<? # Plot a 3D function include("gifplot.php"); # 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); $frame->clear(BLACK); $p3 = new Plot3D($frame,$xmin,$ymin,$zmin,$xmax,$ymax,$zmax); $p3->lookat(2*($zmax-$zmin)); $p3->autoperspective(40); $p3->rotu(60); $p3->rotr(30); $p3->rotd(10); function drawsolid() { global $xmax; global $xmin; global $ymax; global $ymin; global $zmin; global $zmax; global $nxpoints; global $nypoints; global $p3; $p3->clear(BLACK); $p3->start(); $dx = 1.0*($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; } $p3->solidquad($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"; ?>