about summary refs log blame commit diff stats
path: root/html/mandelbrot.mu.html
blob: d4264d380b77f1ad997514dff0a4cd2a64f211dd (plain) (tree)
ref='#n193'>193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237



















                                                                                                               







































                                                                                                                           






                                                                                                                                                                  
                                                                              


                                                                                                                                                                                                                                                                                                                                              

















































                                                                                                                                                                                                                                                                                                                                                       
                                                                                                                                                           


















































































































                                                                                                                                                                                                                                                                                                                                                          



                                     
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - mandelbrot.mu</title>
<meta name="Generator" content="Vim/8.1">
<meta name="plugin-version" content="vim8.1_v1">
<meta name="syntax" content="none">
<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal-dark">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #000000; background-color: #a8a8a8; }
body { font-size:12pt; font-family: monospace; color: #000000; background-color: #a8a8a8; }
a { color:inherit; }
* { font-size:12pt; font-size: 1em; }
.PreProc { color: #c000c0; }
.Special { color: #ff6060; }
.LineNr { }
.Constant { color: #008787; }
.Delimiter { color: #c000c0; }
.muFunction { color: #af5f00; text-decoration: underline; }
.muComment { color: #005faf; }
-->
</style>

<script type='text/javascript'>
<!--

/* function to open any folds containing a jumped-to line before jumping to it */
function JumpToLine()
{
  var lineNum;
  lineNum = window.location.hash;
  lineNum = lineNum.substr(1); /* strip off '#' */

  if (lineNum.indexOf('L') == -1) {
    lineNum = 'L'+lineNum;
  }
  var lineElem = document.getElementById(lineNum);
  /* Always jump to new location even if the line was hidden inside a fold, or
   * we corrected the raw number to a line ID.
   */
  if (lineElem) {
    lineElem.scrollIntoView(true);
  }
  return true;
}
if ('onhashchange' in window) {
  window.onhashchange = JumpToLine;
}

