D1X 3DS

A Nintendo 3DS port of Descent I (D1X), built for the New 3DS family (New 3DS / New 2DS XL). Hardware-rendered via picaGL on the PICA200 GPU, with glasses-free autostereoscopic 3D seamlessly driven by the console's 3D depth slider.

This is a fork of DXX-Switch / DXX-Retro, which is a fork of DXX-Rebirth, which is a fork of the original engine by Parallax Software.

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Branches

Branch	What it is
master	Stable Descent I with stereoscopic 3D. The playable, recommended build. Stereo is opt-in and 3D-slider-gated (see below).
stereo-3d	DEPRECATED — superseded by master. Kept only for history.

[!WARNING] stereo-3d is deprecated. Stereoscopic 3D was merged into master (slider-gated: raise the 3DS 3D slider to enable depth, lower it for mono). Build/install master for all current features. The stereo-3d branch is no longer maintained and, if built, may install as a separate app icon.

master is the one to build/install. The 3D work is documented in docs/STEREO_3D.md; the developer-side trace of that code lives in docs/stereo-3d-logic-map.md.

What's new in v2.1.2

This release introduces the Complete 3DS Multiplayer Touchscreen Suite for UDP / Wi-Fi network play:

• Lobby Start Instant Launch:
  • Added a prominent top-screen "START GAME" menu option.
  • Enabled instant match start via the physical START button.
  • Added a dedicated blue [ START NETGAME ] touch button on the bottom screen.
• LAN Game Browser Polish:
  • Added a bottom-screen [ RESCAN LAN ] button.
  • Mapped physical (X) as an instant rescan shortcut so players can discover hosted games without backing out of the menu.
  • Added L / R bumper page navigation with dynamic Page X/Y counters.
  • Replaced legacy PC function-key text with clean 3DS-specific instructions.
• Direct Join via On-Screen Keyboard (swkbd):
  • Fully integrated Nintendo 3DS software keyboard (swkbd) for typing host IP addresses and custom ports with the stylus.
  • Added bottom-screen [ ENTER IP ADDRESS ] and [ CONNECT ] touch buttons.
  • Added a CONNECT TO HOST menu item for D-Pad / (A) navigation and wired physical START button shortcut.
• In-Game Multiplayer Scoreboard Overlay:
  • During multiplayer matches (Game_mode & GM_MULTI), the inactive bottom-screen [ SAVE ] button automatically transforms into a context-aware [ SCORE ] button.
  • Tapping [ SCORE ] cycles the kill matrix / scoreboard overlay (OFF -> Kills -> Deaths -> Team, PC F7) with real-time HUD status messages.
• AutoDemo Storage Protection:
  • Disabled automatic multiplayer demo recording by default (PlayerCfg.AutoDemo = 0) to prevent matches from inadvertently consuming SD card storage space.
• VCR Demo Playback Touch Controller:
  • Automatically transforms the bottom touchscreen into an active VCR remote during demo playback.
  • Full transport deck: Jump to Start (|<<), Fast Rewind (<<), Step Backward 1 Frame (<|), Play/Pause, Step Forward 1 Frame (|>), Fast Forward 2x (>>), Jump to End (>>|), and Stop & Exit ([STOP & EXIT]).
  • Live progress bar showing real-time playback percentage (0%–100%) with visual gradient indicator.
  • Real-time transport status display (PLAYING (1x), PAUSED, FAST FORWARD (2x), REWINDING, STEP FORWARD, STEP BACKWARD).

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What's new in v2.1.1

This release delivers a comprehensive performance overhaul that eliminates framerate drops and ensures a rock-solid 60 FPS flight experience on New 3DS:

