// Copyright 1998-2014 Epic Games, Inc. All Rights Reserved.

#include "ImageWrapperPrivatePCH.h"
#include "BmpImageSupport.h"


/**
 * BMP image wrapper class.
 * This code was adapted from UTextureFactory::ImportTexture, but has not been throughly tested.
 */

FBmpImageWrapper::FBmpImageWrapper(bool bInHasHeader, bool bInHalfHeight)
	: FImageWrapperBase()
	, bHasHeader(bInHasHeader)
	, bHalfHeight(bInHalfHeight)
{
}


void FBmpImageWrapper::Compress( int32 Quality )
{
	checkf(false, TEXT("BMP compression not supported"));
}


void FBmpImageWrapper::Uncompress( const ERGBFormat::Type InFormat, const int32 InBitDepth )
{
	const uint8* Buffer = CompressedData.GetData();

	if( !bHasHeader || ((CompressedData.Num()>=sizeof(FBitmapFileHeader)+sizeof(FBitmapInfoHeader)) && Buffer[0]=='B' && Buffer[1]=='M') )
	{
		UncompressBMPData(InFormat, InBitDepth);
	}
}

void FBmpImageWrapper::UncompressBMPData( const ERGBFormat::Type InFormat, const int32 InBitDepth )
{
	const uint8* Buffer = CompressedData.GetData();
	const FBitmapInfoHeader* bmhdr = NULL;
	const uint8* Bits = NULL;
	if(bHasHeader)
	{
		bmhdr = (FBitmapInfoHeader *)(Buffer + sizeof(FBitmapFileHeader));
		Bits = Buffer + ((FBitmapFileHeader *)Buffer)->bfOffBits;
	}
	else
	{
		bmhdr = (FBitmapInfoHeader *)Buffer;
		Bits = Buffer + sizeof(FBitmapInfoHeader);
	}

	if( bmhdr->biCompression != BCBI_RGB )
	{
		UE_LOG(LogImageWrapper, Error, TEXT("RLE compression of BMP images not supported") );
		return;
	}

	if( bmhdr->biPlanes==1 && bmhdr->biBitCount==8 )
	{
		// Do palette.
		const uint8* bmpal = (uint8*)CompressedData.GetData() + sizeof(FBitmapInfoHeader);

		// Set texture properties.
		Width = bmhdr->biWidth;
		Height = bHalfHeight ? bmhdr->biHeight / 2 : bmhdr->biHeight;
		Format = ERGBFormat::BGRA;
		RawData.Empty(Height * Width * 4);
		RawData.AddUninitialized(Height * Width * 4);

		FColor* ImageData = (FColor*)RawData.GetData();

		// If the number for color palette entries is 0, we need to default to 2^biBitCount entries.  In this case 2^8 = 256
		int32 clrPaletteCount = bmhdr->biClrUsed ? bmhdr->biClrUsed : 256;
		TArray<FColor>	Palette;
		for( int32 i=0; i<clrPaletteCount; i++ )
			Palette.Add(FColor( bmpal[i*4+2], bmpal[i*4+1], bmpal[i*4+0], 255 ));
		while( Palette.Num()<256 )
			Palette.Add(FColor(0,0,0,255));

		// Copy upside-down scanlines.
		int32 SizeX = Width;
		int32 SizeY = Height;
		for(int32 Y = 0;Y < Height;Y++)
		{
			for(int32 X = 0;X < Width;X++)
			{
				ImageData[(SizeY - Y - 1) * SizeX + X] = Palette[*(Bits + Y * Align(Width,4) + X)];
			}
		}
	}
	else if( bmhdr->biPlanes==1 && bmhdr->biBitCount==24 )
	{
		// Set texture properties.
		Width = bmhdr->biWidth;
		Height = bHalfHeight ? bmhdr->biHeight / 2 : bmhdr->biHeight;
		Format = ERGBFormat::BGRA;
		RawData.Empty(Height * Width * 4);
		RawData.AddUninitialized(Height * Width * 4);

		uint8* ImageData = RawData.GetData();

