FMath.DegToRad(): use look-up table.

GitOrigin-RevId: 2dab2e175c

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) {