Added simple trajectory sample

.gitignore

@@ -57,3 +57,6 @@ $RECYCLE.BIN/
 *.lnk
 
 # End of https://www.toptal.com/developers/gitignore/api/code,nim,linux,windows
+
+raytracer_nim
+output.ppm

src/raytracer_nim.nim

@@ -1,5 +1,25 @@
-# This is just an example to get you started. A typical binary package
-# uses this file as the main entry point of the application.
+import "./tuple", "./canvas"
+
+type 
+  Projectile = object
+    position: Tuple4
+    velocity: Tuple4
+  Environment = object
+    gravity: Tuple4
+    wind: Tuple4
+
+proc tick(proj: Projectile, env: Environment): Projectile = Projectile(position: proj.position + proj.velocity, velocity: proj.velocity + env.gravity + env.wind)
 
 when isMainModule:
-  echo("Hello, World!")
+  var world = canvas(800, 600)
+  let start = point(0, 1, 0)
+  let velocity = normalize(vector(0.5, 1.2, 0)) * 11.25
+  var projectile = Projectile(position: start, velocity: velocity)
+  let environment = Environment(gravity: vector(0, -0.1, 0), wind: vector(-0.01, 0, 0))
+  let colour = colour(1, 0, 0)
+  while projectile.position.x >= 0 and projectile.position.x < 800 and projectile.position.y >= 0 and projectile.position.y < 600:
+    world.writePixel(projectile.position.x, 600 - projectile.position.y, colour)
+    projectile = projectile.tick(environment)
+  writeFile("output.ppm", world.toPPM())
+
+