PocketCompiler 3DS

PocketCompiler
General
Author	PlanetDogeCodes
Type	Other Apps
Version	0.36
License	Apache-2.0
Last Updated	2026/06/17
Links
Download
Website
Source

PocketCompiler is an experimental Nintendo 3DS HTML/JS/CSS compiler and code editor

It's designed to let you write HTML/JS/CSS on the 3DS, allowing for easy development. You can:

• Edit code on the bottom screen.
• Preview output/status on the top screen.
• Save/load projects from the SD card.

The default project path is sdmc:/3ds/PocketCompiler/projects/

Features

• Basic HTML parsing.
• Simple CSS.
• Basic JavaScript runtime capabilities.
• DOM-like elements.
• Keyboard/Mouse/Touch events.
• Nearly complete iframe support.
• document.write()
• Limited API and link fetching.
• IndexedDB-adjacent SD-card storage.
• Custom Canvas rendering.
• Custom WebGL rendering.
• Image loading.
• Web audio support.

Canvas / WebGL

PocketCompiler has rendering systems for:

• canvas command buffers
• rectangles, lines, text, placeholders
• getContext("webgl") detection
• buffers
• shaders/programs
• uniforms/attributes
• textures
• draw calls
• viewport/depth/blend/scissor state
• Citro3D backend scaffolding

This is not yet full WebGL.

Storage

PocketCompiler includes SD-card-backed storage systems:

sdmc:/3ds/PocketCompiler/idb/
sdmc:/3ds/PocketCompiler/cache_api/
sdmc:/3ds/PocketCompiler/resource_cache/

Supported or scaffolded:

• IndexedDB-style databases/object stores
• put, get, delete, clear, count
• localStorage-style storage
• sessionStorage-style storage
• Cache API-style storage
• binary-safe values
• 1 MB per-value/resource cap

Audio

PocketCompiler includes a small Web Audio-style system:

• AudioContext-like runtime
• OscillatorNode-like node
• GainNode-like node
• sine/square/triangle/sawtooth tones
• NDSP-backed output when available
• safe fallback if audio fails

Limitations

PocketCompiler is still in early development.

It does not yet fully support:

• Complete HTML parsing
• Full CSS layout/cascade
• Full modern JavaScript/browser behavior
• Complete Promise/event-loop behavior
• Full WebGL 1.0
• Real GLSL shader translation
• Full Canvas 2D API
• Full Web Audio API
• Full IndexedDB compatibility
• Complete iframe isolation
• Pointer lock

The 3DS also has very limited RAM, CPU, GPU power, and screen space, so PocketCompiler uses strict safety limits (1 MB per resource/value/cache entry, bounded event queues, bounded command buffers, bounded editor/runtime structures)

Controls

D-Pad - Arrow key movement

Circle Pad - Move mouse cursor (it's just a dot)

A - Click, Edit code line

B - Undo

X - Save project

Y - Load project

Start - Run/Compile

Select - Show controls menu

Screenshots

Changelog

v0.36

• Crash / correctness fixes:
  • editor_find and editor_find_prev: start_line was not clamped before use — with a corrupted or uninitialized value it could make editor_get_line walk off the end of the buffer. Now clamped to [0, total-1].
  • editor_replace_at: added col > llen guard so an exact-end-of-line replacement can't produce a negative memcpy count.
  • we_eval_js: added !g_web_engine.loaded check — without it, a stale non-NULL js_ctx pointer left from a previous we_unload() call could be dereferenced.
  • draw_console: i < WJS_LOG_MAX_LINES guard added — a corrupted g_wjs_log_n could have caused a read past the log array bounds.
• Compiler warning fixes:
  • (down & KEY_X) && ... — explicit parentheses added (GCC -Wall warning eliminated).
  • Two strcat() calls replaced with strncat().
  • LAYOUT_ED_H corrected to 178.0f (was 180.0f) — the 2px mismatch caused the cursor-to-line mapping to select the wrong line near the bottom of the editor panel.

v0.34

• Slight UI changes
• Bordered rendering for text & iframe
• Memory usage fixes
• More accurate CSS parsing

File	Fixes/Changes
web_layout.c	Body avail_w bug fixed: was 2×margin_left, now margin_left + margin_right.
web_layout.c	Text node lay_w uses full available container width for alignment.
web_render.c	Scale formula size/11.0f → size/30.0f (correct for system font at scale 1.0 ≈ 30px).
web_render.c	TEXT nodes use parent container width for proper text alignment.
web_render.c	Bottom border drawn on document viewport to frame the output area.
web_engine.c	css_apply_ua_defaults() called after css_reset(), before parse — so user styles always win.
web_engine.c	RUNNING bar cleaned up; conflicting title bar overlay removed.

v0.33.5

• Hopefully fixed crashing issues

v0.33.4

• MAYBE fixed crashing issues (untested, will update when tested)

v0.33.3

• Fixed surface-level crashing issues

v0.33.2

• Maybe fixed crashing issues
• Stability fixes
• Fixed errors while compiling

v0.33

• Fixed scrolling
• Fixed line truncation
• Added more complete rendering capabilities
• Added pointer lock integration
• Added page interaction

v0.32

• Fixed the HTML rendering engine
• Slight UI changes

v0.31.1

• Completely overhauled the UI (AI was used to help with this)
• New frame buffer that minimizes the visual bug to almost unnoticeable proportions.

Pre-Release v0.30

• Fixed app crashing on file explorer open (MAYBE FR THIS TIME)
• Fixed the visual bug (kinda)

Credits

PocketCompiler project and idea by PlanetDogeCodes (me). Some browser runtime features, custom Canvas/WebGL Integration, and 3DS Optimizations were all made with help from GPT-5.5 xhigh. Some UI elements and DOM-style event handling were made with help from Claude Sonnet 4.6

Built with:

• Visual Studio Code
• devkitPro
• devkitARM
• libctru
• Citro2D
• Citro3D

External links

• GitHub - https://github.com/PlanetDogeCodes/Pocket-Compiler
• Universal-DB - https://db.universal-team.net/3ds/pocket-compiler