/indra/llimage/llimage.cpp

/** 
 * @file llimage.cpp
 * @brief Base class for images.
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "llimage.h"

#include "llmath.h"
#include "v4coloru.h"
#include "llmemtype.h"

#include "llimagebmp.h"
#include "llimagetga.h"
#include "llimagej2c.h"
#include "llimagejpeg.h"
#include "llimagepng.h"
#include "llimagedxt.h"
#include "llimageworker.h"
#include "llmemory.h"

//---------------------------------------------------------------------------
// LLImage
//---------------------------------------------------------------------------

//static
std::string LLImage::sLastErrorMessage;
LLMutex* LLImage::sMutex = NULL;
LLPrivateMemoryPool* LLImageBase::sPrivatePoolp = NULL ;

//static
void LLImage::initClass()
{
	sMutex = new LLMutex(NULL);

	LLImageBase::createPrivatePool() ;
}

//static
void LLImage::cleanupClass()
{
	delete sMutex;
	sMutex = NULL;

	LLImageBase::destroyPrivatePool() ;
}

//static
const std::string& LLImage::getLastError()
{
	static const std::string noerr("No Error");
	return sLastErrorMessage.empty() ? noerr : sLastErrorMessage;
}

//static
void LLImage::setLastError(const std::string& message)
{
	LLMutexLock m(sMutex);
	sLastErrorMessage = message;
}

//---------------------------------------------------------------------------
// LLImageBase
//---------------------------------------------------------------------------

LLImageBase::LLImageBase()
	: mData(NULL),
	  mDataSize(0),
	  mWidth(0),
	  mHeight(0),
	  mComponents(0),
	  mBadBufferAllocation(false),
	  mAllowOverSize(false),
	  mMemType(LLMemType::MTYPE_IMAGEBASE)
{
}

// virtual
LLImageBase::~LLImageBase()
{
	deleteData(); // virtual
}

//static 
void LLImageBase::createPrivatePool() 
{
	if(!sPrivatePoolp)
	{
		sPrivatePoolp = LLPrivateMemoryPoolManager::getInstance()->newPool(LLPrivateMemoryPool::STATIC_THREADED) ;
	}
}
	
//static 
void LLImageBase::destroyPrivatePool() 
{
	if(sPrivatePoolp)
	{
		LLPrivateMemoryPoolManager::getInstance()->deletePool(sPrivatePoolp) ;
		sPrivatePoolp = NULL ;
	}
}

// virtual
void LLImageBase::dump()
{
	llinfos << "LLImageBase mComponents " << mComponents
		<< " mData " << mData
		<< " mDataSize " << mDataSize
		<< " mWidth " << mWidth
		<< " mHeight " << mHeight
		<< llendl;
}

// virtual
void LLImageBase::sanityCheck()
{
	if (mWidth > MAX_IMAGE_SIZE
		|| mHeight > MAX_IMAGE_SIZE
		|| mDataSize > (S32)MAX_IMAGE_DATA_SIZE
		|| mComponents > (S8)MAX_IMAGE_COMPONENTS
		)
	{
		llerrs << "Failed LLImageBase::sanityCheck "
			   << "width " << mWidth
			   << "height " << mHeight
			   << "datasize " << mDataSize
			   << "components " << mComponents
			   << "data " << mData
			   << llendl;
	}
}

// virtual
void LLImageBase::deleteData()
{
	FREE_MEM(sPrivatePoolp, mData) ;
	mData = NULL;
	mDataSize = 0;
}

// virtual
U8* LLImageBase::allocateData(S32 size)
{
	LLMemType mt1(mMemType);
	
	if (size < 0)
	{
		size = mWidth * mHeight * mComponents;
		if (size <= 0)
		{
			llerrs << llformat("LLImageBase::allocateData called with bad dimensions: %dx%dx%d",mWidth,mHeight,(S32)mComponents) << llendl;
		}
	}
	
	//make this function thread-safe.
	static const U32 MAX_BUFFER_SIZE = 4096 * 4096 * 16 ; //256 MB
	if (size < 1 || size > MAX_BUFFER_SIZE) 
	{
		llinfos << "width: " << mWidth << " height: " << mHeight << " components: " << mComponents << llendl ;
		if(mAllowOverSize)
		{
			llinfos << "Oversize: " << size << llendl ;
		}
		else
		{
			llerrs << "LLImageBase::allocateData: bad size: " << size << llendl;
		}
	}
	if (!mData || size != mDataSize)
	{
		deleteData(); // virtual
		mBadBufferAllocation = false ;
		mData = (U8*)ALLOCATE_MEM(sPrivatePoolp, size);
		if (!mData)
		{
			llwarns << "Failed to allocate image data size [" << size << "]" << llendl;
			size = 0 ;
			mWidth = mHeight = 0 ;
			mBadBufferAllocation = true ;
		}
		mDataSize = size;
	}

	return mData;
}

// virtual
U8* LLImageBase::reallocateData(S32 size)
{
	LLMemType mt1(mMemType);
	U8 *new_datap = (U8*)ALLOCATE_MEM(sPrivatePoolp, size);
	if (!new_datap)
	{
		llwarns << "Out of memory in LLImageBase::reallocateData" << llendl;
		return 0;
	}
	if (mData)
	{
		S32 bytes = llmin(mDataSize, size);
		memcpy(new_datap, mData, bytes);	/* Flawfinder: ignore */
		FREE_MEM(sPrivatePoolp, mData) ;
	}
	mData = new_datap;
	mDataSize = size;
	return mData;
}

const U8* LLImageBase::getData() const	
{ 
	if(mBadBufferAllocation)
	{
		llerrs << "Bad memory allocation for the image buffer!" << llendl ;
	}

	return mData; 
} // read only

U8* LLImageBase::getData()				
{ 
	if(mBadBufferAllocation)
	{
		llerrs << "Bad memory allocation for the image buffer!" << llendl ;
	}

	return mData; 
}

bool LLImageBase::isBufferInvalid()
{
	return mBadBufferAllocation || mData == NULL ;
}

void LLImageBase::setSize(S32 width, S32 height, S32 ncomponents)
{
	mWidth = width;
	mHeight = height;
	mComponents = ncomponents;
}

U8* LLImageBase::allocateDataSize(S32 width, S32 height, S32 ncomponents, S32 size)
{
	setSize(width, height, ncomponents);
	return allocateData(size); // virtual
}

