A Perfect Circle In Games

[The Driver]

Why is it that in computer games, there is never a perfect curve or circle, and seems jagged. For example, look at this picture below.

Here, if you look at the wheels, you can see they are not actually circular. Why is this?

[Gerard]

Everything in games is made up of triangles. Absolutely everything.

Triangles, called 'polygons' in modelling, are pretty simple things to work with, they are just three coordinates, with something like a colour or a texture in the middle. Two polygons can make up a square, and lots of little triangles can make something resembling a circle. See how this image below creates a spheroid from thousands of polygons:

Why do they use polygons? Well with 2D games, objects are just made with pictures - just loads of pixels. If you want to rotate an object in a 2D game, you just switch to a side-view image, then a back view, then the other side, then the front again. The problem with that is you only get 4 views, and you can't rotate to any other degree than that. Of course there's nothing stopping you making 360 pictures of the object at loads of tiny angles, but thats a lot of work for one image and takes up loads of space.

Polygons, however, are mathematical; they are perfect shapes that the computer can deal with easily. They are actually programmed as three-dimensional shapes rather than lots of different shots. The computer can actually rotate these shapes itself, and add on any effects such as lighting and shadows and movement easily. Since the rotations are done by a mathematical formula that will project the shape at any angle of rotation, only one image needs to be stored in the game. Therefore, with polygon games you have very smooth rotations in a much smaller file size, which you can do more stuff with.

You should be able to see the disadvantage here. That sphere above uses tens of thousands of polygons, which are just three points of the triangle, and don't forget the polygon next door uses two of the same coordinates. If you wanted a perfect wheel, with all the tubing and a perfect circle, you'd need millions of polygons. You can halve the size of the data in the wireframe image by halving the number of polygons.

In that bike, they won't be using too many polygons, to save space and load quicker. In games where you have cars as the focus (racing games) you'd have loads more, but GTA is more about what you DO with the bike than what it looks like. I think it's realistic enough, if a bit jagged.

Hope that answers your question

[evabin2libertycity?]

dude its just a little off. they cant make it perfect. just enjoy it now and appriceate that the circles arent squares. which was wat it use 2 be like. old vidiogames like super nintendo where all made of squares.