1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2<HTML> 3<HEAD> 4<META http-equiv="Content-Type" content="text/html; charset=windows-1252"> 5<META name="GENERATOR" content="Microsoft FrontPage 5.0"> 6<META http-equiv="Content-Style-Type" content="text/css"> 7<LINK rel="stylesheet" type="text/css" href="../../CSS/revolution.css"> 8<TITLE>GXInitLightPosv</TITLE> 9</HEAD> 10<BODY> 11<H1 align="left">GXInitLightPosv</H1> 12<H2>C Specification</H2> 13<DL> 14 <DD> 15<PRE><CODE>#include <revolution/gx.h></CODE></PRE> 16 <DD> 17<PRE><CODE>#define GXInitLightPosv(lo, vec) \ 18(GXInitLightPos((lo), *(f32*)(vec), *((f32*)(vec)+1), *((f32*)(vec)+2)))</CODE></PRE> 19</DL> 20<H2>Arguments</H2> 21<TABLE border="1" cellpadding="3" cellspacing="0.1"> 22 <TBODY> 23 <TR> 24<TD width="120" bgcolor="#ffffe8"><EM><STRONG><CODE>lo</CODE></STRONG></EM></TD> 25<TD width="520">Pointer to a light object.</TD> 26 </TR> 27 <TR> 28<TD width="120" bgcolor="#ffffe8"><EM><STRONG><CODE>vec</CODE></STRONG></EM></TD> 29<TD width="520">Position vector. <BR>You may use an array of <CODE>f32</CODE> type or structure.</TD> 30 </TR> 31 </TBODY> 32</TABLE> 33<H2>Return Values</H2> 34<P>None.</P> 35<H2>Description</H2> 36<P>This macro function sets the position of the light in the light object using a vector structure. The Revolution graphics hardware supports local diffuse lights. The position of the light should be in the same space as a transformed vertex position (i.e., view space).</P> 37<P>The memory for the light object must be allocated by the application; this function does not load any hardware registers. To load a light object into a hardware light, use <a href="GXLoadLightObjImm.html"><code>GXLoadLightObjImm</code></a> or <code><a href="GXLoadLightObjIndx.html">GXLoadLightObjIndx</a></code>.</P> 38<H2>Example</H2> 39<P>You may set an array of f32 values as <strong><em>vec </em></strong>argument<strong><em>.</em></strong></P> 40<P><font size="2"><code>// Use an array<br> f32 pos[3] = { 0.0f, 0.0f, 100.0f };<br> GXLightObj myLightObj;<br> <br> GXInitLightPosv( &myLightObj, pos );</code></font></P> 41<P>You can also use a structure which contains three f32 members (like Vec type of matrix-vector library).</P> 42<P><font size="2"><code>// Use a structure<br> typedef structure<br> {<br> f32 x, y, z;<br> } Point3d;<br> <br> Point3d pos;<br> GXLightObj myLightObj;<br> <br> pos.x = pos.y = pos.z = 0.0f;<br> GXInitLightPosv( &myLightObj, &pos );</code></font></P> 43<H2>See Also</H2> 44<P><CODE><A href="GXInitLightPos.html">GXInitLightPos</A></CODE></P> 45<P><A href="GXLightObjInitFlow.html">GXLightObj Initialization Flow</A></P> 46<H2>Revision History</H2> 47<P>03/01/2006 Initial version.</P> 48</BODY> 49</HTML>