Casso is a retro / classic-machine platform emulator and from-scratch AS65-compatible 6502 / 65C02 assembler, written in C++. Today the platform emulator targets the Apple II family (][, ][+, //e, //c); the abstractions are generic enough to host other 6502-based machines later.
Two of the three built-in themes booting the casso-rocks demo disk — same Apple //e core, different chrome:
 |
 |
The project includes:
- Apple II platform emulator — GUI-based Apple II, II+, //e, //e Enhanced, and //c emulator with D3D11 rendering, WASAPI audio, Disk II controller with realistic mechanical sounds, in-app blank-disk creation (DOS 3.3 / ProDOS / raw across WOZ / DSK / PO, optionally bootable) with per-disk write protection, Mockingboard sound card (dual 6522 VIA + AY-3-8910 PSG), an emulated ImageWriter II printer (parallel card, real-3D live preview with mechanical audio, PNG / clipboard / Windows-print delivery with print preview), analog game I/O (joystick/paddle via the PREAD timer), data-driven machine configs, 80-column text + Double Hi-Res, auxiliary RAM, audit-correct Language Card state machine, and cycle-accurate IRQ/NMI infrastructure.
- 6502 CPU emulator — passes Klaus Dormann's functional test suite and Tom Harte's SingleStepTests for all 151 legal opcodes plus the stable undocumented NMOS opcodes (SAX, LAX, DCP, ISC, SLO, RLA, SRE, RRA and the NOP family). The Harte vectors are recorded from real hardware, so they are an independent oracle rather than a restatement of our own assumptions. 200 vectors per opcode are checked in and run on every build; the full 10,000 per opcode are a download away and are what you run when touching the CPU core — see docs/testing.md.
- AS65-compatible assembler — a from-scratch reimplementation of Frank A. Vorstenbosch's AS65, intended as a drop-in replacement. Supports the complete AS65 syntax: macros, conditional assembly (
if/ifdef/ifndef/else/endif), the full expression evaluator (arithmetic, bitwise, logical, shift,</>byte selectors, current-PC*),equ/=constants,include, three-segment model (code/data/bss), AS65-style listing output, and AS65 command-line flags (-l,-t,-s,-s2,-z,-c,-w,-d,-g, ...) including flag concatenation (-tlfile). - Merlin dialect —
CassoCli merlin <source>assembles Glen Bredon's Merlin, in the absolute subset that needs no linker. A dialect is a spelling table and a line model behind one profile seam, with the two-pass engine, the expression evaluator and the opcode tables shared with AS65; the invocation names the dialect and the source is read strictly under it. Merlin brings its field-based line model, its own directive vocabulary, macros and variable symbols, local labels, left-to-right expressions in unsigned 16-bit arithmetic, and a relocating origin. Where support ends is stated by name rather than failing as a syntax error — see docs/merlin-subset.md. ca65 is the next dialect (specs/023-ca65-dialect), and it is deliberately gated on this mechanism rather than on more Merlin: adding it must change nothing here. Its absolute subset comes first, since full compatibility needs a linker. - CLI tool — an assembler under a named dialect (
as65ormerlin), or therunsubcommand to load and execute a binary or assembly source. - First-run asset bootstrap — Casso fetches the ROMs, sample disks, and Disk II audio samples it needs on first launch (with user consent), so a fresh
Casso.exeboots to a usable //e BASIC prompt with no manual setup. - Headless test harness —
HeadlessHostdrives the emulator with no Win32 window, enabling deterministic integration tests for cold boot, disk boot, video framebuffer hashing, and reset semantics. - 3500+ unit tests — comprehensive coverage of CPU instruction encoding, addressing modes, arithmetic, branching, assembler features, audio pipeline (speaker + drive + printer + Mockingboard), 6522 VIA timers/IRQ + AY-3-8910 synthesis, //e MMU + Language Card, video timing, Disk II nibble engine, WOZ + nibblized image formats, 80-col + DHGR video, the printer pipeline (interpreter, renderer, pagination, pacing, head mechanics + drain engine, preview model, persistence, slot firmware), reset semantics, perf budget, and backwards-compat for ][ and ][ plus machines.
- About
- What's New
- Project Structure
- Requirements
- Quick Start
- CPU Emulation Status
- Assembler
- Why "Casso"?
- Acknowledgments and Attributions
- Contributing
- License
See CHANGELOG.md for the granular history, and ARCHITECTURE.md for a technical overview of the emulator's internals (projects, threading, the memory model, and the optimization log).
