Image.cpp

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/*  Visualization Library                                                             */
/*  http://visualizationlibrary.org                                                   */
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/*  Copyright (c) 2005-2020, Michele Bosi                                             */
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#include <vlCore/Image.hpp>
#include <vlCore/checks.hpp>
#include <vlCore/Say.hpp>
#include <vlCore/Log.hpp>
#include <vlCore/VisualizationLibrary.hpp>
#include <vlCore/FileSystem.hpp>
#include <vlCore/VirtualFile.hpp>
#include <vlCore/glsl_math.hpp>
#include <vlCore/ResourceDatabase.hpp>
#include <vlCore/LoadWriterManager.hpp>

#include <map>
#include <cmath>

using namespace vl;

//-----------------------------------------------------------------------------
// Image
//-----------------------------------------------------------------------------
Image::~Image()
{
  reset();
}
//-----------------------------------------------------------------------------
Image::Image()
{
  VL_DEBUG_SET_OBJECT_NAME()
  mPixels = new Buffer;
  reset();
}
//-----------------------------------------------------------------------------
Image::Image( void* buffer_ptr, int buffer_bytes )
{
  VL_DEBUG_SET_OBJECT_NAME()
  mPixels = new Buffer;
  reset();
  mPixels->setUserAllocatedBuffer( buffer_ptr, buffer_bytes );
}
//-----------------------------------------------------------------------------
Image::Image( const Image& other ): Object( other )
{
  VL_DEBUG_SET_OBJECT_NAME()
  mPixels = new Buffer;
  reset();
  *this = other;
}
//-----------------------------------------------------------------------------
Image::Image( const String& path )
{
  VL_DEBUG_SET_OBJECT_NAME()
  mPixels = new Buffer;
  reset();

  setObjectName(path.toStdString().c_str());
  ref<Image> img = loadImage(path);
  if (!img)
  {
    mFilePath = path;
    return;
  }
  // quicker than *this = *img;
  mPixels->swap(*img->mPixels);
  mMipmaps.swap(img->mMipmaps);
  mWidth  = img->mWidth;
  mHeight = img->mHeight;
  mDepth  = img->mDepth;
  mPitch  = img->mPitch;
  mByteAlign = img->mByteAlign;
  mFormat    = img->mFormat;
  mType      = img->mType;
  mIsCubemap = img->mIsCubemap;
  mIsNormalMap = img->mIsNormalMap;
  mHasAlpha    = img->mHasAlpha;
  mFilePath    = img->mFilePath;
}
//-----------------------------------------------------------------------------
Image::Image( int x, int y, int z, int bytealign, EImageFormat format, EImageType type ):
  mWidth(x), mHeight(y), mDepth(z), mPitch(0), mByteAlign(1), mFormat(format), mType(type), mIsCubemap(false), mIsNormalMap(false), mHasAlpha(false)
{
  VL_DEBUG_SET_OBJECT_NAME()
  mPixels = new Buffer;
  setByteAlignment(bytealign);

  if (x && y && z)
    allocate3D(x,y,z,bytealign,format,type);
  else
  if (x && y)
    allocate2D(x,y,bytealign,format,type);
  else
  if (x)
    allocate1D(x,format,type);
}
//-----------------------------------------------------------------------------
bool Image::isValid() const
{
  // size check

  bool x = mWidth > 0 && mHeight == 0 && mDepth == 0;
  bool y = mWidth > 0 && mHeight > 0 && mDepth == 0;
  bool z = mWidth > 0 && mHeight > 0 && mDepth > 0;

  // format check

  bool okformat = false;

  // these go well with all but compressed formats

  switch(type())
  {
    default:
    break;

    case IT_UNSIGNED_BYTE:
    case IT_BYTE:
    case IT_UNSIGNED_SHORT:
    case IT_SHORT:
    case IT_UNSIGNED_INT:
    case IT_INT:
    case IT_FLOAT:
    {
      switch(format())
      {
        case IF_COMPRESSED_RGB_S3TC_DXT1:
        case IF_COMPRESSED_RGBA_S3TC_DXT1:
        case IF_COMPRESSED_RGBA_S3TC_DXT3:
        case IF_COMPRESSED_RGBA_S3TC_DXT5:
        {
          break;
        }

        default:
        {
          okformat = true;
        }
      }
    }
  }

  // compressed type go well only with compressed formats

  switch(type())
  {
    default:
    break;

    case IT_IMPLICIT_TYPE:
    {
      switch(format())
      {
        case IF_COMPRESSED_RGB_S3TC_DXT1:
        case IF_COMPRESSED_RGBA_S3TC_DXT1:
        case IF_COMPRESSED_RGBA_S3TC_DXT3:
        case IF_COMPRESSED_RGBA_S3TC_DXT5:
        {
          okformat = true;
          break;
        }

        default:
        {
          break;
        }
      }
    }
  }

  switch(format())
  {
    default:
    break;

    // depth stencil
    case IF_DEPTH_STENCIL:
    {
      switch(type())
      {
        case IT_FLOAT_32_UNSIGNED_INT_24_8_REV:
        case IT_UNSIGNED_INT_24_8:
          okformat = true;
        default:
        break;
      }
    }
    break;

    // three components types

    case IF_RGB:
    case IF_BGR:
    {
      switch(type())
      {
        case IT_UNSIGNED_BYTE_3_3_2:
        case IT_UNSIGNED_BYTE_2_3_3_REV:
        case IT_UNSIGNED_SHORT_5_6_5:
        case IT_UNSIGNED_SHORT_5_6_5_REV:
        case IT_UNSIGNED_INT_5_9_9_9_REV: /* EXT_texture_shared_exponent, support only GL_RGB */
        case IT_UNSIGNED_INT_10F_11F_11F_REV: /* EXT_packed_float, supports only GL_RGB */
        {
          okformat = true;
          break;
        }

        default:
        {
          break;
        }
      }
      break;
    }

    // four components types

    case IF_RGBA:
    case IF_BGRA:
    {
      switch(type())
      {
        case IT_UNSIGNED_SHORT_4_4_4_4:
        case IT_UNSIGNED_SHORT_4_4_4_4_REV:
        case IT_UNSIGNED_SHORT_5_5_5_1:
        case IT_UNSIGNED_SHORT_1_5_5_5_REV:
        case IT_UNSIGNED_INT_8_8_8_8:
        case IT_UNSIGNED_INT_8_8_8_8_REV:
        case IT_UNSIGNED_INT_10_10_10_2:
        case IT_UNSIGNED_INT_2_10_10_10_REV:
        {
          okformat = true;
          break;
        }

        default:
        {
          break;
        }
      }
    }
  }

  #ifndef NDEBUG
    bool isvalid = okformat && (x|y|z) && (pitch() % mByteAlign == 0);
    Log::debug( isvalid ? "" : ( okformat ? "Image::isValid(): invalid dimensions or pitch/bytealign combination:\n" : "Image::isValid() reported an invalid format/type combination:\n") + print() );
  #endif

  return okformat && (x|y|z) && (pitch() % mByteAlign == 0);
}
//-----------------------------------------------------------------------------
String Image::printType() const
{
  std::map<int, const char*> ty;

  ty[IT_IMPLICIT_TYPE] = "IT_IMPLICIT_TYPE";
  ty[IT_UNSIGNED_BYTE] = "IT_UNSIGNED_BYTE";
  ty[IT_BYTE] = "IT_BYTE";
  ty[IT_UNSIGNED_SHORT] = "IT_UNSIGNED_SHORT";
  ty[IT_SHORT] = "IT_SHORT";
  ty[IT_UNSIGNED_INT] = "IT_UNSIGNED_INT";
  ty[IT_INT] = "IT_INT";
  ty[IT_FLOAT] = "IT_FLOAT";
  ty[IT_UNSIGNED_BYTE_3_3_2] = "IT_UNSIGNED_BYTE_3_3_2";
  ty[IT_UNSIGNED_BYTE_2_3_3_REV] = "IT_UNSIGNED_BYTE_2_3_3_REV";
  ty[IT_UNSIGNED_SHORT_5_6_5] = "IT_UNSIGNED_SHORT_5_6_5";
  ty[IT_UNSIGNED_SHORT_5_6_5_REV] = "IT_UNSIGNED_SHORT_5_6_5_REV";
  ty[IT_UNSIGNED_SHORT_4_4_4_4] = "IT_UNSIGNED_SHORT_4_4_4_4";
  ty[IT_UNSIGNED_SHORT_4_4_4_4_REV] = "IT_UNSIGNED_SHORT_4_4_4_4_REV";
  ty[IT_UNSIGNED_SHORT_5_5_5_1] = "IT_UNSIGNED_SHORT_5_5_5_1";
  ty[IT_UNSIGNED_SHORT_1_5_5_5_REV] = "IT_UNSIGNED_SHORT_1_5_5_5_REV";
  ty[IT_UNSIGNED_INT_8_8_8_8] = "IT_UNSIGNED_INT_8_8_8_8";
  ty[IT_UNSIGNED_INT_8_8_8_8_REV] = "IT_UNSIGNED_INT_8_8_8_8_REV";
  ty[IT_UNSIGNED_INT_10_10_10_2] = "IT_UNSIGNED_INT_10_10_10_2";
  ty[IT_UNSIGNED_INT_2_10_10_10_REV] = "IT_UNSIGNED_INT_2_10_10_10_REV";
  ty[IT_UNSIGNED_INT_5_9_9_9_REV] = "IT_UNSIGNED_INT_5_9_9_9_REV";
  ty[IT_UNSIGNED_INT_10F_11F_11F_REV] = "IT_UNSIGNED_INT_10F_11F_11F_REV";
  ty[IT_UNSIGNED_INT_24_8] = "IT_UNSIGNED_INT_24_8";
  ty[IT_FLOAT_32_UNSIGNED_INT_24_8_REV] = "IT_FLOAT_32_UNSIGNED_INT_24_8_REV";

