Applications and Tools, Second Life

Ambient Occlusion - Shadows in Second Life

On a platform where every object needs to be rezzed from the point of viewing, Second Life has had to make trade-offs to the appearance of the world. On gaming platforms, these trade-offs are handled through things like texture baking, polygon counts, and distribution of content on CD.

Platforms like Blue Mars are throwing caution to the wind and assuming that computer power will continue to grow exponentially, to the point where the world will catch up to THEM rather than them catch up to the world. The difference in the visual appearance can be astonishing. Blue Mars will run off the Crysis engine. In the meantime, Second Life has scrambled to manage the visual display of the world while trying not to leave too many users in the dust, unable to access the Grid (or at least see it in all its full glory) if they don’t keep their graphics cards and processor speed up-to-date.

One of the major issues with how the world looks is shadows. Windlight gave us sky and water - a major step forward in how the world looks. While Windlight adds a lot, it was also, um, watered down in my opinion. Earlier release versions of Windlight had more punch, and until Linden releases the ability to control the environment settings at the region level, it will never have the full impact it could have.

But it’s not just wind and water that a world of beauty makes - it’s also shadows. And ambient occlusion is one piece of the puzzle being worked on in a cubbyhole somewhere at the Lab. Dave has been running tests of ambient occlusion which is defined according to Wikipedia:

Ambient occlusion is a shading method used in 3D computer graphics which helps add realism to local reflection models by taking into account attenuation of light due to occlusion. Unlike local methods like Phong shading, ambient occlusion is a global method, meaning the illumination at each point is a function of other geometry in the scene. However, it is a very crude approximation to full global illumination. The soft appearance achieved by ambient occlusion alone is similar to the way an object appears on an overcast day.

Dave has posted some tests of ambient occlusion, or as he calls it deferred rendering. The screen shots are encouraging:

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