OpenSceneGraph/src/osg/dxtctool.cpp

// dxtctool.cpp: implementation of DXTC Tools functions.
// 
// Copyright (C) 2002 Tanguy Fautr<74>.
// For conditions of distribution and use,
// see copyright notice in dxtctool.h
//
//////////////////////////////////////////////////////////////////////

#include "dxtctool.h"


namespace dxtc_tool {




//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////



//////////////////////////////////////////////////////////////////////
// Members Functions
//////////////////////////////////////////////////////////////////////

bool dxtc_pixels::OpenGLSize() const
{
	size_t Width = m_Width;
	size_t Height = m_Height;
	// size_t TotalTrueBits = 0;

	if ((Width == 0) || (Height == 0))
		return false;

	for (; (Width % 2) == 0; Width /= 2);
	for (; (Height % 2) == 0; Height /= 2);

	if ((Width != 1) || (Height != 1))
		return false;
	else
		return true;
}



bool dxtc_pixels::VFlip() const
{
	// Check that the given dimentions are 2^x, 2^y
	if (! OpenGLSize())
		return false;

	// Check that the given format are supported
	if (! SupportedFormat())
		return false;

	// Nothing to do if Height == 1
	if (m_Height == 1)
		return true;
		
	if (DXT1())
		VFlip_DXT1();
	else if (DXT3())
		VFlip_DXT3();
	else if (DXT5())
		VFlip_DXT5();
	else
		return false; // We should never get there

	return true;
}



void dxtc_pixels::VFlip_DXT1() const
{
	// const size_t Size = ((m_Width + 3) / 4) * ((m_Height + 3) / 4) * BSIZE_DXT1;
	__int8 * const pPixels = (__int8 * const) m_pPixels;

	if (m_Height == 2)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j)
			BVF_Color_H2(pPixels + j * BSIZE_DXT1);

	if (m_Height == 4)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j)
			BVF_Color_H4(pPixels + j * BSIZE_DXT1);

	if (m_Height > 4)
		for (size_t i = 0; i < ((m_Height + 7) / 8); ++i)
			for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
				const size_t TargetRow = ((m_Height + 3) / 4) - (i + 1);
				BVF_Color(GetBlock(i, j, BSIZE_DXT1), GetBlock(TargetRow, j, BSIZE_DXT1));
			}
}



void dxtc_pixels::VFlip_DXT3() const
{
	// const size_t Size = ((m_Width + 3) / 4) * ((m_Height + 3) / 4) * BSIZE_DXT3;
	// __int8 * const pPixels = (__int8 * const) m_pPixels;

	if (m_Height == 2)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
			BVF_Alpha_DXT3_H2(((__int8 * const) m_pPixels) + (j * BSIZE_DXT3));
			BVF_Color_H2(((__int8 * const) m_pPixels) + (j * BSIZE_DXT3 + BSIZE_ALPHA_DXT3));
		}

	if (m_Height == 4)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
			BVF_Alpha_DXT3_H4(((__int8 * const) m_pPixels) + (j * BSIZE_DXT3));
			BVF_Color_H4(((__int8 * const) m_pPixels) + (j * BSIZE_DXT3 + BSIZE_ALPHA_DXT3));
		}

	if (m_Height > 4)
		for (size_t i = 0; i < ((m_Height + 7) / 8); ++i)
			for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
				const size_t TargetRow = ((m_Height + 3) / 4) - (i + 1);
				BVF_Alpha_DXT3(GetBlock(i, j, BSIZE_DXT3), GetBlock(TargetRow, j, BSIZE_DXT3));
				BVF_Color(((__int8 * const) GetBlock(i, j, BSIZE_DXT3)) + BSIZE_ALPHA_DXT3, 
						  ((__int8 * const) GetBlock(TargetRow, j, BSIZE_DXT3)) + BSIZE_ALPHA_DXT3);
			}
}



void dxtc_pixels::VFlip_DXT5() const
{
	// const size_t Size = ((m_Width + 3) / 4) * ((m_Height + 3) / 4) * BSIZE_DXT5;
	// __int8 * const pPixels = (__int8 * const) m_pPixels;

	if (m_Height == 2)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
			BVF_Alpha_DXT5_H2(((__int8 * const) m_pPixels) + (j * BSIZE_DXT5));
			BVF_Color_H2(((__int8 * const) m_pPixels) + (j * BSIZE_DXT5 + BSIZE_ALPHA_DXT5));
		}

	if (m_Height == 4)
		for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
			BVF_Alpha_DXT5_H4(((__int8 * const) m_pPixels) + (j * BSIZE_DXT5));
			BVF_Color_H4(((__int8 * const) m_pPixels) + (j * BSIZE_DXT5 + BSIZE_ALPHA_DXT5));
		}

	if (m_Height > 4)
		for (size_t i = 0; i < ((m_Height + 7) / 8); ++i)
			for (size_t j = 0; j < (m_Width + 3) / 4; ++j) {
				const size_t TargetRow = ((m_Height + 3) / 4) - (i + 1);
				BVF_Alpha_DXT5(GetBlock(i, j, BSIZE_DXT5), GetBlock(TargetRow, j, BSIZE_DXT5));
				BVF_Color(((__int8 * const) GetBlock(i, j, BSIZE_DXT5)) + BSIZE_ALPHA_DXT5, 
						  ((__int8 * const) GetBlock(TargetRow, j, BSIZE_DXT5)) + BSIZE_ALPHA_DXT5);
			}
}




}; // namespace dxtc_tool