CassoCli now assembles Merlin source — Glen Bredon's Merlin Pro, the
assembler most Apple II software of the era was written in — unmodified, with
the output verified byte-for-byte against six objects shipped on the Merlin
Pro 2.23 distribution disk, including its own macro library. Merlin arrives as
a dialect: a directive vocabulary and a line model behind one profile seam,
sharing the two-pass engine, expression evaluator and opcode tables that as65
has always used, so the next dialect is a profile rather than a second
assembler.
The command line names the dialect rather than guessing it — CassoCli as65 input.a65 and CassoCli merlin PROG.S; the old bare CassoCli input.a65
form is gone — and run takes --as65 or --merlin to say which
assembler reads a source. Under as65, the CPU is chosen with AS65's own
-x (the --cpu flag is retired); under merlin, the source chooses it
with XC, as Merlin does. Merlin output can be wrapped for an Apple II disk
with --dos-bin, and -d NAME=value answers the questions a KBD directive
would have asked at the keyboard.
The rest of the CLI got a pass while the hood was up: --help wraps to the
width of your terminal and is organized by mode; an argument the tool does not
know is refused — with the full usage and the offending argument named last —
instead of warned about and ignored; the five output formats are mutually
exclusive; -w wraps the listing; -t shows decimal beside hex; and -g writes
its symbols by address and again by name. See
docs/Assembler.md for the reference and
docs/merlin-subset.md for what Merlin support covers
and where it ends.
Casso now checks disk integrity when a .woz disk is inserted. If the checksums are incorrect, Casso treats the disk as read-only to prevent further corruption or data loss. A Salvage wizard opens and offers to salvage data into a structurally correct copy of the original disk.
The missing keystone of the write workflow: Casso can now make fresh disks.
The insert-disk picker's pinned <Create new disk...> row opens a themed
save-style dialog — browse folders right in the dialog, pick the format
(DOS 3.3, ProDOS 1.1.1, or unformatted raw media) and the image type
(WOZ, DSK, or PO; only legal pairings are offered), name the file,
and the new disk mounts straight into the drive that opened the picker. A
created disk is immediately usable — SAVE and CATALOG work with no INIT
step, exactly like a disk a period formatter produced — and a Make bootable
checkbox installs the real OS from the stock master disks (downloaded on
demand): DOS 3.3 disks boot to a clean Applesoft prompt, ProDOS disks boot
through PRODOS into BASIC.SYSTEM. The dialog refuses targets currently
mounted in a drive, confirms overwrites and drive replacement, and reopens in
the folder you last created in.
Alongside it, a write-protect toggle for mounted disks: the Disk menu
names its target — "Write-protect "Blank Disk.woz"" flips to "Allow writes
to "Blank Disk.woz"" once protected. WOZ images carry the flag inside the
file (it travels with the image); sector formats use the host file's
read-only attribute. The drive widget's brass padlock and a cause-specific
tooltip ("WOZ write-protect flag", "file is read-only", "no write
permission") track every change, and a protected disk fails a guest SAVE
with WRITE PROTECTED, just like the notch tab on real media.
Fixed a //c mouse-interrupt bug that made MousePaint's main app unusable —
menus and tools ignored every click and the cursor lagged. The //c only
partially decodes its paddle-timer strobe, so any $C070–$C07F access
clears the VBL interrupt; Casso recognized only the literal $C070. Mouse apps
that acknowledge the VBL via a $C07x write (MousePaint writes $C079 each
interrupt) therefore never cleared it, and the resulting interrupt storm starved
the app of CPU. Also trimmed the per-instruction //c mouse tick cost (~31%).
Casso now emulates a full Apple ImageWriter II dot-matrix printer, end to
end — a parallel printer card sits in slot 1 (default on ][, ][+, //e, and //e
Enhanced) and the guest can print for real. PR#1 lists a BASIC program or
CATALOGs a disk in an original 95-glyph dot-matrix font; The Print Shop prints
its banners, signs, and greeting cards in full four-color glory, its command set
locked from real Print Shop byte captures (ESC-G / ESC-L bit image, seven-color
ribbon with overprint composites, and the documented pitch and line-spacing
family).
