Demo/sgi/gl/nurbs.py

   1 #! /usr/bin/env python
   2
   3 # Rotate a 3D surface created using NURBS.
   4 #
   5 # Press left mouse button to toggle surface trimming.
   6 # Press ESC to quit.
   7 #
   8 # See the GL manual for an explanation of NURBS.
   9
  10 from gl import *
  11 from GL import *
  12 from DEVICE import *
  13
  14 TRUE = 1
  15 FALSE = 0
  16 ORDER = 4
  17
  18 idmat = [1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1]
  19
  20 surfknots = [-1, -1, -1, -1, 1, 1, 1, 1]
  21
  22 def make_ctlpoints():
  23         c = []
  24         #
  25         ci = []
  26         ci.append(-2.5,  -3.7,  1.0)
  27         ci.append(-1.5,  -3.7,  3.0)
  28         ci.append(1.5,  -3.7, -2.5)
  29         ci.append(2.5,  -3.7,  -0.75)
  30         c.append(ci)
  31         #
  32         ci = []
  33         ci.append(-2.5,  -2.0,  3.0)
  34         ci.append(-1.5,  -2.0,  4.0)
  35         ci.append(1.5,  -2.0,  -3.0)
  36         ci.append(2.5,  -2.0,  0.0)
  37         c.append(ci)
  38         #
  39         ci = []
  40         ci.append(-2.5, 2.0,  1.0)
  41         ci.append(-1.5, 2.0,  0.0)
  42         ci.append(1.5,  2.0,  -1.0)
  43         ci.append(2.5,  2.0,  2.0)
  44         c.append(ci)
  45         #
  46         ci = []
  47         ci.append(-2.5,  2.7,  1.25)
  48         ci.append(-1.5,  2.7,  0.1)
  49         ci.append(1.5,  2.7,  -0.6)
  50         ci.append(2.5,  2.7,  0.2)
  51         c.append(ci)
  52         #
  53         return c
  54
  55 ctlpoints = make_ctlpoints()
  56
  57 trimknots = [0., 0., 0.,  1., 1.,  2., 2.,  3., 3.,   4., 4., 4.]
  58
  59 def make_trimpoints():
  60         c = []
  61         c.append(1.0, 0.0, 1.0)
  62         c.append(1.0, 1.0, 1.0)
  63         c.append(0.0, 2.0, 2.0)
  64         c.append(-1.0, 1.0, 1.0)
  65         c.append(-1.0, 0.0, 1.0)
  66         c.append(-1.0, -1.0, 1.0)
  67         c.append(0.0, -2.0, 2.0)
  68         c.append(1.0, -1.0, 1.0)
  69         c.append(1.0, 0.0, 1.0)
  70         return c
  71
  72 trimpoints = make_trimpoints()
  73
  74 def main():
  75         init_windows()
  76         setup_queue()
  77         make_lights()
  78         init_view()
  79         #
  80         set_scene()
  81         setnurbsproperty( N_ERRORCHECKING, 1.0 )
  82         setnurbsproperty( N_PIXEL_TOLERANCE, 50.0 )
  83         trim_flag = 0
  84         draw_trim_surface(trim_flag)
  85         #
  86         while 1:
  87                 while qtest():
  88                         dev, val = qread()
  89                         if dev == ESCKEY:
  90                                 return
  91                         elif dev == WINQUIT:
  92                                 dglclose(-1)    # this for DGL only
  93                                 return
  94                         elif dev == REDRAW:
  95                                 reshapeviewport()
  96                                 set_scene()
  97                                 draw_trim_surface(trim_flag)
  98                         elif dev == LEFTMOUSE:
  99                                 if val:
 100                                         trim_flag = (not trim_flag)
 101                 set_scene()
 102                 draw_trim_surface(trim_flag)
 103
 104 def init_windows():
 105         foreground()
 106         #prefposition(0, 500, 0, 500)
 107         wid = winopen('nurbs')
 108         wintitle('NURBS Surface')
 109         doublebuffer()
 110         RGBmode()
 111         gconfig()
 112         lsetdepth(0x000, 0x7fffff)
 113         zbuffer( TRUE )
 114
 115 def setup_queue():
 116         qdevice(ESCKEY)
 117         qdevice(REDRAW)
 118         qdevice(RIGHTMOUSE)
 119         qdevice(WINQUIT)
 120         qdevice(LEFTMOUSE) #trimming
 121
 122 def init_view():
 123         mmode(MPROJECTION)
 124         ortho( -4., 4., -4., 4., -4., 4. )
 125         #
 126         mmode(MVIEWING)
 127         loadmatrix(idmat)
 128         #
 129         lmbind(MATERIAL, 1)
 130
 131 def set_scene():
 132         lmbind(MATERIAL, 0)
 133         RGBcolor(150,150,150)
 134         lmbind(MATERIAL, 1)
 135         clear()
 136         zclear()
 137         #
 138         rotate( 100, 'y' )
 139         rotate( 100, 'z' )
 140
 141 def draw_trim_surface(trim_flag):
 142         bgnsurface()
 143         nurbssurface(surfknots, surfknots, ctlpoints, ORDER, ORDER, N_XYZ)
 144         if trim_flag:
 145                 bgntrim()
 146                 nurbscurve(trimknots, trimpoints, ORDER-1, N_STW)
 147                 endtrim()
 148         endsurface()
 149         swapbuffers()
 150
 151 def make_lights():
 152         lmdef(DEFLMODEL,1,[])
 153         lmdef(DEFLIGHT,1,[])
 154         #
 155         # define material #1
 156         #
 157         a = []
 158         a = a + [EMISSION, 0.0, 0.0, 0.0]
 159         a = a + [AMBIENT,  0.1, 0.1, 0.1]
 160         a = a + [DIFFUSE,  0.6, 0.3, 0.3]
 161         a = a + [SPECULAR,  0.0, 0.6, 0.0]
 162         a = a + [SHININESS, 2.0]
 163         a = a + [LMNULL]
 164         lmdef(DEFMATERIAL, 1, a)
 165         #
 166         # turn on lighting
 167         #
 168         lmbind(LIGHT0, 1)
 169         lmbind(LMODEL, 1)
 170
 171 main()