  VL_CHECK(ty[type()] != NULL)

  return ty[type()];
}
//-----------------------------------------------------------------------------
String Image::printFormat() const
{
  std::map<int, const char*> fo;

  fo[IF_RGB] = "IF_RGB";
  fo[IF_RGBA] = "IF_RGBA";
  fo[IF_BGR] = "IF_BGR";
  fo[IF_BGRA] = "IF_BGRA";
  fo[IF_RED] = "IF_RED";
  fo[IF_GREEN] = "IF_GREEN";
  fo[IF_BLUE] = "IF_BLUE";
  fo[IF_ALPHA] = "IF_ALPHA";
  fo[IF_LUMINANCE] = "IF_LUMINANCE";
  fo[IF_LUMINANCE_ALPHA] = "IF_LUMINANCE_ALPHA";
  fo[IF_DEPTH_COMPONENT] = "IF_DEPTH_COMPONENT";
  fo[IF_STENCIL_INDEX] = "IF_STENCIL_INDEX";
  fo[IF_DEPTH_STENCIL] = "IF_DEPTH_STENCIL";
  fo[IF_COMPRESSED_RGB_S3TC_DXT1] = "IF_COMPRESSED_RGB_S3TC_DXT1";
  fo[IF_COMPRESSED_RGBA_S3TC_DXT1] = "IF_COMPRESSED_RGBA_S3TC_DXT1";
  fo[IF_COMPRESSED_RGBA_S3TC_DXT3] = "IF_COMPRESSED_RGBA_S3TC_DXT3";
  fo[IF_COMPRESSED_RGBA_S3TC_DXT5] = "IF_COMPRESSED_RGBA_S3TC_DXT5";

  VL_CHECK( fo[format()] != NULL );

  return fo[format()];
}
//-----------------------------------------------------------------------------
String Image::print() const
{
  return Say(
  "name   = %s\n"
  "width  = %n\n"
  "height = %n\n"
  "depth  = %n\n"
  "format = %s\n"
  "type   = %s\n"
  "pitch  = %n\n"
  "bytealign = %n\n"
  )
  << objectName().c_str()
  << width()
  << height()
  << depth()
  << printFormat()
  << printType()
  << pitch()
  << byteAlignment();
}
//-----------------------------------------------------------------------------
EImageDimension Image::dimension() const
{
  if(mWidth > 0 && mHeight == 0 && mDepth == 0 && !mIsCubemap) return ID_1D;
  if(mWidth > 0 && mHeight > 0  && mDepth == 0 && !mIsCubemap) return ID_2D;
  if(mWidth > 0 && mHeight > 0  && mDepth >  0 && !mIsCubemap) return ID_3D;
  if(mWidth > 0 && mHeight > 0  && mDepth == 0 &&  mIsCubemap) return ID_Cubemap;
  return ID_Error;
}
//-----------------------------------------------------------------------------
int Image::bitsPerPixel(EImageType type, EImageFormat format)
{
  int comp_size = 0;

  switch(type)
  {
    default:
    break;

    case IT_UNSIGNED_BYTE:  comp_size = sizeof(unsigned char)  * 8; break;
    case IT_BYTE:           comp_size = sizeof(GLbyte)   * 8; break;
    case IT_UNSIGNED_SHORT: comp_size = sizeof(GLushort) * 8; break;
    case IT_SHORT:          comp_size = sizeof(GLshort)  * 8; break;
    case IT_UNSIGNED_INT:   comp_size = sizeof(unsigned int)   * 8; break;
    case IT_INT:            comp_size = sizeof(int)    * 8; break;
    case IT_FLOAT:          comp_size = sizeof(float)  * 8; break;

    case IT_UNSIGNED_BYTE_3_3_2:          return 8;
    case IT_UNSIGNED_BYTE_2_3_3_REV:      return 8;
    case IT_UNSIGNED_SHORT_5_6_5:         return 16;
    case IT_UNSIGNED_SHORT_5_6_5_REV:     return 16;
    case IT_UNSIGNED_SHORT_4_4_4_4:       return 16;
    case IT_UNSIGNED_SHORT_4_4_4_4_REV:   return 16;
    case IT_UNSIGNED_SHORT_5_5_5_1:       return 16;
    case IT_UNSIGNED_SHORT_1_5_5_5_REV:   return 16;
    case IT_UNSIGNED_INT_8_8_8_8:         return 32;
    case IT_UNSIGNED_INT_8_8_8_8_REV:     return 32;
    case IT_UNSIGNED_INT_10_10_10_2:      return 32;
    case IT_UNSIGNED_INT_2_10_10_10_REV:  return 32;
    case IT_UNSIGNED_INT_5_9_9_9_REV:     return 32; /* EXT_texture_shared_exponent, support only IF_RGB */
    case IT_UNSIGNED_INT_10F_11F_11F_REV: return 32; /* EXT_packed_float, supports only IF_RGB */
    case IT_UNSIGNED_INT_24_8:            return 32; /* EXT_packed_depth_stencil, supports only IF_DEPTH_STENCIL */
    case IT_FLOAT_32_UNSIGNED_INT_24_8_REV: return 64; /* EXT_depth_buffer_float, supports only IF_DEPTH_STENCIL */
  }

  switch(format)
  {
    case IF_RED:             return comp_size * 1;
    case IF_GREEN:           return comp_size * 1;
    case IF_BLUE:            return comp_size * 1;
    case IF_ALPHA:           return comp_size * 1;
    case IF_DEPTH_COMPONENT: return comp_size * 1;
    case IF_STENCIL_INDEX:   return comp_size * 1;
    case IF_LUMINANCE:       return comp_size * 1;
    case IF_LUMINANCE_ALPHA: return comp_size * 2;
    case IF_DEPTH_STENCIL:   return comp_size * 0;
    case IF_RG:              return comp_size * 2;
    case IF_RGB:             return comp_size * 3;
    case IF_BGR:             return comp_size * 3;
    case IF_RGBA:            return comp_size * 4;
    case IF_BGRA:            return comp_size * 4;

     // compressed formats

    case IF_COMPRESSED_RGB_S3TC_DXT1:  return 4; // 8 bytes (64 bits) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT1: return 4; // 8 bytes (64 bits) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT3: return 8; // 16 bytes (128 bits) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT5: return 8; // 16 bytes (128 bits) per block per 16 pixels
    default:
      break;
  }

  VL_TRAP()
  return 0;
}
//-----------------------------------------------------------------------------
int Image::alphaBits() const
{
  int comp_size = 0;

  switch(format())
  {
    case IF_RED:             return comp_size * 0;
    case IF_GREEN:           return comp_size * 0;
    case IF_BLUE:            return comp_size * 0;
    case IF_ALPHA:           return comp_size * 1;
    case IF_DEPTH_COMPONENT: return comp_size * 0;
    case IF_STENCIL_INDEX:   return comp_size * 0;
    case IF_LUMINANCE:       return comp_size * 0;
    case IF_LUMINANCE_ALPHA: return comp_size * 1;
    case IF_DEPTH_STENCIL:   return comp_size * 0;
    case IF_RGB:             return comp_size * 0;
    case IF_BGR:             return comp_size * 0;
    case IF_RGBA:            return comp_size * 1;
    case IF_BGRA:            return comp_size * 1;

     // compressed formats

    case IF_COMPRESSED_RGB_S3TC_DXT1:  return 0; // 8 bytes (64 bits) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT1: return 1; // 8 bytes (64 bits) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT3: return 4; // 16 bytes (64 bits for uncompressed alpha + 64 bits for RGB) per block per 16 pixels
    case IF_COMPRESSED_RGBA_S3TC_DXT5: return 4; // 16 bytes (64 bits for   compressed alpha + 64 bits for RGB) per block per 16 pixels
    default:
      break;
  }

  switch(type())
  {
    default:
    break;

    case IT_UNSIGNED_BYTE:  comp_size = sizeof(unsigned char)  * 8; break;
    case IT_BYTE:           comp_size = sizeof(GLbyte)   * 8; break;
    case IT_UNSIGNED_SHORT: comp_size = sizeof(GLushort) * 8; break;
    case IT_SHORT:          comp_size = sizeof(GLshort)  * 8; break;
    case IT_UNSIGNED_INT:   comp_size = sizeof(unsigned int)   * 8; break;
    case IT_INT:            comp_size = sizeof(int)    * 8; break;
    case IT_FLOAT:          comp_size = sizeof(float)  * 8; break;

    case IT_UNSIGNED_BYTE_3_3_2:          return 0;
    case IT_UNSIGNED_BYTE_2_3_3_REV:      return 0;
    case IT_UNSIGNED_SHORT_5_6_5:         return 0;
    case IT_UNSIGNED_SHORT_5_6_5_REV:     return 0;
    case IT_UNSIGNED_SHORT_4_4_4_4:       return 4;
    case IT_UNSIGNED_SHORT_4_4_4_4_REV:   return 4;
    case IT_UNSIGNED_SHORT_5_5_5_1:       return 1;
    case IT_UNSIGNED_SHORT_1_5_5_5_REV:   return 1;
    case IT_UNSIGNED_INT_8_8_8_8:         return 8;
    case IT_UNSIGNED_INT_8_8_8_8_REV:     return 8;
    case IT_UNSIGNED_INT_10_10_10_2:      return 2;
    case IT_UNSIGNED_INT_2_10_10_10_REV:  return 2;
    case IT_UNSIGNED_INT_5_9_9_9_REV:     return 0; /* EXT_texture_shared_exponent, support only GL_RGB */
    case IT_UNSIGNED_INT_10F_11F_11F_REV: return 0; /* EXT_packed_float, supports only GL_RGB */
    case IT_UNSIGNED_INT_24_8:            return 0; /* EXT_packed_depth_stencil, supports only GL_DEPTH_STENCIL */
    case IT_FLOAT_32_UNSIGNED_INT_24_8_REV: return 0; /* EXT_depth_buffer_float, supports only IF_DEPTH_STENCIL */
  }

