source-engine/bitmap/ImageByteSwap.cpp

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: Image Byte Swapping. Isolate routines to own module to allow librarian
// to ignore xbox 360 dependenices in non-applicable win32 projects.
//
//=============================================================================//

#if defined( _WIN32 ) && !defined( _X360 ) && !defined( DX_TO_GL_ABSTRACTION )
#include <windows.h>
#endif
#include "tier0/platform.h"
#include "tier0/dbg.h"
#include "bitmap/imageformat.h"

// Should be last include
#include "tier0/memdbgon.h"

#if defined( _WIN32 ) && !defined( _X360 ) && !defined( NO_X360_XDK ) && !defined( DX_TO_GL_ABSTRACTION )
// the x86 version of the 360 (used by win32 tools)
// It would have been nice to use the 360 D3DFORMAT bit encodings, but the codes
// are different for WIN32, and this routine is used by a WIN32 library to
// manipulate 360 data, so there can be no reliance on WIN32 D3DFORMAT bits
#pragma warning(push)
#pragma warning(disable : 4458)  // warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc (disabled due to std headers having exception syntax)
#include "..\x360xdk\include\win32\vs2005\d3d9.h"
#include "..\x360xdk\include\win32\vs2005\XGraphics.h"
#pragma warning(pop)
#endif

namespace ImageLoader
{

//-----------------------------------------------------------------------------
// Known formats that can be converted.  Used as a trap for 360 formats
// that may occur but have not been validated yet.
//-----------------------------------------------------------------------------
	bool IsFormatValidForConversion( ImageFormat fmt )
	{
		switch ( fmt )
		{
			case IMAGE_FORMAT_RGBA8888: 
			case IMAGE_FORMAT_ABGR8888:
			case IMAGE_FORMAT_RGB888:
			case IMAGE_FORMAT_BGR888:
			case IMAGE_FORMAT_ARGB8888:
			case IMAGE_FORMAT_BGRA8888:
			case IMAGE_FORMAT_BGRX8888:
			case IMAGE_FORMAT_UVWQ8888:
			case IMAGE_FORMAT_RGBA16161616F:
			case IMAGE_FORMAT_RGBA16161616:
			case IMAGE_FORMAT_UVLX8888:
			case IMAGE_FORMAT_DXT1:
			case IMAGE_FORMAT_DXT1_ONEBITALPHA:
			case IMAGE_FORMAT_DXT3:
			case IMAGE_FORMAT_DXT5:
			case IMAGE_FORMAT_UV88:
				return true;

				// untested formats
			default:
			case IMAGE_FORMAT_RGB565: 
			case IMAGE_FORMAT_I8:
			case IMAGE_FORMAT_IA88:
			case IMAGE_FORMAT_A8:
			case IMAGE_FORMAT_RGB888_BLUESCREEN:
			case IMAGE_FORMAT_BGR888_BLUESCREEN:
			case IMAGE_FORMAT_BGR565:
			case IMAGE_FORMAT_BGRX5551:
			case IMAGE_FORMAT_BGRA4444:
			case IMAGE_FORMAT_BGRA5551:
			case IMAGE_FORMAT_ATI1N:
			case IMAGE_FORMAT_ATI2N:
				break;
		}

		return false;
	}


//-----------------------------------------------------------------------------
// Swaps the image element type within the format.
// This is to ensure that >8 bit channels are in the correct endian format
// as expected by the conversion process, which varies according to format,
// input, and output.
//-----------------------------------------------------------------------------
	void PreConvertSwapImageData( unsigned char *pImageData, int nImageSize, ImageFormat imageFormat, int width, int stride )
	{

		Assert( IsFormatValidForConversion( imageFormat ) );

#if !defined( DX_TO_GL_ABSTRACTION ) && !defined( NO_X360_XDK )
		if ( IsPC() )
		{
			// running as a win32 tool, data is in expected order
			// for conversion code
			return;
		}

		// running on 360 and converting, input data must be x86 order
		// swap to ensure conversion code gets valid data
		XGENDIANTYPE xEndian;
		switch ( imageFormat )
		{
			default:
				return;

			case IMAGE_FORMAT_RGBA16161616F:
			case IMAGE_FORMAT_RGBA16161616:
				xEndian = XGENDIAN_8IN16;
				break;
		}

		int count;
		if ( !stride )
		{
			stride = XGENDIANTYPE_GET_DATA_SIZE( xEndian );
			count = nImageSize / stride;
			XGEndianSwapMemory( pImageData, pImageData, xEndian, stride, count );
		}
		else
		{
			int nRows = nImageSize/stride;
			for ( int i=0; i<nRows; i++ )
			{
				XGEndianSwapMemory( pImageData, pImageData, xEndian, XGENDIANTYPE_GET_DATA_SIZE( xEndian ), width );
				pImageData += stride;
			}
		}
#endif
	}

