feat(rtlisp): add rt_inerp binary and demo script

scenes/demo-1.lisp

@@ -0,0 +1,79 @@
+(set 'red
+     (material
+      (color 1 0 0)
+      (color 1 0 0)
+      (color 0.5 0 0)
+      50 0.25))
+(set 'blue
+     (material
+      (color 0 0 1)
+      (color 0 0 1)
+      (color 0 0 0.6)
+      50 0.25))
+(set 'green
+     (material
+      (color 0 1 0)
+      (color 0 1 0)
+      (color 0 0.6 0)
+      50 0.25))
+(set 'white
+     (material
+      (color 1 1 1)
+      (color 1 1 1)
+      (color 0.6 0.6 0.6)
+      100 0.5))
+(set 'black
+     (material
+      (color 0 0 0)
+      (color 0 0 0)
+      (color 0.6 0.6 0.6)
+      100 0.5))
+
+(set 's1
+     (sphere
+      (point 0 1 0) 1 blue))
+(set 's2
+     (sphere
+      (point 2 0.5 2) 0.5 green))
+
+(defun spiral-sphere (i n)
+  (sphere
+   (progn
+     (print "Spiral Sphere at: ")
+     (println (point
+               (* 2 (cos (/ (* i 6.2) n)))
+               0.5
+               (* 2 (sin (/ (* i 6.2) n)))))
+     )
+   0.5 red))
+
+(defun spiral (scn i n)
+  (if (< i n)
+      (scene-add
+       (spiral scn (+ i 1) n)
+       (spiral-sphere i n))
+      scn))
+
+(set 'p1
+     (checkerboard
+      (point 0 0 0)
+      (vector 0 1 0)
+      black white 0.5
+      (vector 0.5 0 1)))
+
+(set 'l1 (light (point 3 10 5) (color 1 1 1)))
+(set 'l2 (light (point 2 10 5) (color 1 1 1)))
+
+
+(set 'scn (scene
+           (color 0.1 0.1 0.1)
+           '(s1 s2 p1)
+           '(l1 l2)))
+
+(set 'scn (spiral scn 0.0 10.0))
+
+(println (cons "Final Scene:" scn))
+
+(set 'cam (camera (point 0 3 6) (point 0 0 0) (vector 0 1 0) 40 1920 1080))
+
+(render cam scn 5 4 "demo-1.png")