//a picture of the Grand Canyon using 
//USGS DEM data
//by Kurt Bangert
//http://www.travelnotes.de/rays/

#include "colors.inc"

global_settings { max_trace_level 20 } 

#declare gctex=texture{
pigment {
	 gradient y      
          color_map {[0.0 color  rgb<.5,.4,.4>]
                     [0.021 color rgb<.52,.482,.543>]
                     [0.05  color rgb<.612,.558,.629>]
                     [0.1   color rgb<.609,.557,.557>]
                     [0.2   color rgb<.758,.676,.660>]
                     [0.22  color rgb<.753,.644,.625>]
                     [0.30  color rgb<.847,.769,.742>]
                     [0.40  color rgb<.726,.679,.707>]
                     [0.50  color rgb<.734,.637,.687>]
                     [0.56  color rgb<.648,.535,.585>]
                     [0.57  color rgb<.719,.671,.695>]
                     [0.60  color rgb<.730,.679,.707>]
                     [0.67  color rgb<.777,.719,.726>]
                     [0.69  color rgb<.710,.539,.578>]
                     [0.72  color rgb<.687,.531,.566>]
                     [0.74  color rgb<.746,.660,.699>]
                     [0.79  color rgb<.703,.582,.617>]
                     [0.86  color rgb<.746,.648,.703>]
                     [0.90  color rgb<.824,.781,.808>]
                     [0.93  color rgb<.898,.867,.882>]
                     [1.0   color DarkGreen]
       		     }} 
          finish {ambient 0.2 diffuse 0.8}
}
	   
camera {location <-25,5,-30>
 angle 37
 look_at <-4,-3,4>}

light_source { < -10,20,-25>  color rgb <1.3,.8,1.3> }

#declare canyon=object {height_field { gif "grandcan.gif" 
 scale <50,2,50> translate<-25,0,-25> }
} 

//canyon
object{canyon texture{gctex scale 2}}

//river
object{box {<-50,0,-50><50,.3,50> translate<-25,0,-25> }
 texture {
 normal {granite 0.8 scale <.1,1,.1>}
 pigment{color rgb<.3,.4,.45>} 
 finish {ambient 0.2 diffuse 0.6 reflection 0.2}} 
}    

fog { distance 30 color rgb<0.5 0.5 .7 >}