• Decoupled Rear-View Mirror Cadence:
  • Live 3D rear-view mirror rendering is now smoothly decoupled to an alternate-frame cadence (30 FPS mirror, 60 FPS flight).
  • Maintains full tactical rear awareness while freeing up critical GPU fillrate and CPU cycles for the primary top-screen combat cockpit.
• Rear-View Depth Culling:
  • Implemented dynamic depth culling (Render_depth capped to 18) for the rear-view camera, completely eliminating unnecessary overdraw of distant geometry in the rear-view viewport.
• Eliminated SD Card Diagnostic Stalls:
  • Root-caused and resolved severe framerate drops (down to 36 FPS or lower), which particularly affected users with large SD cards (256GB / 512GB).
  • Removed synchronous per-frame SD card diagnostic file writes (lum_trace.txt and pgl_trace.txt) and frame-buffer pixel hashing loops from the low-level rendering pipeline.
• Bottom-Screen Latency Decoupling:
  • Removed redundant VBlank synchronization stalls during bottom-screen presentations, ensuring completely smooth frame pacing and zero top-screen stutter.
• Compiler & Math Stability:
  • Standardized clean -O2 optimization flags across the codebase to ensure robust struct alignment, deterministic fixed-point math, and total stability.

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What's new in v2.1.0

This release introduces the Tri-View Bottom Screen Tactical Dashboard, Hardware-Calibrated Gyro Aim Assist, Roland SC-55 High-Fidelity Audio, and significant engine stability and visual upgrades:

• Tri-View Bottom Screen Tactical Dashboard:
  • Live 3D Rear-View Mirror: Full real-time 3D camera rendering looking out the back of the ship, perfectly centered on the top panel of the bottom screen.
  • Tactical Mini-Radar: Live 360-degree radar sweep showing nearby robots and powerups with dedicated in-box + and − zoom buttons.
  • Mini Wireframe Automap: Real-time 3D mine wireframe overview with independent in-box + and − zoom buttons.
  • Tap to Fullscreen: Tap either the radar or minimap square to expand it fullscreen on the bottom screen; tap again to return to tri-view.
  • Touch Button Bar: Quick-tap buttons for HUD toggle, Gyroscope toggle, Primary weapon cycle, Secondary weapon cycle, Save, and Menu.
  • Custom Handheld Typography: Compact, clean labels and status indicators designed specifically for legibility on the 3DS bottom screen.
• Hardware-Calibrated Gyroscope Aim Assist:
  • Handheld motion aiming: Tilt the console to pitch and yaw your ship with precision gyro aim assist.
  • Drift suppression & auto-calibration: Stationary auto-calibration and deadband filtering counteract resting tremors and handheld tilt bias.
  • Dedicated Gyroscope Settings menu (OPTIONS -> CONTROLS -> GYROSCOPE SETTINGS) with adjustable Deadzone (0–16), Sensitivity (1–16), and on-demand "Calibrate Zero Bias".
• Visuals & Hardware Acceleration:
  • 24-bit True Color & Dithering: 24-bit framebuffer rendering with spatial color dithering to eliminate banding across dark mines and lighting gradients.
  • Crisp Font Rendering: Point/nearest-neighbor filtering enforced on font textures, eliminating fuzzy text across HUD and menus while 3D geometry retains smooth bilinear filtering.
  • +10% Ambient Brightness Boost: Tuned lighting curve to illuminate dark mine tunnels without washing out highlights.
  • Sharper Top Automap: 40% thinner wireframe lines for a cleaner, high-precision top-screen map.
  • Stereo 3D Polish: Smooth display buffer synchronization eliminates flashing banners during level transitions and demo playback.
• Audio Overhaul & Jukebox:
  • Roland SC-55 Soundtrack: High-fidelity Roland Sound Canvas SC-55 hardware MP3 soundtrack recorded by Brandon Blume (recommended by GBAtemp user bakuDD), with automatic fallback.
  • In-Game / Menu Jukebox: Track selector to preview and play any soundtrack piece on demand.
  • Frame-Pacing & Buffer Fixes: Audio buffer underrun fixes and elimination of sound BFS stalls in large rooms.
• Controls & Navigation:
  • Top-Screen Precision Crosshairs: Added crosshairs for cockpit aiming and dogfighting.
  • Free-Cam Navigation: Integrated free-camera exploration mode.
• Save System & Mid-Game Lifecycle Improvements:
  • Visual Save Game Thumbnails: Save slots now capture and display a live gameplay screenshot thumbnail directly in the save/load menu for instant visual recognition of your game state.
  • Seamless Mid-Game Flow: Starting a new game or loading an existing save from the in-game pause menu cleanly unwinds menu overlays and transitions directly into gameplay without requiring a manual game abort.
  • System Stability & Sleep Support: Full aptMainLoop pumping across all modal event loops ensures system sleep, HOME button suspend, and power-down operate cleanly without system freezes or GPU crashes.

