1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
# Plot a 3D function
require 'gifplot'
include Gifplot
include Math
# 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))
end
# 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*[XMAX-XMIN,YMAX-YMIN,ZMAX-ZMIN].max)
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 0...NXPOINTS
y = YMIN
for j in 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 = (c1+c2+c3+c4)/4
c = 0 if (c < 0)
c = 239 if 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
end
x = x + dx
end
end
puts "Making a nice 3D plot..."
drawsolid()
FrameBuffer_writeGIF(frame,cmap,"image.gif")
puts "Wrote image.gif"
|
