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>GXSetTevAlphaIn</title> 10</head> 11 12<body> 13 14<h1 align="left">GXSetTevAlphaIn</h1> 15 16<h2>Syntax</h2> 17<dl><dd><pre class="construction"> 18#include <revolution/gx.h> 19 20void GXSetTevAlphaIn( 21 <a href="../Enumerated_Types/GXTevStageID.html">GXTevStageID</a> stage, 22 <a href="../Enumerated_Types/GXTevAlphaArg.html">GXTevAlphaArg</a> a, 23 <a href="../Enumerated_Types/GXTevAlphaArg.html">GXTevAlphaArg</a> b, 24 <a href="../Enumerated_Types/GXTevAlphaArg.html">GXTevAlphaArg</a> c, 25 <a href="../Enumerated_Types/GXTevAlphaArg.html">GXTevAlphaArg</a> d ); 26</pre></dd></dl> 27 28<h2>Arguments</h2> 29<TABLE class="arguments" border="1" > 30 <tr> 31<TH>stage</TH> 32<TD>Name of the <a href="../Enumerated_Types/GXTevStageID.html">stage</a>. Accepted values are: <code>GX_TEVSTAGE0</code>, <code>GX_TEVSTAGE1</code>, <code>GX_TEVSTAGE2</code>, ... , <code>GX_TEVSTAGE15</code>.</TD> 33 </tr> 34 <tr> 35<TH><a name="a">a</a></TH> 36<TD>Input <a href="../Enumerated_Types/GXTevColorArg.html">operand</a>. An unsigned 8-bit value for the component. Accepted values are:<BR> 37 <TABLE class="arguments" border="1" > 38 <tr> 39<TD bgcolor="#C0C0C0">Name</TD> 40<TD bgcolor="#C0C0C0">Input</TD> 41 </tr> 42 <tr> 43<TH>GX_CA_A0</TH> 44<TD>Alpha from the <CODE>TEVREG0</CODE> register.</TD> 45 </tr> 46 <tr> 47<TH>GX_CA_A1</TH> 48<TD>Alpha from the <CODE>TEVREG1</CODE> register.</TD> 49 </tr> 50 <tr> 51<TH>GX_CA_A2</TH> 52<TD>Alpha from the <CODE>TEVREG2</CODE> register.</TD> 53 </tr> 54 <tr> 55<TH>GX_CA_APREV</TH> 56<TD>Alpha from the <CODE>TEVPREV</CODE> register.</TD> 57 </tr> 58 <tr> 59<TH>GX_CA_TEXA</TH> 60<TD>Alpha from the texture.</TD> 61 </tr> 62 <tr> 63<TH>GX_CA_RASA</TH> 64<TD>Alpha from the rasterized vertex color.</TD> 65 </tr> 66 <tr> 67<TH>GX_CA_ZERO</TH> 68<TD>0.0 fixed.</TD> 69 </tr> 70 <tr> 71<TH>GX_CA_KONST</TH> 72<TD>Constant alpha input (see the <A href="GXSetTevKAlphaSel.html"><CODE>GXSetTevKAlphaSel</CODE></A> function).</TD> 73 </tr> 74 </TABLE> 75 </TD> 76 </tr> 77 <tr> 78<TH>b </TH> 79<TD>Input <A href="../Enumerated_Types/GXTevAlphaArg.html">operand</A>. An unsigned 8-bit value for the element. Applicable values are the same as for <SPAN class="argument">a</SPAN>.</TD> 80 </tr> 81 <tr> 82<TH>c</TH> 83<TD>Input <A href="../Enumerated_Types/GXTevAlphaArg.html">operand</A>. An unsigned 8-bit value for the element. Applicable values are the same as for <SPAN class="argument">a</SPAN>.</TD> 84 </tr> 85 <tr> 86<TH>d</TH> 87<TD>Input <A href="../Enumerated_Types/GXTevAlphaArg.html">operand</A>. A signed 1-bit + 10-bit value per element. Applicable values are the same as for <SPAN class="argument">a</SPAN>.</TD> 88 </tr> 89</TABLE> 90 91<h2>Return Values</h2> 92<p>None.