Data commit

Task/Draw-a-sphere/Nim/draw-a-sphere.nim

@@ -0,0 +1,31 @@
+import math
+
+type Point = tuple[x,y,z: float]
+
+const shades = ".:!*oe&#%@"
+
+proc normalize(x, y, z: float): Point =
+  let len = sqrt(x*x + y*y + z*z)
+  (x / len, y / len, z / len)
+
+proc dot(a, b: Point): float =
+  result = max(0, - a.x*b.x - a.y*b.y - a.z*b.z)
+
+let light = normalize(30.0, 30.0, -50.0)
+
+proc drawSphere(r: int; k, ambient: float) =
+  for i in -r .. r:
+    let x = i.float + 0.5
+    for j in -2*r .. 2*r:
+      let y = j.float / 2.0 + 0.5
+      if x*x + y*y <= float r*r:
+        let
+          v = normalize(x, y, sqrt(float(r*r) - x*x - y*y))
+          b = pow(dot(light, v), k) + ambient
+          i = clamp(int((1.0 - b) * shades.high.float), 0, shades.high)
+        stdout.write shades[i]
+      else: stdout.write ' '
+    stdout.write "\n"
+
+drawSphere 20, 4.0, 0.1
+drawSphere 10, 2.0, 0.4