94 lines
3.4 KiB
C#
94 lines
3.4 KiB
C#
using System.Drawing;
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namespace PongGame.Hubs;
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/// <summary>
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/// Pong game state saving the positions of the paddles and the ball.
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/// The Pong board has aspect ratio 1:2 with height 500 and width 1000.
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/// </summary>
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public struct PongGameState {
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public const float HEIGHT = 500.0f;
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public const float WIDTH = 2 * HEIGHT;
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public const float PADDLE1_OFFSET = 50.0f;
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public const float PADDLE2_OFFSET = 1000 - PADDLE1_OFFSET;
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public static readonly PongGameState Initial = new() {
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BallState = PongBallState.Initial,
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Paddle1 = PongPaddleState.Initial,
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Paddle2 = PongPaddleState.Initial,
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Status = GameStatus.WaitingForPlayers
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};
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public PongPaddleState Paddle1;
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public PongPaddleState Paddle2;
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public PongBallState BallState;
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public GameStatus Status;
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public static void Update(ref PongGameState state) {
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if (state.Status is not GameStatus.InProgress) return;
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PongPaddleState.Update(ref state.Paddle1);
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PongPaddleState.Update(ref state.Paddle2);
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PongBallState.Update(ref state.BallState);
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Collide(in state.Paddle1, ref state.BallState, true);
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Collide(in state.Paddle2, ref state.BallState, false);
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}
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private static void Collide(in PongPaddleState paddle, ref PongBallState ballState, bool left) {
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var paddleX = left ? PADDLE1_OFFSET : PADDLE2_OFFSET;
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var intersection = RectangleF.Intersect(paddle.GetCollider(paddleX), ballState.GetCollider());
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if (intersection.IsEmpty) return;
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// TODO: continuous collision
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var ratio = (ballState.Y - paddle.Height + PongPaddleState.PADDLE_HALF_LENGTH) / PongPaddleState.PADDLE_LENGTH;
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var upAngle = left ? MathF.PI * 3 / 8 : MathF.PI * 5 / 8;
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var downAngle = -upAngle;
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ballState.BallAngle = ratio * downAngle + (1 - ratio) * upAngle;
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}
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public struct PongBallState {
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public const float BALL_SPEED = 8;
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public const float BALL_RADIUS = 2;
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public static readonly PongBallState Initial = new() {
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BallAngle = 0.0f,
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X = WIDTH / 2,
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Y = HEIGHT / 2
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};
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public float X;
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public float Y;
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public float BallAngle;
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public static void Update(ref PongBallState state) {
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var (dy, dx) = MathF.SinCos(state.BallAngle);
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state.X += BALL_SPEED * dx;
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state.Y -= BALL_SPEED * dy;
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}
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public RectangleF GetCollider() => new(X - BALL_RADIUS, Y - BALL_RADIUS, 2 * BALL_RADIUS, 2 * BALL_RADIUS);
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}
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public struct PongPaddleState {
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public const float PADDLE_LENGTH = HEIGHT / 10;
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public const float PADDLE_HALF_LENGTH = PADDLE_LENGTH / 2;
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public const float PADDLE_WIDTH = PADDLE_LENGTH / 6;
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public const float PADDLE_SPEED = 8;
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public static readonly PongPaddleState Initial = new() {
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Direction = PongPaddleDirection.Stop,
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Height = HEIGHT / 2
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};
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public float Height;
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public PongPaddleDirection Direction;
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public static void Update(ref PongPaddleState state) {
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state.Height = Math.Clamp(state.Height + ((int)state.Direction) * PADDLE_SPEED, PADDLE_HALF_LENGTH, HEIGHT - PADDLE_HALF_LENGTH);
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}
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public RectangleF GetCollider(float x) => new(x - PADDLE_HALF_LENGTH, Height - PADDLE_HALF_LENGTH, PADDLE_WIDTH, PADDLE_LENGTH);
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}
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} |