  VL_TRAP()

  return 0;
}
//-----------------------------------------------------------------------------
int Image::isCompressedFormat(EImageFormat fmt)
{
  switch(fmt)
  {
  case IF_COMPRESSED_RGB_S3TC_DXT1:
  case IF_COMPRESSED_RGBA_S3TC_DXT1:
  case IF_COMPRESSED_RGBA_S3TC_DXT3:
  case IF_COMPRESSED_RGBA_S3TC_DXT5:
    return true;

  default:
    return false;
  }
}
//-----------------------------------------------------------------------------
int Image::requiredMemory() const
{
  VL_CHECK( isValid() )
  return requiredMemory(width(), height(), depth(), byteAlignment(), format(), type(), isCubemap());
}
//-----------------------------------------------------------------------------
int Image::byteAlignment() const
{
  return mByteAlign;
}
//-----------------------------------------------------------------------------
void Image::setByteAlignment(int bytealign)
{
  if (!mPixels->empty())
    return;

  switch(bytealign)
  {
  case 0:
    bytealign = sizeof(unsigned char*);
  case 1:
  case 2:
  case 4:
  case 8:
    break;
  default:
    VL_TRAP()
  }

  mByteAlign = bytealign;

  updatePitch();
}
//-----------------------------------------------------------------------------
void Image::updatePitch()
{
  int xbits  = mWidth * bitsPerPixel();
  int xbytes = xbits/8 + ( (xbits % 8) ? 1 : 0 );
  mPitch     = xbytes/mByteAlign*mByteAlign + ( (xbytes % mByteAlign) ? mByteAlign : 0 );
}
//-----------------------------------------------------------------------------
void Image::allocate()
{
  mMipmaps.clear();
  mPixels->resize(requiredMemory());
}
//-----------------------------------------------------------------------------
void Image::allocate1D(int x, EImageFormat format, EImageType type)
{
  reset();

  VL_CHECK(x);
  setWidth(x);
  setHeight(0);
  setDepth(0);
  setFormat(format);
  setType(type);
  setByteAlignment(1);
  mIsCubemap = false;

  if ( ! requiredMemory() ) {
    Log::bug("Image::allocate1D() failed, probably your image settings are invalid.\n");
  } else {
    if ( mPixels->allocationMode() == vl::Buffer::AutoAllocatedBuffer ) {
      mPixels->resize( requiredMemory() );
    }
  }
}
//-----------------------------------------------------------------------------
void Image::allocate2D(int x, int y, int bytealign, EImageFormat format, EImageType type)
{
  reset();

  VL_CHECK(x);
  VL_CHECK(y);
  setWidth(x);
  setHeight(y);
  setDepth(0);
  setFormat(format);
  setType(type);
  setByteAlignment(bytealign);
  mIsCubemap = false;

  if ( ! requiredMemory() ) {
    Log::bug("Image::allocate2D() failed, probably your image settings are invalid.\n");
  } else {
    if ( mPixels->allocationMode() == vl::Buffer::AutoAllocatedBuffer ) {
      mPixels->resize( requiredMemory() );
    }
  }
}
//-----------------------------------------------------------------------------
void Image::allocate3D(int x, int y, int z, int bytealign, EImageFormat format, EImageType type)
{
  reset();

  VL_CHECK(x);
  VL_CHECK(y);
  VL_CHECK(z);
  setWidth(x);
  setHeight(y);
  setDepth(z);
  setFormat(format);
  setType(type);
  setByteAlignment(bytealign);
  mIsCubemap = false;

  if ( ! requiredMemory() ) {
    Log::bug("Image::allocate3D() failed, probably your image settings are invalid.\n");
  } else {
    if ( mPixels->allocationMode() == vl::Buffer::AutoAllocatedBuffer ) {
      mPixels->resize( requiredMemory() );
    }
  }
}
//-----------------------------------------------------------------------------
void Image::allocateCubemap(int x, int y, int bytealign, EImageFormat format, EImageType type)
{
  reset();

  setWidth(x);
  setHeight(y);
  setDepth(0);
  setFormat(format);
  setType(type);
  setByteAlignment(bytealign);
  mIsCubemap = true;

  if ( ! requiredMemory() ) {
    Log::bug("Image::allocateCubemap() failed, probably your image settings are invalid.\n");
  } else {
    if ( mPixels->allocationMode() == vl::Buffer::AutoAllocatedBuffer ) {
      mPixels->resize( requiredMemory() );
    }
  }
}
//-----------------------------------------------------------------------------
void Image::reset(int x, int y, int z, int bytealign, EImageFormat format, EImageType type, bool is_cubemap)
{
  reset();

  setWidth(x);
  setHeight(y);
  setDepth(z);
  setFormat(format);
  setType(type);
  setByteAlignment(bytealign);
  mIsCubemap = is_cubemap;
}
//-----------------------------------------------------------------------------
void Image::reset()
{
  if ( mPixels->allocationMode() == vl::Buffer::AutoAllocatedBuffer ) {
    mPixels->clear();
  }
  mMipmaps.clear();
  mObjectName.clear();
  mWidth = 0;
  mHeight = 0;
  mDepth = 0;
  mPitch = 0;
  mFormat = IF_RGBA;
  mType = IT_UNSIGNED_BYTE;
  mByteAlign = 1;
  mIsCubemap   = false;
  mIsNormalMap = false;
  mHasAlpha    = false;
}
//-----------------------------------------------------------------------------
Image& Image::operator=(const Image& other)
{
  super::operator=(other);

  // deep copy of the pixels
  *mPixels = *other.mPixels;

  // copy image info
  mWidth  = other.mWidth;
  mHeight  = other.mHeight;
  mDepth  = other.mDepth;
  mPitch  = other.mPitch;
  mByteAlign = other.mByteAlign;
  mFormat    = other.mFormat;
  mType      = other.mType;
  mIsCubemap = other.mIsCubemap;
  mIsNormalMap = other.mIsNormalMap;
  mHasAlpha    = other.mHasAlpha;

  // deep copy of the mipmaps
  mMipmaps.resize(other.mMipmaps.size());
  for(int i=0; i<(int)mMipmaps.size(); ++i)
  {
    mMipmaps[i] = new Image;
    *mMipmaps[i] = *other.mMipmaps[i];
  }
  return *this;
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsXP() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return pixels();
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsXP()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return pixels();
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsXN() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 1;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsXN()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 1;
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsYP() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 2;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsYP()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 2;
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsYN() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 3;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsYN()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 3;
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsZP() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 4;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsZP()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 4;
}
//-----------------------------------------------------------------------------
const unsigned char* Image::pixelsZN() const
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 5;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsZN()
{
  VL_CHECK( dimension() == 4 )
  if( dimension() != 4 || !pixels())
    return NULL;
  else
    return (unsigned char*)pixels() + requiredMemory2D( width(), height(), byteAlignment(), format(), type() ) * 5;
}
//-----------------------------------------------------------------------------
unsigned char* Image::pixelsZSlice(int slice)
{
  VL_CHECK(slice < depth());
  VL_CHECK(slice >= 0 );
  if (mIsCubemap || !pixels())
    return NULL;
  else
  {
    return (unsigned char*)pixels() + pitch()*height()*slice;
  }
}
//-----------------------------------------------------------------------------
ref<Image> vl::createCubemap(const Image* xp, const Image* xn, const Image* yp, const Image* yn, const Image* zp, const Image* zn)
{
  // check validity of all the images
  // contract:
  // - they must be all isValid() images, must have been allocated, must be 2D images, must
  // - have exactly the same dimensions, format, type, byte alignment.
  // - they must be square

  const Image* img[] = {xp, xn, yp, yn, zp, zn};

  // check they are square (later we check they have the same size)
  if (img[0]->width() != img[0]->height())
  {
    Log::error("Cubemap creation failed: all the images must be square.\n");
    return NULL;
  }

  for(int i=0; i<6; ++i)
  {
    if (img[i] == NULL || !img[i]->isValid() || img[i]->pixels() == NULL || img[i]->dimension() != 2)
    {
      Log::error("Cubemap creation failed: one or more image is invalid (could be NULL, not allocated, not 2D, wrong internal_ configuration or other).\n");
      return NULL;
    }

    // check that they have the same size
    if (img[0]->width() != img[i]->width())
    {
      Log::error("Cubemap creation failed: the faces of the cube must have the very same dimensions.\n");
      return NULL;
    }

    // check that they have the same size
    if (img[0]->height() != img[i]->height())
    {
      Log::error("Cubemap creation failed: the faces of the cube must have the very same dimensions.\n");
      return NULL;
    }

    // check that they have the same format
    if (img[0]->format() != img[i]->format())
    {
      Log::error("Cubemap creation failed: the faces of the cube must have the very same format.\n");
      return NULL;
    }

    // check that they have the same type
    if (img[0]->type() != img[i]->type())
    {
      Log::error("Cubemap creation failed: the faces of the cube must have the very same type.\n");
      return NULL;
    }

    // check that they have the same byte alignment
    if (img[0]->byteAlignment() != img[i]->byteAlignment())
    {
      Log::error("Cubemap creation failed: the faces of the cube must have the very same byte alignment.\n");
      return NULL;
    }

    // check that they have the same required memory
    if (img[0]->requiredMemory() != img[i]->requiredMemory())
    {
      Log::error("Cubemap creation failed: the faces of the cube must require the very same amount of memory.\n");
      return NULL;
    }
  }

