Magical Pop'n Recomp

With Python 3 and either a toolchain folder holding llvm-mingw in the repository root or the Microsoft C++ Build Tools, run Builder.bat or:

python tools/pipeline.py ROM [--out DIR]

To package the builder yourself:

python -m PyInstaller builder/Builder.spec

The whole game is compiled before it starts. There's nothing to configure:

• The repository ships a code map (data/codemap.txt): the addresses of every routine found by many hours of automated play, plus a checksum of the code bytes at each one, and no game data. Every entry whose code matches your ROM is used. The map covers the original Japanese release, the FastROM v1.1 patch (Japanese and English) and the English translation patch, so all of these build straight away.
• Static analysis adds everything reachable from those routines, including routines referenced through pointer tables in the code.
• After compiling, the builder test-plays the finished game and recompiles once more if that test found anything new.

As a safety net, any code the build still missed runs through a built-in interpreter instead of stopping, and building again includes it.

Plug in or pair any controller, before or during play, and it works straight away. You can use several at once. Buttons go by position, as on a Super Famicom pad: bottom = B, right = A, left = Y, top = X. The game reads:

• Xbox-style controllers (XInput): all four slots. This also covers most modern third-party pads, 8BitDo pads in X mode, Steam Input and DS4Windows.
• Every other controller: read directly through Windows (HID), so any USB or Bluetooth gamepad or joystick gives its buttons, sticks and d-pad.
• Built-in layouts:
  • DualShock 4 and DualSense, over USB and Bluetooth.
  • Switch Pro Controller and the Nintendo Switch Online SNES controller, which the game wakes up and switches to their full report.
  • 8BitDo pads in D-input mode, common USB SNES-style pads, and the usual PC gamepad layout.

The F1 menu, styled after the Super Famicom cover art, is a single list on a pink panel, with the selected row highlighted. Use Up and Down to pick a row, Left and Right to change it, and Enter to activate. Esc goes back, and closes the menu from the main page. The mouse works too: hover to select, left-click to change or activate, right-click to change the other way. A note under the list explains the selected setting, and settings are saved automatically.

Sprite limit is off by default. The SNES can only draw so many sprites on one line (32 sprites or 34 eight-pixel slices), and anything past that is cut off. The game hits the limit in a few busy moments, such as the heroine running past the dust cloud on the title screen. With the setting off, every sprite is drawn. Turn it on for the original look. Only the picture changes: the game still sees the hardware's overflow flags as before, so it plays the same.

Check for updates (on by default): when the game starts it looks for a newer release on this repository. If there is one, a box offers to update. Choose Yes and the game downloads the new builder (about 90 MB), rebuilds itself from the ROM it was made from (a minute or two) and starts again, with your saves and settings kept. Nothing about you or your game is sent. Updating this way works from version 0.9.4.1 onwards.

Remove slowdown (on by default): when the game can't finish a frame in time, as in busy scenes, it gets extra processor time instead of slowing down like the original. Only the game's own work gets the extra time; the picture, timers and music stay exactly on time. About three quarters of the slowdown is gone; very long loading moments can still slow down briefly. Turn it off for the original timing, slowdown included.

Continue on launch (off by default) saves your exact place when you quit and resumes it the next time you start. Settings are saved in settings.ini next to the game, and save states in states\.

• Motion smoothing (off by default; set it to 120 under Video, for screens faster than 75 Hz): the game still runs at its native 60 fps, and an in-between picture is drawn after every game frame. On a 240 Hz monitor each picture stays up for exactly two refreshes, on a 120 Hz one for one. A 144 Hz monitor can't divide 120 evenly, so it gets a new picture on 5 refreshes out of every 6. A display thread redraws the frame with the console's own graphics chip, with each layer's scroll position and every sprite placed where they are at that exact moment between the last two frames. Pixel art stays crisp: nothing is blended or smeared. In-between pictures are drawn at half-pixel precision, across and down, so a background that scrolls one pixel per frame still gets a step in between. Sprites move with the game objects they belong to, the camera follows a steady path instead of the game's uneven whole-pixel steps, and brightness fades pass through in-between levels. Pictures are timed by a clock locked to the monitor's real refresh signal, so each one stays on screen for exactly the same number of refreshes (two each at 120 fps on a 240 Hz screen). Each picture is drawn a few milliseconds before its refresh and presented just after it, so a slow moment in the graphics driver doesn't make it miss its refresh. It uses VSync and adds about 1.5 frames (~28 ms) of delay. Set it to 60 under Video for the lowest latency.
• With motion smoothing at 60 (or on a 60 Hz screen), each game frame is shown as it is. On a 120 Hz or 240 Hz monitor each frame stays for exactly 2 or 4 refreshes, so motion stays perfectly even, and the wait for the next refresh shrinks to about 8 ms or 4 ms. Other refresh rates (such as 144 Hz) use timer pacing.
• Low latency (applies with motion smoothing at 60): the frame is shown the moment the console finishes drawing it. Controller input is then read as late as possible, just before the game's own read, about 3 ms before the next frame is due. Together this removes more than a frame of delay compared with ordinary emulation.
• Audio runs on its own WASAPI thread. Gentle rate control (at most ±1% pitch, inaudible) keeps about 20 ms of sound buffered, so it never crackles or drifts.