/** 
 * @file llimagegl.cpp
 * @brief Generic GL image handler
 *
 * $LicenseInfo:firstyear=2001&license=viewergpl$
 * 
 * Copyright (c) 2001-2007, Linden Research, Inc.
 * 
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
 * the GPL can be found in doc/GPL-license.txt in this distribution, or
 * online at http://secondlife.com/developers/opensource/gplv2
 * 
 * There are special exceptions to the terms and conditions of the GPL as
 * it is applied to this Source Code. View the full text of the exception
 * in the file doc/FLOSS-exception.txt in this software distribution, or
 * online at http://secondlife.com/developers/opensource/flossexception
 * 
 * By copying, modifying or distributing this software, you acknowledge
 * that you have read and understood your obligations described above,
 * and agree to abide by those obligations.
 * 
 * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
 * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
 * COMPLETENESS OR PERFORMANCE.
 * $/LicenseInfo$
 */


// TODO: create 2 classes for images w/ and w/o discard levels?

#include "linden_common.h"

#include "llimagegl.h"

#include "llerror.h"
#include "llimage.h"

#include "llmath.h"
#include "llgl.h"

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

const F32 MIN_TEXTURE_LIFETIME = 10.f;

//statics
LLGLuint LLImageGL::sCurrentBoundTextures[MAX_GL_TEXTURE_UNITS] = { 0 };

S32 LLImageGL::sGlobalTextureMemory		= 0;
S32 LLImageGL::sBoundTextureMemory		= 0;
S32 LLImageGL::sCurBoundTextureMemory	= 0;
S32 LLImageGL::sCount					= 0;

BOOL LLImageGL::sGlobalUseAnisotropic	= FALSE;
F32 LLImageGL::sLastFrameTime			= 0.f;

std::set<LLImageGL*> LLImageGL::sImageList;

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

//static
S32 LLImageGL::dataFormatBits(S32 dataformat)
{
	switch (dataformat)
	{
	  case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:	return 4;
	  case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:	return 8;
	  case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:	return 8;
	  case GL_LUMINANCE:						return 8;
	  case GL_ALPHA:							return 8;
	  case GL_COLOR_INDEX:						return 8;
	  case GL_LUMINANCE_ALPHA:					return 16;
	  case GL_RGB:								return 24;
	  case GL_RGB8:								return 24;
	  case GL_RGBA:								return 32;
	  case GL_BGRA:								return 32;		// Used for QuickTime media textures on the Mac
	  default:
		llerrs << "LLImageGL::Unknown format: " << dataformat << llendl;
		return 0;
	}
}

//static
S32 LLImageGL::dataFormatBytes(S32 dataformat, S32 width, S32 height)
{
	if (dataformat >= GL_COMPRESSED_RGB_S3TC_DXT1_EXT &&
		dataformat <= GL_COMPRESSED_RGBA_S3TC_DXT5_EXT)
	{
		if (width < 4) width = 4;
		if (height < 4) height = 4;
	}
	S32 bytes ((width*height*dataFormatBits(dataformat)+7)>>3);
	S32 aligned = (bytes+3)&~3;
	return aligned;
}

//static
S32 LLImageGL::dataFormatComponents(S32 dataformat)
{
	switch (dataformat)
	{
	  case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:	return 3;
	  case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:	return 4;
	  case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:	return 4;
	  case GL_LUMINANCE:						return 1;
	  case GL_ALPHA:							return 1;
	  case GL_COLOR_INDEX:						return 1;
	  case GL_LUMINANCE_ALPHA:					return 2;
	  case GL_RGB:								return 3;
	  case GL_RGBA:								return 4;
	  case GL_BGRA:								return 4;		// Used for QuickTime media textures on the Mac
	  default:
		llerrs << "LLImageGL::Unknown format: " << dataformat << llendl;
		return 0;
	}
}

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

// static
void LLImageGL::bindExternalTexture(LLGLuint gl_name, S32 stage, LLGLenum bind_target )
{
	glActiveTextureARB(GL_TEXTURE0_ARB + stage);
	glClientActiveTextureARB(GL_TEXTURE0_ARB + stage);
	glBindTexture(bind_target, gl_name);
	sCurrentBoundTextures[stage] = gl_name;
}

// static
void LLImageGL::unbindTexture(S32 stage, LLGLenum bind_target)
{
	// LLGLSLShader can return -1
	if (stage >= 0)
	{
		glActiveTextureARB(GL_TEXTURE0_ARB + stage);
		glClientActiveTextureARB(GL_TEXTURE0_ARB + stage);
		glBindTexture(bind_target, 0);
		sCurrentBoundTextures[stage] = 0;
	}
}

