But... lighting is already taken care of in raytracing. It's like the grand unified theory of 3D engines. How is solving lighting problem (admittedly in quite a spikky way) better than raytracing? Okay, yes, it can be done now, etc, etc.. but..?
No — radiosity goes beyond raytracing and starts working with more complex dispersion patterns of light.
Ray tracing works by tracing a path from the supposed eye (or eyes, in 3D) to the scene, then looking at what light falls on the object at that position. Non-trivial raytracing packages support seeing specular reflections; many also cope with objects being illuminated by reflected light.
Radiosity, however, also deals with diffuse reflection. If, instead of illuminating the scene with a "sunlight" point source you put it in a room, paint the ceiling a greenish hue and install a few uplighters, everything in the room gets illuminated by light from every point on the ceiling; penumbral shadows abound. If you put a fruit bowl on the mahogany table, the underside will be tinged red by the light that every point on the table reflects diffusely from every point on the ceiling. While in theory you might be able to raytrace it, in practice you need more sophisticated techniques.
Yeah. Radiosity existed (in a crude form) a few years ago. There are many techniques to deal with diffuse reflections in raytracing, such as storing a 'smoothness' factor for the object being reflected off. A number of rays are then bounced off this object for each pixel, with the 'smoothness' factor dictating how randomly far off the standard angle each one can be. This can then be extrapolated as a sample of the diffuse light reaching the object. Over a whole picture this can give the appearance of diffuse lighting.
Apparently this is called 'photon mapping' (although I described it for each pixel, but obviously the 'photons' would have to come from the light source).
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Date: 2007-04-26 09:59 am (UTC)How long until I can have a USB socket in my head?
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Date: 2007-04-26 10:07 am (UTC)no subject
Date: 2007-04-26 10:17 am (UTC)no subject
Date: 2007-04-26 10:18 am (UTC)no subject
Date: 2007-04-26 10:20 am (UTC)Heh.
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Date: 2007-04-26 10:27 am (UTC)*Picks up a gauntlet*
*SLAP*
A duel to the death is the only answer!
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Date: 2007-04-26 12:12 pm (UTC)"You wiiiiin!"
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Date: 2007-04-26 10:07 am (UTC)no subject
Date: 2007-04-26 10:09 am (UTC)no subject
Date: 2007-04-26 10:59 am (UTC)Ray tracing works by tracing a path from the supposed eye (or eyes, in 3D) to the scene, then looking at what light falls on the object at that position. Non-trivial raytracing packages support seeing specular reflections; many also cope with objects being illuminated by reflected light.
Radiosity, however, also deals with diffuse reflection. If, instead of illuminating the scene with a "sunlight" point source you put it in a room, paint the ceiling a greenish hue and install a few uplighters, everything in the room gets illuminated by light from every point on the ceiling; penumbral shadows abound. If you put a fruit bowl on the mahogany table, the underside will be tinged red by the light that every point on the table reflects diffusely from every point on the ceiling. While in theory you might be able to raytrace it, in practice you need more sophisticated techniques.
no subject
Date: 2007-04-26 12:11 pm (UTC)no subject
Date: 2007-04-26 12:57 pm (UTC)no subject
Date: 2007-04-26 10:30 am (UTC)No more dodgy shadows that change shape depending on which position you look at them from, or that disappear slightly into some objects! XD
No more st00pidly expensive graphics cards! Just extortionately expensive CPUs...