# 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_ColorMap("cmap"); $frame = new_FrameBuffer(500,500); FrameBuffer_clear($frame,$BLACK); $p3 = new_Plot3D($frame,$xmin,$ymin,$zmin,$xmax,$ymax,$zmax); Plot3D_lookat($p3,2*($zmax-$zmin)); Plot3D_autoperspective($p3,40); Plot3D_rotu($p3,60); Plot3D_rotr($p3,30); Plot3D_rotd($p3,10); sub drawsolid { Plot3D_clear($p3,$BLACK); Plot3D_start($p3); 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) { $c = 239; } Plot3D_solidquad($p3,$x,$y,$z1,$x+$dx,$y,$z2,$x+$dx,$y+$dy,$z3,$x,$y+$dy,$z4,$c+16); $y = $y + $dy; } $x = $x + $dx; } } print "Making a nice 3D plot...\n"; drawsolid(); FrameBuffer_writeGIF($frame,$cmap,"image.gif"); print "Wrote image.gif\n";