// static (duplicated for speed and to avoid GL_TEXTURE_2D default argument which requires GL header dependency)
void LLImageGL::unbindTexture(S32 stage)
{
	// LLGLSLShader can return -1
	if (stage >= 0)
	{
		glActiveTextureARB(GL_TEXTURE0_ARB + stage);
		glClientActiveTextureARB(GL_TEXTURE0_ARB + stage);
		glBindTexture(GL_TEXTURE_2D, 0);
		sCurrentBoundTextures[stage] = 0;
	}
}

// static
void LLImageGL::updateStats(F32 current_time)
{
	sLastFrameTime = current_time;
	sBoundTextureMemory = sCurBoundTextureMemory;
	sCurBoundTextureMemory = 0;
}

//static
S32 LLImageGL::updateBoundTexMem(const S32 delta)
{
	LLImageGL::sCurBoundTextureMemory += delta;
	return LLImageGL::sCurBoundTextureMemory;
}

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

//static 
void LLImageGL::destroyGL(BOOL save_state)
{
	for (S32 stage = 0; stage < gGLManager.mNumTextureUnits; stage++)
	{
		LLImageGL::unbindTexture(stage, GL_TEXTURE_2D);
	}
	for (std::set<LLImageGL*>::iterator iter = sImageList.begin();
		 iter != sImageList.end(); iter++)
	{
		LLImageGL* glimage = *iter;
		if (glimage->mTexName && glimage->mComponents)
		{
			if (save_state)
			{
				glimage->mSaveData = new LLImageRaw;
				glimage->readBackRaw(glimage->mCurrentDiscardLevel, glimage->mSaveData, false);
			}
			glimage->destroyGLTexture();
			stop_glerror();
		}
	}
}

//static 
void LLImageGL::restoreGL()
{
	for (std::set<LLImageGL*>::iterator iter = sImageList.begin();
		 iter != sImageList.end(); iter++)
	{
		LLImageGL* glimage = *iter;
		if (glimage->mSaveData.notNull() && glimage->mSaveData->getComponents())
		{
			if (glimage->getComponents())
			{
				glimage->createGLTexture(glimage->mCurrentDiscardLevel, glimage->mSaveData);
				stop_glerror();
			}
			glimage->mSaveData = NULL; // deletes data
		}
	}
}

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

//static 
BOOL LLImageGL::create(LLPointer<LLImageGL>& dest, BOOL usemipmaps)
{
	dest = new LLImageGL(usemipmaps);
	return TRUE;
}

BOOL LLImageGL::create(LLPointer<LLImageGL>& dest, U32 width, U32 height, U8 components, BOOL usemipmaps)
{
	dest = new LLImageGL(width, height, components, usemipmaps);
	return TRUE;
}

BOOL LLImageGL::create(LLPointer<LLImageGL>& dest, const LLImageRaw* imageraw, BOOL usemipmaps)
{
	dest = new LLImageGL(imageraw, usemipmaps);
	return TRUE;
}

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

LLImageGL::LLImageGL(BOOL usemipmaps)
	: mSaveData(0)
{
	init(usemipmaps);
	setSize(0, 0, 0);
	sImageList.insert(this);
	sCount++;
}

LLImageGL::LLImageGL(U32 width, U32 height, U8 components, BOOL usemipmaps)
	: mSaveData(0)
{
	llassert( components <= 4 );
	init(usemipmaps);
	setSize(width, height, components);
	sImageList.insert(this);
	sCount++;
}

LLImageGL::LLImageGL(const LLImageRaw* imageraw, BOOL usemipmaps)
	: mSaveData(0)
{
	init(usemipmaps);
	setSize(0, 0, 0);
	sImageList.insert(this);
	sCount++;
	createGLTexture(0, imageraw); 
}

LLImageGL::~LLImageGL()
{
	LLImageGL::cleanup();
	sImageList.erase(this);
	sCount--;
}

void LLImageGL::init(BOOL usemipmaps)
{
#ifdef DEBUG_MISS
	mMissed				= FALSE;
#endif

	mTextureMemory    = 0;
	mLastBindTime     = 0.f;

	mTarget			  = GL_TEXTURE_2D;
	mBindTarget		  = GL_TEXTURE_2D;
	mUseMipMaps		  = usemipmaps;
	mHasMipMaps		  = FALSE;
	mAutoGenMips	  = FALSE;
	mTexName          = 0;
	mIsResident       = 0;
	mClampS			  = FALSE;
	mClampT			  = FALSE;
	mMipFilterNearest  = FALSE;
	mWidth				= 0;
	mHeight				= 0;
	mComponents			= 0;
	
	mMaxDiscardLevel = MAX_DISCARD_LEVEL;
	mCurrentDiscardLevel = -1;
	mDontDiscard = FALSE;
	
	mFormatInternal = -1;
	mFormatPrimary = (LLGLenum) 0;
	mFormatType = GL_UNSIGNED_BYTE;
	mFormatSwapBytes = FALSE;
	mHasExplicitFormat = FALSE;
}

void LLImageGL::cleanup()
{
	if (!gGLManager.mIsDisabled)
	{
		destroyGLTexture();
	}
	mSaveData = NULL; // deletes data
}

