PVR2MDL

Developed by Alexey Leusin, Novosibirsk, 2018
If you like my work and want to buy me a beer =), you can do it here: paypal.me/AlexeyLN

This is fork of my PS2 HL mdltool that is intended to convert
Dreamcast Half-Life *.MDL models with *.PVR textures to
normal format, that is recognisable by PC Half-Life.

How to use:
1) Windows explorer - drag and drop model file on pvr2mdl.exe
2) Command line\Batch:
		pvr2mdl [filename]
	Optional feature - extract textures from model (in *.BMP format):
		pvr2mdl extract [filename]

Original models would be backuped in "***-backup.mdl" files.

I found no sources that explain how twiddling works in words, so
here is my explanation:
- twiddling is appliable to square images only
- image should be stored as one continous block in memory
- to convert x and y coordinates to twiddled first you need to double
	position of every set bit inside them.
	Example: x = 10, y = 7 => x = 1010b, y = 111b
	x has set bits at positions 1 and 3 so new positions are 2 and 6:
		new_x = 1000100b = 68;
	y has set bits at 0, 1 and 2, so new positions are: 0, 2, 4.
		new_y = 10101b = 21;
- end result of twiddleing is linear pixel number that is calculated by
	applying bitwise or on new_y and double value of new_x.
	Example: let's find linear pixel number for values from
	previous section:
	x_new * 2 = 68 * 2 = 136 = 10001000b;
	Bitwise or: 10001000b | 10101b = 10011101b = 157;
	So the end result is: OriginalImage[10][7] = TwiddledImage[157];

Sources:
Got info on general structure of PVRs here:
	http://fabiensanglard.net/Mykaruga/tools/segaPVRFormat.txt
Got info on how twiddling works here:
	https://github.com/yevgeniy-logachev/spvr2png/blob/master/SegaPVRImage.c

And finally, some formal stuff:
=====================================================================
LICENSE
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Copyright (c) 2018, Alexey Leushin
All rights reserved.

Redistribution and use in source and binary forms, with or
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=====================================================================