commit f9217e45eac5b753684ecef105c1c09c40fe3888
Author: Samrat Man Singh <samratmansingh@gmail.com>
Date:   Thu Mar 10 12:38:27 2016 +0545

    Initial commit

diff --git a/src/raytracer.ml b/src/raytracer.ml
new file mode 100644
index 00000000..fbeea03c
--- /dev/null
+++ b/src/raytracer.ml
@@ -0,0 +1,63 @@
+open Core.Std
+open Printf
+open Vec3
+    
+type sphere = { center: Vec3.vec3;
+                radius: float }
+type ray = { origin: Vec3.vec3;
+             dir: Vec3.vec3 }
+
+let hit_sphere sphere ray =
+  let oc = sub ray.dir sphere.center in
+  let a = dot ray.dir ray.dir in
+  let b = dot oc ray.dir in
+  let c = (dot oc oc) -. (sphere.radius *. sphere.radius) in
+  let discriminant = b*.b -. a*.c in
+
+  ( discriminant > 0.0)
+
+let get_color ray =
+  if (hit_sphere {center = Vec3.of_floats (0., 0., -1.);
+                  radius = 0.5}
+        ray)
+  then Vec3.of_floats (1., 0., 0.)
+  else let unit_direction = unit_vector ray.dir in
+    let t = 0.5 *. (unit_direction.y +. 1.0) in
+    add (mul (1.0 -. t) {x= 1.0; y=1.0; z= 1.0}) (mul t {x= 0.5; y= 0.7; z= 1.0})
+          
+
+let main() =
+  let nx = 200 in
+  let ny = 100 in
+  print_string "P3\n";
+  printf "%d\n" nx;
+  printf "%d\n"  ny;
+  print_string "\n255\n";
+
+  let lower_left_corner = Vec3.of_floats (-2., -1., -1.) in
+  let horizontal = Vec3.of_floats (4., 0., 0.) in
+  let vertical = Vec3.of_floats (0., 2., 0.) in
+  let origin = Vec3.of_floats (0., 0., 0.) in
+  let color = ref {x=0.; y=0.; z=0.} in
+  for j = ny downto 1 do
+    for i = 0 to nx-1 do
+      let u = (Float.of_int i) /. (Float.of_int nx) in
+      let v = (Float.of_int j) /. (Float.of_int ny) in
+
+      let r = { origin = origin;
+                dir = Vec3.add lower_left_corner (Vec3.add (Vec3.mul u horizontal) (Vec3.mul v vertical)) } in
+      color := get_color r;
+
+      let {x=r; y=g; z=b} = !color in
+      let (ir, ig, ib) = (Int.of_float (r*.255.99),
+                          Int.of_float (g*.255.99),
+                          Int.of_float (b*.255.99)) in
+      printf "%d " ir;
+      printf "%d " ig;
+      printf "%d " ib;
+      print_newline();
+    done
+  done
+;;
+
+(* main() *)
diff --git a/src/vec3.ml b/src/vec3.ml
new file mode 100644
index 00000000..663a041a
--- /dev/null
+++ b/src/vec3.ml
@@ -0,0 +1,38 @@
+type vec3 = { x: float;
+              y: float;
+              z: float }
+
+let of_floats (e1, e2, e3) =
+  {x = e1; y = e2; z = e3}
+
+let add v w =
+  {x = v.x +. w.x; 
+   y = v.y +. w.y; 
+   z = v.z +. w.z}
+
+let sub v w =
+  {x = v.x -. w.x;
+   y = v.y -. w.y; 
+   z = v.z -. w.z}
+
+let dot v w =
+  v.x*.w.x +. v.y*.w.y +.v.z*.w.z
+
+let cross v w =
+  {x = v.y*.w.z -. v.z*.w.y;
+   y = v.z*.w.x -. v.x*.w.z;
+   z = v.x*.w.y -. v.y*.w.x}
+
+let length v =
+  sqrt (dot v v)
+
+let unit_vector v =
+  let l = length v in
+  { x = v.x /. l;
+    y = v.y /. l;
+    z = v.z /. l }
+
+let mul t v =
+  { x = t *. v.x;
+    y = t *. v.y;
+    z = t *. v.z }
diff --git a/src/vec3.mli b/src/vec3.mli
new file mode 100644
index 00000000..d29871fa
--- /dev/null
+++ b/src/vec3.mli
@@ -0,0 +1,11 @@
+type vec3 = { x: float;
+              y: float;
+              z: float }
+
+val of_floats : float * float * float -> vec3
+val add : vec3 -> vec3 -> vec3
+val sub : vec3 -> vec3 -> vec3
+val dot : vec3 -> vec3 -> float
+val cross: vec3 -> vec3 -> vec3
+val mul : float -> vec3 -> vec3
+val unit_vector : vec3 -> vec3