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

static bool check_power_of_two(S32 dim)
{
	while(dim > 1)
	{
		if (dim & 1)
		{
			return false;
		}
		dim >>= 1;
	}
	return true;
}

//static
bool LLImageGL::checkSize(S32 width, S32 height)
{
	return check_power_of_two(width) && check_power_of_two(height);
}

void LLImageGL::setSize(S32 width, S32 height, S32 ncomponents)
{
	if (width != mWidth || height != mHeight || ncomponents != mComponents)
	{
		// Check if dimensions are a power of two!
		if (!checkSize(width,height))
		{
			llerrs << llformat("Texture has non power of two dimention: %dx%d",width,height) << llendl;
		}
		
		if (mTexName)
		{
// 			llwarns << "Setting Size of LLImageGL with existing mTexName = " << mTexName << llendl;
			destroyGLTexture();
		}
		
		mWidth = width;
		mHeight = height;
		mComponents = ncomponents;
		if (ncomponents > 0)
		{
			mMaxDiscardLevel = 0;
			while (width > 1 && height > 1 && mMaxDiscardLevel < MAX_DISCARD_LEVEL)
			{
				mMaxDiscardLevel++;
				width >>= 1;
				height >>= 1;
			}
		}
		else
		{
			mMaxDiscardLevel = MAX_DISCARD_LEVEL;
		}
	}
}

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

// virtual
void LLImageGL::dump()
{
	llinfos << "mMaxDiscardLevel " << S32(mMaxDiscardLevel)
			<< " mLastBindTime " << mLastBindTime
			<< " mTarget " << S32(mTarget)
			<< " mBindTarget " << S32(mBindTarget)
			<< " mUseMipMaps " << S32(mUseMipMaps)
			<< " mHasMipMaps " << S32(mHasMipMaps)
			<< " mCurrentDiscardLevel " << S32(mCurrentDiscardLevel)
			<< " mFormatInternal " << S32(mFormatInternal)
			<< " mFormatPrimary " << S32(mFormatPrimary)
			<< " mFormatType " << S32(mFormatType)
			<< " mFormatSwapBytes " << S32(mFormatSwapBytes)
			<< " mHasExplicitFormat " << S32(mHasExplicitFormat)
#if DEBUG_MISS
			<< " mMissed " << mMissed
#endif
			<< llendl;

	llinfos << " mTextureMemory " << mTextureMemory
			<< " mTexNames " << mTexName
			<< " mIsResident " << S32(mIsResident)
			<< llendl;
}

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

BOOL LLImageGL::bindTextureInternal(const S32 stage) const
{
	if (gGLManager.mIsDisabled)
	{
		llwarns << "Trying to bind a texture while GL is disabled!" << llendl;
	}

	glActiveTextureARB(GL_TEXTURE0_ARB + stage);
		
	if (sCurrentBoundTextures[stage] && sCurrentBoundTextures[stage] == mTexName)
	{
		// already set!
		return TRUE;
	}

	if (mTexName != 0)
	{
#ifdef DEBUG_MISS
		mMissed = ! getIsResident(TRUE);
#endif

		glBindTexture(mBindTarget, mTexName);
		sCurrentBoundTextures[stage] = mTexName;

		if (mLastBindTime != sLastFrameTime)
		{
			// we haven't accounted for this texture yet this frame
			updateBoundTexMem(mTextureMemory);
			mLastBindTime = sLastFrameTime;
		}
		
		return TRUE;
	}
	else
	{
		glBindTexture(mBindTarget, 0);
		sCurrentBoundTextures[stage] = 0;
		return FALSE;
	}
}

//virtual
BOOL LLImageGL::bind(const S32 stage) const
{
	if (stage == -1)
	{
		return FALSE;
	}
	BOOL res = bindTextureInternal(stage);
	//llassert(res);
	return res;
}

void LLImageGL::setExplicitFormat( LLGLint internal_format, LLGLenum primary_format, LLGLenum type_format, BOOL swap_bytes )
{
	// Note: must be called before createTexture()
	// Note: it's up to the caller to ensure that the format matches the number of components.
	mHasExplicitFormat = TRUE;
	mFormatInternal = internal_format;
	mFormatPrimary = primary_format;
	if(type_format == 0)
		mFormatType = GL_UNSIGNED_BYTE;
	else
		mFormatType = type_format;
	mFormatSwapBytes = swap_bytes;
}

