Games: Pong, Snake and Tetris as seeded state machines, and a tune

The rules of the three Games (issue #101), with no screen and no keyboard in them: time and keys go in, the new state and what happened come out, and a seed decides the dice. With a player for a tune a note at a time, and Korobeiniki's notes. Host-tested. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk
2026-10-13 22:59:05 +02:00
parent 5c660d866d
commit 68d50b320f
9 changed files with 1417 additions and 0 deletions
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+#pragma once
+
+#include <cstdint>
+
+#include "game_rng.h"
+
+namespace roro::games {
+
+// Pong against the device (issue #101): the player's paddle on the left, the device's on the
+// right, first to 7. The ball goes faster with each return, and the device's paddle only moves so
+// fast: a steep, fast ball gets past it. Lengths are pixels of the 240 x 122 field, times seconds.
+class Pong {
+   public:
+    static constexpr float kWidth = 240, kHeight = 122;
+    static constexpr float kPaddleH = 24, kPaddleW = 3, kMargin = 6, kBall = 4;
+    static constexpr float kPlayerSpeed = 150, kDeviceSpeed = 88;
+    static constexpr float kServeSpeed = 110, kMaxSpeed = 270, kFaster = 1.06f;
+    static constexpr float kServePause = 0.8f;
+    static constexpr int kWinScore = 7;
+
+    enum Event : uint8_t { Wall = 1, Hit = 2, Point = 4, Over = 8 };
+    enum class Phase : uint8_t { Serve, Play, Over };
+
+    explicit Pong(uint32_t seed) : rng_(seed) { start(); }
+    void start();
+    // `seconds` later, with the player's paddle asked up (-1), down (1) or left alone (0).
+    // What happened, as Events.
+    uint8_t step(float seconds, int move);
+
+    Phase phase() const { return phase_; }
+    float ballX() const { return x_; }
+    float ballY() const { return y_; }
+    float speed() const { return speed_; }
+    float playerY() const { return player_; }  // the paddle's middle
+    float deviceY() const { return device_; }
+    int playerScore() const { return playerScore_; }
+    int deviceScore() const { return deviceScore_; }
+    bool playerWon() const { return playerScore_ >= kWinScore; }
+    int rally() const { return rally_; }          // the player's returns since the serve
+    int longestRally() const { return longest_; }  // in this game
+
+   private:
+    uint8_t tick(float dt, int move);
+    void serve(bool toPlayer);
+    bool meets(float paddleY) const;
+    void bounceOff(float paddleY, bool toRight);
+
+    Rng rng_;
+    Phase phase_ = Phase::Serve;
+    float x_ = 0, y_ = 0, vx_ = 0, vy_ = 0, speed_ = 0;
+    float player_ = 0, device_ = 0, wait_ = 0;
+    int playerScore_ = 0, deviceScore_ = 0, rally_ = 0, longest_ = 0;
+};
+
+}  // namespace roro::games