ANEW -surface3d_demo

NEEDS -gnuplot

DOC
(*
	from mpl_toolkits.mplot3d import Axes3D
	from matplotlib import cm
	import matplotlib.pyplot as plt
	import numpy as np

	fig = plt.figure()
	ax = Axes3D(fig)
	X = np.arange(-5, 5, 0.25)
	Y = np.arange(-5, 5, 0.25)
	X, Y = np.meshgrid(X, Y)
	R = np.sqrt(X**2 + Y**2)
	Z = np.sin(R)
	ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.jet)

	plt.show()
*)
ENDDOC

#40 =: sz

   sz DOUBLE ARRAY  x{
   sz DOUBLE ARRAY  y{
sz sz DOUBLE MATRIX z{{

: COMPUTE-FIG ( -- )
	5e FLOCAL range
	x{ sz  range FNEGATE range F2* sz S>F F/  LINSPACE 
	y{ sz  range FNEGATE range F2* sz S>F F/  LINSPACE 
	sz 0 ?DO
		 sz 0 ?DO  x{ I } DF@ FSQR  y{ J } DF@ FSQR F+ FSQRT 
			   FSIN  z{{ J I }} DF! 
		     LOOP 
	    LOOP ;

: surface3d ( -- )
	0 FIGURE CLF  TRUE GRID  
	COMPUTE-FIG  
	S" set palette color model XYZ" TWEAK$ \ just for screen fun, default and printed is B&W
	x{ y{ z{{ S" @white" SPLOT ;