//---------------------------------------------------------------------------
// LLImageRaw
//---------------------------------------------------------------------------

S32 LLImageRaw::sGlobalRawMemory = 0;
S32 LLImageRaw::sRawImageCount = 0;

LLImageRaw::LLImageRaw()
	: LLImageBase()
{
	mMemType = LLMemType::MTYPE_IMAGERAW;
	++sRawImageCount;
}

LLImageRaw::LLImageRaw(U16 width, U16 height, S8 components)
	: LLImageBase()
{
	mMemType = LLMemType::MTYPE_IMAGERAW;
	//llassert( S32(width) * S32(height) * S32(components) <= MAX_IMAGE_DATA_SIZE );
	allocateDataSize(width, height, components);
	++sRawImageCount;
}

LLImageRaw::LLImageRaw(U8 *data, U16 width, U16 height, S8 components)
	: LLImageBase()
{
	mMemType = LLMemType::MTYPE_IMAGERAW;
	if(allocateDataSize(width, height, components))
	{
		memcpy(getData(), data, width*height*components);
	}
	++sRawImageCount;
}

//LLImageRaw::LLImageRaw(const std::string& filename, bool j2c_lowest_mip_only)
//	: LLImageBase()
//{
//	createFromFile(filename, j2c_lowest_mip_only);
//}

LLImageRaw::~LLImageRaw()
{
	// NOTE: ~LLimageBase() call to deleteData() calls LLImageBase::deleteData()
	//        NOT LLImageRaw::deleteData()
	deleteData();
	--sRawImageCount;
}

// virtual
U8* LLImageRaw::allocateData(S32 size)
{
	U8* res = LLImageBase::allocateData(size);
	sGlobalRawMemory += getDataSize();
	return res;
}

// virtual
U8* LLImageRaw::reallocateData(S32 size)
{
	sGlobalRawMemory -= getDataSize();
	U8* res = LLImageBase::reallocateData(size);
	sGlobalRawMemory += getDataSize();
	return res;
}

// virtual
void LLImageRaw::deleteData()
{
	sGlobalRawMemory -= getDataSize();
	LLImageBase::deleteData();
}

void LLImageRaw::setDataAndSize(U8 *data, S32 width, S32 height, S8 components) 
{ 
	if(data == getData())
	{
		return ;
	}

	deleteData();

	LLImageBase::setSize(width, height, components) ;
	LLImageBase::setDataAndSize(data, width * height * components) ;
	
	sGlobalRawMemory += getDataSize();
}

BOOL LLImageRaw::resize(U16 width, U16 height, S8 components)
{
	if ((getWidth() == width) && (getHeight() == height) && (getComponents() == components))
	{
		return TRUE;
	}
	// Reallocate the data buffer.
	deleteData();

	allocateDataSize(width,height,components);

	return TRUE;
}

#if 0
U8 * LLImageRaw::getSubImage(U32 x_pos, U32 y_pos, U32 width, U32 height) const
{
	LLMemType mt1(mMemType);
	U8 *data = new U8[width*height*getComponents()];

	// Should do some simple bounds checking
	if (!data)
	{
		llerrs << "Out of memory in LLImageRaw::getSubImage" << llendl;
		return NULL;
	}

	U32 i;
	for (i = y_pos; i < y_pos+height; i++)
	{
		memcpy(data + i*width*getComponents(),		/* Flawfinder: ignore */
				getData() + ((y_pos + i)*getWidth() + x_pos)*getComponents(), getComponents()*width);
	}
	return data;
}
#endif

BOOL LLImageRaw::setSubImage(U32 x_pos, U32 y_pos, U32 width, U32 height,
							 const U8 *data, U32 stride, BOOL reverse_y)
{
	if (!getData())
	{
		return FALSE;
	}
	if (!data)
	{
		return FALSE;
	}

	// Should do some simple bounds checking

	U32 i;
	for (i = 0; i < height; i++)
	{
		const U32 row = reverse_y ? height - 1 - i : i;
		const U32 from_offset = row * ((stride == 0) ? width*getComponents() : stride);
		const U32 to_offset = (y_pos + i)*getWidth() + x_pos;
		memcpy(getData() + to_offset*getComponents(),		/* Flawfinder: ignore */
				data + from_offset, getComponents()*width);
	}

	return TRUE;
}

void LLImageRaw::clear(U8 r, U8 g, U8 b, U8 a)
{
	llassert( getComponents() <= 4 );
	// This is fairly bogus, but it'll do for now.
	U8 *pos = getData();
	U32 x, y;
	for (x = 0; x < getWidth(); x++)
	{
		for (y = 0; y < getHeight(); y++)
		{
			*pos = r;
			pos++;
			if (getComponents() == 1)
			{
				continue;
			}
			*pos = g;
			pos++;
			if (getComponents() == 2)
			{
				continue;
			}
			*pos = b;
			pos++;
			if (getComponents() == 3)
			{
				continue;
			}
			*pos = a;
			pos++;
		}
	}
}

// Reverses the order of the rows in the image
void LLImageRaw::verticalFlip()
{
	LLMemType mt1(mMemType);
	S32 row_bytes = getWidth() * getComponents();
	llassert(row_bytes > 0);
	std::vector<U8> line_buffer(row_bytes);
	S32 mid_row = getHeight() / 2;
	for( S32 row = 0; row < mid_row; row++ )
	{
		U8* row_a_data = getData() + row * row_bytes;
		U8* row_b_data = getData() + (getHeight() - 1 - row) * row_bytes;
		memcpy( &line_buffer[0], row_a_data,  row_bytes );
		memcpy( row_a_data,  row_b_data,  row_bytes );
		memcpy( row_b_data,  &line_buffer[0], row_bytes );
	}
}


void LLImageRaw::expandToPowerOfTwo(S32 max_dim, BOOL scale_image)
{
	// Find new sizes
	S32 new_width = MIN_IMAGE_SIZE;
	S32 new_height = MIN_IMAGE_SIZE;

	while( (new_width < getWidth()) && (new_width < max_dim) )
	{
		new_width <<= 1;
	}

	while( (new_height < getHeight()) && (new_height < max_dim) )
	{
		new_height <<= 1;
	}

	scale( new_width, new_height, scale_image );
}

void LLImageRaw::contractToPowerOfTwo(S32 max_dim, BOOL scale_image)
{
	// Find new sizes
	S32 new_width = max_dim;
	S32 new_height = max_dim;

	while( (new_width > getWidth()) && (new_width > MIN_IMAGE_SIZE) )
	{
		new_width >>= 1;
	}

	while( (new_height > getHeight()) && (new_height > MIN_IMAGE_SIZE) )
	{
		new_height >>= 1;
	}

	scale( new_width, new_height, scale_image );
}

void LLImageRaw::biasedScaleToPowerOfTwo(S32 max_dim)
{
	// Strong bias towards rounding down (to save bandwidth)
	// No bias would mean THRESHOLD == 1.5f;
	const F32 THRESHOLD = 1.75f; 

