105 lines
2.5 KiB
C++
105 lines
2.5 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// Purpose: A set of utilities to render standard shapes
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//
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//===========================================================================//
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#include "tier2/meshutils.h"
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//-----------------------------------------------------------------------------
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// Helper methods to create various standard index buffer types
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//-----------------------------------------------------------------------------
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void GenerateSequentialIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
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{
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if ( !pIndices )
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return;
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// Format the sequential buffer
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for ( int i = 0; i < nIndexCount; ++i )
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{
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pIndices[i] = (unsigned short)( i + nFirstVertex );
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}
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}
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void GenerateQuadIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
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{
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if ( !pIndices )
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return;
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// Format the quad buffer
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int i;
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int numQuads = nIndexCount / 6;
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int baseVertex = nFirstVertex;
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for ( i = 0; i < numQuads; ++i)
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{
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// Triangle 1
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pIndices[0] = (unsigned short)( baseVertex );
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pIndices[1] = (unsigned short)( baseVertex + 1 );
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pIndices[2] = (unsigned short)( baseVertex + 2 );
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// Triangle 2
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pIndices[3] = (unsigned short)( baseVertex );
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pIndices[4] = (unsigned short)( baseVertex + 2 );
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pIndices[5] = (unsigned short)( baseVertex + 3 );
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baseVertex += 4;
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pIndices += 6;
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}
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}
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void GeneratePolygonIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
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{
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if ( !pIndices )
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return;
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int i;
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int numPolygons = nIndexCount / 3;
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for ( i = 0; i < numPolygons; ++i)
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{
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// Triangle 1
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pIndices[0] = (unsigned short)( nFirstVertex );
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pIndices[1] = (unsigned short)( nFirstVertex + i + 1 );
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pIndices[2] = (unsigned short)( nFirstVertex + i + 2 );
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pIndices += 3;
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}
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}
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void GenerateLineStripIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
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{
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if ( !pIndices )
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return;
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int i;
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int numLines = nIndexCount / 2;
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for ( i = 0; i < numLines; ++i)
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{
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pIndices[0] = (unsigned short)( nFirstVertex + i );
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pIndices[1] = (unsigned short)( nFirstVertex + i + 1 );
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pIndices += 2;
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}
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}
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void GenerateLineLoopIndexBuffer( unsigned short* pIndices, int nIndexCount, int nFirstVertex )
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{
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if ( !pIndices )
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{
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return;
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}
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int i;
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int numLines = nIndexCount / 2;
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pIndices[0] = (unsigned short)( nFirstVertex + numLines - 1 );
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pIndices[1] = (unsigned short)( nFirstVertex );
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pIndices += 2;
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for ( i = 1; i < numLines; ++i)
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{
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pIndices[0] = (unsigned short)( nFirstVertex + i - 1 );
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pIndices[1] = (unsigned short)( nFirstVertex + i );
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pIndices += 2;
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}
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}
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