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Install (Descent I)

You must supply your own Descent I game data — it is copyrighted and is not included in this repo (and was scrubbed from history before publish).

1. Create /3ds/D1/ on your SD card.
2. Copy descent.hog and descent.pig into it. These ship with a legitimate purchase of the game — tested with Descent I on Steam. (Other releases — GOG, CD-ROM — should work but are untested here.)

Then pick one install method:

A. CIA (install to home menu) — use the d1x-3ds.cia from a release:

• Copy d1x-3ds.cia to your SD card, install it with FBI, and launch from the home menu.

B. 3DSX (Homebrew Launcher, no install) — use the d1x-3ds.3dsx from a release:

• Copy d1x-3ds.3dsx into sd:/3ds/D1X-3DS/.
• Launch D1X 3DS from the Homebrew Menu (hold the appropriate exploit at boot, or use a forwarder).

Binaries come from Releases, not the repo. The repo ships source + a Docker build flow. Grab the prebuilt d1x-3ds.cia / d1x-3ds.3dsx from the Releases page (or build them yourself — see Building).

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Music

The 3DS SDL_mixer port has no HMP/MIDI decoder, so the stock tracks inside descent.hog cannot be played directly. To get in-game music you must supply converted audio files (one-time setup):

1. Download the Roland SC-55 MP3 Pack (Recommended). Grab the authentic Roland Sound Canvas SC-55 hardware recordings by Brandon Blume from Duke4.net SC-55 Archive (recommended by GBAtemp user bakuDD). Extract the 27 .mp3 files directly into /3ds/D1/mp3/ on your SD card. They are pre-named (game01.mp3 through game22.mp3, briefing.mp3, credits.mp3, descent.mp3, endgame.mp3, endlevel.mp3) and work immediately.
2. Or get an upstream OGG pack. The upstream DXX-Rebirth project supports community OGG music AddOn packs for Descent 1 & 2. Drop the extracted tracks into /3ds/D1/ogg/.
3. Or convert the game's own tracks. The HMP tracks are already inside descent.hog. Render them with TiMidity++ + a soundfont, then encode to MP3/OGG/WAV. Example (per track):

   timidity game01.hmp -Ow -o - | ffmpeg -i - -b:a 192k game01.mp3
   

4. Install location. Place the tracks on your SD card matching the format:
   • MP3: /3ds/D1/mp3/<name>.mp3
   • OGG: /3ds/D1/ogg/<name>.ogg
   • WAV: /3ds/D1/wav/<name>.wav The 3DS fallback chain automatically tries wav/ → mp3/ → ogg/.

The midi/ folder written by some older builds is not used for playback (SDL_mixer can't decode it) — it can be deleted. For custom playlists, list your own tracks in a descent.sng song file in any SDL_mixer-supported format (.mp3, .ogg, .flac); filenames must match the song names in the list.

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3DS controls

START acts as keyboard Esc / in-game menu; SELECT opens the full top-screen 3D automap.

Action	Button / Input
Fire primary	R
Fire secondary / missile	L
Accelerate (forward engine)	X
Reverse / brake	B
Slide left (strafe)	Y
Slide right (strafe)	A
Drop bomb	L (hold context)
Flare	ZR
Rear view (hold)	ZL
Automap (full 3D map)	SELECT
Menu / pause / back	START (Esc)
Aim assist	Gyroscope (tilt console to pitch/yaw)
Flight steering	Circle Pad (analog pitch/turn)
Look / strafe vertical	C-Stick (New 3DS)
Cycle cockpit view	D-PAD UP (prev) / D-PAD DOWN (next)
Weapon prev / next	D-PAD LEFT / D-PAD RIGHT
Quick save	START + X
Quick load	START + Y
Controls help screen	START + SELECT
Death screen dismiss	any face button / START

Cockpit views: full cockpit → status bar → full screen (cycles). Top-screen HUD includes precision crosshairs for aiming.

