6 # Here is the function to plot
7 function func($x, $y) {
8 return 5*cos(2*sqrt($x*$x+$y*$y))*exp(-0.3*sqrt($x*$x+$y*$y));
11 # Here are some plotting parameters
23 $cmap = new_ColorMap("cmap");
24 $frame = new_FrameBuffer(500,500);
25 FrameBuffer_clear($frame, BLACK);
27 $p3 = new_Plot3D($frame,$xmin,$ymin,$zmin,$xmax,$ymax,$zmax);
28 Plot3D_lookat($p3, 2*($zmax-$zmin));
29 Plot3D_autoperspective($p3, 40);
34 function drawsolid() {
45 Plot3D_clear($p3, BLACK);
47 $dx = 1.0*($xmax-$xmin)/$nxpoints;
48 $dy = 1.0*($ymax-$ymin)/$nypoints;
49 $cscale = 240.0/($zmax-$zmin);
51 for ($i = 0; $i < $nxpoints; $i++) {
53 for ($j = 0; $j < $nypoints; $j++) {
55 $z2 = func($x+$dx,$y);
56 $z3 = func($x+$dx,$y+$dy);
57 $z4 = func($x,$y+$dy);
58 $c1 = $cscale*($z1-$zmin);
59 $c2 = $cscale*($z2-$zmin);
60 $c3 = $cscale*($z3-$zmin);
61 $c4 = $cscale*($z4-$zmin);
62 $c = ($c1+$c2+$c3+$c4)/4;
63 if ($c < 0) { $c = 0; }
64 if ($c > 239) { $c = 239; }
65 Plot3D_solidquad($p3, $x,$y,$z1,$x+$dx,$y,$z2,$x+$dx,$y+$dy,$z3,$x,$y+$dy,$z4,$c+16);
72 print "Making a nice 3D plot...\n";
75 FrameBuffer_writeGIF($frame, $cmap,"image.gif");
76 print "Wrote image.gif\n";