From a21802e9f2e5c7ba677a6d945579bed9259e5cf3 Mon Sep 17 00:00:00 2001
From: Colin McMillen <colin@semicolin.games>
Date: Sat, 15 Feb 2020 15:14:44 -0500
Subject: [PATCH] FMath.DegToRad(): use look-up table.

GitOrigin-RevId: 2dab2e175cf99448595304eeb7593bf499485273
---
 Shared/Geometry.cs | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Shared/Geometry.cs b/Shared/Geometry.cs
index b5a22e5..58e1eff 100644
--- a/Shared/Geometry.cs
+++ b/Shared/Geometry.cs
@@ -19,8 +19,24 @@ namespace SemiColinGames {
   public static class FMath {
     public const float PI = (float) Math.PI;
 
-    public static float DegToRad(float degrees) {
-      return PI / 180 * degrees;
+    private static float[] degToRad = new float[360];
+
+    static FMath() {
+      for (int i = 0; i < degToRad.Length; i++) {
+        degToRad[i] = PI / 180 * i;
+      }
+    }
+
+    // Converts degrees to radians using a look-up table. Expects the input to be near [0, 360)
+    // and will loop for potentially a long while if that's not the case.
+    public static float DegToRad(int degrees) {
+      while (degrees < 0) {
+        degrees += 360;
+      }
+      while (degrees >= 360) {
+        degrees -= 360;
+      }
+      return degToRad[degrees];
     }
 
     public static float Sin(double degrees) {