  // create a cube map image from the given 2D images

  ref<Image> cubemap = new Image;

  cubemap->allocateCubemap( img[0]->width(), img[0]->height(), img[0]->byteAlignment(), img[0]->format(), img[0]->type() );

  memcpy( cubemap->pixelsXP(), img[0]->pixels(), img[0]->requiredMemory() );
  memcpy( cubemap->pixelsXN(), img[1]->pixels(), img[0]->requiredMemory() );
  memcpy( cubemap->pixelsYP(), img[2]->pixels(), img[0]->requiredMemory() );
  memcpy( cubemap->pixelsYN(), img[3]->pixels(), img[0]->requiredMemory() );
  memcpy( cubemap->pixelsZP(), img[4]->pixels(), img[0]->requiredMemory() );
  memcpy( cubemap->pixelsZN(), img[5]->pixels(), img[0]->requiredMemory() );

  return cubemap.get();
}
//-----------------------------------------------------------------------------
void Image::flipVertically()
{
  if (dimension() == ID_1D)
    return;

  VL_CHECK(pixels());
  int row_size = pitch();
  std::vector<unsigned char> row1;
  row1.resize(row_size);

  std::vector<unsigned char*> pxl;

  if (dimension() == ID_2D)
  {
    pxl.push_back( (unsigned char*)pixels() );
  }
  else
  if (dimension() == ID_Cubemap)
  {
    pxl.push_back( (unsigned char*)pixelsXP() );
    pxl.push_back( (unsigned char*)pixelsXN() );
    pxl.push_back( (unsigned char*)pixelsYP() );
    pxl.push_back( (unsigned char*)pixelsYN() );
    pxl.push_back( (unsigned char*)pixelsZP() );
    pxl.push_back( (unsigned char*)pixelsZN() );
  }
  else
  if (dimension() == ID_3D)
  {
    for(int zslice=0; zslice<depth(); zslice++)
      pxl.push_back( (unsigned char*)pixelsZSlice(zslice) );
  }

  for(unsigned img=0; img<pxl.size(); img++)
  {
    for(int i=0; i<height()/2; ++i)
    {
      int j = height() - 1 - i;
      memcpy(&row1[0], pxl[img]+i*row_size, row_size);
      memcpy(pxl[img]+i*row_size, pxl[img]+j*row_size, row_size);
      memcpy(pxl[img]+j*row_size,  &row1[0], row_size);
    }
  }
}
//-----------------------------------------------------------------------------
int Image::requiredMemory(int width, int height, int depth, int bytealign, EImageFormat format, EImageType type, bool is_cubemap)
{
  // byte align

  switch(bytealign)
  {
  case 1:
  case 2:
  case 4:
  case 8:
    break;
  case 0:
  default:
    bytealign = sizeof(unsigned char*);
  }

  // fix width and height to match compression scheme

  switch(format)
  {
    case IF_COMPRESSED_RGB_S3TC_DXT1:
    case IF_COMPRESSED_RGBA_S3TC_DXT1:
    case IF_COMPRESSED_RGBA_S3TC_DXT3:
    case IF_COMPRESSED_RGBA_S3TC_DXT5:
      if (width % 4)
        width = width - width % 4 + 4;
      if (height % 4)
        height = height - height % 4 + 4;
    default:
      break;
  }

  // pitch

  int xbits = width * bitsPerPixel(type, format);
  int xbytes = xbits/8 + ( (xbits % 8) ? 1 : 0 );
  int pitch  = xbytes/bytealign*bytealign + ( (xbytes % bytealign) ? bytealign : 0 );

  // computation

  height = height ? height : 1;
  depth  = depth  ? depth  : 1;
  int req_mem = pitch * height * depth;

  // minimum memory taken by a compressed block
  if (req_mem < 8 && format == IF_COMPRESSED_RGB_S3TC_DXT1)
    req_mem = 8;

  if (req_mem < 8 && format == IF_COMPRESSED_RGBA_S3TC_DXT1)
    req_mem = 8;

  if (req_mem < 16 && format == IF_COMPRESSED_RGBA_S3TC_DXT3)
    req_mem = 16;

  if (req_mem < 16 && format == IF_COMPRESSED_RGBA_S3TC_DXT5)
    req_mem = 16;

  // todo: add other compression schemes
  // ...

  // cubemap
  if (is_cubemap)
    req_mem *= 6;

  return req_mem;
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const fvec4& c0, const fvec4& c1)
{
  std::vector<fvec4> colors;
  colors.push_back(c0); colors.push_back(c1);
  return makeColorSpectrum(width, colors);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const fvec4& c0, const fvec4& c1, const fvec4& c2)
{
  std::vector<fvec4> colors;
  colors.push_back(c0); colors.push_back(c1); colors.push_back(c2);
  return makeColorSpectrum(width, colors);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const fvec4& c0, const fvec4& c1, const fvec4& c2, const fvec4& c3)
{
  std::vector<fvec4> colors;
  colors.push_back(c0); colors.push_back(c1); colors.push_back(c2); colors.push_back(c3);
  return makeColorSpectrum(width, colors);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const fvec4& c0, const fvec4& c1, const fvec4& c2, const fvec4& c3, const fvec4& c4)
{
  std::vector<fvec4> colors;
  colors.push_back(c0); colors.push_back(c1); colors.push_back(c2); colors.push_back(c3); colors.push_back(c4);
  return makeColorSpectrum(width, colors);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const fvec4& c0, const fvec4& c1, const fvec4& c2, const fvec4& c3, const fvec4& c4, const fvec4& c5)
{
  std::vector<fvec4> colors;
  colors.push_back(c0); colors.push_back(c1); colors.push_back(c2); colors.push_back(c3); colors.push_back(c4); colors.push_back(c5);
  return makeColorSpectrum(width, colors);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeNonUniformColorSpectrum(size_t width, size_t col_count, const fvec4* colors, const float* col_pos)
{
  //     c0    c1    c2    c4
  // |---t0----t1----t2----t4---|
  // before t0 the color is pure c0
  // after t4 the color is pure t4

  ref<Image> img = new Image(width, 0, 0, 1, IF_RGBA, IT_UNSIGNED_BYTE);
  ubvec4* px = (ubvec4*)img->pixels();
  int last = (int)col_count-1;
  for(int i=0; i<img->width(); ++i)
  {
    float t = (float)i/(img->width()-1);
    if (t<=col_pos[0])
      px[i] = (ubvec4)(colors[0]*255.0f);
    else
    if (t>=col_pos[last])
      px[i] = (ubvec4)(colors[last]*255.0f);
    else
    {
      for(size_t j=0; j<col_count-1; ++j)
      {
        if (t>=col_pos[j] && t<=col_pos[j+1])
        {
          float tt = 0;
          if (col_pos[j+1]-col_pos[j] != 0)
            tt = (t-col_pos[j])/(col_pos[j+1]-col_pos[j]);
          VL_CHECK(tt>=0 && tt<=1.0f)
          px[i] = (ubvec4)((colors[j] * (1.0f-tt) + colors[j+1] * tt)*255.0f);
          break;
        }
      }
    }
  }
  return img;
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeNonUniformColorSpectrum(int width, const std::vector<fvec4>& colors, const std::vector<float>& col_pos)
{
  if (colors.empty() || colors.size() != col_pos.size())
    return NULL;
  else
    return makeNonUniformColorSpectrum(width, colors.size(), &colors[0], &col_pos[0]);
}
//-----------------------------------------------------------------------------
ref<Image> vl::makeColorSpectrum(size_t width, const std::vector<fvec4>& colors)
{
  ref<Image> img = new Image(width, 0, 0, 1, IF_RGBA, IT_UNSIGNED_BYTE);
  int index = (int)colors.size() - 1;
  for(int i=0; i<img->width(); ++i)
  {
    int   coli = (int)(index * (float)i/img->width());
    float colt = (index * (float)i/img->width()) - coli;
    img->pixels()[i*4 + 0] = (unsigned char)(255.0 * (colors[coli].r()*(1.0f-colt) + colors[coli+1].r()*colt));
    img->pixels()[i*4 + 1] = (unsigned char)(255.0 * (colors[coli].g()*(1.0f-colt) + colors[coli+1].g()*colt));
    img->pixels()[i*4 + 2] = (unsigned char)(255.0 * (colors[coli].b()*(1.0f-colt) + colors[coli+1].b()*colt));
    img->pixels()[i*4 + 3] = 255;
  }
  return img;
}
//-----------------------------------------------------------------------------
ref<Image> vl::assemble3DImage(const std::vector< ref<Image> >& images)
{
  if (images.empty())
    return NULL;
  // sanity checks
  for(unsigned i=1; i<images.size(); ++i)
  {
    if (images[i]->width()  != images[0]->width())  return NULL;
    if (images[i]->height() != images[0]->height()) return NULL;
    if (images[i]->depth()  != images[0]->depth())  return NULL;
    if (images[i]->type()   != images[0]->type())   return NULL;
    if (images[i]->format() != images[0]->format()) return NULL;
    if (images[i]->byteAlignment()  != images[0]->byteAlignment())  return NULL;
    if (images[i]->bitsPerPixel()   != images[0]->bitsPerPixel())   return NULL;
    if (images[i]->requiredMemory() != images[0]->requiredMemory()) return NULL;
  }

  ref<Image> img = new Image;
  img->allocate3D( images[0]->width(), images[0]->height(), images.size(), 1, images[0]->format(), images[0]->type() );
  VL_CHECK(img->requiredMemory() == images[0]->requiredMemory()*(int)images.size())
  for(unsigned i=0; i<images.size(); ++i)
  {
    VL_CHECK(images[i]->pixels())
    memcpy(img->pixelsZSlice(i), images[i]->pixels(), images[i]->requiredMemory());
  }
  return img;
}
//-----------------------------------------------------------------------------
bool vl::loadImagesFromDir(const String& dir_path, const String& ext, std::vector< ref<Image> >& images)
{
  images.clear();
  if (ext.empty() || dir_path.empty())
    return false;
  ref<VirtualDirectory> dir = defFileSystem()->locateDirectory(dir_path);
  if (!dir)
    return false;
  std::vector<String> files;
  dir->listFiles(files);
  std::sort(files.begin(), files.end());
  for(unsigned i=0; i<files.size(); ++i)
  {
    if (files[i].extractFileExtension().toLowerCase() == ext.toLowerCase())
    {
      images.push_back( loadImage(files[i]) );
      if (images.back().get() == NULL)
        return false;
    }
  }
  return true;
}
//-----------------------------------------------------------------------------
ref<Image> vl::loadImage( const String& path )
{
  ref<VirtualFile> file = defFileSystem()->locateFile(path);
  if ( !file )
  {
    Log::error( Say("File '%s' not found.\n") << path );
    return NULL;
  }
  else
    return loadImage(file.get());
}
//-----------------------------------------------------------------------------
ref<Image> vl::loadImage( VirtualFile* file )
{
  ref<ResourceDatabase> res_db = defLoadWriterManager()->loadResource(file);

  if (!res_db)
  {
    Log::error( Say("vl::loadImage('%s') failed.\n") << file->path() );
    return NULL;
  }

  ref<Image> img;

  img = res_db->get<Image>(0);