	// Find new sizes
	S32 larger_w = max_dim;	// 2^n >= mWidth
	S32 smaller_w = max_dim;	// 2^(n-1) <= mWidth
	while( (smaller_w > getWidth()) && (smaller_w > MIN_IMAGE_SIZE) )
	{
		larger_w = smaller_w;
		smaller_w >>= 1;
	}
	S32 new_width = ( (F32)getWidth() / smaller_w > THRESHOLD ) ? larger_w : smaller_w;


	S32 larger_h = max_dim;	// 2^m >= mHeight
	S32 smaller_h = max_dim;	// 2^(m-1) <= mHeight
	while( (smaller_h > getHeight()) && (smaller_h > MIN_IMAGE_SIZE) )
	{
		larger_h = smaller_h;
		smaller_h >>= 1;
	}
	S32 new_height = ( (F32)getHeight() / smaller_h > THRESHOLD ) ? larger_h : smaller_h;


	scale( new_width, new_height );
}




// Calculates (U8)(255*(a/255.f)*(b/255.f) + 0.5f).  Thanks, Jim Blinn!
inline U8 LLImageRaw::fastFractionalMult( U8 a, U8 b )
{
	U32 i = a * b + 128;
	return U8((i + (i>>8)) >> 8);
}


void LLImageRaw::composite( LLImageRaw* src )
{
	LLImageRaw* dst = this;  // Just for clarity.

	llassert(3 == src->getComponents());
	llassert(3 == dst->getComponents());

	if( 3 == dst->getComponents() )
	{
		if( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) )
		{
			// No scaling needed
			if( 3 == src->getComponents() )
			{
				copyUnscaled( src );  // alpha is one so just copy the data.
			}
			else
			{
				compositeUnscaled4onto3( src );
			}
		}
		else
		{
			if( 3 == src->getComponents() )
			{
				copyScaled( src );  // alpha is one so just copy the data.
			}
			else
			{
				compositeScaled4onto3( src );
			}
		}
	}
}

// Src and dst can be any size.  Src has 4 components.  Dst has 3 components.
void LLImageRaw::compositeScaled4onto3(LLImageRaw* src)
{
	LLMemType mt1(mMemType);
	llinfos << "compositeScaled4onto3" << llendl;

	LLImageRaw* dst = this;  // Just for clarity.

	llassert( (4 == src->getComponents()) && (3 == dst->getComponents()) );

	S32 temp_data_size = src->getWidth() * dst->getHeight() * src->getComponents();
	llassert_always(temp_data_size > 0);
	std::vector<U8> temp_buffer(temp_data_size);

	// Vertical: scale but no composite
	for( S32 col = 0; col < src->getWidth(); col++ )
	{
		copyLineScaled( src->getData() + (src->getComponents() * col), &temp_buffer[0] + (src->getComponents() * col), src->getHeight(), dst->getHeight(), src->getWidth(), src->getWidth() );
	}

	// Horizontal: scale and composite
	for( S32 row = 0; row < dst->getHeight(); row++ )
	{
		compositeRowScaled4onto3( &temp_buffer[0] + (src->getComponents() * src->getWidth() * row), dst->getData() + (dst->getComponents() * dst->getWidth() * row), src->getWidth(), dst->getWidth() );
	}
}


// Src and dst are same size.  Src has 4 components.  Dst has 3 components.
void LLImageRaw::compositeUnscaled4onto3( LLImageRaw* src )
{
	/*
	//test fastFractionalMult()
	{
		U8 i = 255;
		U8 j = 255;
		do
		{
			do
			{
				llassert( fastFractionalMult(i, j) == (U8)(255*(i/255.f)*(j/255.f) + 0.5f) );
			} while( j-- );
		} while( i-- );
	}
	*/

	LLImageRaw* dst = this;  // Just for clarity.

	llassert( (3 == src->getComponents()) || (4 == src->getComponents()) );
	llassert( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) );


	U8* src_data = src->getData();
	U8* dst_data = dst->getData();
	S32 pixels = getWidth() * getHeight();
	while( pixels-- )
	{
		U8 alpha = src_data[3];
		if( alpha )
		{
			if( 255 == alpha )
			{
				dst_data[0] = src_data[0];
				dst_data[1] = src_data[1];
				dst_data[2] = src_data[2];
			}
			else
			{

				U8 transparency = 255 - alpha;
				dst_data[0] = fastFractionalMult( dst_data[0], transparency ) + fastFractionalMult( src_data[0], alpha );
				dst_data[1] = fastFractionalMult( dst_data[1], transparency ) + fastFractionalMult( src_data[1], alpha );
				dst_data[2] = fastFractionalMult( dst_data[2], transparency ) + fastFractionalMult( src_data[2], alpha );
			}
		}

		src_data += 4;
		dst_data += 3;
	}
}

// Fill the buffer with a constant color
void LLImageRaw::fill( const LLColor4U& color )
{
	S32 pixels = getWidth() * getHeight();
	if( 4 == getComponents() )
	{
		U32* data = (U32*) getData();
		for( S32 i = 0; i < pixels; i++ )
		{
			data[i] = color.mAll;
		}
	}
	else
	if( 3 == getComponents() )
	{
		U8* data = getData();
		for( S32 i = 0; i < pixels; i++ )
		{
			data[0] = color.mV[0];
			data[1] = color.mV[1];
			data[2] = color.mV[2];
			data += 3;
		}
	}
}




// Src and dst can be any size.  Src and dst can each have 3 or 4 components.
void LLImageRaw::copy(LLImageRaw* src)
{
	if (!src)
	{
		llwarns << "LLImageRaw::copy called with a null src pointer" << llendl;
		return;
	}

	LLImageRaw* dst = this;  // Just for clarity.

