Quote:
Originally Posted by JAMF
There are other ways to achieve craters. A basic double pyramid with 6 sides only costs 16 triangles. Inverted, that looks like a hole. Graphic cards of today have a trick called tessellation. If the crater object was marked as an object that would receive tessellation, the card would increase that 16 triangles to 48, fo example. The crater now looks much smoother and the circular hole will have 12 sides.
Now add another trick, normal mapping ( Dot3 bump mapping). Simplified, it's a texture, which tells the card to add extra height/thickness to a point on a model. Say white is very high/thick and black is nothing/zero. Lay a black&white noise texture over the crater and you get the inside surface to look like it's just exploded and it's covered with clumps of dirt and sand.
These effects should have little effect on the frame rate, as they can be distance-indexed, so they start to show only when you get closer. Similar to the LoD models aircraft have.
Bump mapping is an optical illusion, normal mapping really adds surface detail.
Left is bump-, right is normal-mapped. Notice the visual edge of the spheres:
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Oleg said a couple of times that craters will be bump mapped or similar (tessellation maybe), hopefully using the latest graphics technology for DX11.
I find it amazing what the new techniques can add to a flat modelled surface:
Video of tessellation on/off, a comparison:
Tessellation explained:
OFF/ON