  VL_CHECK( !file->isOpen() )
  file->close();

  if (img)
  {
    img->setObjectName( file->path().toStdString().c_str() );
    img->setFilePath( file->path() );
  }

  return img;
}
//-----------------------------------------------------------------------------
bool vl::saveImage( Image* img, const String& path)
{
  ref<ResourceDatabase> res_db = new ResourceDatabase;
  res_db->resources().push_back(img);
  bool ok = defLoadWriterManager()->writeResource(path, res_db.get());
  if (!ok)
    Log::error( Say("vl::saveImage('%s') failed.\n") << path );
  return ok;
}
//-----------------------------------------------------------------------------
bool vl::saveImage( Image* img, VirtualFile* file )
{
  ref<ResourceDatabase> res_db = new ResourceDatabase;
  res_db->resources().push_back(img);
  bool ok = defLoadWriterManager()->writeResource(file, res_db.get());
  if (!ok)
    Log::error( Say("vl::saveImage('%s') failed.\n") << file->path() );
  return ok;
}
//-----------------------------------------------------------------------------
ref<Image> vl::loadCubemap(const String& xp_file, const String& xn_file, const String& yp_file, const String& yn_file, const String& zp_file, const String& zn_file)
{
  ref<Image> xp = loadImage(xp_file);
  ref<Image> xn = loadImage(xn_file);
  ref<Image> yp = loadImage(yp_file);
  ref<Image> yn = loadImage(yn_file);
  ref<Image> zp = loadImage(zp_file);
  ref<Image> zn = loadImage(zn_file);

  if (!xp || !xn || !yp || !yn || !zp || !zn)
  {
    Log::error("vl::loadCubemap() failed.\n");
    return NULL;
  }

  ref<Image> img = vl::createCubemap(xp.get(), xn.get(), yp.get(), yn.get(), zp.get(), zn.get());

  return img;
}
//-----------------------------------------------------------------------------
ref<Image> vl::loadRAW(VirtualFile* file, long long file_offset, int width, int height, int depth, int bytealign, EImageFormat format, EImageType type)
{
  ref<Image> img = new Image(width, height, depth, bytealign, format, type);
  if ( file->isOpen() || file->open(OM_ReadOnly) )
  {
    bool ok = file_offset == -1 || file->seekSet(file_offset);
    if (!ok)
    {
      Log::error( Say("loadRAW('%s'): seek set to position %n failed.\n") << file_offset );
      return NULL;
    }
    int count = (int)file->read( img->pixels(), img->requiredMemory() );
    if (count != img->requiredMemory())
      Log::error( Say("loadRAW('%s'): error reading RAW file.\n") << file->path() );
    return img;
  }
  else
  {
    Log::error( Say("loadRAW('%s'): could not open file for reading.\n") << file->path() );
    return NULL;
  }
}
//-----------------------------------------------------------------------------
ref<Image> vl::Image::convertType(EImageType new_type) const
{
  switch(type())
  {
    case IT_UNSIGNED_BYTE:
    case IT_BYTE:
    case IT_UNSIGNED_SHORT:
    case IT_SHORT:
    case IT_UNSIGNED_INT:
    case IT_INT:
    case IT_FLOAT:
      break;
    default:
      Log::error("Image::convertType(): unsupported source image type.\n");
      return NULL;
  }

  switch(new_type)
  {
    case IT_UNSIGNED_BYTE:
    case IT_BYTE:
    case IT_UNSIGNED_SHORT:
    case IT_SHORT:
    case IT_UNSIGNED_INT:
    case IT_INT:
    case IT_FLOAT:
      break;
    default:
      Log::error("Image::convertType(): unsupported destination image type.\n");
      return NULL;
  }

  switch(format())
  {
    case IF_RGB:
    case IF_RGBA:
    case IF_BGR:
    case IF_BGRA:
    case IF_RED:
    case IF_GREEN:
    case IF_BLUE:
    case IF_ALPHA:
    case IF_LUMINANCE:
    case IF_LUMINANCE_ALPHA:
    case IF_DEPTH_COMPONENT:
      break;
    default:
      Log::error("Image::convertType(): unsupported image format.\n");
      return NULL;
  }

  ref<Image> img = new Image;
  img->setObjectName( objectName().c_str() );
  img->setFormat(format());
  img->setType(new_type);
  img->setWidth(width());
  img->setHeight(height());
  img->setDepth(depth());
  img->setByteAlignment(1);
  img->mIsCubemap = isCubemap();
  img->mIsNormalMap = mIsNormalMap;
  img->mHasAlpha    = mHasAlpha;
  img->allocate();

  int components = 0;
  switch(format())
  {
    case IF_RGB:   components = 3; break;
    case IF_RGBA:  components = 4; break;
    case IF_BGR:   components = 3; break;
    case IF_BGRA:  components = 4; break;
    case IF_RED:   components = 1; break;
    case IF_GREEN: components = 1; break;
    case IF_BLUE:  components = 1; break;
    case IF_ALPHA: components = 1; break;
    case IF_LUMINANCE:       components = 1; break;
    case IF_LUMINANCE_ALPHA: components = 2; break;
    case IF_DEPTH_COMPONENT: components = 1; break;
    default:
      break;
  }

  int line_count = img->height()?img->height():1;
  if (img->depth())
    line_count *= img->depth();
  else
  if (img->isCubemap())
    line_count *= 6;

  for(int i=0; i<line_count; ++i)
  {
    const void* srcLine = pixels()      + pitch()*i;
    void* dstLine = img->pixels() + img->pitch()*i;

    const unsigned char* srcUByte  = (const unsigned char*)srcLine;
    const GLbyte*        srcSByte  = (const GLbyte*)srcLine;
    const GLushort*      srcUShort = (const GLushort*)srcLine;
    const GLshort*       srcSShort = (const GLshort*)srcLine;
    const unsigned int*  srcUInt   = (const unsigned int*)srcLine;
    const int*           srcSInt   = (const int*)srcLine;
    const float*         srcFloat  = (const float*)srcLine;

    unsigned char* dstUByte  = (unsigned char*)dstLine;
    GLbyte*        dstSByte  = (GLbyte*)dstLine;
    GLushort*      dstUShort = (GLushort*)dstLine;
    GLshort*       dstSShort = (GLshort*)dstLine;
    unsigned int*  dstUInt   = (unsigned int*)dstLine;
    int*           dstSInt   = (int*)dstLine;
    float*         dstFloat  = (float*)dstLine;

    for(int j=0; j<img->width(); ++j)
    {
      for(int c=0; c<components; ++c)
      {
        double dval = 0;
        long long qint = 0;

        // convert dst format to double

        switch(type())
        {
          case IT_UNSIGNED_BYTE:  qint = *srcUByte;  dval = qint/255.0; ++srcUByte; break;
          case IT_BYTE:           qint = *srcSByte;  dval = qint/127.0; ++srcSByte; break;
          case IT_UNSIGNED_SHORT: qint = *srcUShort; dval = qint/65535.0; ++srcUShort; break;
          case IT_SHORT:          qint = *srcSShort; dval = qint/32767.0; ++srcSShort; break;
          case IT_UNSIGNED_INT:   qint = *srcUInt;   dval = qint/4294967295.0; ++srcUInt; break;
          case IT_INT:            qint = *srcSInt;   dval = qint/2147483647.0; ++srcSInt; break;
          case IT_FLOAT:          dval = *srcFloat;  ++srcFloat; break;
          default:
            return NULL;
        }

        // clamp 0.0 >= dval >= 1.0
        dval = dval < 0.0 ? 0.0 :
               dval > 1.0 ? 1.0 :
               dval;