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

void LLImageGL::setImage(const LLImageRaw* imageraw)
{
	llassert((imageraw->getWidth() == getWidth(mCurrentDiscardLevel)) &&
			 (imageraw->getHeight() == getHeight(mCurrentDiscardLevel)) &&
			 (imageraw->getComponents() == getComponents()));
	const U8* rawdata = imageraw->getData();
	setImage(rawdata, FALSE);
}

void LLImageGL::setImage(const U8* data_in, BOOL data_hasmips)
{
// 	LLFastTimer t1(LLFastTimer::FTM_TEMP1);
	
	bool is_compressed = false;
	if (mFormatPrimary >= GL_COMPRESSED_RGBA_S3TC_DXT1_EXT && mFormatPrimary <= GL_COMPRESSED_RGBA_S3TC_DXT5_EXT)
	{
		is_compressed = true;
	}

	{
// 		LLFastTimer t2(LLFastTimer::FTM_TEMP2);
		llverify(bindTextureInternal(0));
	}
	
	if (mUseMipMaps)
	{
// 		LLFastTimer t2(LLFastTimer::FTM_TEMP3);
		if (data_hasmips)
		{
			// NOTE: data_in points to largest image; smaller images
			// are stored BEFORE the largest image
			for (S32 d=mCurrentDiscardLevel; d<=mMaxDiscardLevel; d++)
			{
				S32 w = getWidth(d);
				S32 h = getHeight(d);
				S32 gl_level = d-mCurrentDiscardLevel;
				if (d > mCurrentDiscardLevel)
				{
					data_in -= dataFormatBytes(mFormatPrimary, w, h); // see above comment
				}
				if (is_compressed)
				{
// 					LLFastTimer t2(LLFastTimer::FTM_TEMP4);
					S32 tex_size = dataFormatBytes(mFormatPrimary, w, h);
					glCompressedTexImage2DARB(mTarget, gl_level, mFormatPrimary, w, h, 0, tex_size, (GLvoid *)data_in);
					stop_glerror();
				}
				else
				{
// 					LLFastTimer t2(LLFastTimer::FTM_TEMP4);

					if(mFormatSwapBytes)
					{
						glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);
						stop_glerror();
					}
						
					glTexImage2D(mTarget, gl_level, mFormatInternal, w, h, 0, mFormatPrimary, GL_UNSIGNED_BYTE, (GLvoid*)data_in);
					
					if(mFormatSwapBytes)
					{
						glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
						stop_glerror();
					}
						
					stop_glerror();
				}
				stop_glerror();
			}			
		}
		else if (!is_compressed)
		{
			if (mAutoGenMips)
			{
				glTexParameteri(mBindTarget, GL_GENERATE_MIPMAP_SGIS, TRUE);
				stop_glerror();
				{
// 					LLFastTimer t2(LLFastTimer::FTM_TEMP4);

					if(mFormatSwapBytes)
					{
						glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);
						stop_glerror();
					}

					glTexImage2D(mTarget, 0, mFormatInternal,
								 getWidth(mCurrentDiscardLevel), getHeight(mCurrentDiscardLevel), 0,
								 mFormatPrimary, mFormatType,
								 data_in);
					stop_glerror();

					if(mFormatSwapBytes)
					{
						glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
						stop_glerror();
					}
				}
			}
			else
			{
				// Create mips by hand
				// about 30% faster than autogen on ATI 9800, 50% slower on nVidia 4800
				// ~4x faster than gluBuild2DMipmaps
				S32 width = getWidth(mCurrentDiscardLevel);
				S32 height = getHeight(mCurrentDiscardLevel);
				S32 nummips = mMaxDiscardLevel - mCurrentDiscardLevel + 1;
				S32 w = width, h = height;
				const U8* prev_mip_data = 0;
				const U8* cur_mip_data = 0;
				for (int m=0; m<nummips; m++)
				{
					if (m==0)
					{
						cur_mip_data = data_in;
					}
					else
					{
						S32 bytes = w * h * mComponents;
						U8* new_data = new U8[bytes];
						LLImageBase::generateMip(prev_mip_data, new_data, w, h, mComponents);
						cur_mip_data = new_data;
					}
					llassert(w > 0 && h > 0 && cur_mip_data);
					{
// 						LLFastTimer t1(LLFastTimer::FTM_TEMP4);
						if(mFormatSwapBytes)
						{
							glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);
							stop_glerror();
						}

						glTexImage2D(mTarget, m, mFormatInternal, w, h, 0, mFormatPrimary, mFormatType, cur_mip_data);
						stop_glerror();

