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# Plot a 3D function
# This example uses the low-level C interface.
from _gifplot import *
from math import *
# Here is the function to plot
def func(x,y):
return 5*cos(2*sqrt(x*x+y*y))*exp(-0.3*sqrt(x*x+y*y))
# Here are some plotting parameters
xmin = -5.0
xmax = 5.0
ymin = -5.0
ymax = 5.0
zmin = -5.0
zmax = 5.0
# Grid resolution
nxpoints = 60
nypoints = 60
cmap = new_ColorMap("cmap")
frame = new_FrameBuffer(500,500)
FrameBuffer_clear(frame,BLACK)
p3 = new_Plot3D(frame,xmin,ymin,zmin,xmax,ymax,zmax)
Plot3D_lookat(p3,2*max([xmax-xmin,ymax-ymin,zmax-zmin]))
Plot3D_autoperspective(p3,40)
Plot3D_rotu(p3,60)
Plot3D_rotr(p3,30)
Plot3D_rotd(p3,10)
def drawsolid():
Plot3D_clear(p3,BLACK)
Plot3D_start(p3)
dx = 1.0*(xmax-xmin)/nxpoints
dy = 1.0*(ymax-ymin)/nypoints
cscale = 240.0/(zmax-zmin)
x = xmin
for i in xrange(0,nxpoints):
y = ymin
for j in xrange(0,nypoints):
z1 = func(x,y)
z2 = func(x+dx,y)
z3 = func(x+dx,y+dy)
z4 = func(x,y+dy)
c1 = cscale*(z1-zmin)
c2 = cscale*(z2-zmin)
c3 = cscale*(z3-zmin)
c4 = cscale*(z4-zmin)
c = int((c1+c2+c3+c4)/4)
if (c < 0) : c = 0
if c > 239 : c = 239
Plot3D_solidquad(p3,x,y,z1,x+dx,y,z2,x+dx,y+dy,z3,x,y+dy,z4,c+16)
y = y + dy
x = x + dx
print "Making a nice 3D plot..."
drawsolid()
FrameBuffer_writeGIF(frame,cmap,"image.gif")
print "Wrote image.gif"
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