        // convert double to dst format

        switch(img->type())
        {
          case IT_UNSIGNED_BYTE:  *dstUByte  = (unsigned char) (dval*255.0); ++dstUByte; break;
          case IT_BYTE:           *dstSByte  = (GLbyte)  (dval*127.0); ++dstSByte; break;
          case IT_UNSIGNED_SHORT: *dstUShort = (GLushort)(dval*65535.0); ++dstUShort; break;
          case IT_SHORT:          *dstSShort = (GLshort) (dval*32767.0); ++dstSShort; break;
          case IT_UNSIGNED_INT:   *dstUInt   = (unsigned int)  (dval*4294967295.0); ++dstUInt; break;
          case IT_INT:            *dstSInt   = (int)   (dval*2147483647.0); ++dstSInt; break;
          case IT_FLOAT:          *dstFloat  = (float)dval; ++dstFloat; break;
          default:
            return NULL;
        }
      }
    }
  }

  return img;
}
//-----------------------------------------------------------------------------
namespace {
  template<typename T>
  void equalizeTemplate(void* ptr, int pitch, int comps, int w, int h, T max_val)
  {
    // find min/max
    T vmin = *((T*)ptr);
    T vmax = *((T*)ptr);
    for(int y=0; y<h; ++y)
    {
      T* px = (T*)((char*)ptr + pitch*y);
      for(int x=0; x<w; ++x)
      {
        for(int i=0; i<comps; ++i)
        {
          if (vmin > px[x*comps+i]) vmin = px[x*comps+i];
          if (vmax < px[x*comps+i]) vmax = px[x*comps+i];
        }
      }
    }
    // equalize
    T range = vmax-vmin;
    for(int y=0; y<h; ++y)
    {
      T* px = (T*)((char*)ptr + pitch*y);
      for(int x=0; x<w; ++x)
      {
        for(int i=0; i<comps; ++i)
          px[x*comps+i] = (T)(((float)px[x*comps+i]-vmin)/range*max_val);
      }
    }
  }
}
bool Image::equalize()
{
  int comps = 0;
  switch(format())
  {
    case IF_RGB:   comps = 3; break;
    case IF_RGBA:  comps = 4; break;
    case IF_BGR:   comps = 3; break;
    case IF_BGRA:  comps = 4; break;
    case IF_RED:   comps = 1; break;
    case IF_GREEN: comps = 1; break;
    case IF_BLUE:  comps = 1; break;
    case IF_ALPHA: comps = 1; break;
    case IF_LUMINANCE: comps = 1; break;
    case IF_LUMINANCE_ALPHA: comps = 2; break;
    case IF_DEPTH_COMPONENT: comps = 1; break;
    default:
      Log::error("Image::equalize(): unsupported image format().\n");
      return false;
  }
  int w = width();
  int h = height()?height():1;
  int d = depth()?depth():1;
  if (isCubemap())
    h=h*6;
  else
    h=h*d;

  switch(type())
  {
    case IT_UNSIGNED_BYTE:  equalizeTemplate<unsigned char> (pixels(), pitch(), comps, w, h, 0xFF);      break;
    case IT_UNSIGNED_SHORT: equalizeTemplate<unsigned short>(pixels(), pitch(), comps, w, h, 0xFFFF);     break;
    case IT_UNSIGNED_INT:   equalizeTemplate<unsigned int>  (pixels(), pitch(), comps, w, h, 0xFFFFFFFF); break;
    case IT_FLOAT:          equalizeTemplate<float>         (pixels(), pitch(), comps, w, h, 1.0f);       break;
      break;
    default:
      Log::error("Image::equalize(): unsupported image type(). Types supported are IT_UNSIGNED_BYTE, IT_UNSIGNED_SHORT, IT_UNSIGNED_INT, IT_FLOAT.\n");
      return false;
  }
  return true;
}
//-----------------------------------------------------------------------------
bool Image::contrastHounsfieldAuto()
{
  if ( !tags()->has("WindowCenter") || !tags()->has("WindowWidth") || !tags()->has("BitsStored") || !tags()->has("RescaleIntercept"))
    return false;

  float center    = tags()->value("WindowCenter").toFloat();
  float width     = tags()->value("WindowWidth").toFloat();
  float range     = (1<<tags()->value("BitsStored").toInt()) - 1.0f;
  float intercept = tags()->value("RescaleIntercept").toFloat();
  float slope     = tags()->value("RescaleSlope").toFloat();

  // Hounsfield units: -1000 = air, +1000 = solid bone
  // Transform from Hounsfield units to normalized 0..1 units
  center = (center-intercept) / range / slope;
  width  = width / range / slope;
  return contrast( center-width/2.0f, center+width/2.0f );
}
//-----------------------------------------------------------------------------
bool Image::contrastHounsfield(float center, float width, float intercept, float range)
{
  // Hounsfield units: -1000 = air, +1000 = solid bone
  // Transform from Hounsfield units to normalized 0..1 units
  center = (center-intercept) / range;
  width  = width / range;
  return contrast( center-width/2.0f, center+width/2.0f );
}
//-----------------------------------------------------------------------------
namespace {
  template<typename T>
  void contrastTemplate(void* ptr, int pitch, int w, int h, T max_val, float black, float white)
  {
    float range = white-black;
    for(int y=0; y<h; ++y)
    {
      T* px = (T*)((char*)ptr + pitch*y);
      for(int x=0; x<w; ++x)
      {
        float t = (float)px[x]/max_val; // 0..1
        t = (t-black)/range;
        t = vl::clamp(t, 0.0f, 1.0f);
        px[x] = (T)(t*max_val);
      }
    }
  }
}
bool Image::contrast(float black, float white)
{
  switch(format())
  {
    case IF_RED:
    case IF_GREEN:
    case IF_BLUE:
    case IF_ALPHA:
    case IF_LUMINANCE:
    case IF_DEPTH_COMPONENT:
      break;
    default:
      Log::error("Image::equalize(): unsupported image format().\n");
      return false;
  }
  int w = width();
  int h = height()?height():1;
  int d = depth()?depth():1;
  if (isCubemap())
    h=h*6;
  else
    h=h*d;

  switch(type())
  {
    case IT_UNSIGNED_BYTE:  contrastTemplate<unsigned char> (pixels(), pitch(), w, h, 0xFF, black, white);       break;
    case IT_UNSIGNED_SHORT: contrastTemplate<unsigned short>(pixels(), pitch(), w, h, 0xFFFF, black, white);     break;
    case IT_UNSIGNED_INT:   contrastTemplate<unsigned int>  (pixels(), pitch(), w, h, 0xFFFFFFFF, black, white); break;
    case IT_FLOAT:          contrastTemplate<float>         (pixels(), pitch(), w, h, 1.0f, black, white);       break;
      break;
    default:
      Log::error("Image::equalize(): unsupported image type(). Types supported are IT_UNSIGNED_BYTE, IT_UNSIGNED_SHORT, IT_UNSIGNED_INT, IT_FLOAT.\n");
      return false;
  }
  return true;
}
//-----------------------------------------------------------------------------
namespace
{
  class rgbal
  {
  public:
    rgbal(): r(-1), g(-1), b(-1), a(-1), l(-1) {}
    int r,g,b,a,l;
  };

  template<typename T>
  void convert(const T*src_px, T*dst_px, T max_value, const rgbal& srco, const rgbal& dsto)
  {
    // set dst default values first
    if (dsto.r != -1)
      dst_px[dsto.r] = 0;
    if (dsto.g != -1)
      dst_px[dsto.g] = 0;
    if (dsto.b != -1)
      dst_px[dsto.b] = 0;
    if (dsto.a != -1)
      dst_px[dsto.a] = max_value;
    if (dsto.l != -1)
      dst_px[dsto.l] = 0;

    // try copy src -> dst
    if (dsto.r != -1 && srco.r != -1 )
      dst_px[dsto.r] = src_px[srco.r];
    if (dsto.g != -1 && srco.g != -1)
      dst_px[dsto.g] = src_px[srco.g];
    if (dsto.b != -1 && srco.b != -1)
      dst_px[dsto.b] = src_px[srco.b];
    if (dsto.a != -1 && srco.a != -1)
      dst_px[dsto.a] = src_px[srco.a];
    if (dsto.l != -1 && srco.l != -1)
      dst_px[dsto.l] = src_px[srco.l];

    // try rgb -> gray conversion
    if (dsto.l != -1 && srco.r != -1 && srco.g != -1 && srco.b != -1)
    {
      dvec3 col(src_px[srco.r], src_px[srco.g], src_px[srco.b]);
      double gray = dot(col / dvec3(max_value,max_value,max_value), dvec3(0.299,0.587,0.114));
      dst_px[dsto.l] = T(gray * max_value);
    }
    else
    // try r -> gray conversion
    if (dsto.l != -1 && srco.r != -1 && srco.g == -1 && srco.b == -1)
      dst_px[dsto.l] = src_px[srco.r];
    else
    // try g -> gray conversion
    if (dsto.l != -1 && srco.r == -1 && srco.g != -1 && srco.b == -1)
      dst_px[dsto.l] = src_px[srco.g];
    else
    // try b -> gray conversion
    if (dsto.l != -1 && srco.r == -1 && srco.g == -1 && srco.b != -1)
      dst_px[dsto.l] = src_px[srco.b];
    else
    // try gray -> r,g,b
    if (srco.l != -1)
    {
      if (dsto.r != -1)
        dst_px[dsto.r] = src_px[srco.l];
      if (dsto.g != -1)
        dst_px[dsto.g] = src_px[srco.l];
      if (dsto.b != -1)
        dst_px[dsto.b] = src_px[srco.l];
    }
  }
}
ref<Image> vl::Image::convertFormat(EImageFormat new_format) const
{
  switch(type())
  {
    case IT_UNSIGNED_BYTE:
    case IT_BYTE:
    case IT_UNSIGNED_SHORT:
    case IT_SHORT:
    case IT_UNSIGNED_INT:
    case IT_INT:
    case IT_FLOAT:
      break;
    default:
      Log::error("Image::convertType(): unsupported image type.\n");
      return NULL;
  }

  switch(format())
  {
    case IF_RGB:
    case IF_RGBA:
    case IF_BGR:
    case IF_BGRA:
    case IF_RED:
    case IF_GREEN:
    case IF_BLUE:
    case IF_ALPHA:
    case IF_LUMINANCE:
    case IF_LUMINANCE_ALPHA:
      break;
    default:
      Log::error("Image::convertType(): unsupported source image format.\n");
      return NULL;
  }

  switch(new_format)
  {
    case IF_RGB:
    case IF_RGBA:
    case IF_BGR:
    case IF_BGRA:
    case IF_RED:
    case IF_GREEN:
    case IF_BLUE:
    case IF_ALPHA:
    case IF_LUMINANCE:
    case IF_LUMINANCE_ALPHA:
      break;
    default:
      Log::error("Image::convertType(): unsupported destination image format.\n");
      return NULL;
  }

  ref<Image> img = new Image;
  img->setObjectName( objectName().c_str() );
  img->setFormat(new_format);
  img->setType(type());
  img->setWidth(width());
  img->setHeight(height());
  img->setDepth(depth());
  img->setByteAlignment(1);
  img->mIsCubemap = isCubemap();
  img->mIsNormalMap = mIsNormalMap;
  img->mHasAlpha    = mHasAlpha;
  img->allocate();

  rgbal srco; // = {-1,-1,-1,-1,-1},
  rgbal dsto; // = {-1,-1,-1,-1,-1};