						if(mFormatSwapBytes)
						{
							glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
							stop_glerror();
						}
					}
					if (prev_mip_data && prev_mip_data != data_in)
					{
						delete[] prev_mip_data;
					}
					prev_mip_data = cur_mip_data;
					w >>= 1;
					h >>= 1;
				}
				if (prev_mip_data && prev_mip_data != data_in)
				{
					delete[] prev_mip_data;
				}
			}
		}
		else
		{
			llerrs << "Compressed Image has mipmaps but data does not (can not auto generate compressed mips)" << llendl;
		}
		mHasMipMaps = TRUE;
	}
	else
	{
// 		LLFastTimer t2(LLFastTimer::FTM_TEMP5);
		S32 w = getWidth();
		S32 h = getHeight();
		if (is_compressed)
		{
			S32 tex_size = dataFormatBytes(mFormatPrimary, w, h);
			glCompressedTexImage2DARB(mTarget, 0, mFormatPrimary, w, h, 0, tex_size, (GLvoid *)data_in);
			stop_glerror();
		}
		else
		{
			if(mFormatSwapBytes)
			{
				glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);
				stop_glerror();
			}

			glTexImage2D(mTarget, 0, mFormatInternal, w, h, 0,
						 mFormatPrimary, mFormatType, (GLvoid *)data_in);
			stop_glerror();

			if(mFormatSwapBytes)
			{
				glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
				stop_glerror();
			}

		}
		mHasMipMaps = FALSE;
	}
	glFlush();
	stop_glerror();
}

BOOL LLImageGL::setSubImage(const U8* datap, S32 data_width, S32 data_height, S32 x_pos, S32 y_pos, S32 width, S32 height)
{
	if (!width || !height)
	{
		return TRUE;
	}
	if (mTexName == 0)
	{
		llwarns << "Setting subimage on image without GL texture" << llendl;
		return FALSE;
	}
	if (datap == NULL)
	{
		llwarns << "Setting subimage on image with NULL datap" << llendl;
		return FALSE;
	}
	
	if (x_pos == 0 && y_pos == 0 && width == getWidth() && height == getHeight())
	{
		setImage(datap, FALSE);
	}
	else
	{
		if (mUseMipMaps)
		{
			dump();
			llerrs << "setSubImage called with mipmapped image (not supported)" << llendl;
		}
		llassert_always(mCurrentDiscardLevel == 0);
		llassert_always(x_pos >= 0 && y_pos >= 0);
		
		if (((x_pos + width) > getWidth()) || 
			(y_pos + height) > getHeight())
		{
			dump();
			llerrs << "Subimage not wholly in target image!" 
				   << " x_pos " << x_pos
				   << " y_pos " << y_pos
				   << " width " << width
				   << " height " << height
				   << " getWidth() " << getWidth()
				   << " getHeight() " << getHeight()
				   << llendl;
		}

		if ((x_pos + width) > data_width || 
			(y_pos + height) > data_height)
		{
			dump();
			llerrs << "Subimage not wholly in source image!" 
				   << " x_pos " << x_pos
				   << " y_pos " << y_pos
				   << " width " << width
				   << " height " << height
				   << " source_width " << data_width
				   << " source_height " << data_height
				   << llendl;
		}


		glPixelStorei(GL_UNPACK_ROW_LENGTH, data_width);
		stop_glerror();

		if(mFormatSwapBytes)
		{
			glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);
			stop_glerror();
		}

		datap += (y_pos * data_width + x_pos) * getComponents();
		// Update the GL texture
		BOOL res = bindTextureInternal(0);
		if (!res) llerrs << "LLImageGL::setSubImage(): bindTexture failed" << llendl;
		stop_glerror();

		LLGLEnable tex( GL_TEXTURE_2D ); 

		glTexSubImage2D(mTarget, 0, x_pos, y_pos, 
						width, height, mFormatPrimary, mFormatType, datap);
		stop_glerror();

		if(mFormatSwapBytes)
		{
			glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
			stop_glerror();
		}

		glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
		stop_glerror();
	}
	glFlush();
	return TRUE;
}

BOOL LLImageGL::setSubImage(const LLImageRaw* imageraw, S32 x_pos, S32 y_pos, S32 width, S32 height)
{
	return setSubImage(imageraw->getData(), imageraw->getWidth(), imageraw->getHeight(), x_pos, y_pos, width, height);
}

// Copy sub image from frame buffer
BOOL LLImageGL::setSubImageFromFrameBuffer(S32 fb_x, S32 fb_y, S32 x_pos, S32 y_pos, S32 width, S32 height)
{
	if (bindTextureInternal(0))
	{
		glCopyTexSubImage2D(GL_TEXTURE_2D, 0, fb_x, fb_y, x_pos, y_pos, width, height);
		stop_glerror();
		return TRUE;
	}
	else
	{
		return FALSE;
	}
}

