| # 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"; |
| |