-->
</script>
</head>
<body onload='JumpToLine();'>
<a href='https://github.com/akkartik/mu/blob/main/mandelbrot.mu'>https://github.com/akkartik/mu/blob/main/mandelbrot.mu</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">  1 </span><span class="muComment"># Mandelbrot set</span>
<span id="L2" class="LineNr">  2 </span><span class="muComment">#</span>
<span id="L3" class="LineNr">  3 </span><span class="muComment"># Install:</span>
<span id="L4" class="LineNr">  4 </span><span class="muComment">#   $ git clone <a href="https://github.com/akkartik/mu">https://github.com/akkartik/mu</a></span>
<span id="L5" class="LineNr">  5 </span><span class="muComment">#   $ cd mu</span>
<span id="L6" class="LineNr">  6 </span><span class="muComment"># Build on Linux:</span>
<span id="L7" class="LineNr">  7 </span><span class="muComment">#   $ ./translate mandelbrot.mu</span>
<span id="L8" class="LineNr">  8 </span><span class="muComment"># Build on other platforms (slow):</span>
<span id="L9" class="LineNr">  9 </span><span class="muComment">#   $ ./translate_emulated mandelbrot.mu</span>
<span id="L10" class="LineNr"> 10 </span><span class="muComment"># Run:</span>
<span id="L11" class="LineNr"> 11 </span><span class="muComment">#   $ qemu-system-i386 code.img</span>
<span id="L12" class="LineNr"> 12 </span>
<span id="L13" class="LineNr"> 13 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L13'>main</a></span> <a href='500fake-screen.mu.html#L14'>screen</a>: (addr <a href='500fake-screen.mu.html#L14'>screen</a>), keyboard: (addr keyboard), data-disk: (addr disk) <span class="Delimiter">{</span>
<span id="L14" class="LineNr"> 14 </span>  <span class="muComment"># Initially the viewport is centered at 0, 0 in the scene.</span>
<span id="L15" class="LineNr"> 15 </span>  <span class="PreProc">var</span> zero: float
<span id="L16" class="LineNr"> 16 </span>  <span class="PreProc">var</span> scene-cx/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy zero
<span id="L17" class="LineNr"> 17 </span>  <span class="PreProc">var</span> scene-cy/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> copy zero
<span id="L18" class="LineNr"> 18 </span>  <span class="muComment"># Initially the viewport shows a section of the scene 4 units wide.</span>
<span id="L19" class="LineNr"> 19 </span>  <span class="muComment"># scene-width-scale = 0.5</span>
<span id="L20" class="LineNr"> 20 </span>  <span class="PreProc">var</span> scene-width-scale: float
<span id="L21" class="LineNr"> 21 </span>  <span class="PreProc">var</span> dest/<span class="Constant">eax</span>: (addr float) <span class="Special">&lt;-</span> address scene-width-scale
<span id="L22" class="LineNr"> 22 </span>  <a href='408float.mu.html#L3'>fill-in-rational</a> dest, <span class="Constant">1</span>, <span class="Constant">2</span>
<span id="L23" class="LineNr"> 23 </span>  <span class="muComment"># scene-width = 4</span>
<span id="L24" class="LineNr"> 24 </span>  <span class="PreProc">var</span> four: float
<span id="L25" class="LineNr"> 25 </span>  <span class="PreProc">var</span> dest/<span class="Constant">eax</span>: (addr float) <span class="Special">&lt;-</span> address four
<span id="L26" class="LineNr"> 26 </span>  <a href='408float.mu.html#L3'>fill-in-rational</a> dest, <span class="Constant">4</span>, <span class="Constant">1</span>
<span id="L27" class="LineNr"> 27 </span>  <span class="PreProc">var</span> scene-width/<span class="Constant">xmm3</span>: float <span class="Special">&lt;-</span> copy four
<span id="L28" class="LineNr"> 28 </span>  <span class="Delimiter">{</span>
<span id="L29" class="LineNr"> 29 </span>    <a href='mandelbrot.mu.html#L41'>mandelbrot</a> <a href='500fake-screen.mu.html#L14'>screen</a> scene-cx, scene-cy, scene-width
<span id="L30" class="LineNr"> 30 </span>    <span class="muComment"># move the center some % of the current screen-width</span>
<span id="L31" class="LineNr"> 31 </span>    <span class="PreProc">var</span> adj/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> <a href='408float.mu.html#L18'>rational</a> <span class="Constant">2</span>, <span class="Constant">0x1c</span>/<span class="Constant">28</span>
<span id="L32" class="LineNr"> 32 </span>    adj <span class="Special">&lt;-</span> multiply scene-width
<span id="L33" class="LineNr"> 33 </span>    scene-cx <span class="Special">&lt;-</span> subtract adj
<span id="L34" class="LineNr"> 34 </span>    scene-cy <span class="Special">&lt;-</span> add adj
