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8<TITLE>GXPokeAlphaRead</TITLE>
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11<H1 align="left">GXPokeAlphaRead</H1>
12<H2>C Specification</H2>
13<DL>
14  <DD>
15<PRE><CODE>#include &lt;revolution/gx.h&gt;</CODE></PRE>
16  <DD>
17<PRE><CODE>void GXPokeAlphaRead( <a href="../Enumerated_Types/GXAlphaReadMode.html">GXAlphaReadMode</a> mode );</CODE></PRE>
18</DL>
19<H2>Arguments</H2>
20<TABLE border="1" cellpadding="3" cellspacing="0.1">
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23<TD width="120" valign="top" bgcolor="#ffffe8"><EM><STRONG><CODE>mode</FONT></STRONG></EM></TD>
24<TD width="520">Determines value of alpha read from a frame buffer with no alpha channel.  Accepted values are:<BR>
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27          <tr>
28<TD width="150" bgcolor="#C0C0C0">Name</TD>
29<TD width="350" bgcolor="#C0C0C0">Alpha value you can read</TD>
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31          <tr>
32<TD width="150"><code>GX_READ_00</code></TD>
33<TD width="350"><CODE>0x00</CODE></TD>
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36<TD width="150"><code>GX_READ_FF</code></TD>
37<TD width="350"><CODE>0xFF</CODE></TD>
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39          <tr>
40<TD width="150"><code>GX_READ_NONE</code></TD>
41<TD width="350">Alpha value from the EFB</TD>
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45<code>GX_READ_NONE</code> will be used if you want to get an alpha value from the EFB If the EFB doesn't have an lpha plane, the alpha value is undefined.</TD>
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49<H2>Return Values</H2>
50<P>None.</P>
51<H2>Description</H2>
52<P>This function determines the alpha value to read from the EFB. <CODE><I><EM><STRONG>mode</STRONG></EM></I></CODE> is applied only for the <CODE>GXPeek*</CODE> functions. The <CODE>GXPeek*</CODE> functions allow the CPU to read the EFB directly.</P>
53<P>This functionality will work no matter what pixel type is used (see the <A href="../PixelProc/GXSetPixelFmt.html"><CODE>GXSetPixelFmt</CODE></A> function). When using an EFB with an alpha plane, the use of <CODE>GX_READ_NONE</CODE> is recommended to read the correct alpha values from the EFB. When using an EFP without alpha values, use either <CODE>GX_READ_00</CODE> or <CODE>GX_READ_FF</CODE> to get the constant value.</P>
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56<H2>See Also</H2>
57<P><A href="GXPeekARGB.html"><CODE>GXPeekARGB</CODE></A></P>
58<H2>Revision History</H2>
59<P>03/01/2006 Initial version.</P>
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