Print output appears in a live skeuomorphic preview — a real-3D ImageWriter II (the project's own CAD model) with fanfold paper, tractor-feed holes, and perforations, feeding out of the platen as you watch. A single print-head clock drives the whole illusion: the carriage sweeps bidirectionally at true draft speed laying ink column by column, the paper feeds with the head parked, and the mechanical sound (authentic ImageWriter II recordings by Scott Lawrence) is gated to what the head is actually doing — a carriage buzz over ink, line-feed clacks, page feeds, and tear-offs, stereo-panned to the window. A one-page viewport follows the newest rows; scroll back to review earlier pages and it snaps to the live row once printing idles.
Any printout delivers three ways without re-printing — Save as a PNG, Copy to the clipboard, or Print to a real Windows printer (with a paginated print preview) — and the paper stays loaded until you tear it off, so a pending printout even survives across sessions. A command toolbar below the menu bar carries the printer status LED and a preview button, and Settings → Printing states what printer the current machine emulates and how it connects.
A performance pass across the hot paths that run on every emulated instruction
and every drawn frame. On the CPU side, memory reads serve RAM/ROM inline from
a page table instead of a virtual dispatch, I/O decodes through a direct device
map instead of scanning the device list, the language-card ($D000–$FFFF) and
//c internal-ROM ($C100–$CFFF) windows are page-mapped, and the interrupt
poll, video-timing tick, and //c mouse tick shed redundant per-instruction
work — so a steady machine idles at noticeably lower CPU, most visibly on the
//c. On the render side, the 40- and 80-column text screens repaint only the
rows that actually changed — a scrolling catalog or a blinking cursor no longer
redraws all 24 rows — the UI chrome caches its shaped text and geometry instead of
re-shaping every label each frame, and the Mockingboard skips synthesis while
fully muted.
An opt-in CRT monitor desk scene — a checkbox on Settings → Theme (skeuo themes only, off by default) — frames the emulator display in a procedurally-drawn period Apple Monitor //c: snow-white/platinum shell, chunky even bezel with straight sides and a slightly bowed glass, a recessed screen, and the rainbow cassowary brand and a lit power lamp on the chin. The display sits inside the glass at true 100% zoom, the drives scale to sit in proportion beneath it, and the whole scene zooms together as the window resizes. Off by default because the scene trades screen real estate for the look; toggling it applies live, and off restores the classic bare display.
The two latching switches on the //c case are modeled on a skeuomorphic
control strip in the //c's platinum case color: the 80/40
switch drives $C060 (in = 80-column startup, read by a booting disk's
PR#3), the keyboard switch flips the typed stream to Dvorak, and a
reset button reproduces Control-Reset (inert without Ctrl), alongside
disk-use / power indicator LEDs. Both switch positions persist per machine.
Casso now emulates the Apple //c (ROM 4, 5.25"/128K): a Rockwell R65C02 core validated against the Dormann and Harte conformance suites, the slotless phantom-slot firmware map with the 32K bank-switched ROM, the built-in IWM disk drive (plus a connectable external drive), dual 6551 serial ports, and the //c mouse — a full IOU hardware model driven by the machine's real mouse firmware, with the host pointer mapping non-capturing onto the guest. Input mapping split into independent Keys (arrows→joystick) and Pointer (paddle/mouse) selections with a new segmented device selector drawing the real Apple peripherals. The same 65C02 also powers a new Apple //e Enhanced profile (issue #86) — the //e with the enhanced firmware + MouseText video ROM, for the CMOS titles that misbehave on the NMOS //e.
Casso now emulates the Sweet Micro Systems Mockingboard A/C — the de-facto Apple II audio standard. Two clean-room chip cores written from the datasheets (a reusable 6522 VIA and the AY-3-8910 PSG: 3 tone voices + noise + envelope) render to stereo float PCM, with VIA Timer 1 driving the periodic IRQs music players use for tempo. The card ships in slot 4 of the ][+ and //e profiles; it is installed or removed from its slot in the Hardware tab's device list. Games like Ultima IV, Skyfox, and Music Construction Set get their real soundtracks back.
Fixed several bugs that corrupted or silently dropped guest writes to .dsk,
.do, .po, and .woz images — a Logic State Sequencer write-bit error that
garbled DOS 3.3 SAVEs (GH #89), and missing WOZ write-back that discarded
every .woz edit. Dirty disks now also flush automatically when the drive
motor spins down, so changes survive a crash or force-quit.
