Nekar Xenos <vir### [at] iconcoza> wrote:
: If I understand it correctly, the purpose of radiosity is to compensate for
: light scattered by rough surfaces. Normals, as I understand don't do this
: right without radiosity which is why you need to add radiosity.

: Therefore if you were to use isosurfaces or heightfields to make rough
: textures with a relatively low reflection level and a high maximum iteration
: level, you wouldn't need to add radiosity.

: Am I correct or do I have I gone wrong somewhere?

  I'm not completely sure what you are talking about.
  Radiosity (or better called "global illumination") is a process of
calculating the interreflection of light between surfaces, which happens
in the real world.

  A small example of what this is:
  Suppose that you are in a completely dark room, with absolutely no light.
Then you turn on a flashlight torch and point it towards a wall. Immediately
you begin to see other details in the room (for example yourself) although
the flashlight is not directly illuminating anything but part of the wall.
It's the light reflected from the wall that is illuminating other parts of
the room (such as the other walls and yourself) and that's why you are able
to see them.
  Suppose that the wall is red instead of white (as supposed in the example
above). The light reflected from the wall will be mostly pure red (in
practice it will reflect a bit of other frequencies as well, since it's
not possible in practice to get a material with 100% red reflectance, but
the other light frequencies are quite minimal). Thus, you will see the other
details in the room illuminated with red light (although the flaslight
itself emits white light).

  This is what radiosity does: It calculates how the light bounces between
surfaces, illuminating other surfaces (which may not be otherwise directly
illuminated at all).
  This can make visible (3D) shapes which are in shadows, as well as affecting
the illumination of everything, even the lit parts (the so-called
"color-bleeding"): If a white chair is in a red room, the chair will get
a reddish tint even if it's directly illuminated by the light source.
  When done right, this adds even a suprising amount of realism to an image.

  I don't understand your talks about normals and isosurfaces in this
context.

-- 
char*i="b[7FK@`3NB6>B:b3O6>:B:b3O6><`3:;8:6f733:>::b?7B>:>^B>C73;S1";
main(_,c,m){for(m=32;c=*i++-49;c&m?puts(""):m)for(_=(
c/4)&7;putchar(m),_--?m:(_=(1<<(c&3))-1,(m^=3)&3););}    /*- Warp -*/

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