mirror of
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
135 lines
5.3 KiB
Text
135 lines
5.3 KiB
Text
// pong/constants.ne — layout, gameplay, powerup, and phase constants.
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//
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// Everything that feeds Pong's positional layout, animation timing,
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// powerup machine, or score tracking lives here so one central edit
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// can retune the whole game. No code, just `const` entries.
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// ── Playfield layout ──────────────────────────────────────
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//
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// The NES screen is 256×240. We leave the top 16 px for the HUD
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// score strip and the bottom 24 px as a buffer, giving a 200 px
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// tall playfield from y = 16 to y = 216.
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const PLAYFIELD_TOP: u8 = 16
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const PLAYFIELD_BOTTOM: u8 = 216
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const PLAYFIELD_LEFT: u8 = 0
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const PLAYFIELD_RIGHT: u8 = 248
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// ── Paddles ──────────────────────────────────────────────
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//
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// Paddles are 8 px wide. Normal height is 24 px (3 tiles), long
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// mode bumps to 40 px (5 tiles). Paddle y is the top edge.
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const PADDLE_W: u8 = 8
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const PADDLE_H: u8 = 24
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const PADDLE_H_LONG:u8 = 40
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const LEFT_PADDLE_X: u8 = 16 // fixed x for the left paddle
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const RIGHT_PADDLE_X: u8 = 232 // fixed x for the right paddle
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// Human paddle speed and CPU tracking speed.
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const PADDLE_SPEED: u8 = 2
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const CPU_SPEED: u8 = 1
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// When a powerup is caught by a paddle, the catching paddle gets
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// LONG_PADDLE_HITS worth of extended-height paddle.
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const LONG_PADDLE_HITS: u8 = 5
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// ── Ball ─────────────────────────────────────────────────
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//
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// 8×8 sprite. Position is the top-left corner. Velocity is a
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// per-axis (magnitude, sign) pair — u8 magnitude + u8 sign bit
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// (0 = positive / +x right / +y down, 1 = negative).
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const BALL_SIZE: u8 = 8
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const BALL_BASE_DX: u8 = 1
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const BALL_BASE_DY: u8 = 1
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const BALL_FAST_DX: u8 = 2
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const MAX_BALLS: u8 = 3
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// ── Powerup ──────────────────────────────────────────────
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//
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// One powerup active at a time. Spawns periodically, bounces
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// around for a while, despawns if nobody catches it.
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const POWERUP_SIZE: u8 = 8
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const POWERUP_SPEED: u8 = 1
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const POWERUP_SPAWN_FRAMES: u16 = 240 // ~4 s at 60 Hz
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const POWERUP_LIFE_FRAMES: u16 = 480 // ~8 s before despawn
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const PWR_NONE: u8 = 0
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const PWR_LONG: u8 = 1
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const PWR_FAST: u8 = 2
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const PWR_MULTI: u8 = 3
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const PWR_KINDS: u8 = 3 // number of real kinds (LONG / FAST / MULTI)
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// ── Sides ────────────────────────────────────────────────
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//
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// Side indexing for the two paddles. Used by input, AI,
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// collision, powerup apply, and victory.
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const SIDE_LEFT: u8 = 0
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const SIDE_RIGHT: u8 = 1
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// ── Scoring ──────────────────────────────────────────────
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const WIN_SCORE: u8 = 7
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// ── HUD ──────────────────────────────────────────────────
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//
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// Score digits at the top of the screen, 2 digits per side.
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const SCORE_LEFT_X: u8 = 88
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const SCORE_RIGHT_X: u8 = 152
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const SCORE_Y: u8 = 16
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// ── Title menu ───────────────────────────────────────────
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const MODE_CPU_VS_CPU: u8 = 0
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const MODE_HUMAN_VS_CPU: u8 = 1
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const MODE_HUMAN_VS_HUMAN:u8 = 2
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// Title autopilot: if no input for this many frames, the menu
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// commits to CPU VS CPU so the headless golden harness always
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// reaches gameplay.
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const TITLE_AUTO_FRAMES: u8 = 45
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// ── Phase machine (state Playing) ────────────────────────
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//
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// Explicit constants instead of an enum to keep names from
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// colliding with state names.
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const P_SERVE: u8 = 0
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const P_PLAY: u8 = 1
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const P_POINT: u8 = 2
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// Frames spent in each non-PLAY phase.
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const FRAMES_SERVE: u8 = 60 // 1 s countdown before the ball launches
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const FRAMES_POINT: u8 = 40 // 0.67 s pause after a point
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const VICTORY_LINGER_FRAMES: u16 = 240 // 4 s on the victory screen
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// ── Tile indices into the Tileset sprite ─────────────────
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//
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// Every `draw Tileset frame: N` call in render.ne uses a constant
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// from this block. If you add or remove a tile in assets.ne, move
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// the constants too.
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// Tile 0 is the builtin smiley that the linker reserves; every
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// custom tile starts at 1.
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// Alphabet A-Z at indices 1..26 (A = 1, Z = 26).
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const TILE_LETTER_BASE: u8 = 1
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// Digits 0-9 at indices 27..36 (0 = 27).
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const TILE_DIGIT_BASE: u8 = 27
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// Paddle body — top cap / mid / bottom cap.
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const TILE_PADDLE_TOP: u8 = 37
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const TILE_PADDLE_MID: u8 = 38
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const TILE_PADDLE_BOT: u8 = 39
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// Ball (8×8 filled circle).
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const TILE_BALL: u8 = 40
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// Cursor (▶) for the title menu.
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const TILE_CURSOR: u8 = 41
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// Center-line dash (8×8 vertical bar).
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const TILE_CENTER_DASH: u8 = 42
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// Powerup icons — one tile per powerup kind. Indexed as
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// TILE_POWERUP_BASE + (kind - 1), so LONG = +0, FAST = +1,
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// MULTI = +2.
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const TILE_POWERUP_BASE: u8 = 43
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