	if( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) )
	{
		// No scaling needed
		if( src->getComponents() == dst->getComponents() )
		{
			copyUnscaled( src );
		}
		else
		if( 3 == src->getComponents() )
		{
			copyUnscaled3onto4( src );
		}
		else
		{
			// 4 == src->getComponents()
			copyUnscaled4onto3( src );
		}
	}
	else
	{
		// Scaling needed
		// No scaling needed
		if( src->getComponents() == dst->getComponents() )
		{
			copyScaled( src );
		}
		else
		if( 3 == src->getComponents() )
		{
			copyScaled3onto4( src );
		}
		else
		{
			// 4 == src->getComponents()
			copyScaled4onto3( src );
		}
	}
}

// Src and dst are same size.  Src and dst have same number of components.
void LLImageRaw::copyUnscaled(LLImageRaw* src)
{
	LLImageRaw* dst = this;  // Just for clarity.

	llassert( (1 == src->getComponents()) || (3 == src->getComponents()) || (4 == src->getComponents()) );
	llassert( src->getComponents() == dst->getComponents() );
	llassert( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) );

	memcpy( dst->getData(), src->getData(), getWidth() * getHeight() * getComponents() );	/* Flawfinder: ignore */
}


// Src and dst can be any size.  Src has 3 components.  Dst has 4 components.
void LLImageRaw::copyScaled3onto4(LLImageRaw* src)
{
	llassert( (3 == src->getComponents()) && (4 == getComponents()) );

	// Slow, but simple.  Optimize later if needed.
	LLImageRaw temp( src->getWidth(), src->getHeight(), 4);
	temp.copyUnscaled3onto4( src );
	copyScaled( &temp );
}


// Src and dst can be any size.  Src has 4 components.  Dst has 3 components.
void LLImageRaw::copyScaled4onto3(LLImageRaw* src)
{
	llassert( (4 == src->getComponents()) && (3 == getComponents()) );

	// Slow, but simple.  Optimize later if needed.
	LLImageRaw temp( src->getWidth(), src->getHeight(), 3);
	temp.copyUnscaled4onto3( src );
	copyScaled( &temp );
}


// Src and dst are same size.  Src has 4 components.  Dst has 3 components.
void LLImageRaw::copyUnscaled4onto3( LLImageRaw* src )
{
	LLImageRaw* dst = this;  // Just for clarity.

	llassert( (3 == dst->getComponents()) && (4 == src->getComponents()) );
	llassert( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) );

	S32 pixels = getWidth() * getHeight();
	U8* src_data = src->getData();
	U8* dst_data = dst->getData();
	for( S32 i=0; i<pixels; i++ )
	{
		dst_data[0] = src_data[0];
		dst_data[1] = src_data[1];
		dst_data[2] = src_data[2];
		src_data += 4;
		dst_data += 3;
	}
}


// Src and dst are same size.  Src has 3 components.  Dst has 4 components.
void LLImageRaw::copyUnscaled3onto4( LLImageRaw* src )
{
	LLImageRaw* dst = this;  // Just for clarity.
	llassert( 3 == src->getComponents() );
	llassert( 4 == dst->getComponents() );
	llassert( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) );

	S32 pixels = getWidth() * getHeight();
	U8* src_data = src->getData();
	U8* dst_data = dst->getData();
	for( S32 i=0; i<pixels; i++ )
	{
		dst_data[0] = src_data[0];
		dst_data[1] = src_data[1];
		dst_data[2] = src_data[2];
		dst_data[3] = 255;
		src_data += 3;
		dst_data += 4;
	}
}


// Src and dst can be any size.  Src and dst have same number of components.
void LLImageRaw::copyScaled( LLImageRaw* src )
{
	LLMemType mt1(mMemType);
	LLImageRaw* dst = this;  // Just for clarity.

	llassert_always( (1 == src->getComponents()) || (3 == src->getComponents()) || (4 == src->getComponents()) );
	llassert_always( src->getComponents() == dst->getComponents() );

	if( (src->getWidth() == dst->getWidth()) && (src->getHeight() == dst->getHeight()) )
	{
		memcpy( dst->getData(), src->getData(), getWidth() * getHeight() * getComponents() );	/* Flawfinder: ignore */
		return;
	}

	S32 temp_data_size = src->getWidth() * dst->getHeight() * getComponents();
	llassert_always(temp_data_size > 0);
	std::vector<U8> temp_buffer(temp_data_size);

	// Vertical
	for( S32 col = 0; col < src->getWidth(); col++ )
	{
		copyLineScaled( src->getData() + (getComponents() * col), &temp_buffer[0] + (getComponents() * col), src->getHeight(), dst->getHeight(), src->getWidth(), src->getWidth() );
	}

	// Horizontal
	for( S32 row = 0; row < dst->getHeight(); row++ )
	{
		copyLineScaled( &temp_buffer[0] + (getComponents() * src->getWidth() * row), dst->getData() + (getComponents() * dst->getWidth() * row), src->getWidth(), dst->getWidth(), 1, 1 );
	}
}

#if 0
//scale down image by not blending a pixel with its neighbors.
BOOL LLImageRaw::scaleDownWithoutBlending( S32 new_width, S32 new_height)
{
	LLMemType mt1(mMemType);

	S8 c = getComponents() ;
	llassert((1 == c) || (3 == c) || (4 == c) );

	S32 old_width = getWidth();
	S32 old_height = getHeight();
	
	S32 new_data_size = old_width * new_height * c ;
	llassert_always(new_data_size > 0);

	F32 ratio_x = (F32)old_width / new_width ;
	F32 ratio_y = (F32)old_height / new_height ;
	if( ratio_x < 1.0f || ratio_y < 1.0f )
	{
		return TRUE;  // Nothing to do.
	}
	ratio_x -= 1.0f ;
	ratio_y -= 1.0f ;

	U8* new_data = allocateMemory(new_data_size) ;
	llassert_always(new_data != NULL) ;

	U8* old_data = getData() ;
	S32 i, j, k, s, t;
	for(i = 0, s = 0, t = 0 ; i < new_height ; i++)
	{
		for(j = 0 ; j < new_width ; j++)
		{
			for(k = 0 ; k < c ; k++)
			{
				new_data[s++] = old_data[t++] ;
			}
			t += (S32)(ratio_x * c + 0.1f) ;
		}
		t += (S32)(ratio_y * old_width * c + 0.1f) ;
	}

	setDataAndSize(new_data, new_width, new_height, c) ;
	
	return TRUE ;
}
#endif

BOOL LLImageRaw::scale( S32 new_width, S32 new_height, BOOL scale_image_data )
{
	LLMemType mt1(mMemType);
	llassert((1 == getComponents()) || (3 == getComponents()) || (4 == getComponents()) );