<span id="L35" class="LineNr"> 35 </span>    <span class="muComment"># slowly shrink the scene width to zoom in</span>
<span id="L36" class="LineNr"> 36 </span>    scene-width <span class="Special">&lt;-</span> multiply scene-width-scale
<span id="L37" class="LineNr"> 37 </span>    <span class="PreProc">loop</span>
<span id="L38" class="LineNr"> 38 </span>  <span class="Delimiter">}</span>
<span id="L39" class="LineNr"> 39 </span><span class="Delimiter">}</span>
<span id="L40" class="LineNr"> 40 </span>
<span id="L41" class="LineNr"> 41 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L41'>mandelbrot</a></span> <a href='500fake-screen.mu.html#L14'>screen</a>: (addr <a href='500fake-screen.mu.html#L14'>screen</a>), scene-cx: float, scene-cy: float, scene-width: float <span class="Delimiter">{</span>
<span id="L42" class="LineNr"> 42 </span>  <span class="PreProc">var</span> a/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L43" class="LineNr"> 43 </span>  <span class="PreProc">var</span> b/<span class="Constant">ecx</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L44" class="LineNr"> 44 </span>  a, b <span class="Special">&lt;-</span> <a href='500fake-screen.mu.html#L70'>screen-size</a> <a href='500fake-screen.mu.html#L14'>screen</a>
<span id="L45" class="LineNr"> 45 </span>  <span class="PreProc">var</span> width/<span class="Constant">esi</span>: int <span class="Special">&lt;-</span> copy a
<span id="L46" class="LineNr"> 46 </span>  width <span class="Special">&lt;-</span> shift-left <span class="Constant">3</span>/log2-font-width
<span id="L47" class="LineNr"> 47 </span>  <span class="PreProc">var</span> height/<span class="Constant">edi</span>: int <span class="Special">&lt;-</span> copy b
<span id="L48" class="LineNr"> 48 </span>  height <span class="Special">&lt;-</span> shift-left <span class="Constant">4</span>/log2-font-height
<span id="L49" class="LineNr"> 49 </span>  <span class="PreProc">var</span> y/<span class="Constant">ecx</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L50" class="LineNr"> 50 </span>  <span class="Delimiter">{</span>
<span id="L51" class="LineNr"> 51 </span>    compare y, height
<span id="L52" class="LineNr"> 52 </span>    <span class="PreProc">break-if-&gt;=</span>
<span id="L53" class="LineNr"> 53 </span>    <span class="PreProc">var</span> imaginary/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L157'>viewport-to-imaginary</a> y, width, height, scene-cy, scene-width
<span id="L54" class="LineNr"> 54 </span>    <span class="PreProc">var</span> x/<span class="Constant">ebx</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L55" class="LineNr"> 55 </span>    <span class="Delimiter">{</span>
<span id="L56" class="LineNr"> 56 </span>      compare x, width
<span id="L57" class="LineNr"> 57 </span>      <span class="PreProc">break-if-&gt;=</span>
<span id="L58" class="LineNr"> 58 </span>      <span class="PreProc">var</span> real/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L138'>viewport-to-real</a> x, width, scene-cx, scene-width
<span id="L59" class="LineNr"> 59 </span>      <span class="PreProc">var</span> iterations/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L73'>mandelbrot-iterations-for-point</a> real, imaginary, <span class="Constant">0x400</span>/max
<span id="L60" class="LineNr"> 60 </span>      iterations <span class="Special">&lt;-</span> shift-right <span class="Constant">3</span>
<span id="L61" class="LineNr"> 61 </span>      <span class="PreProc">var</span> color/<span class="Constant">edx</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L62" class="LineNr"> 62 </span>      iterations, color <span class="Special">&lt;-</span> <a href='314divide.subx.html#L3'>integer-divide</a> iterations, <span class="Constant">0x18</span>/<span class="Constant">24</span>/size-of-cycle-0
<span id="L63" class="LineNr"> 63 </span>      color <span class="Special">&lt;-</span> add <span class="Constant">0x20</span>/cycle-0
<span id="L64" class="LineNr"> 64 </span>      <a href='500fake-screen.mu.html#L463'>pixel</a> <a href='500fake-screen.mu.html#L14'>screen</a>, x, y, color
<span id="L65" class="LineNr"> 65 </span>      x <span class="Special">&lt;-</span> increment
<span id="L66" class="LineNr"> 66 </span>      <span class="PreProc">loop</span>
<span id="L67" class="LineNr"> 67 </span>    <span class="Delimiter">}</span>
<span id="L68" class="LineNr"> 68 </span>    y <span class="Special">&lt;-</span> increment