The boot / Insert-Disk picker gained a search box and click-to-sort columns,
and — when Casso runs from a source checkout — it's preloaded with the disk
images in the repo's Apple2/Demos/ folder as one-click mounts. The list
scrolls horizontally and the dialog resizes cleanly.
Settings picked up an "Apply now" button to try a theme without closing the dialog, a "restart required" notice with an "OK (reboot)" button when a change needs a power-cycle, and support for a machine with no Disk ][ controller — the Disk tab, the drive band, and boot all adjust when there isn't one.
Under the hood, Casso's window chrome was pulled out into a standalone, reusable Dxui library (Direct2D / DirectWrite) that other projects can build on, with the window host owning the Direct3D swap chain directly.
Real-time action games like Karateka, Choplifter, and Lode Runner are now playable from the host keyboard without a physical joystick. A new Map Arrows to Joystick mode maps the arrow keys to paddle 0/1 (last-pressed-wins on opposing keys) and binds X / Z to buttons 0/1 (the same Open-Apple / Closed-Apple soft-switches the host Alt keys drive, so both input sources coexist); in this mode, those keys are not sent as standard input via the //e keyboard so they don't also type. The //e keyboard itself now generates hardware-faithful auto-repeat (initial delay, then steady cadence) instead of leaning on host-OS key repeat, so timing-sensitive arrow input in games behaves the way it did on real hardware.
Three ways to toggle joystick mode — the Machine menu, a new Ctrl+Shift+J
accelerator, and a dedicated Joystick Mode toggle button in the
bottom drive bar (frameless press-to-pin button with a blue glowing
LED, hover tooltip, and focus ring). A new Input Debug panel
(Ctrl+Shift+I) logs the host → //e key events, the $C000/$C010
strobe, Open/Closed-Apple state, and synthesized joystick/paddle reads
($C064–$C067 PREAD, $C070 PTRIG) with per-lane filter checkboxes,
column sorting, pause, and a Copy-to-clipboard button.
Press F10 to drive the painted chrome with the keyboard: a Tab focus ring walks across menu titles, the Joystick Mode button, and the drive widgets, with Enter/Space to activate and Esc to return to the //e. The ring never leaks keystrokes through to the emulated keyboard, so navigating chrome can't drop stray letters into a //e prompt.
The first-run asset bootstrap — ROMs, sample disks, and Disk II audio samples — now downloads through a single themed progress dialog that fetches every asset concurrently rather than serial-prompting through three separate Win32 dialogs. The boot-disk MRU picker that appears when no disk is configured also paints through the same DirectWrite pipeline as the rest of the chrome, so the entire first-launch path honors the active theme (Skeuomorphic / Dark Modern / Retro Terminal) instead of dropping back to native gray.
Casso's Disk II stack now models quarter-track head positioning and the authentic Logic State Sequencer faithfully enough to boot original, copy-protected Broderbund WOZ disk images straight off the wire. Classics like Karateka, Choplifter, and Lode Runner load and run from their unmodified preservation images, protection schemes and all.
| Karateka | Choplifter | Lode Runner |
|---|---|---|
 |
 |
 |
Casso's entire chrome moved from the legacy Win32 menu bar / Win32 dialogs to a borderless, themed shell rendered straight onto the same D3D11 framebuffer that draws the emulator video — using a native Direct2D / DirectWrite pipeline (DxUiPainter + DwriteTextRenderer), no third-party UI engine.
Three built-in themes — Skeuomorphic, Dark Modern, Retro Terminal — hot-swappable from Settings → Theme with no restart and no machine reset. Each theme ships under Resources/Themes/<Name>/ (extracted to Themes/<Name>/ at first run) with a theme.json describing colors, CRT defaults, drive visual profile, and other UI tokens consumed by the native widget renderer. The token-based custom-theme authoring surface is still being wired through the native widgets — see docs/themes/AUTHORING.md for the current state.
Skeuomorphic drive widgets with realistic Apple Disk II faceplates: perspective-projected case top with two indented lid panels that taper toward the back, nine vent slits down each side, beige case wrapping a black inset faceplate on all four sides, cantilever door hinged at the slot top that tilts up and back (tucking inside the case with a small flap visible when fully open) revealing a recessed finger-pull behind it, status LED, and the Cassowary rainbow logo. Click a drive to pick a disk image, or drag-and-drop a .dsk / .do / .po / .nib file onto it. Eject animates the door open even on an empty drive. A write-protected disk shows a small brass padlock on the faceplate; hovering the drive explains why it is protected — the write-protect setting, the image's own flag, a read-only file, or missing write permission.
