Counter Strike : Global Offensive Source Code
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//===== Copyright © 2005-2005, Valve Corporation, All rights reserved. ======//
//
// Purpose: A set of utilities to render standard shapes
//
//===========================================================================//
#include "tier2/meshutils.h"
#include "tier0/platform.h"
// NOTE: This has to be the last file included!
#include "tier0/memdbgon.h"
//-----------------------------------------------------------------------------
// Helper methods to create various standard index buffer types
//-----------------------------------------------------------------------------
void GenerateSequentialIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
{
if ( !pIndices )
return;
// Format the sequential buffer
for ( int i = 0; i < nIndexCount; ++i )
{
pIndices[i] = (unsigned short)( i + nFirstVertex );
}
}
void GenerateQuadIndexBuffer( unsigned short *pIndices, int nIndexCount, int nFirstVertex )
{
if ( !pIndices )
return;
// Format the quad buffer
int i;
int numQuads = nIndexCount / 6;
unsigned short baseVertex = (unsigned short)nFirstVertex;
if ( ( (size_t)pIndices & 0x3 ) == 0 )
{
// Fast version, requires aligned indices
int *pWrite = (int*)pIndices;
int nWrite = ( baseVertex << 16 ) | baseVertex;
for ( i = 0; i < numQuads; ++i )
{
// Have to deal with endian-ness
if ( IsX360() || IsPS3() )
{
// this avoids compiler write reodering and prevents the write-combined out-of-order penalty
// _WriteBarrier won't compile here, and volatile is ignored
// the compiler otherwise scrambles these writes
*pWrite++ = nWrite + 1;
*pWrite++ = nWrite + ( 2 << 16 );
*pWrite++ = nWrite + ( 2 << 16 ) + 3;
}
else
{
pWrite[0] = nWrite + ( 1 << 16 );
pWrite[1] = nWrite + 2;
pWrite[2] = nWrite + ( 3 << 16 ) + 2;
pWrite += 3;
}
nWrite += ( 4 << 16 ) | 4;
}
}
else
{
for ( i = 0; i < numQuads; ++i )
{
pIndices[0] = baseVertex;
pIndices[1] = baseVertex + 1;
pIndices[2] = baseVertex + 2;
// Triangle 2
pIndices[3] = baseVertex;
pIndices[4] = baseVertex + 2;
pIndices[5] = baseVertex + 3;
baseVertex += 4;
pIndices += 6;
}
}
}
void GeneratePolygonIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
{
if ( !pIndices )
return;
int i, baseVertex;
int numPolygons = nIndexCount / 3;
baseVertex = nFirstVertex;
for ( i = 0; i < numPolygons; ++i)
{
// Triangle 1
pIndices[0] = (unsigned short)( nFirstVertex );
pIndices[1] = (unsigned short)( nFirstVertex + i + 1 );
pIndices[2] = (unsigned short)( nFirstVertex + i + 2 );
pIndices += 3;
}
}
void GenerateLineStripIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
{
if ( !pIndices )
return;
int i, baseVertex;
int numLines = nIndexCount / 2;
baseVertex = nFirstVertex;
for ( i = 0; i < numLines; ++i)
{
pIndices[0] = (unsigned short)( nFirstVertex + i );
pIndices[1] = (unsigned short)( nFirstVertex + i + 1 );
pIndices += 2;
}
}
void GenerateLineLoopIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
{
if ( !pIndices )
{
return;
}
int i, baseVertex;
int numLines = nIndexCount / 2;
baseVertex = nFirstVertex;
pIndices[0] = (unsigned short)( nFirstVertex + numLines - 1 );
pIndices[1] = (unsigned short)( nFirstVertex );
pIndices += 2;
for ( i = 1; i < numLines; ++i)
{
pIndices[0] = (unsigned short)( nFirstVertex + i - 1 );
pIndices[1] = (unsigned short)( nFirstVertex + i );
pIndices += 2;
}
}