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Loading Textures

Started by THACO 16 replies 1k views
Original Post
THACO
THACO
I am curious what best format would be to use for textures. I would use textures for sprites and also texture mapping on 3d objects, Should i use .bmp .tga .jpeg. Also I see at the tutorials at NeHe they use the GLaux for loading of bmps and i was looing around the internet and saw that glaux is old and unsupported because of some flaws and memory leaks. Are there any other tutorials or functions to use, are there functions in GLUT to help with loading of textures? -THACO p.s. i use eclipse with c++ and when i include the glaux library the exe will not run because it cannot find glaux.dll i can still compile using LCC compiler instead of mingw but its a pain.
Kris2456
Kris2456
out of all those .TGA is the best. It supports the ALPHA channel, which is really handy (They hav to be 32bit tho). Use Photoshop or PSP for those. Also, for a nice .TGA loader. Nip over to www.gametutorials.com for a really neat .tga loader.

As for GLUT i dontuse it, so i wudnt know...


------------

"Here lies a toppled God,
His fall was not a small one,
We but built his pedastle,
A narrow, and a tall one"
Frank Herbert (Dune:Messiah)

[edited by - Kris2456 on June 7, 2004 5:55:19 PM]
------------ "Here lies a toppled God,His fall was not a small one,We but built his pedastle,A narrow, and a tall one" Frank Herbert (Dune:Messiah)
sirSolarius
sirSolarius
Why don''t you just write a graphics library that reads and writes to all of those formats? You can get a lot of information online, and if you aren''t sure what you want to use, just support them all.
Raduprv
Raduprv
If you don''t need an alpha channel, use bmp 8 bit.
256 colors/texture is more than enough, the size is smaller than 16/32 TGA (uncompressed TGA), and there is no image loss.
JPG is a bad idea, since you might want to use texture compression, in which case the quality would be further degraded.
THACO
THACO
That sounds good,thanks Raduprv for reminding me about 8 bit bmps that is a good idea.
Kris thanks for the link that will be very helpful
sirSolarius i would like to do that because the more the better but if there are certain reason for certain formats its always good to know the proper time to use formats

-THACO
leiavoia
leiavoia
I vote for PNG, since it''s losslessly compressable (ah, English...) and supports a full alpha channel as well.

If you use SDL as your foundation, you can load in any filetype using SDL_image. There''s no reason to write your own file loading library if it''s already been done.
Raduprv
Raduprv
Just decide on a format, and make your own loading function.
My BMP loading function is about 60 lines of C. I made it in a few hours. There is no need to have additional dependencies for loading a texture.
_the_phantom_
_the_phantom_
or use one of the many libraries out there, such as FreeImage, Corona and DevIL (too tired to get links, search sourceforge.net for details)
Khaos Dragon
Khaos Dragon
In my recent post about color keying I posted a function which can load in bmp, jpg, gif, png, and tga and convert it to an opengl texture. It also can color key the texture if you want.
It is dependent upon sdl and sdl_image...

Xarragon
Xarragon
Well, in the end, OpenGL always want pure RGB/RGBA data, so whatever format you use, you must decompress it into this. This might hoever be different if you use texture compression, but I couldn''t tell for sure.

TGA is, as said, a good format, since it has alpha, and can be saved to by many programs. If you use uncompressed TGA''s, the code to load it is really simple as well.

In my opinion, the best method is to use some library, just as leiavoia said. As long as you get your RGB/RGBA data in the end, you can use anything.
The only problem is, as always to get people to download the library (unless you link it statically, or can bundle it with your package).

Some people use uncompressed image formats, and then compress all data with a general-purpose algorithm. The drawback to this is that the compression ratio is likely to be less efficient for image data, compared to that of a image-specific algorithm.

Xarragonxarragon@swipnet.se
nife
nife
Just one question: Why the **** should anyone use libraris for bitmap''s or targa''s when it''s soooo easy to write one yourself.??? It''s really not that hard, I mean take a look at some (official) papers describing the header and body and the rest is almost piece of cake! The only strange things is that bitmaps''s are organized in a row system with a 0x00 at the end of each vertical row and targa''s is organized in BGR (or BGRA) instead of RGB (or RGBA).
Killers don't end up in jailThey end up on a high-score!
Deranged
Deranged
quote:
Original post by nife
Just one question: Why the **** should anyone use libraris for bitmap''s or targa''s when it''s soooo easy to write one yourself.??? It''s really not that hard, I mean take a look at some (official) papers describing the header and body and the rest is almost piece of cake! The only strange things is that bitmaps''s are organized in a row system with a 0x00 at the end of each vertical row and targa''s is organized in BGR (or BGRA) instead of RGB (or RGBA).





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_the_phantom_
_the_phantom_
errm, because they are there to be used?
Look at it this way, I could go out and code it but I dont want to, I''d much rather use a tried and tested lib and just drop it in my app then bother about it.
If you want to go out and reinvent the wheel all the fine, whatever, but personaly I prefer to do other stuff and use whats avalible to me than write everything again from the ground up, thus why I use all manner of libs such as image loading/saving, networking, STL and Boost.
THACO
THACO
I personally would like to create everything myself because i will be using this for a school project and probably in my own engine, also it is good to learn how to read in file formats, i have done some work with reading in files before but i still could use some work. The only reason i would stay away from libraries is because this should not be to hard to learn and it will help me in more ways than just texture loading, it will also help me with reading file formats.

-THACO
_the_phantom_
_the_phantom_
meh, your choice but i cant help feel its a large waste of time, I mean where does it stop? "I wont use the STL because i want to do it myself", "I wont use a ready made scripting language coz i want to do it myself" and so on and so on.. *shrugs*
Unless they say ''you must recreate the wheel for everything'' then i dont see the issue with school work and the libs I use are all zlib/png licence stuff which is basicaly ''do what you like with it'', so no worries about including it in engines etc... still, *shrugs* do as you want...
THACO
THACO
I don''t mean any disrespect about it. I want to be able to tell people i did it all, that and with school the whole honor code stuff. Maybe i just have to much pride and am to stubborn, but it is also a great feeling when you do something yourself.

-THACO
Kris2456
Kris2456
It is not so much recreating the wheel. Maybe he wants to learn it himself, u get 20 times more satisfaction if u can say "I made this" not "I did the gfx". Altho if u want to jus create not learn, use libs by all means. Hope u have fun with ur project THACO remember to use these sites as they are really useful:

Nehe
Game Tutorials
ultimate game programming

Go for it!

------------

"Here lies a toppled God,
His fall was not a small one,
We but built his pedastle,
A narrow, and a tall one"
Frank Herbert (Dune:Messiah)

[edited by - Kris2456 on June 9, 2004 10:29:37 AM]

[edited by - Kris2456 on June 9, 2004 10:30:33 AM]
------------ "Here lies a toppled God,His fall was not a small one,We but built his pedastle,A narrow, and a tall one" Frank Herbert (Dune:Messiah)
SoDdit
SoDdit
quote:
Original post by Xarragon
Well, in the end, OpenGL always want pure RGB/RGBA data, so whatever format you use, you must decompress it into this. This might hoever be different if you use texture compression, but I couldn''t tell for sure.

You can use the DXT texture compression (ie .DDS files) to store and use the textures. this is handy if you''ve got a load of large textures (my terrain engine uses 64 x 1024x1024 32 bit textures so it needs compression. other nice thing about this is that the DDS plugin for photoshop generates the mip maps for you as well so you get compression for all mipmap levels.

i is 1337

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