# Plot a 3D function use gifplot; package gifplot; # Here is the function to plot sub func { my $x = shift; my $y = shift; return 5*cos(2*sqrt($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 gifplot::ColorMap("cmap"); $frame = new gifplot::FrameBuffer(500,500); $frame->clear($BLACK); $p3 = new gifplot::Plot3D($frame,$xmin,$ymin,$zmin,$xmax,$ymax,$zmax); $p3->lookat(2*($zmax-$zmin)); $p3->autoperspective(40); $p3->rotu(60); $p3->rotr(30); $p3->rotd(10); sub drawsolid { $p3->clear($BLACK); $p3->start(); my $dx = 1.0*($xmax-$xmin)/$nxpoints; my $dy = 1.0*($ymax-$ymin)/$nypoints; my $cscale = 240.0/($zmax-$zmin); my $x = $xmin; for ($i = 0; $i < $nxpoints; $i++) { my $y = $ymin; for ($j = 0; $j < $nypoints; $j++) { my $z1 = func($x,$y); my $z2 = func($x+$dx,$y); my $z3 = func($x+$dx,$y+$dy); my $z4 = func($x,$y+$dy); my $c1 = $cscale*($z1-$zmin); my $c2 = $cscale*($z2-$zmin); my $c3 = $cscale*($z3-$zmin); my $c4 = $cscale*($z4-$zmin); my $c = ($c1+$c2+$c3+$c4)/4; if ($c < 0) { $c = 0; } if ($c > 239) { $c = 239; } $p3->solidquad($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...\n"; drawsolid(); $frame->writeGIF($cmap,"image.gif"); print "Wrote image.gif\n";