</p> 93 94<H2>Description</H2> 95<P>This function sets the input operands for one <SPAN class="argument">stage</SPAN> of the texture environment (TEV) alpha combiner unit. The input operands <SPAN class="argument">a</SPAN>, <SPAN class="argument">b</SPAN>, and <SPAN class="argument">c</SPAN> are unsigned 8-bit inputs (0 <= <SPAN class="argument">a, b, c</SPAN> <= 255). The <SPAN class="argument">d</SPAN> input operand is a signed 10-bit input (-1024 <= <SPAN class="argument">d</SPAN> <= 1023).</P> 96<P>Each TEV stage implements the following function:</P> 97<DL><DD><CODE><EM>reg</EM></CODE> = ( <SPAN class="argument">d</SPAN> ( <CODE><EM>op</EM></CODE> ) (( 1.0 - <SPAN class="argument">c</SPAN> ) * <SPAN class="argument">a</SPAN> + <SPAN class="argument">c</SPAN> * <SPAN class="argument">b</SPAN> ) + <CODE><EM>bias</EM></CODE>) * <CODE><EM>scale</EM></CODE>;</DD></DL> 98<P>The operations described by <CODE><EM>op</EM>, <EM>bias</EM>,</CODE> and <CODE><EM>scale</EM></CODE> are programmable using the <A href="GXSetTevAlphaOp.html"><CODE>GXSetTevAlphaOp</CODE></A> function.</P> 99<P>The output of this stage is directed by default to the <CODE>GX_TEVPREV</CODE> register (see <A href="../Management/GXInit.html"><CODE>GXInit</CODE></A>), but can be set explicitly by the <A href="GXSetTevAlphaOp.html"><CODE>GXSetTevAlphaOp</CODE></A> function. When the input <SPAN class="argument">a</SPAN>, <SPAN class="argument">b</SPAN> or <SPAN class="argument">c</SPAN> is from a signed 10-bit number (either the results of a previous TEV stage or an input constant), only the 8 least-significant bits are used. The number is not converted; upper bits are simply discarded.</P> 100<P>The registers used to store the output of TEV stages can also be used as inputs: <CODE>GX_CA_A0</CODE>, <CODE>GX_CA_A1</CODE>, <CODE>GX_CA_A2</CODE>, and <CODE>GX_CA_APREV</CODE>. These registers can be set with constant alpha values using the <A href="GXSetTevColor.html"><CODE>GXSetTevColor</CODE></A> or <A href="GXSetTevColorS10.html"><CODE>GXSetTevColorS10</CODE></A> functions.</P> 101<P>The input operand <CODE>GX_CA_RASA</CODE> is the solution for the <A href="../list.html#Lighting">per-vertex lighting</A> equation. The input operand <CODE>GX_CA_TEXA</CODE> is the texture alpha input for this stage. You can select the colors and textures to which these inputs correspond using the <A href="GXSetTevOrder.html"><CODE>GXSetTevOrder</CODE></A> function.</P> 102 103<h2>See Also</h2> 104<P class="reference"> 105<A href="GXSetTevOp.html">GXSetTevOp</A>, 106<A href="GXSetTevColorIn.html">GXSetTevColorIn</A>, 107<A href="GXSetTevAlphaOp.html">GXSetTevAlphaOp</A>, 108<A href="GXSetTevKAlphaSel.html">GXSetTevKAlphaSel</A> 109</p> 110 111<h2>Revision History</h2> 112<P> 1132008/05/26 Corrected errors.<br>2006/03/01 Initial version.<br> 114</P> 115 116<hr><p>CONFIDENTIAL</p></body> 117</HTML>