BOOL LLImageGL::createGLTexture(S32 discard_level, const LLImageRaw* imageraw, S32 usename/*=0*/)
{
	if (gGLManager.mIsDisabled)
	{
		llwarns << "Trying to create a texture while GL is disabled!" << llendl;
		return FALSE;
	}
	llassert(gGLManager.mInited || gNoRender);
	stop_glerror();

	if (discard_level < 0)
	{
		llassert(mCurrentDiscardLevel >= 0);
		discard_level = mCurrentDiscardLevel;
	}
	discard_level = llclamp(discard_level, 0, (S32)mMaxDiscardLevel);

	// Actual image width/height = raw image width/height * 2^discard_level
	S32 w = imageraw->getWidth() << discard_level;
	S32 h = imageraw->getHeight() << discard_level;

	// setSize may call destroyGLTexture if the size does not match
	setSize(w, h, imageraw->getComponents());

	if( !mHasExplicitFormat )
	{
		switch (mComponents)
		{
		  case 1:
			// Use luminance alpha (for fonts)
			mFormatInternal = GL_LUMINANCE8;
			mFormatPrimary = GL_LUMINANCE;
			mFormatType = GL_UNSIGNED_BYTE;
			break;
		  case 2:
			// Use luminance alpha (for fonts)
			mFormatInternal = GL_LUMINANCE8_ALPHA8;
			mFormatPrimary = GL_LUMINANCE_ALPHA;
			mFormatType = GL_UNSIGNED_BYTE;
			break;
		  case 3:
			mFormatInternal = GL_RGB8;
			mFormatPrimary = GL_RGB;
			mFormatType = GL_UNSIGNED_BYTE;
			break;
		  case 4:
			mFormatInternal = GL_RGBA8;
			mFormatPrimary = GL_RGBA;
			mFormatType = GL_UNSIGNED_BYTE;
			break;
		  default:
			llerrs << "Bad number of components for texture: " << (U32)getComponents() << llendl;
		}
	}

 	const U8* rawdata = imageraw->getData();
	return createGLTexture(discard_level, rawdata, FALSE, usename);
}

BOOL LLImageGL::createGLTexture(S32 discard_level, const U8* data_in, BOOL data_hasmips, S32 usename)
{
	llassert(data_in);

	if (discard_level < 0)
	{
		llassert(mCurrentDiscardLevel >= 0);
		discard_level = mCurrentDiscardLevel;
	}
	discard_level = llclamp(discard_level, 0, (S32)mMaxDiscardLevel);

	if (mTexName != 0 && discard_level == mCurrentDiscardLevel)
	{
		// This will only be true if the size has not changed
		setImage(data_in, data_hasmips);
		return TRUE;
	}
	
	GLuint old_name = mTexName;
// 	S32 old_discard = mCurrentDiscardLevel;
	
	if (usename != 0)
	{
		mTexName = usename;
	}
	else
	{
		glGenTextures(1, (GLuint*)&mTexName);
		stop_glerror();
		{
// 			LLFastTimer t1(LLFastTimer::FTM_TEMP6);
			llverify(bindTextureInternal(0));
			glTexParameteri(mBindTarget, GL_TEXTURE_BASE_LEVEL, 0);
			glTexParameteri(mBindTarget, GL_TEXTURE_MAX_LEVEL,  mMaxDiscardLevel-discard_level);
		}
	}
	if (!mTexName)
	{
		llerrs << "LLImageGL::createGLTexture failed to make texture" << llendl;
	}

	if (mUseMipMaps)
	{
		mAutoGenMips = gGLManager.mHasMipMapGeneration;
#if LL_DARWIN
		// On the Mac GF2 and GF4MX drivers, auto mipmap generation doesn't work right with alpha-only textures.
		if(gGLManager.mIsGF2or4MX && (mFormatInternal == GL_ALPHA8) && (mFormatPrimary == GL_ALPHA))
		{
			mAutoGenMips = FALSE;
		}
#endif
	}

	mCurrentDiscardLevel = discard_level;

	setImage(data_in, data_hasmips);

	setClamp(mClampS, mClampT);
	setMipFilterNearest(mMipFilterNearest);
	
	// things will break if we don't unbind after creation
	unbindTexture(0, mBindTarget);
	stop_glerror();

	if (old_name != 0)
	{
		sGlobalTextureMemory -= mTextureMemory;
		glDeleteTextures(1, &old_name);
		stop_glerror();
	}

	mTextureMemory = getMipBytes(discard_level);
	sGlobalTextureMemory += mTextureMemory;
		
