rmance utility function for drawing a simple quad. Not intended for drawing large quantities of geometry.</p>
<dl><dt><b>Parameters:</b></dt><dd>
  <table class="params">
    <tr><td class="paramname">x1</td><td></td></tr>
    <tr><td class="paramname">y1</td><td></td></tr>
    <tr><td class="paramname">z1</td><td></td></tr>
    <tr><td class="paramname">x2</td><td></td></tr>
    <tr><td class="paramname">y2</td><td></td></tr>
    <tr><td class="paramname">z2</td><td></td></tr>
    <tr><td class="paramname"