How much difference does texture size make?

I'm wondering about whether using 256x256 textures or 128 x 128 even improves performance much, how much extra load is caused by using larger textures? I've often saved 1024 x 1024 textures to something smaller for signs and such like but is there a point to doing this? Does it make much of a difference?

Take a look at the size of both data files before uploading - one in 1024x1024 and one saved as 128x128. That it the difference.

The bigger the textures, the bigger the data transmission, the longer the load time. So I'd really suggest using smaller files for smaller stuff - not only for your own load times, but for other people's too.

Yup it's other people I'm thinking about, myself too but where I'm responsible for putting up textures I'd rather not cause unneccessary load times. I just wondered if the system does something to the upload that makes it a pointless exercise, I know they get converted on upload to jpeg2000, or I think they do, I'm sure I read that somewhere.

They are converted, but the amount of memory they take up still varies by pixel dimensions.

Here's a link to a sticky in the texturing tips forum started by Chosen Few. It may answer your question about exactly what sorts of difference texture size can make.

/109/e6/150360/1.html

Yes, they get converted to JPEG2000 format on upload. So there is no benefit from using PNG or JPG or TGA or some other format, in terms of data compression offered by that format.

But the raw size of the image in pixels makes a LOT of difference. It seems they tweaked things so a 512 x 512 texture gets priority over other sizes on loading initially. This was probably to make avatar skin and clothing textures load faster, since they are all 512 x 512. But the larger the image is, in pixels, the more data it has to put into cache and move around as you encounter it. So for most things, smaller is better. Use the smallest size you can that gets the level of detail you actually need.

For example, I *could* use a 1024 x 1024 texture for the primer end of a temp-rezzed shell casing for a gun. But odds are pretty good that NO ONE will ever zoom in on the tail of that ejected shell casing close enough, in the one minute before it de-rezzes, to see any more detail than a, 8 x 8 pixel solid color chip would have given me.

On the other hand, a photograph of a loved one, on a bedside table, may be a very small detail in the scene, but may still be something people would zoom in close to enjoy - so a 512 x 512 texture may be worth using there, even though frm 3 M away you see no difference between that and a 64 x 64 texture..

Wow what an excellent post, that was exactly the sort of information I was looking for.

Thanks Novis, Nimune and Ceera for your input too, I didn't even think about going below 128 x 128.

Now that the question has been answered I have a related question..........perhaps it's derailing the thread a bit. If so, please forgive.

Any texture has a definite data size according to the bits involved in it's shown state for the viewer. For ease of an example lets say you have a texture that is 256 x 256 pixels and has X number of bits that need to be transmitted to the viewer. If you set your repeats to 2 per face horizontal and 2 per vertical does that require 4 times the bits to be transmitted to the viewer? So now you have 4 tiles instead of 1. Each tile is still 256 by 256 pixels...........or is each tile reduced to 128 by 128 pixels?

It would seem it would 4 tiles at 256 each, but then it might be that the repeats decrease the bits for each tile by half. I don't know.

Just curious mainly..........but I think it might be good to know one way or the other.

A 256x256 is 4x bigger then a 128x128
a 512x512 is 16x bigger then a 128x128
a 1024x1024 is 64x bigger then a 128x128

The bigger the file the longer it takes to load it.

So size does matter...even with textures... lol

Its the same texture so it will only use the amount of space as a single repeat. Ie a tiled version will load just as fast as a single repeat.



As to the other thing..

1024's are mainly to be looked at as Master's for further processing.. at least that is how I treat them.

9 out of 10 times you can get away with 512 or 256 if the subject is simple.


Again.. it depends on the amount of detail you want. For example, a 128 x 256 Door Texture, unless its just solid colors will look like a hunk of garbage, compared to a 512 x 1024

strictly a matter of preference and what you can accept as being good enough