	// mark this as bound at this point, so we don't throw it out immediately
	mLastBindTime = sLastFrameTime;

	return TRUE;
}

BOOL LLImageGL::setDiscardLevel(S32 discard_level)
{
	llassert(discard_level >= 0);
	llassert(mCurrentDiscardLevel >= 0);

	discard_level = llclamp(discard_level, 0, (S32)mMaxDiscardLevel);	

	if (mDontDiscard)
	{
		// don't discard!
		return FALSE;
	}
	else if (discard_level == mCurrentDiscardLevel)
	{
		// nothing to do
		return FALSE;
	}
	else if (discard_level < mCurrentDiscardLevel)
	{
		// larger image
		dump();
		llerrs << "LLImageGL::setDiscardLevel() called with larger discard level; use createGLTexture()" << llendl;
		return FALSE;
	}
	else if (mUseMipMaps)
	{
		LLPointer<LLImageRaw> imageraw = new LLImageRaw;
		while(discard_level > mCurrentDiscardLevel)
		{
			if (readBackRaw(discard_level, imageraw, false))
			{
				break;
			}
			discard_level--;
		}
		if (discard_level == mCurrentDiscardLevel)
		{
			// unable to increase the discard level
			return FALSE;
		}
		return createGLTexture(discard_level, imageraw);
	}
	else
	{
#if !LL_LINUX && !LL_SOLARIS
		 // *FIX: This should not be skipped for the linux client.
		llerrs << "LLImageGL::setDiscardLevel() called on image without mipmaps" << llendl;
#endif
		return FALSE;
	}
}

BOOL LLImageGL::readBackRaw(S32 discard_level, LLImageRaw* imageraw, bool compressed_ok)
{
	if (discard_level < 0)
	{
		discard_level = mCurrentDiscardLevel;
	}
	
	if (mTexName == 0 || discard_level < mCurrentDiscardLevel)
	{
		return FALSE;
	}

	S32 gl_discard = discard_level - mCurrentDiscardLevel;

	llverify(bindTextureInternal(0));
	
	LLGLint glwidth = 0;
	glGetTexLevelParameteriv(mTarget, gl_discard, GL_TEXTURE_WIDTH, (GLint*)&glwidth);
	if (glwidth == 0)
	{
		// No mip data smaller than current discard level
		return FALSE;
	}

	S32 width = getWidth(discard_level);
	S32 height = getHeight(discard_level);
	S32 ncomponents = getComponents();
	if (ncomponents == 0)
	{
		return FALSE;
	}

	if (width <= 0 || width > 2048 || height <= 0 || height > 2048 || ncomponents < 1 || ncomponents > 4)
	{
		llerrs << llformat("LLImageGL::readBackRaw: bogus params: %d x %d x %d",width,height,ncomponents) << llendl;
	}
	
	LLGLint is_compressed = 0;
	if (compressed_ok)
	{
		glGetTexLevelParameteriv(mTarget, is_compressed, GL_TEXTURE_COMPRESSED, (GLint*)&is_compressed);
	}
	if (is_compressed)
	{
		LLGLint glbytes;
		glGetTexLevelParameteriv(mTarget, gl_discard, GL_TEXTURE_COMPRESSED_IMAGE_SIZE, (GLint*)&glbytes);
		imageraw->allocateDataSize(width, height, ncomponents, glbytes);
		glGetCompressedTexImageARB(mTarget, gl_discard, (GLvoid*)(imageraw->getData()));
		stop_glerror();
	}
	else
	{
		imageraw->allocateDataSize(width, height, ncomponents);
		glGetTexImage(GL_TEXTURE_2D, gl_discard, mFormatPrimary, mFormatType, (GLvoid*)(imageraw->getData()));
		stop_glerror();
	}
		
	return TRUE;
}

void LLImageGL::destroyGLTexture()
{
	stop_glerror();

	if (mTexName != 0)
	{
		for (int i = 0; i < gGLManager.mNumTextureUnits; i++)
		{
			if (sCurrentBoundTextures[i] == mTexName)
			{
				unbindTexture(i, GL_TEXTURE_2D);
				stop_glerror();
			}
		}

		sGlobalTextureMemory -= mTextureMemory;
		mTextureMemory = 0;

		glDeleteTextures(1, (GLuint*)&mTexName);
		mTexName = 0;

		stop_glerror();
	}
}

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

void LLImageGL::setClamp(BOOL clamps, BOOL clampt)
{
	mClampS = clamps;
	mClampT = clampt;
	if (mTexName != 0)
	{
		glTexParameteri(mBindTarget, GL_TEXTURE_WRAP_S, clamps ? GL_CLAMP_TO_EDGE : GL_REPEAT);
		glTexParameteri(mBindTarget, GL_TEXTURE_WRAP_T, clampt ? GL_CLAMP_TO_EDGE : GL_REPEAT);
	}
	stop_glerror();
}

