025)
        vertexWriter.addData3f(-0.10,0.0,0.0)
        vertexWriter.addData3f(-0.15,0.0,0.0)

        # create the primitives
        line = GeomLines(Geom.UHStatic)
        line.addVertices(0,1)
        line.addVertices(1,2)
        line.addVertices(2,3)
        line.addVertices(3,4)
        line.addVertices(4,5)
        line.addVertices(5,6)
        line.closePrimitive()

        # add the lines to a geom object
        lineGeom = Geom(vdata)
        lineGeom.addPrimitive(line)

        # create the node..
        lineGN=GeomNode("centremark")
        lineGN.addGeom(lineGeom)

        # and parent the node to aspect2d
        lineNP = aspect2d.attachNewNode(lineGN)
        return lineNP

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def create_line(x1, z1, x2, z2):
    format = GeomVertexFormat.getV3n3c4t2()
    vdata = GeomVertexData('', format, Geom.UHStatic)
    vertex = GeomVertexWriter(vdata, 'vertex')
    normal = GeomVertexWriter(vdata, 'normal')
    vertex.addData3f(x1, 0, z1)
    vertex.addData3f(x2, 0, z2) 
    for _i in range(2):
        normal.addData3f(0, - 1, 0)
    prim_hint = Geom.UHStatic
    prim = GeomLines(prim_hint)
    prim.addVertices(0, 1)
    prim.closePrimitive()
    geom = Geom(vdata)
    geom.addPrimitive(prim)
    node = GeomNode('')
    node.addGeom(geom)
    return (node, vdata)

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def create_table_geom():
    format = GeomVertexFormat.getV3n3c4t2()
    # GeomVertexData. 
    vdata = GeomVertexData('table_vertex', format, Geom.UHStatic)
    
    vertex = GeomVertexWriter(vdata, 'vertex')
    normal = GeomVertexWriter(vdata, 'normal')
    color = GeomVertexWriter(vdata, 'color')
    texcoord = GeomVertexWriter(vdata, 'texcoord')

    vertex.addData3f(xmax, ymin, 0)
    normal.addData3f(0, 0, 1)
    color.addData4f(0, 0, 1, 1)
    texcoord.addData2f(1, 0)
    
    vertex.addData3f(xmax, ymax, 0)
    normal.addData3f(0, 0, 1)
    color.addData4f(0, 0, 1, 1)
    texcoord.addData2f(1, 1)
    
    vertex.addData3f(xmin, ymax, 0)
    normal.addData3f(0, 0, 1)
    color.addData4f(0, 0, 1, 1)
    texcoord.addData2f(0, 1)
    
    vertex.addData3f(xmin, ymin, 0)
    normal.addData3f(0, 0, 1)
    color.addData4f(0, 0, 1, 1)
    texcoord.addData2f(0, 0)
    
    prim = GeomTriangles(Geom.UHStatic)
    prim.addVertex(0)
    prim.addVertex(1)
    prim.addVertex(2)
    prim.closePrimitive()
    
    prim.addVertex(0)
    prim.addVertex(2)
    prim.addVertex(3)
    prim.closePrimitive()

    geom = Geom(vdata)
    geom.addPrimitive(prim)
    return geom

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
class HalfEdgeMeshNode(GeomNode):
    def __init__(self, name, halfedge_mesh, color, wireframe=False):
        GeomNode.__init__(self, name)
        self._halfedge_mesh = halfedge_mesh
        self._color = color
        self._wireframe = wireframe

        self._create_vertex_data()
        self._create_geoms()

        # set visualisation parameters
        if self._wireframe:
            self.setAttrib(RenderModeAttrib.make(RenderModeAttrib.MWireframe, 2, 1))
        self.setAttrib(CullFaceAttrib.make(CullFaceAttrib.MCullNone))

    def _create_vertex_data(self):
        """Creates and fills the vertex data store."""
        format = GeomVertexFormat.getV3n3cp()
        vdata = GeomVertexData("surface", format, Geom.UHDynamic)
        tri = GeomTriangles(Geom.UHDynamic)

        vertex = GeomVertexWriter(vdata, "vertex")
        normal = GeomVertexWriter(vdata, "normal")
        color = GeomVertexWriter(vdata, "color")

        for triangle in self._halfedge_mesh.faces:
            for v in triangle.iter_vertices():
                vertex.addData3f(*v.coordinates)
                normal.addData3f(*v.normal)
                color.addData4f(*self._color)
                tri.addNextVertices(1)

        self._vdata = vdata
        tri.closePrimitive()
        self._geom_primitives = [tri]

    def _create_geoms(self):
        """Creates a Geom attached to self and adds the current primitives."""
        self._geom = Geom(self._vdata)
        for primitive in self._geom_primitives:
            self._geom.addPrimitive(primitive)
        self.addGeom(self._geom)

# 需要导入模块: from pandac.PandaModules import Geom [as 别名]
# 或者: from pandac.PandaModules.Geom import addPrimitive [as 别名]
def makeCircle(vdata, numVertices=40,offset=Vec3(0,0,0), direction=1):
	circleGeom=Geom(vdata)

	vertWriter=GeomVertexWriter(vdata, "vertex")
	normalWriter=GeomVertexWriter(vdata, "normal")
	colorWriter=GeomVertexWriter(vdata, "color")
	uvWriter=GeomVertexWriter(vdata, "texcoord")
	drawWriter=GeomVertexWriter(vdata, "drawFlag")

	#make sure we start at the end of the GeomVertexData so we dont overwrite anything
	#that might be there already
	startRow=vdata.getNumRows()

	vertWriter.setRow(startRow)
	colorWriter.setRow(startRow)
	uvWriter.setRow(startRow)
	normalWriter.setRow(startRow)
	drawWriter.setRow(startRow)

	angle=2*math.pi/numVertices
	currAngle=angle

	for i in range(numVertices):
		position=Vec3(math.cos(currAngle)+offset.getX(), math.sin(currAngle)+offset.getY(),offset.getZ())
		vertWriter.addData3f(position)
		uvWriter.addData2f(position.getX()/2.0+0.5,position.getY()/2.0+0.5)
		colorWriter.addData4f(1.0, 1.0, 1.0, 1.0)
		position.setZ(position.getZ()*direction)
		position.normalize()
		normalWriter.addData3f(position)
		
		#at default Opengl only draws "front faces" (all shapes whose vertices are arranged CCW). We
		#need direction so we can specify which side we want to be the front face
		currAngle+=angle*direction

	circle=GeomTrifans(Geom.UHStatic)
	circle.addConsecutiveVertices(startRow, numVertices)
	circle.closePrimitive()

	circleGeom.addPrimitive(circle)
	
	return circleGeom