<? # Plot a 3D function dl("libgifplot.so"); # Here is the function to plot function func($x, $y) { return 5*cos(2*sqrt($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); function drawsolid() { global $p3; global $xmax; global $xmin; global $ymax; global $ymin; global $zmin; global $zmax; global $nxpoints; global $nypoints; Plot3D_clear($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 = 0; $i < $nxpoints; $i++) { $y = $ymin; for ($j = 0; $j < $nypoints; $j++) { $z1 = func($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+$c4)/4; if ($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"; ?>