void LLImageGL::setMipFilterNearest(BOOL nearest, BOOL min_nearest)
{
	mMipFilterNearest = nearest;

	if (mTexName != 0)
	{
		if (min_nearest)
		{
			glTexParameteri(mBindTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
		}
		else if (mHasMipMaps)
		{
			glTexParameteri(mBindTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
		}
		else
		{
			glTexParameteri(mBindTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		}
		if (mMipFilterNearest)
		{
			glTexParameteri(mBindTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		}
		else 
		{
			glTexParameteri(mBindTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		}
		if (gGLManager.mHasAnisotropic)
		{
			if (sGlobalUseAnisotropic && !mMipFilterNearest)
			{
				F32 largest_anisotropy;
				glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &largest_anisotropy);
				glTexParameterf(mBindTarget, GL_TEXTURE_MAX_ANISOTROPY_EXT, largest_anisotropy);
			}
			else
			{
				glTexParameterf(mBindTarget, GL_TEXTURE_MAX_ANISOTROPY_EXT, 1.f);
			}
		}
	}
	
	stop_glerror();
}

BOOL LLImageGL::getIsResident(BOOL test_now)
{
	if (test_now)
	{
		if (mTexName != 0)
		{
			glAreTexturesResident(1, (GLuint*)&mTexName, &mIsResident);
		}
		else
		{
			mIsResident = FALSE;
		}
	}

	return mIsResident;
}

S32 LLImageGL::getHeight(S32 discard_level) const
{
	if (discard_level < 0)
	{
		discard_level = mCurrentDiscardLevel;
	}
	S32 height = mHeight >> discard_level;
	if (height < 1) height = 1;
	return height;
}

S32 LLImageGL::getWidth(S32 discard_level) const
{
	if (discard_level < 0)
	{
		discard_level = mCurrentDiscardLevel;
	}
	S32 width = mWidth >> discard_level;
	if (width < 1) width = 1;
	return width;
}

S32 LLImageGL::getBytes(S32 discard_level) const
{
	if (discard_level < 0)
	{
		discard_level = mCurrentDiscardLevel;
	}
	S32 w = mWidth>>discard_level;
	S32 h = mHeight>>discard_level;
	if (w == 0) w = 1;
	if (h == 0) h = 1;
	return dataFormatBytes(mFormatPrimary, w, h);
}

S32 LLImageGL::getMipBytes(S32 discard_level) const
{
	if (discard_level < 0)
	{
		discard_level = mCurrentDiscardLevel;
	}
	S32 w = mWidth>>discard_level;
	S32 h = mHeight>>discard_level;
	S32 res = dataFormatBytes(mFormatPrimary, w, h);
	if (mUseMipMaps)
	{
		while (w > 1 && h > 1)
		{
			w >>= 1; if (w == 0) w = 1;
			h >>= 1; if (h == 0) h = 1;
			res += dataFormatBytes(mFormatPrimary, w, h);
		}
	}
	return res;
}

BOOL LLImageGL::getBoundRecently() const
{
	return (BOOL)(sLastFrameTime - mLastBindTime < MIN_TEXTURE_LIFETIME);
}

void LLImageGL::setTarget(const LLGLenum target, const LLGLenum bind_target)
{
	mTarget = target;
	mBindTarget = bind_target;
}

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

// Manual Mip Generation
/*
		S32 width = getWidth(discard_level);
		S32 height = getHeight(discard_level);
		S32 w = width, h = height;
		S32 nummips = 1;
		while (w > 4 && h > 4)
		{
			w >>= 1; h >>= 1;
			nummips++;
		}
		stop_glerror();
		w = width, h = height;
		const U8* prev_mip_data = 0;
		const U8* cur_mip_data = 0;
		for (int m=0; m<nummips; m++)
		{
			if (m==0)
			{
				cur_mip_data = rawdata;
			}
			else
			{
				S32 bytes = w * h * mComponents;
				U8* new_data = new U8[bytes];
				LLImageBase::generateMip(prev_mip_data, new_data, w, h, mComponents);
				cur_mip_data = new_data;
			}
			llassert(w > 0 && h > 0 && cur_mip_data);
			U8 test = cur_mip_data[w*h*mComponents-1];
			{
				glTexImage2D(mTarget, m, mFormatInternal, w, h, 0, mFormatPrimary, mFormatType, cur_mip_data);
				stop_glerror();
			}
			if (prev_mip_data && prev_mip_data != rawdata)
			{
				delete prev_mip_data;
			}
			prev_mip_data = cur_mip_data;
			w >>= 1;
			h >>= 1;
		}
		if (prev_mip_data && prev_mip_data != rawdata)
		{
			delete prev_mip_data;
		}
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL,  nummips);
*/