//*******************************************************************
//
//  macro : M_Iris
//      parameters :
//          MI_n         : number of iris 'petals'
//          MI_s         : radius of iris, oriented on (x,y) plane
//          MI_open      : opening fraction - 0 is closed, 1 is open
//          MI_is_union  : whether petals are unioned or merged
//
//*******************************************************************
#macro M_Iris ( MI_n, MI_s, MI_open, MI_is_union )
	intersection {
		cylinder { -0.05*z, 0.05*z, 1 }
		#if (MI_is_union)
			union {
		#else
			merge {
		#end
			#local MI_c = 0; #while (MI_c < MI_n)
				cylinder { -0.01*z, 0.01*z, 1
					rotate -3*y
					translate y
					rotate 60*z
					translate -y rotate -MI_open*MI_open*120*z translate y
					rotate 360*(MI_c/MI_n)*z
				}
			#local MI_c = MI_c + 1; #end
		}
		scale MI_s
	}
#end
			
global_settings { assumed_gamma 1.0 }

background { color rgb 0.6 }

camera {
	location  <0.0, 20.0, -50.0>
	direction <0.0, 0.0, 4>
	look_at   <0.0, 0.0, 0.0>
}

light_source {
	0*x
	colour rgb 1.0
	translate <-2000, 4000, -2000>
}

// closed
union {
	torus { 4, 0.2 rotate 90*x }
	M_Iris(10, 4, 0.0, true)
	pigment { rgb <1, .9, .8> }
	finish { diffuse 0.5 specular 0.5 metallic }
	translate <-4, 1, 3>
}

// half way
union {
	torus { 4, 0.2 rotate 90*x }
	M_Iris(10, 4, 0.5, true)
	pigment { rgb <.9, .8, 1> }
	finish { diffuse 0.5 specular 0.5 metallic }
}

// open
union {
	torus { 4, 0.2 rotate 90*x }
	M_Iris(10, 4, 1.0, true)
	pigment { rgb <.8, 1, .9> }
	finish { diffuse 0.5 specular 0.5 metallic }
	translate <4, -1, -3>
}