Bottom-Screen Tri-View Tactical Dashboard

The bottom screen features a synchronized Tri-View Tactical Dashboard while you play:

1. Live 3D Rear-View Mirror (Top Rectangle):
   • Full 3D camera rendering looking behind your ship in real time.
   • Centered with an unobstructed wide field of view.
2. Tactical Mini-Radar (Bottom-Left Square):
   • Real-time 360-degree radar sweep showing nearby hostile robots (red), hostages (green), and power-ups (yellow).
   • In-box + and − touch buttons to independently zoom radar range (15m to 240m).
3. Mini Wireframe Automap (Bottom-Right Square):
   • 3D wireframe overview of the local mine structure and visited rooms.
   • In-box + and − touch buttons to independently zoom map scale.
4. Touch Interactions & Controls:
   • Tap-to-Fullscreen: Tap either the radar or minimap square to instantly expand it fullscreen on the bottom screen; tap again to return to Tri-View.
   • Top Quick Bar: Tap HUD to toggle on-screen gauges, GYRO to toggle gyro aim assist on/off, PRIMARY to cycle primary weapons, and SECONDARY to cycle missiles/bombs.
   • Bottom Bar: MENU opens the in-game main menu overlay, SAVE opens the save-slot selection dialog, and REC toggles demo recording.

Gyroscope Aim Assist & Settings

Gyro aim assist allows fine-tuned motion aiming by tilting the console:

• Toggle gyro on or off anytime via the bottom-screen GYRO touch button.
• Configure motion response under OPTIONS -> CONTROLS -> GYROSCOPE SETTINGS:
  • Deadzone (0–16): Suppresses resting hand tremors and drift.
  • Sensitivity (1–16): Adjusts rotational speed multiplier.
  • Calibrate Zero Bias: Re-centers the zero baseline on demand for your current grip angle.

Stereoscopic 3D controls (3D-slider-gated, in master)

Hold START and press:

Combo	Action
START + D-UP / D-DOWN	Stereo separation strength up / down
START + ZR	Toggle method: PARALLEL ↔ TOE-IN
START + L / R	Convergence distance down / up

See docs/STEREO_3D.md for what parallel vs toe-in means and how to tune depth live (no rebuild). Settings persist to the SD card.

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What was fixed in this fork

These were broken or missing in the original 3DS port and are now working:

• .cia launch crash (8 MB stack). Resolved via __stacksize__ = 8 MB.
• Death screen hang. The "press any key" screen was keyboard-only and left you stuck after dying. Now dismissable with any controller button / START.
• Quick-load input death. state_quick_load()/state_quick_save() were called inside the event-poll loop, corrupting the window/event stack so all joystick input died after a load. Now deferred to run after the poll loop returns.
• Cockpit view cycling via bare D-Pad Up/D-Pad Down (no keyboard).
• Bilinear texture filtering forced on (PICA200 defaulted to nearest).
• Level select uses a d-pad number slider instead of keyboard text entry.
• Automap boundaries — picaGL has no GL_LINES; edges now draw as thin GL_TRIANGLE_STRIP quads.
• Blank top screen / strobing / briefing-banner regressions (a long chain of render-path fixes, v86–v99) — resolved; see commit history.
• Cheat menu & on-device checkboxes — accessible via pause menu (Cheats), with gamepad button A toggling checkbox and radio options in place.
• Streamlined handheld options — eliminated desktop-specific crash hazards in favor of a robust handheld menu (brightness slider, reticle, transparency, dynamic lighting, FPS counter, cockpit toggle).

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Known issues and missing features

• Network / multiplayer. Intentionally disabled (single-player 3DS build).
• D1 end-of-level flythrough. Skipped to avoid a crash (endlevel.c bails before the camera flythrough). Levels still advance correctly.
• Stereoscopic 3D — Fully integrated in master and hardware slider-gated (raise slider to enable, lower to return to mono). Due to rendering the scene twice per frame for stereo depth, framerates may modulate in particularly heavy geometric scenes.
• Original (Old) 3DS / 2DS — untested; see below.

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Original (Old) 3DS / 2DS

This port was developed and tested only on New 3DS hardware. The main reasons original-3DS support was not pursued: the original has fewer physical buttons (no ZL/ZR, single circle pad) so several combos would need a remap pass, and it runs at a lower CPU clock (no osSetSpeedupEnable boost). The two-pass stereo render is especially unlikely to be playable there. If you want to attempt it, see docs/ORIGINAL_3DS_NOTES.md for the specific code paths to touch.

