################################################################
# tutorial.py            Andy Beall 1999
#
# This script demonstrates the following techniques:
# - transparency (alpha type)
# - rotation animations
#  - animated background colors
# - keyboard handling
#  - expiration timers
# - VRML object initialization
#
# The user can press either the "1", "2", or "3" key and toggle
# between the different modes.
################################################################
################################################################

import vrut
import math

vrut.go(vrut.NICE)
 

# These are constants
INITIALIZE = 1
ANIMATE = 2
SPEED = 1

# These are globals
angle = 0.0
red   = .6
green = .6
blue  = 1
key1  = 0
key2  = 0
key3  = 0
 

# Load the VRML geometry files here
tunnel = vrut.addchild('tut_torus.wrl')
ground = vrut.addchild('tut_ground.wrl')
 

################################################################
# Callback function to handle whenever user presses a key
def mykeyboard(key):
 global key1, key2, key3

 if key == '1':
  key1 = key1 ^ 1

  if key1 == 1:
   tunnel.alpha(1)
  else:
   tunnel.appearance()

 if key == '2':
  key2 = key2 ^ 1
 

 if key == '3':
  key3 = key3 ^ 1

  if key3 == 1:
   ground.curtain(vrut.OPEN)
  else:
   ground.curtain(vrut.CLOSE)
 

################################################################\
# Callback function to handle expiration timers
def mytimer(num):
 global angle, red, green, blue

 # Handle all initializations
 if num == INITIALIZE:

  # Initialize the VRUT context
  vrut.reset(vrut.HEAD_POS)
  vrut.translate(vrut.HEAD_POS, 3, 0, 0)
  vrut.setfov(60, 1.33)
  vrut.override()

  # Initialize the geometry
  tunnel.center(10,0,0)
  ground.center(10,0,0)
  ground.curtain(vrut.CLOSE)
  ground.translate(0,-1,0)
  vrut.starttimer(ANIMATE, .01)

 # Handle all animations
 if num == ANIMATE:
  angle = angle - SPEED
  tunnel.rotate(0,1,0, angle)

  if key2 == 1:
   red   = (math.sin(angle/101)+1)/2
   green = (math.sin(angle/83)+1)/2
   blue  = (math.sin(angle/59)+1)/2

  if key3 == 1:
   ground.rotate(0,1,0, -angle/3)

  vrut.clearcolor(red, green, blue)
  vrut.starttimer(ANIMATE, .01)
 
 

################################################################\
################################################################\

# One-time setup of callback events
vrut.callback(vrut.TIMER_EVENT, 'mytimer')
vrut.callback(vrut.KEYBOARD_EVENT, 'mykeyboard')
vrut.starttimer(INITIALIZE, .1)