<span id="L69" class="LineNr"> 69 </span>    <span class="PreProc">loop</span>
<span id="L70" class="LineNr"> 70 </span>  <span class="Delimiter">}</span>
<span id="L71" class="LineNr"> 71 </span><span class="Delimiter">}</span>
<span id="L72" class="LineNr"> 72 </span>
<span id="L73" class="LineNr"> 73 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L73'>mandelbrot-iterations-for-point</a></span> real: float, imaginary: float, max: int<span class="PreProc"> -&gt; </span>_/<span class="Constant">eax</span>: int <span class="Delimiter">{</span>
<span id="L74" class="LineNr"> 74 </span>  <span class="PreProc">var</span> zero: float
<span id="L75" class="LineNr"> 75 </span>  <span class="PreProc">var</span> x/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> copy zero
<span id="L76" class="LineNr"> 76 </span>  <span class="PreProc">var</span> y/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy zero
<span id="L77" class="LineNr"> 77 </span>  <span class="PreProc">var</span> iterations/<span class="Constant">ecx</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">0</span>
<span id="L78" class="LineNr"> 78 </span>  <span class="Delimiter">{</span>
<span id="L79" class="LineNr"> 79 </span>    <span class="PreProc">var</span> done?/<span class="Constant">eax</span>: boolean <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L94'>mandelbrot-done?</a> x, y
<span id="L80" class="LineNr"> 80 </span>    compare done?, <span class="Constant">0</span>/false
<span id="L81" class="LineNr"> 81 </span>    <span class="PreProc">break-if-!=</span>
<span id="L82" class="LineNr"> 82 </span>    compare iterations, max
<span id="L83" class="LineNr"> 83 </span>    <span class="PreProc">break-if-&gt;=</span>
<span id="L84" class="LineNr"> 84 </span>    <span class="PreProc">var</span> newx/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L112'>mandelbrot-x</a> x, y, real
<span id="L85" class="LineNr"> 85 </span>    <span class="PreProc">var</span> newy/<span class="Constant">xmm3</span>: float <span class="Special">&lt;-</span> <a href='mandelbrot.mu.html#L124'>mandelbrot-y</a> x, y, imaginary
<span id="L86" class="LineNr"> 86 </span>    x <span class="Special">&lt;-</span> copy newx
<span id="L87" class="LineNr"> 87 </span>    y <span class="Special">&lt;-</span> copy newy
<span id="L88" class="LineNr"> 88 </span>    iterations <span class="Special">&lt;-</span> increment
<span id="L89" class="LineNr"> 89 </span>    <span class="PreProc">loop</span>
<span id="L90" class="LineNr"> 90 </span>  <span class="Delimiter">}</span>
<span id="L91" class="LineNr"> 91 </span>  <span class="PreProc">return</span> iterations
<span id="L92" class="LineNr"> 92 </span><span class="Delimiter">}</span>
<span id="L93" class="LineNr"> 93 </span>
<span id="L94" class="LineNr"> 94 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L94'>mandelbrot-done?</a></span> x: float, y: float<span class="PreProc"> -&gt; </span>_/<span class="Constant">eax</span>: boolean <span class="Delimiter">{</span>
<span id="L95" class="LineNr"> 95 </span>  <span class="muComment"># x*x + y*y &gt; 4</span>
<span id="L96" class="LineNr"> 96 </span>  <span class="PreProc">var</span> x2/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> copy x
<span id="L97" class="LineNr"> 97 </span>  x2 <span class="Special">&lt;-</span> multiply x
<span id="L98" class="LineNr"> 98 </span>  <span class="PreProc">var</span> y2/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy y
<span id="L99" class="LineNr"> 99 </span>  y2 <span class="Special">&lt;-</span> multiply y
<span id="L100" class="LineNr">100 </span>  <span class="PreProc">var</span> sum/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> copy x2
<span id="L101" class="LineNr">101 </span>  sum <span class="Special">&lt;-</span> add y2
<span id="L102" class="LineNr">102 </span>  <span class="PreProc">var</span> four/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">4</span>
<span id="L103" class="LineNr">103 </span>  <span class="PreProc">var</span> four-f/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> convert four
<span id="L104" class="LineNr">104 </span>  compare sum, four-f
<span id="L105" class="LineNr">105 </span>  <span class="Delimiter">{</span>
<span id="L106" class="LineNr">106 </span>    <span class="PreProc">break-if-float&gt;</span>
<span id="L107" class="LineNr">107 </span>    <span class="PreProc">return</span> <span class="Constant">0</span>/false
