Fix ray calculations by normalizing angles properly

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/main.dart

@@ -24,8 +24,9 @@ const double gameWidth = 320;
 const double gameHeight = 256;
 
 extension GameValues on double {
-  /// Normalizes an angle back into [0, 2π].
-  double get normalize => (this % (2 * math.pi) + 2 * math.pi) % (2 * math.pi);
+  /// Normalizes an angle back into [0, 2π) from (-π, π].
+  double get normalizeAngle =>
+      (this % (2 * math.pi) + 2 * math.pi) % (2 * math.pi);
 
   /// Returns the degree angle
   double get radianToDegree {
@@ -52,14 +53,14 @@ extension GameValues on double {
   // Flutter's coordinate system flips the y-axis, which is why we have -sin() -- to flip
   // it back in the correct direction.
   Offset get direction => Offset(
-    math.cos(normalize),
-    -math.sin(normalize),
+    math.cos(normalizeAngle),
+    math.sin(normalizeAngle),
   );
 
   /// Get the delta from the given angle
   Offset get playerDelta => Offset(
-    math.cos(this) * Player.speed,
-    math.sin(this) * Player.speed,
+    direction.dx * Player.speed,
+    direction.dy * Player.speed,
   );
 }
 
@@ -191,7 +192,7 @@ class _PlayerState extends State<Player> {
       widget.onRaysUpdated(
         calculateRays(
           widget.rayData.playerPosition,
-          widget.rayData.playerAngle.playerDelta,
+          widget.rayData.playerAngle,
         ),
       );
 
@@ -243,28 +244,23 @@ class _PlayerState extends State<Player> {
     // Where is the player now?
     Offset playerPosition = widget.rayData.playerPosition;
     double playerAngle = widget.rayData.playerAngle;
-    final Offset direction = playerAngle.direction;
 
     // How many pixels away from a wall to stay
     const double buffer = 8;
 
     if (keys.contains(LogicalKeyboardKey.keyA)) {
-      // Move left
+      // Turn left
       playerAngle -= 0.1;
-      if (playerAngle < 0) {
-        playerAngle += 2 * math.pi;
-      }
       handled = true;
     } else if (keys.contains(LogicalKeyboardKey.keyD)) {
-      // Move right
+      // Turn right
       playerAngle += 0.1;
-
-      if (playerAngle > 2 * math.pi) {
-        playerAngle -= 2 * math.pi;
-      }
       handled = true;
     }
 
+    // Capture the direction *after* it's potentially mutated
+    final Offset direction = playerAngle.direction;
+
     if (keys.contains(LogicalKeyboardKey.keyW)) {
       if (safeDistanceToWall(playerPosition, direction) >
           Player.speed + buffer) {
@@ -283,7 +279,7 @@ class _PlayerState extends State<Player> {
 
     if (handled) {
       widget.onRaysUpdated(
-        calculateRays(playerPosition, playerAngle.playerDelta),
+        calculateRays(playerPosition, playerAngle),
       );
       widget.onAngleUpdated(playerAngle);
       widget.onPositionUpdated(playerPosition);
@@ -293,7 +289,7 @@ class _PlayerState extends State<Player> {
     return false;
   }
 
-  List<Ray> calculateRays(Offset offset, Offset delta) {
+  List<Ray> calculateRays(Offset offset, double playerAngle) {
     const double dr = math.pi / 180;
 
     final List<Ray> rays = [];
@@ -312,14 +308,7 @@ class _PlayerState extends State<Player> {
     double rayY = 0;
     double disT = 0;
 
-    double rayAngle = delta.direction - (dr * 30);
-
-    if (rayAngle < 0) {
-      rayAngle += 2 * math.pi;
-    }
-    if (rayAngle > 2 * math.pi) {
-      rayAngle -= 2 * math.pi;
-    }
+    double rayAngle = (playerAngle - (dr * 30)).normalizeAngle;
 
     int r;
     for (r = 0; r < 60; r++) {
@@ -492,14 +481,8 @@ class _PlayerState extends State<Player> {
       }
 
       // * Increase the ray angle to draw the next ray
-      rayAngle += dr;
-
-      if (rayAngle < 0) {
-        rayAngle += 2 * math.pi;
-      }
-      if (rayAngle > 2 * math.pi) {
-        rayAngle -= 2 * math.pi;
-      }
+      rayAngle =
+          (playerAngle.normalizeAngle - (dr * 30) + r * dr).normalizeAngle;
     }
 
     return rays;
@@ -608,13 +591,7 @@ class WallPainter extends CustomPainter {
       const double dr = math.pi / 180;
       final double rayAngle = playerAngle - (dr * 30) + (i * dr);
 
-      double correctedAngle = playerAngle - rayAngle;
-      if (correctedAngle < 0) {
-        correctedAngle += 2 * math.pi;
-      }
-      if (correctedAngle > 2 * math.pi) {
-        correctedAngle -= 2 * math.pi;
-      }
+      final double correctedAngle = (playerAngle - rayAngle).normalizeAngle;
 
       final double disT = ray.distance * math.cos(correctedAngle);