Consolidated Settings panel replaces the old OptionsDialog and MachinePickerDialog. Machine selection, machine info, emulation speed, video color mode, disk write mode, floppy sound + mechanism (with per-sound Motor / Head / Door volume, per-drive stereo pan, and play-button audition), write-protect, theme picker, and the new CRT controls live in one non-modal in-window panel with full keyboard navigation.
CRT effects — scanlines, phosphor bloom, and color bleed (each independently toggleable, with its own parameter sliders), plus persistence trails, contrast, and gamma sliders. Per-monitor presets (Color / Green / Amber / White) seed sensible defaults; themes can override; user tweaks persist as overrides on top of either. The Settings popup gets out of your way as you scrub a control — the panel fades, the emulator behind it stays sharp inside a per-pixel clip, and only the focused control remains opaque — so you can evaluate the effect of every parameter change live.
Unified user preferences persist in %LOCALAPPDATA%\Casso\UserPrefs.json: global UI state under global, and per-machine deltas under machines keyed by display name. Most settings live there today; a small set of legacy values (last-loaded machine, per-machine last-inserted disk paths, audio download consent, window placement) still live in the registry for backwards compatibility and will migrate to JSON in a follow-up.
Realistic mechanical sounds during disk activity, mixed into the WASAPI pipeline alongside the //e speaker:
- Stereo motor hum, head-step clicks, track-0 / max-track bumps, and disk insert / eject sounds.
- Per-drive equal-power stereo panning: single-drive profiles play centered; in two-drive profiles Drive 1 leans left, Drive 2 leans right.
- Step-vs-seek discrimination: contiguous step bursts during DOS RWTS recalibration fuse into a continuous seek buzz instead of N overlapping clicks.
- View → Options... dialog with a Drive Audio toggle (default on) and a Disk II mechanism dropdown (Shugart SA400 by default, or Alps 2124A). Both persist per-machine via the registry.
- First-run consent dialog downloads the actual recordings from the OpenEmulator project; OGGs are decoded in memory via vendored
stb_vorbisand written as WAV (no.oggretained on disk). Asked once per machine, persisted thereafter. - Generic
IDriveAudioSink/IDriveAudioSource/DriveAudioMixerabstraction so future drive types (//c internal 5.25, DuoDisk, Apple 5.25 Drive, ProFile, ...) plug in without touching the mixer.
Casso.sln
├── CassoCore/ Static library — CPU emulator, assembler, parser, opcode table
├── CassoEmuCore/ Static library — Apple II devices, video modes, audio generator + drive-audio mixer
├── Dxui/ Static library — reusable Direct2D/DirectWrite UI framework (host window, panels, layouts, widgets, menu bar, popup host, dialogs)
├── Casso/ Win32 application — Apple II platform emulator (D3D11, WASAPI, Disk II audio)
├── CassoCli/ Console application — assembler CLI (`as65`, `merlin`) with `run` subcommand
└── UnitTest/ Test DLL — Microsoft Native CppUnitTest (3350+ tests)
- Windows 10/11
- PowerShell 7 (
pwsh) for build/test scripts - Visual Studio 2026 (v18.x)
- Workload: Desktop development with C++
- Components: MSVC build tools, Windows SDK, C++ unit test framework
- Optional: MSVC ARM64 build tools (for ARM64 builds)
- Optional: VS Code (repo includes
.vscode/tasks)
# Build Debug for current architecture (Ctrl+Shift+B in VS Code)
.\scripts\Build.ps1
# Build Release
.\scripts\Build.ps1 -Configuration Release
# Build all platforms
.\scripts\Build.ps1 -Target BuildAllRelease
# Rebuild with code analysis (warnings as errors)
.\scripts\Build.ps1 -Configuration Release -RunCodeAnalysis# Build and run tests
.\scripts\RunTests.ps1
# Or use VS Code: Run Tests (current arch)CassoCli assembles 6502 / 65C02 source and can run it in one step. Full flag
and syntax reference: docs/Assembler.md.