	S32 old_width = getWidth();
	S32 old_height = getHeight();
	
	if( (old_width == new_width) && (old_height == new_height) )
	{
		return TRUE;  // Nothing to do.
	}

	// Reallocate the data buffer.

	if (scale_image_data)
	{
		S32 temp_data_size = old_width * new_height * getComponents();
		llassert_always(temp_data_size > 0);
		std::vector<U8> temp_buffer(temp_data_size);

		// Vertical
		for( S32 col = 0; col < old_width; col++ )
		{
			copyLineScaled( getData() + (getComponents() * col), &temp_buffer[0] + (getComponents() * col), old_height, new_height, old_width, old_width );
		}

		deleteData();

		U8* new_buffer = allocateDataSize(new_width, new_height, getComponents());

		// Horizontal
		for( S32 row = 0; row < new_height; row++ )
		{
			copyLineScaled( &temp_buffer[0] + (getComponents() * old_width * row), new_buffer + (getComponents() * new_width * row), old_width, new_width, 1, 1 );
		}
	}
	else
	{
		// copy	out	existing image data
		S32	temp_data_size = old_width * old_height	* getComponents();
		std::vector<U8> temp_buffer(temp_data_size);
		memcpy(&temp_buffer[0],	getData(), temp_data_size);

		// allocate	new	image data,	will delete	old	data
		U8*	new_buffer = allocateDataSize(new_width, new_height, getComponents());

		for( S32 row = 0; row <	new_height;	row++ )
		{
			if (row	< old_height)
			{
				memcpy(new_buffer +	(new_width * row * getComponents()), &temp_buffer[0] + (old_width *	row	* getComponents()),	getComponents()	* llmin(old_width, new_width));
				if (old_width <	new_width)
				{
					// pad out rest	of row with	black
					memset(new_buffer +	(getComponents() * ((new_width * row) +	old_width)), 0,	getComponents()	* (new_width - old_width));
				}
			}
			else
			{
				// pad remaining rows with black
				memset(new_buffer +	(new_width * row * getComponents()), 0,	new_width *	getComponents());
			}
		}
	}

	return TRUE ;
}

void LLImageRaw::copyLineScaled( U8* in, U8* out, S32 in_pixel_len, S32 out_pixel_len, S32 in_pixel_step, S32 out_pixel_step )
{
	const S32 components = getComponents();
	llassert( components >= 1 && components <= 4 );

	const F32 ratio = F32(in_pixel_len) / out_pixel_len; // ratio of old to new
	const F32 norm_factor = 1.f / ratio;

	S32 goff = components >= 2 ? 1 : 0;
	S32 boff = components >= 3 ? 2 : 0;
	for( S32 x = 0; x < out_pixel_len; x++ )
	{
		// Sample input pixels in range from sample0 to sample1.
		// Avoid floating point accumulation error... don't just add ratio each time.  JC
		const F32 sample0 = x * ratio;
		const F32 sample1 = (x+1) * ratio;
		const S32 index0 = llfloor(sample0);			// left integer (floor)
		const S32 index1 = llfloor(sample1);			// right integer (floor)
		const F32 fract0 = 1.f - (sample0 - F32(index0));	// spill over on left
		const F32 fract1 = sample1 - F32(index1);			// spill-over on right

		if( index0 == index1 )
		{
			// Interval is embedded in one input pixel
			S32 t0 = x * out_pixel_step * components;
			S32 t1 = index0 * in_pixel_step * components;
			U8* outp = out + t0;
			U8* inp = in + t1;
			for (S32 i = 0; i < components; ++i)
			{
				*outp = *inp;
				++outp;
				++inp;
			}
		}
		else
		{
			// Left straddle
			S32 t1 = index0 * in_pixel_step * components;
			F32 r = in[t1 + 0] * fract0;
			F32 g = in[t1 + goff] * fract0;
			F32 b = in[t1 + boff] * fract0;
			F32 a = 0;
			if( components == 4)
			{
				a = in[t1 + 3] * fract0;
			}
		
			// Central interval
			if (components < 4)
			{
				for( S32 u = index0 + 1; u < index1; u++ )
				{
					S32 t2 = u * in_pixel_step * components;
					r += in[t2 + 0];
					g += in[t2 + goff];
					b += in[t2 + boff];
				}
			}
			else
			{
				for( S32 u = index0 + 1; u < index1; u++ )
				{
					S32 t2 = u * in_pixel_step * components;
					r += in[t2 + 0];
					g += in[t2 + 1];
					b += in[t2 + 2];
					a += in[t2 + 3];
				}
			}

			// right straddle
			// Watch out for reading off of end of input array.
			if( fract1 && index1 < in_pixel_len )
			{
				S32 t3 = index1 * in_pixel_step * components;
				if (components < 4)
				{
					U8 in0 = in[t3 + 0];
					U8 in1 = in[t3 + goff];
					U8 in2 = in[t3 + boff];
					r += in0 * fract1;
					g += in1 * fract1;
					b += in2 * fract1;
				}
				else
				{
					U8 in0 = in[t3 + 0];
					U8 in1 = in[t3 + 1];
					U8 in2 = in[t3 + 2];
					U8 in3 = in[t3 + 3];
					r += in0 * fract1;
					g += in1 * fract1;
					b += in2 * fract1;
					a += in3 * fract1;
				}
			}

			r *= norm_factor;
			g *= norm_factor;
			b *= norm_factor;
			a *= norm_factor;  // skip conditional