  // compute src and dst color component offsets

  switch(format())
  {
    case IF_RGB:             srco.r = 0; srco.g = 1; srco.b = 2; break;
    case IF_RGBA:            srco.r = 0; srco.g = 1; srco.b = 2; srco.a = 3; break;
    case IF_BGR:             srco.r = 2; srco.g = 1; srco.b = 0; break;
    case IF_BGRA:            srco.r = 2; srco.g = 1; srco.b = 0; srco.a = 3; break;
    case IF_RED:             srco.r = 0; break;
    case IF_GREEN:           srco.g = 0; break;
    case IF_BLUE:            srco.b = 0; break;
    case IF_ALPHA:           srco.a = 0; break;
    case IF_LUMINANCE:       srco.l = 0; break;
    case IF_LUMINANCE_ALPHA: srco.l = 0; srco.a = 1; break;
    default:
      return NULL;
  }

  switch(new_format)
  {
    case IF_RGB:             dsto.r = 0; dsto.g = 1; dsto.b = 2; break;
    case IF_RGBA:            dsto.r = 0; dsto.g = 1; dsto.b = 2; dsto.a = 3; break;
    case IF_BGR:             dsto.r = 2; dsto.g = 1; dsto.b = 0; break;
    case IF_BGRA:            dsto.r = 2; dsto.g = 1; dsto.b = 0; dsto.a = 3; break;
    case IF_RED:             dsto.r = 0; break;
    case IF_GREEN:           dsto.g = 0; break;
    case IF_BLUE:            dsto.b = 0; break;
    case IF_ALPHA:           dsto.a = 0; break;
    case IF_LUMINANCE:       dsto.l = 0; break;
    case IF_LUMINANCE_ALPHA: dsto.l = 0; dsto.a = 1; break;
    default:
      return NULL;
  }

  int src_comp = 0;
  switch(format())
  {
    case IF_RGB:   src_comp = 3; break;
    case IF_RGBA:  src_comp = 4; break;
    case IF_BGR:   src_comp = 3; break;
    case IF_BGRA:  src_comp = 4; break;
    case IF_RED:   src_comp = 1; break;
    case IF_GREEN: src_comp = 1; break;
    case IF_BLUE:  src_comp = 1; break;
    case IF_ALPHA: src_comp = 1; break;
    case IF_LUMINANCE:       src_comp = 1; break;
    case IF_LUMINANCE_ALPHA: src_comp = 2; break;
    default:
      break;
  }

  int dst_comp = 0;
  switch(new_format)
  {
    case IF_RGB:   dst_comp = 3; break;
    case IF_RGBA:  dst_comp = 4; break;
    case IF_BGR:   dst_comp = 3; break;
    case IF_BGRA:  dst_comp = 4; break;
    case IF_RED:   dst_comp = 1; break;
    case IF_GREEN: dst_comp = 1; break;
    case IF_BLUE:  dst_comp = 1; break;
    case IF_ALPHA: dst_comp = 1; break;
    case IF_LUMINANCE:       dst_comp = 1; break;
    case IF_LUMINANCE_ALPHA: dst_comp = 2; break;
    case IF_DEPTH_COMPONENT: dst_comp = 1; break;
    default:
      break;
  }

  int line_count = img->height()?img->height():1;
  if (img->depth())
    line_count *= img->depth();
  else
  if (img->isCubemap())
    line_count *= 6;

  for(int i=0; i<line_count; ++i)
  {
    const void* srcLine = pixels()      + pitch()*i;
    void* dstLine = img->pixels() + img->pitch()*i;

    const unsigned char* srcUByte  = (const unsigned char*)srcLine;
    const GLbyte*        srcSByte  = (const GLbyte*)srcLine;
    const GLushort*      srcUShort = (const GLushort*)srcLine;
    const GLshort*       srcSShort = (const GLshort*)srcLine;
    const unsigned int*  srcUInt   = (const unsigned int*)srcLine;
    const int*           srcSInt   = (const int*)srcLine;
    const float*         srcFloat  = (const float*)srcLine;

    unsigned char* dstUByte  = (unsigned char*)dstLine;
    GLbyte*        dstSByte  = (GLbyte*)dstLine;
    GLushort*      dstUShort = (GLushort*)dstLine;
    GLshort*       dstSShort = (GLshort*)dstLine;
    unsigned int*  dstUInt   = (unsigned int*)dstLine;
    int*           dstSInt   = (int*)dstLine;
    float*         dstFloat  = (float*)dstLine;

    for(int j=0; j<img->width(); ++j)
    {
      switch(type())
      {
        case IT_UNSIGNED_BYTE:  convert<unsigned char> (srcUByte,  dstUByte,  255,         srco, dsto); srcUByte+=src_comp;  dstUByte+=dst_comp;  break;
        case IT_BYTE:           convert<GLbyte>        (srcSByte,  dstSByte,  127,         srco, dsto); srcSByte+=src_comp;  dstSByte+=dst_comp;  break;
        case IT_UNSIGNED_SHORT: convert<GLushort>      (srcUShort, dstUShort, 65535,       srco, dsto); srcUShort+=src_comp; dstUShort+=dst_comp; break;
        case IT_SHORT:          convert<GLshort>       (srcSShort, dstSShort, 32767,       srco, dsto); srcSShort+=src_comp; dstSShort+=dst_comp; break;
        case IT_UNSIGNED_INT:   convert<unsigned int>  (srcUInt,   dstUInt,   4294967295U, srco, dsto); srcUInt+=src_comp;   dstUInt+=dst_comp;   break;
        case IT_INT:            convert<int>           (srcSInt,   dstSInt,   2147483647,  srco, dsto); srcSInt+=src_comp;   dstSInt+=dst_comp;   break;
        case IT_FLOAT:          convert<float>         (srcFloat,  dstFloat,  1.0f,        srco, dsto); srcFloat+=src_comp;  dstFloat+=dst_comp;  break;
        default:
          return NULL;
      }
    }
  }

  return img;
}
//-----------------------------------------------------------------------------
fvec4 Image::sampleLinear(double x) const
{
  if (x < 0)
    x = 0;
  if (x >= width()-1)
    x = (width()-1) - 0.000001;

  int ix1 = (int)x;
  int ix2 = ix1+1;

  VL_CHECK(ix2<(int)width())

  float w21 = (float)vl::fract(x);
  float w11 = 1.0f - w21;

  fvec4 c11 = sample(ix1);
  fvec4 c21 = sample(ix2);

  return c11*w11 + c21*w21;
}
//-----------------------------------------------------------------------------
fvec4 Image::sampleLinear(double x, double y) const
{
  int h = height()?height():1;
  if (x < 0)
    x = 0;
  if (y < 0)
    y = 0;
  if (x >= width()-1)
    x = (width()-1)  - 0.000001;
  if (y >= h-1)
    y = (h-1) - 0.000001;

  int ix1 = (int)x;
  int iy1 = (int)y;
  int ix2 = ix1+1;
  int iy2 = iy1+1;

  VL_CHECK(ix2<(int)width())
  VL_CHECK(iy2<(int)height())

  double tx  = vl::fract(x);
  double ty  = vl::fract(y);
  double tx1 = 1.0f - vl::fract(x);
  double ty1 = 1.0f - vl::fract(y);

  float w11 = float(tx1*ty1);
  float w12 = float(tx1*ty);
  float w22 = float(tx *ty);
  float w21 = float(tx *ty1);

  fvec4 c11 = sample(ix1, iy1);
  fvec4 c12 = sample(ix1, iy2);
  fvec4 c22 = sample(ix2, iy2);
  fvec4 c21 = sample(ix2, iy1);

  return c11*w11 + c12*w12 + c22*w22 + c21*w21;
}
//-----------------------------------------------------------------------------
fvec4 Image::sampleLinear(double x, double y, double z) const
{
  if (x>width() -1.000001) x = width() -1.000001;
  if (y>height()-1.000001) y = height()-1.000001;
  if (z>depth() -1.000001) z = depth() -1.000001;
  if (x<0) x=0;
  if (y<0) y=0;
  if (z<0) z=0;
  int ix = int(x);
  float xt = float(x - ix);
  int iy = int(y);
  float yt = float(y - iy);
  int iz = int(z);
  float zt = float(z - iz);
  fvec4 val0 = sample(ix  , iy,   iz);
  fvec4 val1 = sample(ix+1, iy,   iz);
  fvec4 val2 = sample(ix+1, iy+1, iz);
  fvec4 val3 = sample(ix,   iy+1, iz);
  fvec4 val4 = sample(ix  , iy,   iz+1);
  fvec4 val5 = sample(ix+1, iy,   iz+1);
  fvec4 val6 = sample(ix+1, iy+1, iz+1);
  fvec4 val7 = sample(ix,   iy+1, iz+1);
  float xt1 = 1-xt;
  float yt1 = 1-yt;
  float zt1 = 1-zt;
  fvec4 v1 = val0*(yt1) + val3*yt;
  fvec4 v2 = val1*(yt1) + val2*yt;
  fvec4 a = v1*(xt1) + v2*xt;
  v1 = val4*(yt1) + val7*yt;
  v2 = val5*(yt1) + val6*yt;
  fvec4 b = v1*(xt1) + v2*xt;
  return a*(zt1) + b*zt;
}
//-----------------------------------------------------------------------------
fvec4 Image::sample(int x, int y, int z) const
{
  VL_CHECK(x<width())
  VL_CHECK(!y || y<height())
  VL_CHECK(!z || z<depth())

