Microsoft format documentation

The Enhanced editions support also version 5 of the BMP format. It is largely the same as version 1 used by the original games, but supports 32-bit colors (still 8 bits per channel, but adds one for alpha).

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Header format

Name			Size	Description
0x00	Signature		2 bytes	'BM'
0x02	FileSize		4 bytes	File size in bytes
0x06	2 reserved words		4 bytes	Unused (=0)
0x0a	DataOffset		4 bytes	File offset to Raster Data
0x0e	Size		4 bytes	Size of InfoHeader =40
0x12	Width		4 bytes	Bitmap Width
0x16	Height		4 bytes	Bitmap Height
0x1a	Planes		2 bytes	Number of Planes (=1)
0x1c	BitCount		2 bytes	Bits per Pixel
0x1e	Compression		4 bytes	Type of Compression: BI_RGB (uncompressed), BI_BITFIELDS (uncompressed with color masks), BI_RLE4 / BI_RLE8 (with runtime encoding)
0x22	ImageSize		4 bytes	(compressed) Size of Image  It is valid to set this =0 if Compression = 0
0x26	XpixelsPerM		4 bytes	Horizontal resolution: Pixels/meter
0x2a	YpixelsPerM		4 bytes	Vertical resolution: Pixels/meter
0x2e	ColorsUsed		4 bytes	Number of actually used colors
0x32	ColorsImportant		4 bytes	Number of important colors  0 = all
0x36	Color masks
		Red mask	4 bytes	Mask identifying bits of red component
		Green mask	4 bytes	Mask identifying bits of green component
		Blue mask	4 bytes	Mask identifying bits of blue component
		Alpha mask	4 bytes	Mask identifying bits of alpha component
0x46	CSType		4 bytes	Color space type
0x4a	RedX		4 bytes	X coordinate of red endpoin
0x4e	RedY		4 bytes	Y coordinate of red endpoin
0x52	RedZ		4 bytes	Z coordinate of red endpoin
0x56	GreenX		4 bytes	X coordinate of green endpoint
0x5a	GreenY		4 bytes	Y coordinate of green endpoint
0x5e	GreenZ		4 bytes	Z coordinate of green endpoint
0x62	BlueX		4 bytes	X coordinate of blue endpoint
0x66	BlueY		4 bytes	Y coordinate of blue endpoint
0x6a	BlueZ		4 bytes	Z coordinate of blue endpoint
0x6e	GammaRed		4 bytes	Gamma red coordinate scale value
0x72	GammaGreen		4 bytes	Gamma green coordinate scale value
0x76	GammaBlue		4 bytes	Gamma blue coordinate scale value
0x7a	Intent		4 bytes	Rendering intent for bitmap
0x7e	ProfileData		4 bytes	Offset to profile data
0x82	ProfileSize		4 bytes	Size of embedded profile data
0x86	Reserved3		4 bytes