#!/usr/bin/env python
# Plot nurbs surface corresponding to a 2D damped oscillation.
# The surface has two holes. A Teapot below the surface is
# visible through these holes.
#
# Copyright (C) 2007 "Peter Roesch" <Peter.Roesch@fh-augsburg.de>
#
# This code is licensed under the PyOpenGL License.
# Details are given in the file license.txt included in this distribution.
import sys
import math
from time import sleep
import traceback
try:
from OpenGL.GLUT import *
from OpenGL.GL import *
from OpenGL.GLU import *
except ImportError, err:
traceback.print_exc()
print ''' Error: PyOpenGL not installed properly!!'''
sys.exit( )
# globals
animationAngle = 0.0
frameRate = 25
curr_time=0.0
nurbsID=0
def animationStep( ):
"""Update animated parameters"""
global animationAngle
global frameRate
animationAngle += 1
while animationAngle > 360:
animationAngle -= 360
global curr_time
curr_time+=0.05
global nurbsID
glDeleteLists( nurbsID, 1 )
nurbsID = glGenLists( 1 )
glNewList( nurbsID, GL_COMPILE )
plotSurface( curr_time )
glEndList( )
sleep( 1 / float( frameRate ) )
glutPostRedisplay( )
sigma = 0.5;
twoSigSq = 2. * sigma * sigma;
def dampedOscillation( u, v, t):
"""Calculation of a R2 -> R1 function at position u,v at curr_time t.
A t-dependent cosine function is multiplied with a 2D gaussian.
Both functions depend on the distance of (u,v) to the origin."""
distSq = u * u + v * v;
dist = math.pi * 4 * math.sqrt( distSq );
global twoSigSq
return 0.5 * math.exp(-distSq / twoSigSq) * math.cos(dist - t);
nPts = 15
degree = 4
samplingTolerance=2.0
xMin, xMax, yMin, yMax = -1.0, 1.0, -1.0, 1.0
xStep = (xMax-xMin)/(nPts-1)
yStep = (yMax-yMin)/(nPts-1)
# initialise a list representing a regular 2D grid of control points.
controlPoints = [ \
[ [ yMin+y*yStep, xMin+x*xStep, 0.0 ] for x in range ( nPts )]\
for y in range( nPts ) ]
# initialise knots ...
knots = [ 0.0 for i in range( degree/2 ) ] +\
[ float(i)/(nPts-1) for i in range( nPts )] +\
[ 1.0 for i in range( (degree+1)/2 ) ]
# initialise enclosing
enclosing=[ [0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0], [0.0, 0.0] ]
# first trim curve is a circle
angleNum = 16
angles = [ -2*math.pi*float(i)/angleNum for i in range( angleNum ) ]
radius=0.05
offset=(0.4, 0.6)
circleDegree=degree
circlePoints = [ \
[ offset[0]+radius*math.cos(theta), offset[1]+radius*math.sin(theta) ]\
for theta in angles ]
for i in range( circleDegree-1 ):
circlePoints = circlePoints + [ circlePoints[i] ]
knotNum = len( circlePoints ) + circleDegree
circleKnots = [ float(i)/(knotNum-1) for i in range( knotNum ) ]
# second trim curve is a square
squareHolePoints=[ [0.4, 0.4], [0.4, 0.45], [0.45, 0.45],\
[0.45, 0.4], [0.4, 0.4] ]
def updateControlPoints( t ):
"""Calculate function values for all 2D grid points."""
for row in controlPoints:
for coord in row:
coord[2] = dampedOscillation( coord[0], coord[1], t )
def plotSurface( t ):
# display surface
updateControlPoints( t )
global controlPoints, knots
global nurb
gluBeginSurface( nurb )
gluNurbsSurface ( nurb, knots, knots, controlPoints, GL_MAP2_VERTEX_3 )
# trim curve enclosing
gluBeginTrim( nurb )
global enclosing
gluPwlCurve( nurb, enclosing, GLU_MAP1_TRIM_2 )
gluEndTrim( nurb )
# trim using square
gluBeginTrim( nurb )
global squareHolePoints
gluPwlCurve( nurb, squareHolePoints, GLU_MAP1_TRIM_2 )
gluEndTrim( nurb )
# trim using circle
gluBeginTrim( nurb )
global circlePoints, circleKnots
gluNurbsCurve ( nurb, circleKnots, circlePoints, GLU_MAP1_TRIM_2 )
gluEndTrim( nurb )
gluEndSurface( nurb )
def display( ):
"""Glut display function."""
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glMatrixMode( GL_PROJECTION )
glLoadIdentity( )
xSize, ySize = glutGet( GLUT_WINDOW_WIDTH ), glutGet( GLUT_WINDOW_HEIGHT )
gluPerspective(60, float(xSize) / float(ySize), 0.1, 50)
glMatrixMode( GL_MODELVIEW )
glLoadIdentity( )
glPushMatrix( )
glTranslatef( 0, 0, -3 )
glRotatef( -30, 1, .3, 0)
glRotatef( animationAngle, 0, 0, 1 )
glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, [0.2, 0.2, 0.2, 1] )
glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, [0.7, 0.7, 0.7, 1] )
glCallList( nurbsID )
glPopMatrix( )
glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, [0.0, 0.0, 0.2, 1] )
glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, [0.0, 0.0, 0.7, 1] )
glTranslatef( 0.0, 0.0, -12.0 )
glCallList( teapotID )
glutSwapBuffers( )
teapotID=0
nurb=None
def init( ):
"""Glut init function."""
glClearColor ( 0, 0, 0, 0 )
glEnable( GL_DEPTH_TEST )
glShadeModel( GL_SMOOTH )
glEnable( GL_LIGHTING )
glEnable( GL_LIGHT0 )
glLightModeli( GL_LIGHT_MODEL_TWO_SIDE, 0 )
glLightfv( GL_LIGHT0, GL_POSITION, [2, 0, 10, 1] )
lA = 0.8; glLightfv( GL_LIGHT0, GL_AMBIENT, [lA, lA, lA, 1] )
lD = 1; glLightfv( GL_LIGHT0, GL_DIFFUSE, [lD, lD, lD, 1] )
lS = 1; glLightfv( GL_LIGHT0, GL_SPECULAR, [lS, lS, lS, 1] )
glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, [0.5, 0.5, 0.5, 1] )
glMaterialf( GL_FRONT_AND_BACK, GL_SHININESS, 50 )
glEnable( GL_AUTO_NORMAL )
global nurb
nurb = gluNewNurbsRenderer()
global samplingTolerance
gluNurbsProperty(nurb, GLU_SAMPLING_TOLERANCE, samplingTolerance)
gluNurbsProperty(nurb, GLU_DISPLAY_MODE, GLU_FILL)
global teapotID
teapotID = glGenLists( 1 )
glNewList( teapotID, GL_COMPILE )
glutSolidTeapot( 1.0 )
glEndList( )
global nurbsID
nurbsID = glGenLists( 1 )
glNewList( nurbsID, GL_COMPILE )
global curr_time
plotSurface( curr_time )
glEndList( )
glutInit( sys.argv )
glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH )
glutInitWindowSize( 250, 250 )
glutInitWindowPosition( 100, 100 )
glutCreateWindow( sys.argv[0] )
init( )
glutDisplayFunc( display )
glutIdleFunc( animationStep )
glutMainLoop( )
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