Balloon Fight — native macOS static recompilation

This folder turns your Balloon Fight.nes into a native Mac app. Nothing is emulated instruction-by-instruction: the game's 6502 machine code is translated ahead of time into C and compiled by clang into an arm64 + x86_64 binary.

Build

Double-click build.command (first time: right-click → Open). It needs Apple's free Command Line Tools and offers to install them if they're missing. The result is Balloon Fight.app, next to your ROM.

To use a ROM somewhere else: ./build.command /path/to/rom.nes

Controls

Defaults (change them in Settings → Controls, ⌘,):

	Player 1	Player 2
Move	Arrow keys	W A S D
A (flap)	X	H
B (rapid flap)	Z	G
Start / Select	Return / Tab	—

Each action takes one key and one controller button per player. Controller 1 drives Player 1, controller 2 drives Player 2, and the left stick always steers. Bindings are saved automatically.

Video

Settings → Video or the View menu:

• Filtering: Nearest (sharp pixels), Linear (smooth), or Sharp linear (whole-pixel nearest scaling first, then linear smoothing for the remainder).
• Pixel aspect: square, or NTSC TV 8:7.
• Scanlines: Off, Light, Medium or Strong; a dark band between game lines, shown once the picture is at least 2× tall. Most even with integer scaling.
• Integer scaling and Crop overscan (hides the top and bottom 8 lines).

⌘R reset · ⌘P pause · ⌘1–4 window size · ⌃⌘F full screen.

How it works

• recomp.py traces all code reachable from the reset/NMI/IRQ vectors (plus entries.txt, the targets of the game's one indirect JMP ($0025), found by playtesting) and emits one C label per 6502 instruction. Branches, jumps and calls become gotos; returns go through a dispatcher. The 6502 stack is kept in emulated RAM, so stack tricks behave like on hardware. Code is split into ~160-instruction functions to keep compile times short.
• Anything the trace missed falls back to a generated interpreter with the same semantics. In 360,000 frames of randomized playtesting across 1P, 2P and Balloon Trip, the fallback was never hit.
• runtime/ holds the hardware: PPU (scanline renderer with dot-timed vblank, NMI and sprite-0 hit), APU (2 pulse, triangle, noise, DMC with the NES mixer), controllers. platform/mac/main.m is the Cocoa/Core Animation/Core Audio/GameController front-end.
• The generated C (gen/) and the app are built from your ROM on your Mac only; this folder contains no game code or data.