<span id="L108" class="LineNr">108 </span>  <span class="Delimiter">}</span>
<span id="L109" class="LineNr">109 </span>  <span class="PreProc">return</span> <span class="Constant">1</span>/true
<span id="L110" class="LineNr">110 </span><span class="Delimiter">}</span>
<span id="L111" class="LineNr">111 </span>
<span id="L112" class="LineNr">112 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L112'>mandelbrot-x</a></span> x: float, y: float, real: float<span class="PreProc"> -&gt; </span>_/<span class="Constant">xmm2</span>: float <span class="Delimiter">{</span>
<span id="L113" class="LineNr">113 </span>  <span class="muComment"># x*x - y*y + real</span>
<span id="L114" class="LineNr">114 </span>  <span class="PreProc">var</span> x2/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> copy x
<span id="L115" class="LineNr">115 </span>  x2 <span class="Special">&lt;-</span> multiply x
<span id="L116" class="LineNr">116 </span>  <span class="PreProc">var</span> y2/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy y
<span id="L117" class="LineNr">117 </span>  y2 <span class="Special">&lt;-</span> multiply y
<span id="L118" class="LineNr">118 </span>  <span class="PreProc">var</span> result/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> copy x2
<span id="L119" class="LineNr">119 </span>  result <span class="Special">&lt;-</span> subtract y2
<span id="L120" class="LineNr">120 </span>  result <span class="Special">&lt;-</span> add real
<span id="L121" class="LineNr">121 </span>  <span class="PreProc">return</span> result
<span id="L122" class="LineNr">122 </span><span class="Delimiter">}</span>
<span id="L123" class="LineNr">123 </span>
<span id="L124" class="LineNr">124 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L124'>mandelbrot-y</a></span> x: float, y: float, imaginary: float<span class="PreProc"> -&gt; </span>_/<span class="Constant">xmm3</span>: float <span class="Delimiter">{</span>
<span id="L125" class="LineNr">125 </span>  <span class="muComment"># 2*x*y + imaginary</span>
<span id="L126" class="LineNr">126 </span>  <span class="PreProc">var</span> two/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">2</span>
<span id="L127" class="LineNr">127 </span>  <span class="PreProc">var</span> result/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> convert two
<span id="L128" class="LineNr">128 </span>  result <span class="Special">&lt;-</span> multiply x
<span id="L129" class="LineNr">129 </span>  result <span class="Special">&lt;-</span> multiply y
<span id="L130" class="LineNr">130 </span>  result <span class="Special">&lt;-</span> add imaginary
<span id="L131" class="LineNr">131 </span>  <span class="PreProc">return</span> result
<span id="L132" class="LineNr">132 </span><span class="Delimiter">}</span>
<span id="L133" class="LineNr">133 </span>
<span id="L134" class="LineNr">134 </span><span class="muComment"># Scale (x, y) pixel coordinates to a complex plane where the viewport width</span>
<span id="L135" class="LineNr">135 </span><span class="muComment"># ranges from -2 to +2. Viewport height just follows the viewport's aspect</span>
<span id="L136" class="LineNr">136 </span><span class="muComment"># ratio.</span>
<span id="L137" class="LineNr">137 </span>
<span id="L138" class="LineNr">138 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L138'>viewport-to-real</a></span> x: int, width: int, scene-cx: float, scene-width: float<span class="PreProc"> -&gt; </span>_/<span class="Constant">xmm0</span>: float <span class="Delimiter">{</span>
<span id="L139" class="LineNr">139 </span>  <span class="muComment"># 0 in the viewport       goes to scene-cx - scene-width/2 </span>
<span id="L140" class="LineNr">140 </span>  <span class="muComment"># width in the viewport   goes to scene-cx + scene-width/2</span>
<span id="L141" class="LineNr">141 </span>  <span class="muComment"># Therefore:</span>
<span id="L142" class="LineNr">142 </span>  <span class="muComment"># x in the viewport       goes to (scene-cx - scene-width/2) + x*scene-width/width</span>
<span id="L143" class="LineNr">143 </span>  <span class="muComment"># At most two numbers being multiplied before a divide, so no risk of overflow.</span>
<span id="L144" class="LineNr">144 </span>  <span class="PreProc">var</span> result/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> convert x
<span id="L145" class="LineNr">145 </span>  result <span class="Special">&lt;-</span> multiply scene-width