			S32 t4 = x * out_pixel_step * components;
			out[t4 + 0] = U8(llround(r));
			if (components >= 2)
				out[t4 + 1] = U8(llround(g));
			if (components >= 3)
				out[t4 + 2] = U8(llround(b));
			if( components == 4)
				out[t4 + 3] = U8(llround(a));
		}
	}
}

void LLImageRaw::compositeRowScaled4onto3( U8* in, U8* out, S32 in_pixel_len, S32 out_pixel_len )
{
	llassert( getComponents() == 3 );

	const S32 IN_COMPONENTS = 4;
	const S32 OUT_COMPONENTS = 3;

	const F32 ratio = F32(in_pixel_len) / out_pixel_len; // ratio of old to new
	const F32 norm_factor = 1.f / ratio;

	for( S32 x = 0; x < out_pixel_len; x++ )
	{
		// Sample input pixels in range from sample0 to sample1.
		// Avoid floating point accumulation error... don't just add ratio each time.  JC
		const F32 sample0 = x * ratio;
		const F32 sample1 = (x+1) * ratio;
		const S32 index0 = S32(sample0);			// left integer (floor)
		const S32 index1 = S32(sample1);			// right integer (floor)
		const F32 fract0 = 1.f - (sample0 - F32(index0));	// spill over on left
		const F32 fract1 = sample1 - F32(index1);			// spill-over on right

		U8 in_scaled_r;
		U8 in_scaled_g;
		U8 in_scaled_b;
		U8 in_scaled_a;

		if( index0 == index1 )
		{
			// Interval is embedded in one input pixel
			S32 t1 = index0 * IN_COMPONENTS;
			in_scaled_r = in[t1 + 0];
			in_scaled_g = in[t1 + 0];
			in_scaled_b = in[t1 + 0];
			in_scaled_a = in[t1 + 0];
		}
		else
		{
			// Left straddle
			S32 t1 = index0 * IN_COMPONENTS;
			F32 r = in[t1 + 0] * fract0;
			F32 g = in[t1 + 1] * fract0;
			F32 b = in[t1 + 2] * fract0;
			F32 a = in[t1 + 3] * fract0;
		
			// Central interval
			for( S32 u = index0 + 1; u < index1; u++ )
			{
				S32 t2 = u * IN_COMPONENTS;
				r += in[t2 + 0];
				g += in[t2 + 1];
				b += in[t2 + 2];
				a += in[t2 + 3];
			}

			// right straddle
			// Watch out for reading off of end of input array.
			if( fract1 && index1 < in_pixel_len )
			{
				S32 t3 = index1 * IN_COMPONENTS;
				r += in[t3 + 0] * fract1;
				g += in[t3 + 1] * fract1;
				b += in[t3 + 2] * fract1;
				a += in[t3 + 3] * fract1;
			}

			r *= norm_factor;
			g *= norm_factor;
			b *= norm_factor;
			a *= norm_factor;

			in_scaled_r = U8(llround(r));
			in_scaled_g = U8(llround(g));
			in_scaled_b = U8(llround(b));
			in_scaled_a = U8(llround(a));
		}

		if( in_scaled_a )
		{
			if( 255 == in_scaled_a )
			{
				out[0] = in_scaled_r;
				out[1] = in_scaled_g;
				out[2] = in_scaled_b;
			}
			else
			{
				U8 transparency = 255 - in_scaled_a;
				out[0] = fastFractionalMult( out[0], transparency ) + fastFractionalMult( in_scaled_r, in_scaled_a );
				out[1] = fastFractionalMult( out[1], transparency ) + fastFractionalMult( in_scaled_g, in_scaled_a );
				out[2] = fastFractionalMult( out[2], transparency ) + fastFractionalMult( in_scaled_b, in_scaled_a );
			}
		}
		out += OUT_COMPONENTS;
	}
}


//----------------------------------------------------------------------------

static struct
{
	const char* exten;
	EImageCodec codec;
}
file_extensions[] =
{
	{ "bmp", IMG_CODEC_BMP },
	{ "tga", IMG_CODEC_TGA },
	{ "j2c", IMG_CODEC_J2C },
	{ "jp2", IMG_CODEC_J2C },
	{ "texture", IMG_CODEC_J2C },
	{ "jpg", IMG_CODEC_JPEG },
	{ "jpeg", IMG_CODEC_JPEG },
	{ "mip", IMG_CODEC_DXT },
	{ "dxt", IMG_CODEC_DXT },
	{ "png", IMG_CODEC_PNG }
};
#define NUM_FILE_EXTENSIONS LL_ARRAY_SIZE(file_extensions)
#if 0
static std::string find_file(std::string &name, S8 *codec)
{
	std::string tname;
	for (int i=0; i<(int)(NUM_FILE_EXTENSIONS); i++)
	{
		tname = name + "." + std::string(file_extensions[i].exten);
		llifstream ifs(tname, llifstream::binary);
		if (ifs.is_open())
		{
			ifs.close();
			if (codec)
				*codec = file_extensions[i].codec;
			return std::string(file_extensions[i].exten);
		}
	}
	return std::string("");
}
#endif
EImageCodec LLImageBase::getCodecFromExtension(const std::string& exten)
{
	for (int i=0; i<(int)(NUM_FILE_EXTENSIONS); i++)
	{
		if (exten == file_extensions[i].exten)
			return file_extensions[i].codec;
	}
	return IMG_CODEC_INVALID;
}
#if 0
bool LLImageRaw::createFromFile(const std::string &filename, bool j2c_lowest_mip_only)
{
	std::string name = filename;
	size_t dotidx = name.rfind('.');
	S8 codec = IMG_CODEC_INVALID;
	std::string exten;
	
	deleteData(); // delete any existing data

	if (dotidx != std::string::npos)
	{
		exten = name.substr(dotidx+1);
		LLStringUtil::toLower(exten);
		codec = getCodecFromExtension(exten);
	}
	else
	{
		exten = find_file(name, &codec);
		name = name + "." + exten;
	}
	if (codec == IMG_CODEC_INVALID)
	{
		return false; // format not recognized
	}

	llifstream ifs(name, llifstream::binary);
	if (!ifs.is_open())
	{
		// SJB: changed from llinfos to lldebugs to reduce spam
		lldebugs << "Unable to open image file: " << name << llendl;
		return false;
	}
	
	ifs.seekg (0, std::ios::end);
	int length = ifs.tellg();
	if (j2c_lowest_mip_only && length > 2048)
	{
		length = 2048;
	}
	ifs.seekg (0, std::ios::beg);

	if (!length)
	{
		llinfos << "Zero length file file: " << name << llendl;
		return false;
	}
	
	LLPointer<LLImageFormatted> image = LLImageFormatted::createFromType(codec);
	llassert(image.notNull());

	U8 *buffer = image->allocateData(length);
	ifs.read ((char*)buffer, length);
	ifs.close();
	
