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

global_settings{assumed_gamma 1.70}
#debug concat("@@F:", str(frame_number,0,0), "\n")


// 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

// return a vector as a debug string (truncated precision) 
#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.z));
	#local rY=0;
	#local rX=0;
	#if (_V.y != 0)
		#local rY=degrees(atan2(_V.x,_V.y));
	#else
		#local rX=rZ;
		#local rZ=0;
	#end
	#debug concat("rY/Z=", str(rY,0,3), ", ", str(rZ,0,3), "\n")
	<-rZ,rX,-rY>
#end

// new bit added here:
#macro ssOffset(bar)
	#local newZ = vnormalize( Lookat-Camera );
	#local newY = y;
	#local newX = vnormalize(vcross(newY,newZ));
	#local newY = vnormalize(vcross(newZ,newX));
	#local barOut = bar.x * newX + bar.y * newY + bar.z * newZ; 
	#debug concat ("bar=", vdebug(bar), " Out=", vdebug(barOut), "\n")
// sphere {bar, 0.51 pigment {Green}
// translate Camera
	barOut		// <bar.x,bar.y,bar.z>
 //}
#end

// scott's suggestion. It gives me another vector, not an angle.
#macro ssVtoA(bar)
	#local newZ = vnormalize( bar );
	#local newY = y;
	#local newX = vnormalize(vcross(newY,newZ));
	#local newY = vnormalize(vcross(newZ,newX));
	#local barOut = bar.x * newX + bar.y * newY + bar.z * newZ; 
	#debug concat ("bar=", vdebug(bar), " Out=", vdebug(barOut), "\n")
	barOut		// <bar.x,bar.y,bar.z>
 //}
#end

// from http://snipd.net/2d-and-3d-vector-normalization-and-angle-calculation-in-c
#macro ac(V)
	#local V = vnormalize(V);
	#local r = vlength(V);
	#local theta = atan2d(sqrt(pow(V.x,2)+pow(V.y,2)),V.z);
	#local phi = atan2d(V.y, V.x);
	#local out = <0, theta, phi>;
	#debug concat("ac=", vdebug(out), "\n")
	out
#end



#declare myclock=clock*4;

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

// swivel up and down around the camera
#local lo0=<0,0,0>;
#local lo1=<2,0,0>;
#local lo2=<0,2,0>;
#local lo3=<0,2,2>;
#local lo4=<-2,1,-2>;
#local lo5=<-2,-2,2>;

#switch (myclock)
	#range(0,0.5)
		#local _i=AniSegment(0,0.5);
		#debug concat("0,0.5 i=", str(_i,0,3), "\n")
		#declare Lookat=Lookat+MoveV(lo0,lo1,_i);
		#break
	#range(0.5,1)
		#local _i=AniSegment(0.5,1);
		#debug concat("0.5,1 i=", str(_i,0,3), "\n")
		#declare Lookat=Lookat+MoveV(lo0,lo2,_i);
		#break
	#range(1,2)
		#local _i=AniSegment(1,2);
		#debug concat("1,2   i=", str(_i,0,3), "\n")
		#declare Lookat=Lookat+MoveV(lo2,lo3,_i);
		#break
	#range(2,3)
		#local _i=AniSegment(2,3);
		#debug concat("2,3   i=", str(_i,0,3), "\n")
		#declare Lookat=Lookat+MoveV(lo3,lo4,_i);
		#break
	#range(3,4)
		#local _i=AniSegment(3,4);
		#debug concat("3,4   i=", str(_i,0,3), "\n")
		#declare Lookat=Lookat+MoveV(lo4,lo5,_i);
		#break
#end

#debug concat("Camera=", vdebug(Camera), " Lookat=", vdebug(Lookat), "\n")
#local V=vnormalize(Lookat-Camera);
#debug concat("V=", vdebug(V), "\n")
sphere {V+Camera,0.02 pigment {Red}}		

#local cyanV=<0,0,10>;
#local cyanVec=Lookat-Camera;
#local cyanRot=VtoA(cyanVec);
#local cyanF=vrotate(cyanV, cyanRot);
#debug concat ("cyanRot=", vdebug(cyanRot), "\n")
sphere {cyanF+Camera, 0.5 pigment {Cyan}}
#debug concat ("cyanF=", vdebug(cyanF), "\n")


#declare myCyl=
	union {
		cylinder {-1*z, 0*z, 0.5
			pigment {Yellow}}
		sphere {0, 0.5
			pigment {Red}}
	}

object {
	myCyl
	scale 0.2
	#local flOfs = <-0.4,-0.3,0.7>;
	translate flOfs
	#local A=VtoA(cyanVec);
	#debug concat("va=", vdebug(A), "\n")
	rotate <cyanRot.x, cyanRot.y, -cyanRot.z>
	translate Camera
}
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
}

#debug "@@end\n"