Function CompressTo88

DevIL/src-IL/src/il_dds-save.cpp:475–540

ILubyte *CompressTo88(ILimage *Image)
{
	ILimage		*TempImage;
	ILubyte		*Data;
	ILuint		i, j;

	if ((Image->Type != IL_UNSIGNED_BYTE && Image->Type != IL_BYTE) || Image->Format == IL_COLOUR_INDEX) {
		TempImage = iConvertImage(iCurImage, IL_BGR, IL_UNSIGNED_BYTE);  // @TODO: Needs to be BGRA.
		if (TempImage == NULL)
			return NULL;
	}
	else {
		TempImage = Image;
	}

	Data = (ILubyte*)ialloc(iCurImage->Width * iCurImage->Height * 2 * iCurImage->Depth);
	if (Data == NULL) {
		if (TempImage != Image)
			ilCloseImage(TempImage);
		return NULL;
	}

	//changed 20040623: Use TempImage's format :)
	switch (TempImage->Format)
	{
		case IL_RGB:
			for (i = 0, j = 0; i < TempImage->SizeOfData; i += 3, j += 2) {
				Data[j  ] = TempImage->Data[i+1];
				Data[j+1] = TempImage->Data[i  ];
			}
			break;

		case IL_RGBA:
			for (i = 0, j = 0; i < TempImage->SizeOfData; i += 4, j += 2) {
				Data[j  ] = TempImage->Data[i+1];
				Data[j+1] = TempImage->Data[i  ];
			}
			break;

		case IL_BGR:
			for (i = 0, j = 0; i < TempImage->SizeOfData; i += 3, j += 2) {
				Data[j  ] = TempImage->Data[i+1];
				Data[j+1] = TempImage->Data[i+2];
			}
			break;

		case IL_BGRA:
			for (i = 0, j = 0; i < TempImage->SizeOfData; i += 4, j += 2) {
				Data[j  ] = TempImage->Data[i+1];
				Data[j+1] = TempImage->Data[i+2];
			}
			break;

		case IL_LUMINANCE:
		case IL_LUMINANCE_ALPHA:
			for (i = 0, j = 0; i < TempImage->SizeOfData; i++, j += 2) {
				Data[j  ] = Data[j+1] = 0; //??? Luminance is no normal map format...
			}