feat: max rotation angle

packages/server/src/handleFrame.ts

@@ -2,34 +2,61 @@ import {
   BASE_SPEED,
   FOOD_PICKUP_RADIUS,
   GameMap,
+  getPlayerHead,
+  Player,
   SPRINT_SPEED,
+  MAX_ANGLE,
 } from "@viper-vortex/shared";
 
+function movePlayer(player: Player, gameMap: GameMap) {
+  // move the player
+  // start with the head
+
+  const head = getPlayerHead(player);
+  const speed = player.isSprinting ? SPRINT_SPEED : BASE_SPEED;
+
+  const currentAngle = player.angle;
+  const targetAngle = player.desiredAngle;
+
+  // calculate the angle to turn
+  let angleDiff = targetAngle - currentAngle;
+  if (angleDiff > Math.PI) angleDiff -= Math.PI * 2;
+  if (angleDiff < -Math.PI) angleDiff += Math.PI * 2;
+
+  // limit the angle to turn
+  if (angleDiff > MAX_ANGLE) angleDiff = MAX_ANGLE;
+  if (angleDiff < -MAX_ANGLE) angleDiff = -MAX_ANGLE;
+
+  // apply the angle
+  player.angle += angleDiff;
+
+  head.x += Math.cos(player.angle) * speed;
+  head.y += Math.sin(player.angle) * speed;
+
+  // if the player reaches the edge of the map, slides along the edge
+  if (head.x < 0) head.x = 0;
+  if (head.y < 0) head.y = 0;
+  if (head.x > gameMap.width) head.x = gameMap.width;
+  if (head.y > gameMap.height) head.y = gameMap.height;
+
+  // then all the other body parts follow by moving to the position of the previous body part
+  for (let i = player.body.length - 1; i > 0; i--) {
+    const currentPart = player.body[i];
+    const previousPart = player.body[i - 1];
+    currentPart.x = previousPart.x;
+    currentPart.y = previousPart.y;
+  }
+  return head;
+}
+
 export default function handleFrame(
   gameMap: GameMap,
   onPlayerDeath: (playerId: string) => void,
 ) {
   for (let player of gameMap.players) {
-    // move the player
-    // start with the head
-    const head = player.body[0];
-    const speed = player.isSprinting ? SPRINT_SPEED : BASE_SPEED;
-    head.x += Math.cos(player.angle) * speed;
-    head.y += Math.sin(player.angle) * speed;
-
-    // if the player reaches the edge of the map, slides along the edge
-    if (head.x < 0) head.x = 0;
-    if (head.y < 0) head.y = 0;
-    if (head.x > gameMap.width) head.x = gameMap.width;
-    if (head.y > gameMap.height) head.y = gameMap.height;
+    movePlayer(player, gameMap);
 
-    // then all the other body parts follow by moving to the position of the previous body part
-    for (let i = player.body.length - 1; i > 0; i--) {
-      const currentPart = player.body[i];
-      const previousPart = player.body[i - 1];
-      currentPart.x = previousPart.x;
-      currentPart.y = previousPart.y;
-    }
+    const head = getPlayerHead(player);
 
     // check for collisions with food. Radius of 10
     for (let i = 0; i < gameMap.food.length; i++) {

packages/server/src/index.ts

@@ -35,6 +35,7 @@ io.on(SOCKET_EVENTS.CONNECT, (socket) => {
     body: [{ x: 0, y: 0 }],
     isSprinting: false,
     angle: 0,
+    desiredAngle: 0,
   };
 
   gameMap.players.push(player);
@@ -51,7 +52,7 @@ io.on(SOCKET_EVENTS.CONNECT, (socket) => {
   socket.on(SOCKET_EVENTS.MOVE, (move) => {
     // we rely on the reference to the player object
     player.isSprinting = move.isSprinting;
-    player.angle = move.angle;
+    player.desiredAngle = move.angle;
   });
 });
 

packages/shared/src/constants.ts

@@ -1,13 +1,27 @@
-export const TPS = 60; // ticks per second
+/**
+ * The number of ticks per second.
+ */
+export const TPS = 60;
 
+/**
+ * The speed at which the player moves when walking.
+ */
 export const BASE_SPEED = 2;
+/**
+ * The speed at which the player moves when sprinting.
+ */
 export const SPRINT_SPEED = 5;
 
 /**
  * The radius of the player's head.
  */
 export const FOOD_PICKUP_RADIUS = 20;
 
+/**
+ * The maximum angle the player can turn in one tick.
+ */
+export const MAX_ANGLE = Math.PI / 20;
+
 /**
  * Enum for socket events.
  * @enum {string}

packages/shared/src/types.ts

@@ -5,8 +5,8 @@ export type GameMap = {
   width: number;
   height: number;
   players: Player[];
-  food: Food[]
-}
+  food: Food[];
+};
 
 /**
  * Represents a player.
@@ -17,26 +17,27 @@ export type Player = {
   name: string;
   color: string;
   isSprinting: boolean;
-  angle: number;
-}
+  angle: number; // in radians
+  desiredAngle: number; // in radians
+};
 
 /**
  * Represents a coordinate.
  */
 export type Position = {
   x: number;
   y: number;
-}
+};
 
 export type Food = {
   id: string;
   position: Position;
-}
+};
 
 /**
  * Represents a player move.
  */
 export type PlayerMove = {
   angle: number;
   isSprinting: boolean;
-}
+};

packages/shared/src/utils.ts

@@ -1,5 +1,5 @@
 import { v4 as uuidv4 } from "uuid";
-import { Food, GameMap } from "./types";
+import { Food, GameMap, Player } from "./types";
 
 /**
  * Create a new game map.
@@ -34,3 +34,7 @@ export function randomDarkColor() {
   const randomColor = Math.floor(Math.random() * 16777215).toString(16);
   return "#" + randomColor;
 }
+
+export function getPlayerHead(player: Player) {
+  return player.body[0];
+}