<span id="L146" class="LineNr">146 </span>  <span class="PreProc">var</span> width-f/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> convert width
<span id="L147" class="LineNr">147 </span>  result <span class="Special">&lt;-</span> divide width-f
<span id="L148" class="LineNr">148 </span>  result <span class="Special">&lt;-</span> add scene-cx
<span id="L149" class="LineNr">149 </span>  <span class="PreProc">var</span> two/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">2</span>
<span id="L150" class="LineNr">150 </span>  <span class="PreProc">var</span> two-f/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> convert two
<span id="L151" class="LineNr">151 </span>  <span class="PreProc">var</span> half-scene-width/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy scene-width
<span id="L152" class="LineNr">152 </span>  half-scene-width <span class="Special">&lt;-</span> divide two-f
<span id="L153" class="LineNr">153 </span>  result <span class="Special">&lt;-</span> subtract half-scene-width
<span id="L154" class="LineNr">154 </span>  <span class="PreProc">return</span> result
<span id="L155" class="LineNr">155 </span><span class="Delimiter">}</span>
<span id="L156" class="LineNr">156 </span>
<span id="L157" class="LineNr">157 </span><span class="PreProc">fn</span> <span class="muFunction"><a href='mandelbrot.mu.html#L157'>viewport-to-imaginary</a></span> y: int, width: int, height: int, scene-cy: float, scene-width: float<span class="PreProc"> -&gt; </span>_/<span class="Constant">xmm1</span>: float <span class="Delimiter">{</span>
<span id="L158" class="LineNr">158 </span>  <span class="muComment"># 0 in the viewport       goes to scene-cy - scene-width/2*height/width</span>
<span id="L159" class="LineNr">159 </span>  <span class="muComment"># height in the viewport  goes to scene-cy + scene-width/2*height/width</span>
<span id="L160" class="LineNr">160 </span>  <span class="muComment"># Therefore:</span>
<span id="L161" class="LineNr">161 </span>  <span class="muComment"># y in the viewport       goes to (scene-cy - scene-width/2*height/width) + y*scene-width/width</span>
<span id="L162" class="LineNr">162 </span>  <span class="muComment">#  scene-cy - scene-width/width * (height/2 + y)</span>
<span id="L163" class="LineNr">163 </span>  <span class="muComment"># At most two numbers being multiplied before a divide, so no risk of overflow.</span>
<span id="L164" class="LineNr">164 </span>  <span class="PreProc">var</span> result/<span class="Constant">xmm0</span>: float <span class="Special">&lt;-</span> convert y
<span id="L165" class="LineNr">165 </span>  result <span class="Special">&lt;-</span> multiply scene-width
<span id="L166" class="LineNr">166 </span>  <span class="PreProc">var</span> width-f/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> convert width
<span id="L167" class="LineNr">167 </span>  result <span class="Special">&lt;-</span> divide width-f
<span id="L168" class="LineNr">168 </span>  result <span class="Special">&lt;-</span> add scene-cy
<span id="L169" class="LineNr">169 </span>  <span class="PreProc">var</span> two/<span class="Constant">eax</span>: int <span class="Special">&lt;-</span> copy <span class="Constant">2</span>
<span id="L170" class="LineNr">170 </span>  <span class="PreProc">var</span> two-f/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> convert two
<span id="L171" class="LineNr">171 </span>  <span class="PreProc">var</span> second-term/<span class="Constant">xmm1</span>: float <span class="Special">&lt;-</span> copy scene-width
<span id="L172" class="LineNr">172 </span>  second-term <span class="Special">&lt;-</span> divide two-f
<span id="L173" class="LineNr">173 </span>  <span class="PreProc">var</span> height-f/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> convert height
<span id="L174" class="LineNr">174 </span>  second-term <span class="Special">&lt;-</span> multiply height-f
<span id="L175" class="LineNr">175 </span>  <span class="PreProc">var</span> width-f/<span class="Constant">xmm2</span>: float <span class="Special">&lt;-</span> convert width
<span id="L176" class="LineNr">176 </span>  second-term <span class="Special">&lt;-</span> divide width-f
<span id="L177" class="LineNr">177 </span>  result <span class="Special">&lt;-</span> subtract second-term
<span id="L178" class="LineNr">178 </span>  <span class="PreProc">return</span> result
<span id="L179" class="LineNr">179 </span><span class="Delimiter">}</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->