Between BMP and TGA...which is the better format to use for BZII?

[BNG Da BZ Fool]

TS 7.6 supports BMP and TGA, but not the PIC format native to BZII. Are there any advantages to use TGA over BMP?

Also, other then file size should I use 256 color, 16 bit, or 24 bit format? The reason I ask is that 16 kb is half the file size as 24 bit BMPs and 256 bit half the size of 16 bit. Been working on skinning stuff lately, but still need to figure out how to use layers and understand how to do multiple layer textures. I have been working with Paint.Net as it supports this and deems a bit easier to use then GIMP. Tanks BNG.

[General BlackDragon]

.PNG is also supported by BZ2.

If it doesn't support PNG, go with TGA (smaller file size)

Conventionally, BMPs are pure images, and TGAs are used in bz2 because of their ability to have alpha channels. Same with pics, but .pics are smaller format i think.

[Nielk1]

I use PICs :-p

Doesn't matter once you make them into bz2dxt files though.

[Zero Angel]

BMP doesnt use any compression, so the file sizes are bigger, and it doesnt support transparancy. The only advantage it has is that everything can edit BMP files. That said, I would not recommend this format.
TGA uses lossless compression, but does not use transparency.
Softimage PIC uses lossless compression and supports transparency, but not all image editors can properly open or save it.
PNG has rather good lossless compression, it supports transparency, and is compatible with almost every image editing program -- but models with PNG textures do not work in 1.2 or earlier.

I'd say go with any of the 3 latter choices -- depending on your needs.

[GSH]

Targa (.tga) files definitely do support transparency. That's the standard file format at work for all our game assets. I can't recall if 1.0-1.2 could read targas w/ transparency correctly, but 1.3pb4/4a definitely ought to. 

-- GSH

[Steeveeo]

Correction (though I may be totally wrong):

TGA supports Alpha maps, which games use to generate transparency, but when I have transparency in a file that I am saving to TGA, the editor warns that all transparency will be lost.

[OvermindDL1]

Transparency *is* an alpha map.  If whatever program you are using cannot save the transparency of something like, say, a PNG, then you need a better program...

There are two ways of representing alpha, either as a secondary grayscale texture to another (a mask), or as a 4th byte in the RGB (making it RGBA or ARGB or whatever).  They are functionally identical.
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[TheJamsh]

XNview cannot (strangely) open .png files.

It can however open .TGA and .PIC files and output them to another format which is useful. PNG is probably best (smaller file size too), but im using TGA as im more familiar with it... and they do support transparency, as do .pic files.

Ive yet to find an image editor that will edit .pic files properly. i think its a softimage thing...

And i cant be bothered with DXTBZ2 textures. they seem to have caused more problems that solutions to be honest, im not even going to bother including them in my mod... people will jsut have to suffer a larger download size thats all...

[Nielk1]

There are two ways of representing alpha, either as a secondary grayscale texture to another (a mask), or as a 4th byte in the RGB (making it RGBA or ARGB or whatever).  They are functionally identical.

PNG can have both of these at the same time, making it rather confusing to work with (I get this often when I use multiple renders that were done as PNGs in a new larger PNG.

[OvermindDL1]

XNView can open PNG files just fine.  In fact it has one of the best PNG compressors beating out every other known program.  I always use it to compress to PNG and it always results in a smaller filesize then other apps I have.

PNG can have both of these at the same time, making it rather confusing to work with (I get this often when I use multiple renders that were done as PNGs in a new larger PNG.

And going through the normal PNG API, you do not see the difference (at least I never have).
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[mrtwosheds]

.dxtbz2....
I use .pic and .png to make em.
.pic seems to be better at alpha channels.
.png is better at transparency's.

[TheJamsh]

am i the only person who has a strange loathing for dxtbz2 type?

okay slightly confused, someone explain in laymans terms the difference between alpha and transparency?

[mrtwosheds]

am i the only person who has a strange loathing for dxtbz2 type?

You probably had hardware issues. They have always worked fine for me and are great for automatic in game quality adjustment, just what bz2 needed.

okay slightly confused, someone explain in laymans terms the difference between alpha and transparency?

Alpha channels are created using a mask, they work on any colour in texture, very useful for putting illuminated areas on unit skins.
Also used in effects such as smoke.tga where black shades need to be shown
use with "srcalpha invsrcalpha modulatealpha" for effects.

Transparencys do not use masks they are usually made by not drawing one colour such as black use with "one one modulate" to hide all the black bits in effects.

PNG's can be made with transparent areas (not a colour at all) most other formats cannot do this.

As Om said technically there is not much difference, but when actually making and applying the textures the two techniques produce different results.

Using photoshop I have noticed that alphachannels(masks) on png's do not always work well once converted to dxtbz2, so I use .pic to make these and convert them to dxtbz2.

Do not use .bmp ingame, they are huge! and will impare game performance if it has to draw allot of them.

[TheJamsh]

i use .tga's in everything, textures for models, effects etc. just be cause it works.

is it worth me swapping them all to .png for a performance difference? or changing effects sprites to dxtbz2?

[OvermindDL1]

For note, an "Alpha Channel" is the the Alpha byte in an RGBA/ARGB set.  And as stated, a mask is just a black and white image that can be applied to an image to generate the alpha channel.  The "Transparency" you talked about is an alpha channel.  An alpha channel and a mask are two different things, but function identically.  If anything treats them different then they are poor implementations.  Since BZ2 uses Freeimage now (I think) then it should handle any and all equally.  As for the dxtbz2 converter, it is a very simple program that just does a pretty simple RGBA/ARGB mapping to the dxts format, so yea, it probably ignores 'separate' masks.  It should really always be as another channel though.

PNGs are generally better in all cases until you get in game, upon which the dxtbz2 format is best since it is optimized for the engine.
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