3e2471fa$1@news.povray.org...

> Well, I'm getting there. HDRI is a way of approximating real-life
situations
> that Pov-Ray can't do, or can't do well -- I'm thinking events like depth
of
> focus, glare, sun flares.

No it's much simpler and limited in scope. Just think of it as a photograph
able to emit bright light. It doesn't add functionality to POV-Ray (it's
possible to have HDRI effects in POV-Ray without a patch), it's just that
HDRI photographs derived from natural environments give very realistic
results when used in 3D pics because they are by definition realistic
(realistic colors AND realistic light intensities). One thing that gives
away images using HDR maps is that the reflection of light sources is not
dimmed on poorly reflective objects (the reflection of a light bulb will be
bright even if the object has refection 0.3).

In fact, here is a basic HDR texture in regular POV-Ray:
texture{
    image_pattern{jpeg "areas_of_light_intensities"}
    texture_map{
        [0 pigment{color White} finish{ambient 0}] // regular White
        [1 pigment{color White} finish{ambient 1000}] // very very bright
White
    }
}

> Next: is HDRI a program in itself?

No, it's a way to store the light intensities with the color pixels. There
are several file formats available (HDR, PIC, TIFF adaptations seem the most
frequent). What MLPOv has is the support for the HDR format. There's a free
program called HDRShop that lets you create and view HDR image though.

G.

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