#version 3.7;
#include "colors.inc"
#include "skies.inc"

global_settings{assumed_gamma 1.70}

#declare myclock=clock*4;

#declare inches=1;
#declare Camera=<0,10,0>;
#declare Lookat=<0,10,1>;

#local loffset0=<-2,2,0>;

// Move a Vector from, to, increment 
#macro MoveV(_from, _to, __i)
	<_from.x+((_to.x-_from.x)*__i),
	 _from.y+((_to.y-_from.y)*__i),
	 _from.z+((_to.z-_from.z)*__i)>
#end

// Animate this segment of the clock from 0 to 1
#macro AniSegment(_start, _end)
	((myclock-_start)/(_end-_start))
#end

#macro vdebug(vec)
	concat("<", str(vec.x,0,2), ", ",str(vec.y,0,2), ", ", str(vec.z,0,2), ">")
#end

// Convert this vector into its angle
#macro VtoA(V)
	#local _V=vnormalize(V);
	#local rZ=degrees(acos(_V.x));
	#local rY=degrees(atan2(_V.y,_V.z));
	//<-rY,-rZ,0>
	
	#local rX=degrees(atan2(sqrt(_V.y*_V.y+_V.z*_V.z),_V.x))-90;
	#local rY=degrees(atan2(sqrt(_V.z*_V.z+_V.x*_V.x),_V.y))-90;
	#local rZ=degrees(atan2(sqrt(_V.x*_V.x+_V.y*_V.y),_V.z));
	#debug concat("rX/Y/Z=<", str(rX,0,2), ", ", str(rY,0,2), ", ", str(rZ,0,2), ">\n")
	//<rX,rY,rZ>
	<rY,-rX,0>
#end

#switch (myclock)
	#range(0,1)
		#local _i=AniSegment(0,1);
		#declare Lookat=Lookat+MoveV(<0,0,0>,loffset0,_i);
		#break
#end

#local V=vnormalize(Lookat-Camera);
sphere {V+Camera,0.02*inches pigment {Red}}		
#declare FlashlightRot=VtoA(V);
#debug concat ("Flashlight V=", vdebug(V), " Rot=", vdebug(FlashlightRot), "\n")
#local FOO=<0,0,10>;
#local FOO=vrotate(FOO, FlashlightRot);	// +Camera;
#debug concat ("rot FOO=", vdebug(FOO), "\n")
sphere {FOO+Camera, 0.5*inches pigment {Cyan}}
#debug concat ("FOO=", vdebug(FOO), "\n")

camera {
	location Camera
	look_at	 Lookat
}

light_source {<0,20,0> rgb 1}
sky_sphere { S_Cloud3 rotate y * 180}
plane { y, 0
	texture {
		checker
		texture {
			pigment {ForestGreen}
		},
		texture {
			pigment{White}
		}
	}
	scale 12*inches
}