	BOOL success;

	success = image->updateData();
	if (success)
	{
		if (j2c_lowest_mip_only && codec == IMG_CODEC_J2C)
		{
			S32 width = image->getWidth();
			S32 height = image->getHeight();
			S32 discard_level = 0;
			while (width > 1 && height > 1 && discard_level < MAX_DISCARD_LEVEL)
			{
				width >>= 1;
				height >>= 1;
				discard_level++;
			}
			((LLImageJ2C *)((LLImageFormatted*)image))->setDiscardLevel(discard_level);
		}
		success = image->decode(this, 100000.0f);
	}

	image = NULL; // deletes image
	if (!success)
	{
		deleteData();
		llwarns << "Unable to decode image" << name << llendl;
		return false;
	}

	return true;
}
#endif
//---------------------------------------------------------------------------
// LLImageFormatted
//---------------------------------------------------------------------------

//static
S32 LLImageFormatted::sGlobalFormattedMemory = 0;

LLImageFormatted::LLImageFormatted(S8 codec)
	: LLImageBase(),
	  mCodec(codec),
	  mDecoding(0),
	  mDecoded(0),
	  mDiscardLevel(-1)
{
	mMemType = LLMemType::MTYPE_IMAGEFORMATTED;
}

// virtual
LLImageFormatted::~LLImageFormatted()
{
	// NOTE: ~LLimageBase() call to deleteData() calls LLImageBase::deleteData()
	//        NOT LLImageFormatted::deleteData()
	deleteData();
}

//----------------------------------------------------------------------------

//virtual
void LLImageFormatted::resetLastError()
{
	LLImage::setLastError("");
}

//virtual
void LLImageFormatted::setLastError(const std::string& message, const std::string& filename)
{
	std::string error = message;
	if (!filename.empty())
		error += std::string(" FILE: ") + filename;
	LLImage::setLastError(error);
}

//----------------------------------------------------------------------------

// static
LLImageFormatted* LLImageFormatted::createFromType(S8 codec)
{
	LLImageFormatted* image;
	switch(codec)
	{
	  case IMG_CODEC_BMP:
		image = new LLImageBMP();
		break;
	  case IMG_CODEC_TGA:
		image = new LLImageTGA();
		break;
	  case IMG_CODEC_JPEG:
		image = new LLImageJPEG();
		break;
	  case IMG_CODEC_PNG:
		image = new LLImagePNG();
		break;
	  case IMG_CODEC_J2C:
		image = new LLImageJ2C();
		break;
	  case IMG_CODEC_DXT:
		image = new LLImageDXT();
		break;
	  default:
		image = NULL;
		break;
	}
	return image;
}

// static
LLImageFormatted* LLImageFormatted::createFromExtension(const std::string& instring)
{
	std::string exten;
	size_t dotidx = instring.rfind('.');
	if (dotidx != std::string::npos)
	{
		exten = instring.substr(dotidx+1);
	}
	else
	{
		exten = instring;
	}
	S8 codec = getCodecFromExtension(exten);
	return createFromType(codec);
}
//----------------------------------------------------------------------------

// virtual
void LLImageFormatted::dump()
{
	LLImageBase::dump();

	llinfos << "LLImageFormatted"
			<< " mDecoding " << mDecoding
			<< " mCodec " << S32(mCodec)
			<< " mDecoded " << mDecoded
			<< llendl;
}

//----------------------------------------------------------------------------

S32 LLImageFormatted::calcDataSize(S32 discard_level)
{
	if (discard_level < 0)
	{
		discard_level = mDiscardLevel;
	}
	S32 w = getWidth() >> discard_level;
	S32 h = getHeight() >> discard_level;
	w = llmax(w, 1);
	h = llmax(h, 1);
	return w * h * getComponents();
}

S32 LLImageFormatted::calcDiscardLevelBytes(S32 bytes)
{
	llassert(bytes >= 0);
	S32 discard_level = 0;
	while (1)
	{
		S32 bytes_needed = calcDataSize(discard_level); // virtual
		if (bytes_needed <= bytes)
		{
			break;
		}
		discard_level++;
		if (discard_level > MAX_IMAGE_MIP)
		{
			return -1;
		}
	}
	return discard_level;
}


//----------------------------------------------------------------------------

// Subclasses that can handle more than 4 channels should override this function.
BOOL LLImageFormatted::decodeChannels(LLImageRaw* raw_image,F32  decode_time, S32 first_channel, S32 max_channel)
{
	llassert( (first_channel == 0) && (max_channel == 4) );
	return decode( raw_image, decode_time );  // Loads first 4 channels by default.
} 

//----------------------------------------------------------------------------

// virtual
U8* LLImageFormatted::allocateData(S32 size)
{
	U8* res = LLImageBase::allocateData(size); // calls deleteData()
	sGlobalFormattedMemory += getDataSize();
	return res;
}

// virtual
U8* LLImageFormatted::reallocateData(S32 size)
{
	sGlobalFormattedMemory -= getDataSize();
	U8* res = LLImageBase::reallocateData(size);
	sGlobalFormattedMemory += getDataSize();
	return res;
}

// virtual
void LLImageFormatted::deleteData()
{
	sGlobalFormattedMemory -= getDataSize();
	LLImageBase::deleteData();
}

//----------------------------------------------------------------------------

// virtual
void LLImageFormatted::sanityCheck()
{
	LLImageBase::sanityCheck();

	if (mCodec >= IMG_CODEC_EOF)
	{
		llerrs << "Failed LLImageFormatted::sanityCheck "
			   << "decoding " << S32(mDecoding)
			   << "decoded " << S32(mDecoded)
			   << "codec " << S32(mCodec)
			   << llendl;
	}
}

//----------------------------------------------------------------------------

BOOL LLImageFormatted::copyData(U8 *data, S32 size)
{
	if ( data && ((data != getData()) || (size != getDataSize())) )
	{
		deleteData();
		allocateData(size);
		memcpy(getData(), data, size);	/* Flawfinder: ignore */
	}
	return TRUE;
}

// LLImageFormatted becomes the owner of data
void LLImageFormatted::setData(U8 *data, S32 size)
{
	if (data && data != getData())
	{
		deleteData();
		setDataAndSize(data, size); // Access private LLImageBase members

		sGlobalFormattedMemory += getDataSize();
	}
}

void LLImageFormatted::appendData(U8 *data, S32 size)
{
	if (data)
	{
		if (!getData())
		{
			setData(data, size);
		}
		else 
		{
			S32 cursize = getDataSize();
			S32 newsize = cursize + size;
			reallocateData(newsize);
			memcpy(getData() + cursize, data, size);
			FREE_MEM(LLImageBase::getPrivatePool(), data);
		}
	}
}