//-----------------------------------------------------------------------------
// Swaps image bytes for use on a big endian platform. This is used after the conversion
// process to match the 360 d3dformats.
//-----------------------------------------------------------------------------
	void PostConvertSwapImageData( unsigned char *pImageData, int nImageSize, ImageFormat imageFormat, int width, int stride )
	{
		Assert( IsFormatValidForConversion( imageFormat ) );

#if !defined( DX_TO_GL_ABSTRACTION ) && !defined( NO_X360_XDK )
		// It would have been nice to use the 360 D3DFORMAT bit encodings, but the codes
		// are different for win32, and this routine is used by a win32 library to
		// manipulate 360 data, so there can be no reliance on D3DFORMAT bits
		XGENDIANTYPE xEndian;
		switch ( imageFormat )
		{
			default:
				return;

			case IMAGE_FORMAT_RGBA16161616:
				if ( IsX360() )
				{
					// running on 360 the conversion output is correct
					return;
				}
				// running on the pc, the output needs to be in 360 order
				xEndian = XGENDIAN_8IN16;
				break;

			case IMAGE_FORMAT_DXT1:
			case IMAGE_FORMAT_DXT1_ONEBITALPHA:
			case IMAGE_FORMAT_DXT3:
			case IMAGE_FORMAT_DXT5:
			case IMAGE_FORMAT_UV88:
			case IMAGE_FORMAT_ATI1N:
			case IMAGE_FORMAT_ATI2N:
				xEndian = XGENDIAN_8IN16;
				break;

			case IMAGE_FORMAT_BGRA8888:
			case IMAGE_FORMAT_BGRX8888:
			case IMAGE_FORMAT_UVWQ8888:
			case IMAGE_FORMAT_UVLX8888:
				xEndian = XGENDIAN_8IN32;
				break;
		}

		int count;
		if ( !stride )
		{
			stride = XGENDIANTYPE_GET_DATA_SIZE( xEndian );
			count = nImageSize / stride;
			XGEndianSwapMemory( pImageData, pImageData, xEndian, stride, count );
		}
		else
		{
			int nRows = nImageSize/stride;
			for ( int i=0; i<nRows; i++ )
			{
				XGEndianSwapMemory( pImageData, pImageData, xEndian, XGENDIANTYPE_GET_DATA_SIZE( xEndian ), width );
				pImageData += stride;
			}
		}
#endif
	}

//-----------------------------------------------------------------------------
// Swaps image bytes.
//-----------------------------------------------------------------------------
	void ByteSwapImageData( unsigned char *pImageData, int nImageSize, ImageFormat imageFormat, int width, int stride )
	{
		Assert( IsFormatValidForConversion( imageFormat ) );

#if !defined( DX_TO_GL_ABSTRACTION ) && !defined( NO_X360_XDK )
		XGENDIANTYPE xEndian;
		switch ( imageFormat )
		{
			case IMAGE_FORMAT_BGR888:
			case IMAGE_FORMAT_I8:
			case IMAGE_FORMAT_A8:
			default:
				return;

			case IMAGE_FORMAT_BGRA8888:
			case IMAGE_FORMAT_BGRX8888:
			case IMAGE_FORMAT_UVWQ8888:
			case IMAGE_FORMAT_UVLX8888:
			case IMAGE_FORMAT_R32F:
			case IMAGE_FORMAT_RGBA32323232F:
				xEndian = XGENDIAN_8IN32;
				break;

			case IMAGE_FORMAT_BGR565:
			case IMAGE_FORMAT_BGRX5551:
			case IMAGE_FORMAT_BGRA5551:
			case IMAGE_FORMAT_BGRA4444:
			case IMAGE_FORMAT_IA88:
			case IMAGE_FORMAT_DXT1:
			case IMAGE_FORMAT_DXT1_ONEBITALPHA:
			case IMAGE_FORMAT_DXT3:
			case IMAGE_FORMAT_DXT5:
			case IMAGE_FORMAT_ATI1N:
			case IMAGE_FORMAT_ATI2N:
			case IMAGE_FORMAT_UV88:
			case IMAGE_FORMAT_RGBA16161616F:
			case IMAGE_FORMAT_RGBA16161616:
				xEndian = XGENDIAN_8IN16;
				break;
		}

		int count;
		if ( !stride )
		{
			stride = XGENDIANTYPE_GET_DATA_SIZE( xEndian );
			count = nImageSize / stride;
			XGEndianSwapMemory( pImageData, pImageData, xEndian, stride, count );
		}
		else
		{
			int nRows = nImageSize/stride;
			for ( int i=0; i<nRows; i++ )
			{
				XGEndianSwapMemory( pImageData, pImageData, xEndian, XGENDIANTYPE_GET_DATA_SIZE( xEndian ), width );
				pImageData += stride;
			}
		}
#endif
	}
	
}