  // find the start of the line
  int h = height()?height():1;
  const unsigned char* px = pixels() + y*pitch() + h*pitch()*z;

  int comp = 0;
  switch(format())
  {
    case IF_RGB:   comp = 3; break;
    case IF_RGBA:  comp = 4; break;
    case IF_BGR:   comp = 3; break;
    case IF_BGRA:  comp = 4; break;
    case IF_RED:   comp = 1; break;
    case IF_GREEN: comp = 1; break;
    case IF_BLUE:  comp = 1; break;
    case IF_ALPHA: comp = 1; break;
    case IF_LUMINANCE:       comp = 1; break;
    case IF_LUMINANCE_ALPHA: comp = 2; break;
    case IF_DEPTH_COMPONENT: comp = 1; break;
    default:
      break;
  }

  switch(type())
  {
    case IT_UNSIGNED_BYTE:  px += x*comp*1; break;
    case IT_BYTE:           px += x*comp*1; break;
    case IT_UNSIGNED_SHORT: px += x*comp*2; break;
    case IT_SHORT:          px += x*comp*2; break;
    case IT_UNSIGNED_INT:   px += x*comp*4; break;
    case IT_INT:            px += x*comp*4; break;
    case IT_FLOAT:          px += x*comp*4; break;
    default:
      break;
  }

  // convert component by component

  fvec4 pixel(0,0,0,0);

  for(int i=0; i<comp; ++i)
  {
    double value = 0;

    switch(type())
    {
      case IT_UNSIGNED_BYTE:  value = (double)((unsigned char*)px)[i]; value/=255.0; break;
      case IT_BYTE:           value = (double)((char*)px)[i]; value/=127.0; break;
      case IT_UNSIGNED_SHORT: value = (double)((unsigned short*)px)[i]; value/=65535.0; break;
      case IT_SHORT:          value = (double)((short*)px)[i]; value/=32767.0; break;
      case IT_UNSIGNED_INT:   value = (double)((unsigned int*)px)[i]; value/=4294967295.0; break;
      case IT_INT:            value = (double)((int*)px)[i]; value/=2147483647.0; break;
      case IT_FLOAT:          value = (double)((float*)px)[i]; break;
      default:
        break;
    }

    pixel[i] = (float)value;
  }

  fvec4 p(0,0,0,0);

  // arrange values based on the format
  switch(format())
  {
    case IF_RGB:   p = pixel; break;
    case IF_RGBA:  p = pixel; break;
    case IF_BGR:   p = pixel; p.r() = pixel.b(); p.b() = pixel.r(); break;
    case IF_BGRA:  p = pixel; p.r() = pixel.b(); p.b() = pixel.r(); break;
    case IF_RED:   p = fvec4(pixel[0], 0, 0, 0); break;
    case IF_GREEN: p = fvec4(0, pixel[0], 0, 0); break;
    case IF_BLUE:  p = fvec4(0, 0, pixel[0], 0); break;
    case IF_ALPHA: p = fvec4(0, 0, 0, pixel[0]); break;
    case IF_LUMINANCE:       p = fvec4(pixel[0], pixel[0], pixel[0], 0); break;
    case IF_LUMINANCE_ALPHA: p = fvec4(pixel[0], pixel[0], pixel[0], pixel[1]); break;
    case IF_DEPTH_COMPONENT: p = fvec4(pixel[0], 0, 0, 0); break;
    default:
      break;
  }

  return p;
}
//-----------------------------------------------------------------------------
ref<Image> Image::subImage(int xstart, int ystart, int width, int height)
{
  VL_CHECK(xstart+width  <= this->width())
  VL_CHECK(ystart+height <= this->height())

  ref<Image> img = new Image;
  img->allocate2D(width, height, 1, format(), type());
  // copy line by line
  for(int i=0; i<height; ++i)
  {
    unsigned char* dst = img->pixels() + img->pitch()*i;
    unsigned char* src = pixels() + pitch()*(i+ystart) + xstart*bitsPerPixel()/8;
    memcpy(dst, src, width*bitsPerPixel()/8);
  }
  return img;
}
//-----------------------------------------------------------------------------
void Image::copySubImage(Image* img_src, RectI src, ivec2 dst)
{
  ref<Image> img = img_src;
  if (img->type() != this->type())
    img = img->convertType(this->type());
  if (img->format() != this->format())
    img = img->convertFormat(this->format());
  // tests
  VL_CHECK(dst.x()>=0)
  VL_CHECK(dst.y()>=0)
  VL_CHECK(dst.x() + src.width()  <= this->width() )
  VL_CHECK(dst.y() + src.height() <= this->height())
  VL_CHECK(src.x()>=0)
  VL_CHECK(src.y()>=0)
  VL_CHECK(src.right() < img->width() )
  VL_CHECK(src.top()   < img->height())
  for(int i=0; i<src.height(); ++i)
  {
    int ysrc = i+src.y();
    int ydst = i+dst.y();
    unsigned char* psrc = img->pixels() + img->pitch()*ysrc + (src.x()*img->bitsPerPixel()/8);
    unsigned char* pdst = this->pixels() + this->pitch()*ydst + (dst.x()*this->bitsPerPixel()/8);
    memcpy(pdst, psrc, src.width()*this->bitsPerPixel()/8);
  }
}
//-----------------------------------------------------------------------------
void Image::substituteColorRGB_RGBA(unsigned int before, unsigned int after)
{
  if (type() != IT_UNSIGNED_BYTE)
  {
    Log::error("Image::substituteColorRGB_RGBA(): this function can be called only on images whose type() is IT_UNSIGNED_BYTE\n");
    return;
  }
  if (format() != IF_RGBA && format() != IF_RGB)
  {
    Log::error("Image::substituteColorRGB_RGBA(): this function can be called only on images whose format() is either IF_RGBA or IF_RGB\n");
    return;
  }
  unsigned char bef[3];
  unsigned char aft[4];
  bef[0] = (unsigned char)((before >> 16) & 0xFF);
  bef[1] = (unsigned char)((before >>  8) & 0xFF);
  bef[2] = (unsigned char)((before >>  0) & 0xFF);

  aft[0] = (unsigned char)((after  >> 24) & 0xFF);
  aft[1] = (unsigned char)((after  >> 16) & 0xFF);
  aft[2] = (unsigned char)((after  >>  8) & 0xFF);
  aft[3] = (unsigned char)((after  >>  0) & 0xFF);

  int comps = format() == IF_RGBA ? 4 : 3;
  int d = depth() ? depth() : 1;
  for(int y=0; y<height()*d; ++y)
  {
    for(int x=0; x<width(); ++x)
    {
      unsigned char* px = pixels() + pitch()*y + x*comps;
      if (px[0] == bef[0] && px[1] == bef[1] && px[2] == bef[2])
      {
        px[0] = aft[0];
        px[1] = aft[1];
        px[2] = aft[2];
        if (comps == 4)
          px[3] = aft[3];
      }
    }
  }
}
//-----------------------------------------------------------------------------
void Image::substituteColorRGB_RGB(unsigned int before, unsigned int after)
{
  if (type() != IT_UNSIGNED_BYTE)
  {
    Log::error("Image::substituteColorRGB_RGB(): this function can be called only on images whose type() is IT_UNSIGNED_BYTE\n");
    return;
  }
  if (format() != IF_RGBA && format() != IF_RGB)
  {
    Log::error("Image::substituteColorRGB_RGB(): this function can be called only on images whose format() is either IF_RGBA or IF_RGB\n");
    return;
  }
  unsigned char bef[3];
  unsigned char aft[3];
  bef[0] = (unsigned char)((before >> 16) & 0xFF);
  bef[1] = (unsigned char)((before >>  8) & 0xFF);
  bef[2] = (unsigned char)((before >>  0) & 0xFF);

  aft[0] = (unsigned char)((after  >> 24) & 0xFF);
  aft[1] = (unsigned char)((after  >> 16) & 0xFF);
  aft[2] = (unsigned char)((after  >>  8) & 0xFF);

  int comps = format() == IF_RGBA ? 4 : 3;
  int d = depth() ? depth() : 1;
  for(int y=0; y<height()*d; ++y)
  {
    for(int x=0; x<width(); ++x)
    {
      unsigned char* px = pixels() + pitch()*y + x*comps;
      if (px[0] == bef[0] && px[1] == bef[1] && px[2] == bef[2])
      {
        px[0] = aft[0];
        px[1] = aft[1];
        px[2] = aft[2];
      }
    }
  }
}
//-----------------------------------------------------------------------------
void Image::substituteColorGreenKey(unsigned int col0, unsigned int col1)
{
  if (type() != IT_UNSIGNED_BYTE)
  {
    Log::error("Image::substituteColorRGB_RGB(): this function can be called only on images whose type() is IT_UNSIGNED_BYTE\n");
    return;
  }
  if (format() != IF_RGBA && format() != IF_RGB)
  {
    Log::error("Image::substituteColorRGB_RGB(): this function can be called only on images whose format() is either IF_RGBA or IF_RGB\n");
    return;
  }
  unsigned char c0[3];
  unsigned char c1[3];
  c0[0] = (unsigned char)((col0 >> 16) & 0xFF);
  c0[1] = (unsigned char)((col0 >>  8) & 0xFF);
  c0[2] = (unsigned char)((col0 >>  0) & 0xFF);

  c1[0] = (unsigned char)((col1 >> 16) & 0xFF);
  c1[1] = (unsigned char)((col1 >>  8) & 0xFF);
  c1[2] = (unsigned char)((col1 >>  0) & 0xFF);

  int comps = format() == IF_RGBA ? 4 : 3;
  int d = depth() ? depth() : 1;
  for(int y=0; y<height()*d; ++y)
  {
    for(int x=0; x<width(); ++x)
    {
      unsigned char* px = pixels() + pitch()*y + x*comps;
      double t = (double)px[1] / 0xFF;
      px[0] = (unsigned char)(c0[0]*(1.0-t) + c1[0]*t);
      px[1] = (unsigned char)(c0[1]*(1.0-t) + c1[1]*t);
      px[2] = (unsigned char)(c0[2]*(1.0-t) + c1[2]*t);
    }
  }
}
//-----------------------------------------------------------------------------