Warp <war### [at] tagpovrayorg> wrote:
> CAS <sup### [at] cstnetcn> wrote:
> > 1: how does pov calculate the value of each pixel of final image?
>
> Via raytracing. Mathematical rays are "shot" from the "camera" towards
> the (mathematically defined) scene geometry, and intersections between
> this ray and the surfaces are calculated. Then the normal vector and
> texture of the surface at that point are calculated, and its color from
> them.
>
> > My
> > understanding is :using the irradiance and surface properties to calculate the
> > value of each pixel of final image. Using the simplistic Phong lighting model to
> > calculate the color of each pixel of final image.I didnot set related "phong"
> > statements but also get a result.
>
> The "phong lighting model" has nothing to do with "phong highlights".
> The latter is one algorithm to calculate (simplistic) highlights, and
> you can use it, or another, or none at all.
>
> The "phong lighting model" means that the color of the surface at a given
> point is calculated by taking the texture color at that point, adding a
> possible (fixed) ambient color to it, multiplying it with a diffuse
> component (which is calculated from the direction and intensity of light
> sources), and adding a specular component to it (which is calculated
> similarly, but with a different algorithm that also takes into account
> the direction of the incoming ray.)
>
> POV-Ray also supports a few alternative lighting models that can be
> added to that.
>
> --
>                                                           - Warp

Thank you for your help.I am sorry to trouble you again! I want to use phong or
radiosity (such illumination model) to calculate,how can I set relation
statements? I have defined some paraments in global_settings {phong{}} but when
pov is running ,it points out "phong 0".What values are these specific
parameters should I set?

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