1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<html> 3 4<head> 5<META http-equiv="Content-Type" content="text/html; charset=windows-1252"> 6<META name="GENERATOR" content="Microsoft FrontPage 5.0"> 7<META http-equiv="Content-Style-Type" content="text/css"> 8<LINK rel="stylesheet" type="text/css" href="../../CSS/revolution.css"> 9<title>GXPokeZMode</title> 10</head> 11 12<body> 13 14<h1 align="left">GXPokeZMode</h1> 15 16 17<h2>C Specification</h2> 18 19<dl> 20 <dd><PRE><CODE>#include <revolution/gx.h></CODE></PRE> 21 </dd> 22 <dd><pre><CODE>void GXPokeZMode( 23 <a href="../Enumerated_Types/GXBool.html">GXBool</a> compare_enable, 24 <a 25href="../Enumerated_Types/GXCompare.html">GXCompare</a> func, 26 <a 27href="../Enumerated_Types/GXBool.html">GXBool</a> update_enable );</CODE></pre> 28 </dd> 29</dl> 30 31<h2>Arguments</h2> 32<TABLE border="1" cellpadding="3" cellspacing="0.1"> 33 <tr> 34<TD width="120" valign="top" bgcolor="#ffffe8"><em><strong>compare_enable</strong></em></TD> 35<TD width="520">When <CODE>GX_TRUE</CODE>, a comparison of the source and destination Z values is enabled. Disabled if not <CODE>GX_TRUE</CODE>.</TD> 36 </tr> 37 <tr> 38<TD width="120" valign="top" bgcolor="#ffffe8"><em><strong>func</strong></em></TD> 39<TD width="520">Z comparison function. <BR>Accepted values are:<BR> 40 <TABLE width="500" border="1" cellspacing="0.1"> 41 42 <tr> 43<TD bgcolor="#C0C0C0" width="150">Name</TD> 44<TD bgcolor="#C0C0C0" width="350">Z comparison process</TD> 45 </tr> 46 <tr> 47<TD width="150"><code>GX_NEVER</code></TD> 48<TD width="350">always a Z test fail</TD> 49 </tr> 50 <tr> 51<TD width="150"><code>GX_LESS</code></TD> 52<TD width="350">The Z test passes if the <code>new Z value < original Z value</code>.</TD> 53 </tr> 54 <tr> 55<TD width="150"><code>GX_LEQUAL</code></TD> 56<TD width="350">The Z test passes if the <code>new Z value <= original Z value</code>.</TD> 57 </tr> 58 <tr> 59<TD height="25" width="150"><code>GX_EQUAL</code></TD> 60<TD height="25" width="350">The Z test passes if the <code>new Z value == original Z value</code>.</TD> 61 </tr> 62 <tr> 63<TD width="150"><code>GX_NEQUAL</code></TD> 64<TD width="350">The Z test passes if the <code>new Z value != original Z value</code>.</TD> 65 </tr> 66 <tr> 67<TD width="150"><code>GX_GEQUAL</code></TD> 68<TD width="350">The Z test passes if the <code>new Z value >= original Z value</code>.</TD> 69 </tr> 70 <tr> 71<TD width="150"><code>GX_GREATER</code></TD> 72<TD width="350">The Z test passes if the <code>new Z value > original Z value</code>.</TD> 73 </tr> 74 <tr> 75<TD width="150"><code>GX_ALWAYS</code></TD> 76<TD width="350">always a Z test pass</TD> 77 </tr> 78 79 </TABLE> 80 </TD> 81 </tr> 82 <tr> 83<TD width="120" valign="top" bgcolor="#ffffe8"><em><strong>update_enable</strong></em></TD> 84<TD width="520">When <CODE>GX_TRUE</CODE>, allows a Z buffer update. If not, disables Z buffer updating, but comparison functionality continues as enabled.</TD> 85 </tr> 86</TABLE> 87<h2>Return Values</h2> 88 89<p>None.</p> 90<H2>Description</H2> 91<P>This function sets the Z-buffer compare mode when writing the embedded frame buffer (EFB) using the <code>GXPoke</code>* functions. The <code>GXPoke</code>* functions allow the CPU to directly write the EFB. </P> 92<P>The result of the Z compare is used to conditionally write color values to the EFB. The Z value will be updated according to the result of the compare if Z update is enabled.</P> 93<P>When <em><strong><code>compare_enable</code></strong></em> is set to <code>GX_DISABLE</code>, poke Z buffering is disabled and the Z buffer is not updated.</P> 94<P>The <em><strong><code>func</code></strong></em> parameter determines the comparison that is performed. In the comparison function, the poked Z value is on the left while the Z value from the Z buffer is on the right. If the result of the comparison is false, the poked Z value is discarded.</P> 95<P>The parameter <code><em><strong>update_enable</strong></em></code> determines whether the Z buffer is updated with the new Z value after a comparison is performed. </P> 96<P>The normal rendering Z mode (<a href="../PixelProc/GXSetZMode.html"><code>GXSetZMode</code></a>) is not affected by this function.</P> 97 98 99 100 101<h2>See Also</h2> 102 103<p><a href="GXPokeBlendMode.html"><CODE>GXPokeBlendMode</CODE></a></p> 104<H2>Revision History</H2> 105<p>2006/03/01 Initial version.</P> 106<hr> 107<P>CONFIDENTIAL</p> 108</BODY> 109</HTML> 110