ExamplesProceduralsPrimitiveVariables
This cookbook example demonstrates how to assign a primitive variable to a renderable. It is based very closely on the Points Render cookbook example, but adds an additional Cs primitive variable which shaders can use to colour the points.
opengl
renderman
from IECore import *
from random import *
def generatePoints( bbox, npoints ):
seed(0)
size = bbox.size()
pdata = V3fVectorData()
for i in range(npoints):
pdata.append( V3f( random() * size.x + bbox.min.x,
random() * size.y + bbox.min.y,
random() * size.z + bbox.min.z ) )
return PointsPrimitive( pdata )
class primitiveVariables(ParameterisedProcedural) :
def __init__(self):
ParameterisedProcedural.__init__( self, "Description here." )
bbox = Box3fParameter( "bbox", "Bounds for points.", Box3f(V3f(0), V3f(1)) )
npoints = IntParameter( "npoints", "Number of points.", 100, minValue=0, maxValue=10000 )
width = FloatParameter( "width", "Point width", 0.05 )
self.parameters().addParameters( [ bbox, npoints, width ] )
self.__points = None
self.__npoints = None
self.__bbox = None
def generatePoints(self, args):
if args['npoints'].value!=self.__npoints or args['bbox'].value!=self.__bbox:
self.__points = generatePoints( args['bbox'].value, args['npoints'].value )
self.__npoints = args['npoints'].value
self.__bbox = args['bbox'].value
return self.__points
def doBound(self, args):
self.generatePoints(args)
return self.__points.bound()
def doRenderState(self, renderer, args):
pass
def doRender(self, renderer, args):
self.generatePoints(args)
self.__points['width'] = PrimitiveVariable( PrimitiveVariable.Interpolation.Constant, args['width'] )
# create an array of colours, one per point
colours = []
for i in range( self.__points['P'].data.size() ):
colours.append( Color3f( random(), random(), random() ) )
print colours[-1]
colour_data = Color3fVectorData( colours )
# attach as a Cs primitive variable
self.__points['Cs'] = PrimitiveVariable( PrimitiveVariable.Interpolation.Varying, colour_data )
# render
self.__points.render( renderer )
registerRunTimeTyped( primitiveVariables )