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8<TITLE>GXPokeAlphaRead</TITLE>
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11<H1 align="left">GXPokeAlphaRead</H1>
12
13<H2>Syntax</H2>
14<dl><dd><pre class="construction">
15#include &lt;revolution/gx.h&gt;
16
17void GXPokeAlphaRead( <A href="../Enumerated_Types/GXAlphaReadMode.html">GXAlphaReadMode</A> mode );
18</pre></dd></dl>
19
20<H2>Arguments</H2>
21<TABLE class="arguments" border="1" >
22  <TBODY>
23    <TR>
24<TH>mode</TH>
25<TD>Determines value of alpha read from a frame buffer with no alpha channel. Accepted values are:<BR>
26      <TABLE class="arguments" border="1" >
27          <tr>
28<TD bgcolor="#C0C0C0">Name</TD>
29<TD bgcolor="#C0C0C0">Alpha value you can read</TD>
30          </tr>
31          <tr>
32<TH>GX_READ_00</TH>
33<TD><CODE>0x00.</CODE></TD>
34          </tr>
35          <tr>
36<TH>GX_READ_FF</TH>
37<TD><CODE>0xFF.</CODE></TD>
38          </tr>
39          <tr>
40<TH>GX_READ_NONE</TH>
41<TD>Alpha value from the EFB.</TD>
42          </tr>
43      </TABLE>
44<CODE>GX_READ_NONE</CODE> can be used if you want to get an alpha value from the EFB. If the EFB doesn't have an alpha plane, the alpha value is undefined.</TD>
45    </TR>
46  </TBODY>
47</TABLE>
48
49<H2>Return Values</H2>
50<P>None.</P>
51
52<H2>Description</H2>
53<P>This function determines the alpha value to read from the EFB. <SPAN class="argument">mode</SPAN> is applied only for the <CODE>GXPeek*</CODE> functions. The <CODE>GXPeek*</CODE> functions allow the CPU to read the EFB directly.</P>
54<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>
55
56<H2>See Also</H2>
57<P class="reference">
58<A href="GXPeekARGB.html">GXPeekARGB</A>
59</P>
60
61<H2>Revision History</H2>
62<P>
632006/03/01 Initial version.<br>
64</P>
65
66<hr><p>CONFIDENTIAL</p></body>
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