"Christoph" <nomail@nomail> wrote in message 
news:web.4905eeb55b9956825c2817dc0@news.povray.org...
> hello!
>
> i am thinking about generating a synthetic ground-truth benchmark image 
> for a 3d
> scanner using povray. therefore i would like to know if and how it is 
> possible
> to simulate a video projector in povray.
>
> it should be possible to simulate each projector pixel using a spotlight 
> and
> place a lens in front of the array, but that would be extremely tedious 
> and
> probably inaccurate.
>
> is there a way to project a bitmap onto a scene, ideally with finite
> depth-of-field? after all, a projector is just a reverse camera ...
>

Yes. You may find the following example helpful. It projects a bitmap onto 
the scene, which, in this case is just a plane.

The bitmap is projected by placing it in front of a light source and adding 
a filter filtering all of the colours in the image at their full intensity 
('filter all 1'). I'm not sure how you'd go about adding a depth of field.

Regards,
Chris B.

camera {location <-0.4,0.4,-1.4> look_at 0}
global_settings {ambient_light 0.05}

// Image to project
plane {z,-0.9
  pigment {
    image_map {
      sys "gear00.bmp"
      once
      filter all 1
    }
    scale 0.1
    translate -0.05
  }
}

// Projector
light_source {<0,0,-1>, rgb 1}
cone {<0,0,-1>,0,<0,0,-0.97>,0.02
  no_shadow
  texture {
    pigment {rgb <1,0,0>}
    finish {ambient 10}
  }
}

// Screen
box {<-0.5,-0.5,0>,<0.5,0.5,0.01> pigment {rgb 1}}

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