using JPG's and TGA's

(=SC=Beef) #1

ok, so ET uses both TGA’s and JPG’s
i know that TGA’s have to be saved as 32 bit (not compressed) for the alpha channel to work, and that ET will accept nothing less than 24 bit.
With JPG, its totally up to the quality you want when you save it.
However, what i want to know is ‘whats the difference’
I can reduce my mod to under 1/2 of the original just just by scripting and changing the TGA’s into JPG’s etc
I notice no difference in quality in game, however that may just be me.
Are TGA’s also used so they can be ‘blended’? im not too sure about that, just a hunch.
so yeah, why should i NOT mod in JPG’s, and what is the difference

(SCDS_reyalP) #2

You need to use TGA if the shader requires an alpha channel. Otherwise you can use jpeg. Jpeg may look worse, but in general if you use a reasonably high quality setting, it isn’t noticeable.

Even if you ship the mod with .jpegs, you should keep your original textures in a lossless format, otherwise you lose quality every time you modify them.

(Ragnar_40k) #3

Is it possible to use 2 jpegs insted of a tga? I mean one 24-bit jpeg for the graphics and one 8 bit (grayscale) jpeg for the alpha channel? And both are combined via a shader script? Thats the way it worked in H&D2 (and I guess in other games too).

(Shaderman) #4

http://splashdamage.com/index.php?name=pnPHPbb2&file=viewtopic&t=10397

I’ve never got an answer on my question here but some days later I read somewhere else that this idea needs support by the engine (should be impossible without modification of Q3 based games).

(Jaquboss) #5

you can use diffirent shaders ( TCE weapons use two jpg instead of tga for shiny effect )

(carnage) #6

when textures are loaded into video memory JPG and TGA are pretty much the same i think. Any texture would be help as three different greyscale channels so i dont see why it would be imposible technicaly to load differnt channels from differnt images e.g. as surgested use a jpg image then the alpha channel from another image

however the q3 engine afaik dosnt suport this probably from the point of veiw that wen developing the engine games were always see to be distributed via CD’s so texture memory sizes wasnt see as such a big issue