Demo/sgi/gl/mixing.py

   1 #! /usr/bin/env python
   2
   3 # Use Gouraud shading to mix colors.  Requires Z-buffer.
   4 # It changes the color assignments so fast that you see white.
   5 # Left button pauses, middle rotates the square.  ESC to quit.
   6 # Experiment with a larger window (too slow) or smaller window (really white).
   7
   8 from GL import *
   9 from gl import *
  10 import DEVICE
  11 from math import *
  12
  13 #
  14 #  tekenvlak : draw a square. with bgnpolygon
  15 #
  16 def tekenvlak (vc) :
  17         bgnpolygon()
  18         #vcarray (vc)
  19         for i in vc :
  20                 c3f (i[1])
  21                 v3f (i[0])
  22         endpolygon()
  23
  24 #
  25 # tekendoos : draw a box
  26 #
  27 def tekendoos (col) :
  28         v = [(-5.0,0.0,0.0),(0.0,5.0,0.0),(5.0,0.0,0.0),(0.0,-5.0,0.0)]
  29         vc = [(v[0],col[0]),(v[1],col[1]),(v[2],col[2]),(v[3],col[1])]
  30         tekenvlak (vc)
  31
  32 #
  33 # initialize gl
  34 #
  35 def initgl () :
  36         #
  37         # open window
  38         #
  39         foreground ()
  40         keepaspect (1, 1)
  41         prefposition (100, 500, 100, 500)
  42         w = winopen ('PYTHON RGB')
  43         keepaspect (1, 1)
  44         winconstraints()
  45         #
  46         # configure pipeline (2buf, GOURAUD and RGBmode)
  47         #
  48         doublebuffer ()
  49         zbuffer (1)
  50         shademodel (GOURAUD)
  51         RGBmode ()
  52         gconfig ()
  53         #
  54         # set viewing
  55         #
  56         perspective (900, 1, 1.0, 10.0)
  57         polarview (10.0, 0, 0, 0)
  58         #
  59         # ask for the REDRAW and ESCKEY events
  60         #
  61         qdevice(DEVICE.MOUSE2)
  62         qdevice(DEVICE.MOUSE3)
  63         qdevice(DEVICE.REDRAW)
  64         qdevice(DEVICE.ESCKEY)
  65
  66
  67 #
  68 # the color black
  69 #
  70 black = 0
  71 #
  72 # GoForIT : use 2buf to redraw the object 2n times. index i is used as
  73 # the (smoothly changing) rotation angle
  74 #
  75 def GoForIt(i) :
  76         col = [(255.0,0.0,0.0), (0.0,255.0,0.0), (0.0,0.0,255.0)]
  77         twist = 0
  78         freeze = 1
  79         while 1 :
  80                 if freeze <> 0 :
  81                         col[0],col[1],col[2] = col[1],col[2],col[0]
  82                 #
  83                 # clear z-buffer and clear background to light-blue
  84                 #
  85                 zclear()
  86                 cpack (black)
  87                 clear()
  88                 #
  89                 tekendoos (col)
  90                 #
  91                 swapbuffers()
  92                 #
  93                 if qtest() <> 0 :
  94                         dev, val = qread()
  95                         if dev == DEVICE.ESCKEY :
  96                                 break
  97                         elif dev == DEVICE.REDRAW :
  98                                 reshapeviewport ()
  99                         elif dev == DEVICE.MOUSE2 and val <> 0 :
 100                                 twist = twist + 30
 101                                 perspective (900, 1, 1.0, 10.0)
 102                                 polarview (10.0, 0, 0, twist)
 103                         elif dev == DEVICE.MOUSE3 and val <> 0 :
 104                                 freeze = 1 - freeze
 105
 106
 107 # the main program
 108 #
 109 def main () :
 110         initgl ()
 111         GoForIt (0)
 112
 113 #
 114 # exec main
 115 #
 116 main  ()