		// Copy upside-down scanlines.
		const uint8* Ptr = Bits;
		for( int32 y=0; y<Height; y++ ) 
		{
			uint8* DestPtr = &ImageData[(Height - 1 - y) * Width * 4];
			uint8* SrcPtr = (uint8*) &Ptr[y * Align(Width*3,4)];
			for( int32 x=0; x<Width; x++ )
			{
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = 0xFF;
			}
		}
	}
	else if( bmhdr->biPlanes==1 && bmhdr->biBitCount==32 )
	{
		// Set texture properties.
		Width = bmhdr->biWidth;
		Height = bHalfHeight ? bmhdr->biHeight / 2 : bmhdr->biHeight;
		Format = ERGBFormat::BGRA;
		RawData.Empty(Height * Width * 4);
		RawData.AddUninitialized(Height * Width * 4);

		uint8* ImageData = RawData.GetData();

		// Copy upside-down scanlines.
		const uint8* Ptr = Bits;
		for( int32 y=0; y<Height; y++ ) 
		{
			uint8* DestPtr = &ImageData[(Height - 1 - y) * Width * 4];
			uint8* SrcPtr = (uint8*) &Ptr[y * Width * 4];
			for( int32 x=0; x<Width; x++ )
			{
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = *SrcPtr++;
				*DestPtr++ = *SrcPtr++;
			}
		}
	}
	else if( bmhdr->biPlanes==1 && bmhdr->biBitCount==16 )
	{
		UE_LOG(LogImageWrapper, Error, TEXT("BMP 16 bit format no longer supported. Use terrain tools for importing/exporting heightmaps.") );
	}
	else
	{
		UE_LOG(LogImageWrapper, Error, TEXT("BMP uses an unsupported format (%i/%i)"), bmhdr->biPlanes, bmhdr->biBitCount );
	}
}

bool FBmpImageWrapper::SetCompressed( const void* InCompressedData, int32 InCompressedSize )
{
	bool bResult = FImageWrapperBase::SetCompressed( InCompressedData, InCompressedSize );

	return bResult && (bHasHeader ? LoadBMPHeader() : LoadBMPInfoHeader());	// Fetch the variables from the header info
}

bool FBmpImageWrapper::LoadBMPHeader()
{
	const FBitmapInfoHeader* bmhdr = (FBitmapInfoHeader *)(CompressedData.GetData() + sizeof(FBitmapFileHeader));
	const FBitmapFileHeader* bmf   = (FBitmapFileHeader *)(CompressedData.GetData() + 0);
	if( (CompressedData.Num() >= sizeof(FBitmapFileHeader) + sizeof(FBitmapInfoHeader)) && CompressedData.GetData()[0] == 'B' && CompressedData.GetData()[1] == 'M' )
	{
		if( bmhdr->biCompression != BCBI_RGB )
		{
			return false;
		}

		if( bmhdr->biPlanes==1 && ( bmhdr->biBitCount==8 || bmhdr->biBitCount==24 || bmhdr->biBitCount==32 ) )
		{
			// Set texture properties.
			Width = bmhdr->biWidth;
			Height = bmhdr->biHeight;
			Format = ERGBFormat::BGRA;
			return true;
		}
	}

	return false;
}

bool FBmpImageWrapper::LoadBMPInfoHeader()
{
	const FBitmapInfoHeader* bmhdr = (FBitmapInfoHeader *)CompressedData.GetData();

	if( bmhdr->biCompression != BCBI_RGB )
	{
		return false;
	}

	if( bmhdr->biPlanes==1 && ( bmhdr->biBitCount==8 || bmhdr->biBitCount==24 || bmhdr->biBitCount==32 ) )
	{
		// Set texture properties.
		Width = bmhdr->biWidth;
		Height = bmhdr->biHeight;
		Format = ERGBFormat::BGRA;
		return true;
	}

	return false;
}