# Assemble a source file to a flat binary. The dialect is NAMED: `as65` is a
# subcommand, not an assumption. `CassoCli input.a65` used to work and no
# longer does -- see the breaking-changes entry in CHANGELOG.md.
CassoCli as65 input.a65 -o output.bin
# Assemble with a listing file and a symbol table
CassoCli as65 input.a65 -o output.bin -l listing.txt -t
# Output Motorola S-record (.s19) or Intel HEX (.hex)
CassoCli as65 input.a65 -s -o output.s19
CassoCli as65 input.a65 -s2 -o output.hex
# Write only the assembled bytes, or a BLOAD-ready DOS 3.3 binary
# (the default is a full 64 KB image padded with the fill byte)
CassoCli as65 input.a65 --raw -o output.bin
CassoCli as65 input.a65 --dos-bin -o output.bin
# Pre-define a symbol on the command line
CassoCli as65 input.a65 -d DEBUG=1 -o output.bin
# Generate a listing with cycle counts
CassoCli as65 input.a65 -c -l listing.txt
# Assemble 65C02 source (CMOS opcodes: STZ, BRA, RMB/SMB/BBR/BBS, ...)
# The default is a strict 6502; 65C02-only opcodes are rejected without -x.
CassoCli as65 input.a65c -x -o output.bin
# Assemble Merlin source. The object written is the assembled stream, since
# Merlin's ORG relocates rather than seeks -- see CassoCli --help for where
# Merlin support ends.
CassoCli merlin SOURCE.S -o OBJECT
# Merlin names its own object file, so -o is only needed to override the source
CassoCli merlin SOURCE.S
# There is no CPU flag here: Merlin selects its CPU in the source, with XC, and
# -x is refused rather than quietly ignored.
# Assemble and run in one step
CassoCli run input.a65
# Run a pre-assembled binary at a chosen address
CassoCli run output.bin --load $8000Run Casso with no arguments for an Apple II+ with an empty drive. ROMs and
sample disks are fetched on first launch, with your consent — there is
nothing to install by hand.
# Launch the emulator (defaults to Apple II+)
Casso
# Pick a machine
Casso --machine Apple2e
# Boot a disk in drive 1
Casso --machine Apple2e --disk1 "Apple2\Demos\casso-rocks.woz"
# Both drives
Casso --machine Apple2c --disk1 "side-a.woz" --disk2 "side-b.woz"Machine names come from Resources/Machines/<Name>/:
Apple2, Apple2Plus, Apple2e, Apple2eEnhanced, Apple2c.
All 56 standard 6502 mnemonics are implemented, plus the 65C02 set. Validated against Klaus Dormann's functional test suite (full pass) and Tom Harte's SingleStepTests (all 151 legal-opcode test sets, 10,000 vectors each).
CassoCli is an as65-compatible 6502 / 65C02 cross-assembler with a built-in
runner. Every flag, directive, addressing mode and output format is documented
in docs/Assembler.md.
While emu is the more obvious name and mascot for an emulator, I wanted Casso to stand out; to be just a little weird; to think different. I picked its larger, flightless, considerably more dangerous cousin: the cassowary—Casso to his friends.
I thus present to you our regal namesake—revel in his splendor!
Cassowary photo by Mr. Smiley / BunyipCo, licensed under CC BY-NC-SA 3.0.
Casso's correctness is validated against two exceptional open-source test suites:
- Klaus Dormann's 6502 Functional Test Suite — @Klaus2m5's exhaustive functional test exercises every documented 6502 behavior: all instructions, addressing modes, flag interactions, BCD arithmetic, and edge cases. Casso passes the full suite.
- Tom Harte's SingleStepTests — @TomHarte's per-opcode test vectors validate every legal 6502 opcode against cycle-accurate reference traces. Casso passes all 151 legal-opcode test sets (10,000 vectors each).
Thank you to both authors for making these invaluable resources freely available. They are the gold standard for 6502 emulator validation.
Casso also builds on several third-party components and assets:
- CRT display shaders — the optional CRT effect is a set of HLSL ports from the libretro
glsl-shaderscollection: crt-pi by Davide Berra (MIT), the ntsc-adaptive chroma stage by Themaister and hunterk (MIT), and the bloom passes by hunterk (public domain). Per-file attribution and license terms are inCasso/Shaders/CRT/LICENSES.md. - stb_vorbis — Sean Barrett's public-domain Ogg Vorbis decoder (nothings.org/stb_vorbis), used to decode the Disk II and printer audio samples.
- ImageWriter II printer sounds — recorded from a real ImageWriter II by Scott Lawrence, licensed under CC BY 4.0.
See CONTRIBUTING.md for commit conventions, build instructions, code style guidelines, and other contributor guidelines.