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Building (Docker)

Prerequisites

• Docker + the devkitpro/devkitarm image (ARM11 cross-toolchain, libctru, libphysfs, SDL 1.2 3DS port).
• bannertool + makerom for .cia packaging (provided by the image / portlibs).

Workflow (persistent build container)

A single long-lived container named dxx-build is reused so the toolchain stays warm:

# one-time: create the build container
docker run -d --name dxx-build -v "$PWD":/src devkitpro/devkitarm sleep infinity

# build D1 (3dsx + elf), then package the CIA
docker exec dxx-build bash -c "cd /src/d1 && rm -rf build && make"
docker exec dxx-build bash -c "cd /src/d1/3ds_data && cp /src/d1/d1x-3ds.elf . && bash make_cia.sh"

Outputs: d1/d1x-3ds.3dsx, d1/d1x-3ds.elf, d1/3ds_data/d1x-3ds.cia.

Verify builds by md5. makerom can report CIA_RC=0 even when make failed — always confirm make succeeded and check the .cia md5 before shipping. (Also: under Docker-on-Windows, make may skip relinking d1 against a rebuilt libpicaGL.a due to mtime skew — do a clean rebuild of both when picaGL changes, and verify the resulting ELF contains the expected strings.)

Graphics backend

• Rendering is hardware-accelerated via picaGL (libs/picaGL, a git submodule) — a thin OpenGL-1.1-compatible layer that translates GL calls into native PICA200 GPU commands. This replaces the desktop OpenGL backend used by upstream DXX-Rebirth, which the 3DS has no driver for.
• SDL is the app framework, not the renderer. On 3DS, SDL (1.2 port) is used only for the event loop, input, audio, and timing. All drawing goes through picaGL/GPU.
• Because picaGL lacks GL_LINES and glLineWidth is a no-op stub, all line drawing must use triangle primitives (see the automap fix above).

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Repository layout

• d1/ — Descent I source (main/, arch/ogl/, arch/sdl/, 2d/, 3ds_data/)
• libs/picaGL/ — 3DS OpenGL backend (git submodule)
• docs/ — STEREO_3D.md, stereo-3d-logic-map.md, ORIGINAL_3DS_NOTES.md
• COPYING.txt — license

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Acknowledgments

This port was developed by Dennis Isaac Gutierrez Zeledon with the assistance of AI coding assistants across its development milestones:

• v2.0.7 – v2.1.2 (Tri-View Tactical Dashboard, Gyro Aim Assist, Roland SC-55 Jukebox, Multiplayer Touchscreen Suite, Save Thumbnails & Performance Overhaul):

  • Assistant: Gemini Antigravity (Google DeepMind)
  • Role: Implementation of the live Tri-View bottom-screen dashboard (3D live rear-view mirror, tactical sweep radar, and wireframe minimap), hardware-calibrated gyroscope aim assist with dedicated options menu, save game screenshot thumbnail system, Roland SC-55 soundtrack Jukebox, complete 3DS multiplayer touchscreen UI suite (LAN browser, Direct Join swkbd, Scoreboard overlay toggle), menu hazard and texture corruption fixes, mid-game menu lifecycle resolution, stereo depth clamping and transitions, 24-bit color dithering, bilinear filtering, 30 FPS decoupled rear-view mirror cadence, SD diagnostic bottleneck elimination, and release hardening.

• v1.0.0 – v2.0.7 (Initial Port, Stereoscopic 3D & CIA Packaging):

  • Assistant: Hermes Agent (Nous Research)
  • Model: tencent/hy3:free (via OpenRouter)
  • Role: Tracing the initial 3DS render/display path, root-causing early stereoscopic-3D bugs, repository preparation and copyright scrub with git filter-repo, branch organization, and initial CIA packaging.

• Community Contributors & Research:

  • CrashMidnick (GBAtemp): Sincere thanks for continued testing and valuable feedback!
  • bakuDD (GBAtemp): Research and recommendation of the authentic Roland Sound Canvas SC-55 soundtrack recordings from sc55.duke4.net by Brandon Blume, providing the definitive high-fidelity audio solution for the 3DS port. Sincere thanks for this great contribution!

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License

See COPYING.txt. DXX-Rebirth and this port are distributed under the GNU General Public License. Descent game data is the property of its respective owners and is not included in this repository.