Newbie questions

[stealth]

Alright, just wondering what Dot3 bump-mapping is, and...I hear it everywhere, I even have a small understanding of what it does, but...what is Anisotropic filtering...

thanks

[EarthQuake]

There's an edit button you know...

[toxicfluff]

stealth said:

Alright, just wondering what Dot3 bump-mapping is, and...I hear it everywhere, I even have a small understanding of what it does, but...what is Anisotropic filtering...

thanks

Anisotropic filtering basically sharpens out textures which you are not facing head on. If you sidestep up to a wall and look along it, you can see it makes a huge difference. If I wasn't so lazy I'd post example pics - as it is, if your card supports it try the above method with it both on and off.

[stealth]

ToXiCFLUFF said:

Anisotropic filtering basically sharpens out textures which you are not facing head on. If you sidestep up to a wall and look along it, you can see it makes a huge difference.

What you described sounds an awful lot like mip-mapping.

[Opulent]

Aliasing is like a rounding error when drawing an edge or pattern which is smaller than a pixel. Anti aliasing provides a sampling algorithm to fix it to make tight details more realistic. A good gaming example is looking at a pyramid edge.. anti-aliasing makes it look perfectly smooth .. without, it looks like a small saw tooth. There are multiple levels or passes that can be applied to improve quality 1x --> 6x or more.

Anisotropic Filtering is similar except that it deals with how textures (not edges or patterns) are drawn to the screen. The filtering is the filtering down of the texture area covered by a single pixel to the one color that pixel will show. If you took a camera shot at 10,000 feet of New York, each pixel would capture the colors of alot of things. Anisotropic Filtering does just that in the games. It is an improvement over previous sampling/filtering methods which would just use the center point color or just use a rough sample. There are multiple levels or passes that can be applied to improve quality 1x --> 16x or more.

I had to look up Dot3 bump mapping as I hadn't any idea what it really was; a good description of it is on here: http://www.riaz.de/tutorials/d3d14/d3d14.html

[stealth]

Thanks many many times Opulent.

[Bucket]

It's funny how we talk about improving quality of pictures by sharpening them-- and we talk of improving quality of graphics by blurring them.

Anyway, what Opulent said is completely right. With all the compression effects available for engines nowadays, there's still one small limitation(obviously prior to the subject feature): the graphics display couldn't blend colors. You know how in Doom, faraway objects look like a garbled mess? That's because the engine has to pick a color to display-- so it simply displays the average color. Rendering engines still do this. Now we can take the information of every color present inside the range of one pixel and average them. So if a white wall intersected a black wall halfway through a pixel, the corner would look grey.

Like Opulent said, you can change the size of the averaging area(say to 2 pixels square). You'd still be doing a pass per pixel, but it would be averaging a 2x2 space. This results in even smoother lines. Mipmapping would actually become defunct if this type of antialiasing were widely used.