//----------------------------------------------------------------------------

BOOL LLImageFormatted::load(const std::string &filename)
{
	resetLastError();

	S32 file_size = 0;
	LLAPRFile infile ;
	infile.open(filename, LL_APR_RB, NULL, &file_size);
	apr_file_t* apr_file = infile.getFileHandle();
	if (!apr_file)
	{
		setLastError("Unable to open file for reading", filename);
		return FALSE;
	}
	if (file_size == 0)
	{
		setLastError("File is empty",filename);
		return FALSE;
	}

	BOOL res;
	U8 *data = allocateData(file_size);
	apr_size_t bytes_read = file_size;
	apr_status_t s = apr_file_read(apr_file, data, &bytes_read); // modifies bytes_read
	if (s != APR_SUCCESS || (S32) bytes_read != file_size)
	{
		deleteData();
		setLastError("Unable to read entire file",filename);
		res = FALSE;
	}
	else
	{
		res = updateData();
	}
	
	return res;
}

BOOL LLImageFormatted::save(const std::string &filename)
{
	resetLastError();

	LLAPRFile outfile ;
	outfile.open(filename, LL_APR_WB);
	if (!outfile.getFileHandle())
	{
		setLastError("Unable to open file for writing", filename);
		return FALSE;
	}
	
	outfile.write(getData(), 	getDataSize());
	outfile.close() ;
	return TRUE;
}

// BOOL LLImageFormatted::save(LLVFS *vfs, const LLUUID &uuid, LLAssetType::EType type)
// Depricated to remove VFS dependency.
// Use:
// LLVFile::writeFile(image->getData(), image->getDataSize(), vfs, uuid, type);

//----------------------------------------------------------------------------

S8 LLImageFormatted::getCodec() const
{
	return mCodec;
}

//============================================================================

static void avg4_colors4(const U8* a, const U8* b, const U8* c, const U8* d, U8* dst)
{
	dst[0] = (U8)(((U32)(a[0]) + b[0] + c[0] + d[0])>>2);
	dst[1] = (U8)(((U32)(a[1]) + b[1] + c[1] + d[1])>>2);
	dst[2] = (U8)(((U32)(a[2]) + b[2] + c[2] + d[2])>>2);
	dst[3] = (U8)(((U32)(a[3]) + b[3] + c[3] + d[3])>>2);
}

static void avg4_colors3(const U8* a, const U8* b, const U8* c, const U8* d, U8* dst)
{
	dst[0] = (U8)(((U32)(a[0]) + b[0] + c[0] + d[0])>>2);
	dst[1] = (U8)(((U32)(a[1]) + b[1] + c[1] + d[1])>>2);
	dst[2] = (U8)(((U32)(a[2]) + b[2] + c[2] + d[2])>>2);
}

static void avg4_colors2(const U8* a, const U8* b, const U8* c, const U8* d, U8* dst)
{
	dst[0] = (U8)(((U32)(a[0]) + b[0] + c[0] + d[0])>>2);
	dst[1] = (U8)(((U32)(a[1]) + b[1] + c[1] + d[1])>>2);
}

//static
void LLImageBase::generateMip(const U8* indata, U8* mipdata, S32 width, S32 height, S32 nchannels)
{
	llassert(width > 0 && height > 0);
	U8* data = mipdata;
	S32 in_width = width*2;
	for (S32 h=0; h<height; h++)
	{
		for (S32 w=0; w<width; w++)
		{
			switch(nchannels)
			{
			  case 4:
				avg4_colors4(indata, indata+4, indata+4*in_width, indata+4*in_width+4, data);
				break;
			  case 3:
				avg4_colors3(indata, indata+3, indata+3*in_width, indata+3*in_width+3, data);
				break;
			  case 2:
				avg4_colors2(indata, indata+2, indata+2*in_width, indata+2*in_width+2, data);
				break;
			  case 1:
				*(U8*)data = (U8)(((U32)(indata[0]) + indata[1] + indata[in_width] + indata[in_width+1])>>2);
				break;
			  default:
				llerrs << "generateMmip called with bad num channels" << llendl;
			}
			indata += nchannels*2;
			data += nchannels;
		}
		indata += nchannels*in_width; // skip odd lines
	}
}


//============================================================================

//static
F32 LLImageBase::calc_download_priority(F32 virtual_size, F32 visible_pixels, S32 bytes_sent)
{
	F32 w_priority;

	F32 bytes_weight = 1.f;
	if (!bytes_sent)
	{
		bytes_weight = 20.f;
	}
	else if (bytes_sent < 1000)
	{
		bytes_weight = 1.f;
	}
	else if (bytes_sent < 2000)
	{
		bytes_weight = 1.f/1.5f;
	}
	else if (bytes_sent < 4000)
	{
		bytes_weight = 1.f/3.f;
	}
	else if (bytes_sent < 8000)
	{
		bytes_weight = 1.f/6.f;
	}
	else if (bytes_sent < 16000)
	{
		bytes_weight = 1.f/12.f;
	}
	else if (bytes_sent < 32000)
	{
		bytes_weight = 1.f/20.f;
	}
	else if (bytes_sent < 64000)
	{
		bytes_weight = 1.f/32.f;
	}
	else
	{
		bytes_weight = 1.f/64.f;
	}
	bytes_weight *= bytes_weight;


	//llinfos << "VS: " << virtual_size << llendl;
	F32 virtual_size_factor = virtual_size / (10.f*10.f);

	// The goal is for weighted priority to be <= 0 when we've reached a point where
	// we've sent enough data.
	//llinfos << "BytesSent: " << bytes_sent << llendl;
	//llinfos << "BytesWeight: " << bytes_weight << llendl;
	//llinfos << "PreLog: " << bytes_weight * virtual_size_factor << llendl;
	w_priority = (F32)log10(bytes_weight * virtual_size_factor);

	//llinfos << "PreScale: " << w_priority << llendl;

	// We don't want to affect how MANY bytes we send based on the visible pixels, but the order
	// in which they're sent.  We post-multiply so we don't change the zero point.
	if (w_priority > 0.f)
	{
		F32 pixel_weight = (F32)log10(visible_pixels + 1)*3.0f;
		w_priority *= pixel_weight;
	}

	return w_priority;
}

//============================================================================