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https://github.com/imjasonh/nescript
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21b91f6398
A complete, playable Pong game split across examples/pong/*.ne files
and pulled in from a top-level examples/pong.ne. Features:
- **Title screen** with a 3-option menu (CPU VS CPU / 1 PLAYER /
2 PLAYERS), a cursor sprite, blinking "PRESS A" prompt, brisk
title march on pulse 2, and autopilot that auto-confirms CPU VS
CPU after 45 frames of no input so the headless jsnes golden
harness reaches gameplay by frame 180.
- **Ball physics** with signed-magnitude velocity (u8 magnitude +
sign bit per axis), wall bounce at top/bottom, paddle AABB
collision with push-out, and score-out detection at left/right
exits.
- **Multi-ball** via parallel ball_* arrays (MAX_BALLS = 3). Each
ball scores a point independently; the round continues until the
last ball exits the playfield.
- **CPU AI** that tracks the nearest active ball heading toward its
side with a per-frame step, 4 px dead zone, and CPU_SPEED = 1 so
rallies can end naturally.
- **Three powerup types** that spawn every ~4 seconds, bounce off
all four walls, and are caught by paddle AABB overlap:
1. LONG — extends the catching paddle from 24 → 40 px for 5 hits
2. FAST — doubles ball x-velocity on the catcher's next hit
3. MULTI — spawns two extra balls on the catcher's next hit
- **Victory** at first-to-7 with a "PLAYER N WINS" banner and the
builtin fanfare, auto-returning to Title.
- **Audio**: 5 user-declared sfx (WallBounce, PaddleHit, Score,
PowerSpawn, PowerCatch) plus a title march and the builtin
fanfare for victory.
Source layout mirrors examples/war:
examples/pong.ne top-level game shell
examples/pong/PLAN.md living design doc
examples/pong/constants.ne layout + gameplay constants
examples/pong/assets.ne 45-tile Tileset (paddles, ball, alphabet,
digits, cursor, center-line, powerup icons)
examples/pong/audio.ne sfx + music declarations
examples/pong/state.ne all mutable globals
examples/pong/rng.ne 8-bit Galois LFSR
examples/pong/render.ne draw helpers
examples/pong/input.ne paddle step (human + CPU AI)
examples/pong/ball.ne multi-ball physics + paddle collision
examples/pong/powerup.ne powerup entity (spawn, bounce, catch, apply)
examples/pong/title_state.ne state Title + menu
examples/pong/play_state.ne state Playing (P_SERVE/P_PLAY/P_POINT)
examples/pong/victory_state.ne state Victory
Verification:
- 616 compiler unit tests pass (cargo test --all-targets)
- cargo fmt / cargo clippy --all-targets -- -D warnings clean
- 33/33 emulator harness goldens match
- examples/pong.nes builds byte-identically from source
https://claude.ai/code/session_0134F5uwDEVTes2Ee9S7JeXy
88 lines
4.3 KiB
Text
88 lines
4.3 KiB
Text
// pong/state.ne — every mutable variable the game touches.
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//
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// As in the war example, keeping these as globals means helper
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// functions can read and write without taking parameters and
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// returning values — the 6502's 8-register ABI makes every extra
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// parameter an extra LDA/STA pair, so the shorter call signatures
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// pay for themselves in the hot loop.
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// ── Paddles ──────────────────────────────────────────────
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//
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// Two parallel u8 arrays indexed by `side` (SIDE_LEFT = 0, SIDE_RIGHT = 1).
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// `paddle_y[i]` — top-edge y of paddle i
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// `paddle_long[i]` — remaining LONG-paddle hits (0 = normal)
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// `paddle_fast[i]` — 1 if catcher's next hit doubles ball x velocity
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// `paddle_multi[i]` — 1 if catcher's next hit spawns two extra balls
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// `score[i]` — current score (0..WIN_SCORE)
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// `is_cpu[i]` — 1 if this side is CPU-controlled
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var paddle_y: u8[2] = [96, 96]
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var paddle_long: u8[2] = [0, 0]
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var paddle_fast: u8[2] = [0, 0]
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var paddle_multi: u8[2] = [0, 0]
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var score: u8[2] = [0, 0]
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var is_cpu: u8[2] = [1, 1]
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// ── Balls ────────────────────────────────────────────────
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//
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// Parallel u8 arrays, one slot per ball up to MAX_BALLS. Each
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// ball's velocity is stored as a (magnitude, sign) pair so the
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// existing u8-only arithmetic suffices — sign 0 means +x right
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// / +y down, sign 1 means -x left / -y up.
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//
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// `ball_active[i]` — 1 if this slot is in play, 0 if free
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// `ball_x[i]` — top-left x in px
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// `ball_y[i]` — top-left y in px
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// `ball_dx[i]` — x speed in px/frame
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// `ball_dy[i]` — y speed in px/frame
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// `ball_dx_sign[i]` — 0 = moving right, 1 = moving left
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// `ball_dy_sign[i]` — 0 = moving down, 1 = moving up
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var ball_active: u8[3] = [0, 0, 0]
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var ball_x: u8[3] = [0, 0, 0]
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var ball_y: u8[3] = [0, 0, 0]
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var ball_dx: u8[3] = [0, 0, 0]
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var ball_dy: u8[3] = [0, 0, 0]
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var ball_dx_sign: u8[3] = [0, 0, 0]
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var ball_dy_sign: u8[3] = [0, 0, 0]
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// ── Powerup ──────────────────────────────────────────────
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//
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// Single-slot powerup entity. `powerup_kind == PWR_NONE` means
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// nothing is on screen; any other value is the current kind plus
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// its position and velocity. `powerup_timer` counts frames since
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// spawn so we can despawn after POWERUP_LIFE_FRAMES.
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var powerup_kind: u8 = 0
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var powerup_x: u8 = 0
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var powerup_y: u8 = 0
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var powerup_dx_sign: u8 = 0
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var powerup_dy_sign: u8 = 0
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var powerup_timer: u16 = 0
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var powerup_cooldown:u16 = 0 // counts down to the next spawn
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// ── Game mode + phase machine ────────────────────────────
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var mode: u8 = 0 // 0/1/2 — CPU vs CPU / human vs CPU / human vs human
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var phase: u8 = 0 // one of the P_* constants
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var phase_timer: u8 = 0 // frames spent in the current phase
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var serving_side:u8 = 0 // which side serves next (alternates)
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// ── Title menu ────────────────────────────────────────────
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var title_cursor: u8 = 0
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var title_timer: u8 = 0
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var title_blink: u8 = 0
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var title_debounce: u8 = 0
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// ── Victory state ─────────────────────────────────────────
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var winner: u8 = 0
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var victory_timer: u16 = 0
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// ── RNG ──────────────────────────────────────────────────
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//
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// 8-bit Galois LFSR state. Seeded from the title frame counter at
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// the moment the title transitions to gameplay so the shuffle of
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// the first serve direction and powerup kinds is deterministic
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// once a user commits. The jsnes headless harness always hits the
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// title autopilot at the same frame, so the seed is stable there
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// too.
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var rng_state: u8 = 0xA7
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// ── Global free-running frame counter ────────────────────
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var global_tick: u16 = 0
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