RetroArch shaders

Leaf includes qualified GLSL shader presets for RetroArch games. Nothing turns on by itself. A fresh install shows the original picture until you choose a preset.

Shaders only affect games running through RetroArch. Standalone emulators like DraStic, PPSSPP, Mupen64Plus, and Flycast have their own video settings.

Choose a Leaf recommendation

1. Launch a game that uses RetroArch.
2. Press MENU, then open Shader.
3. Use Up and Down to browse the recommendations over a frozen still. Leaf does not apply a live preview while you browse.
4. Use Left and Right to choose This game (the default), This folder, or All RetroArch before you apply anything.
5. Select a recommendation or Save current shader. Leaf applies or saves it at the selected scope, then resumes the game.
6. Use Advanced RetroArch menu when you need RetroArch’s full shader screen.

Press B to leave the picker without applying a choice. Off clears the live shader and removes the saved preset at the selected scope. There is no separate Off submenu. A broader preset may return after you reload the game.

The picker shows only recommendations that Leaf qualified for the active system, so you won’t see all thirteen at once. Each built-in system with a packaged RetroArch core has at least two choices. Nintendo 64, Dreamcast, Atomiswave, and Naomi get Sharp Pixels and Sharp Shimmerless for their RetroArch alternatives. Saturn gets Sharp Pixels and Subtle Scanlines. Standalone emulators do not use these shaders.

• Sharp Pixels keeps pixel art crisp without adding a CRT effect.
• Sharp Shimmerless keeps non-integer scaling sharp while reducing shimmer during scrolling.
• Subtle Scanlines adds lightweight scanlines for 8-bit, 16-bit, and PlayStation-era games.
• CRT Lite adds a mild aperture mask and softened scanlines without curvature.
• CRT Sharp combines crisp scaling, scanlines, and a flat aperture mask.
• CRT Curved adds curvature, rounded corners, scanlines, and an aperture mask. It crops slightly at the screen edges.
• GBA Color and GBC Color approximate the softer color response of the original handheld screens.
• Game Boy LCD, Game Boy Color LCD, and Game Boy Advance LCD add a stronger display simulation with a backing texture and pixel grid.
• LCD Grid adds a fine RGB handheld pixel grid.
• LCD Grid Fast is a lighter grid with softer cell edges.

The installed manifest is authoritative if this list changes in a later Leaf release.

Refresh rate and BFI caveats

All thirteen recommendations passed Leaf’s visual and performance checks on the MLP1, but a few combinations need care:

• Keep Black Frame Insertion off with GBA Color and Game Boy Advance LCD when using mGBA. The no-shader mGBA control already falls below full speed at 120 Hz with BFI, so the picker shows that warning instead of blaming the shader.
• Keep BFI off with CRT Lite. A PlayStation test at 120 Hz with BFI measured about 50 fps, while the 60 Hz and 120 Hz tests with BFI off ran at full speed.
• Scanlines, LCD grids, and BFI all reduce brightness. Combining them reduces it further.

The picker detail pane shows the most relevant constraint for the selected preset. If a game runs below full speed, turn BFI off before changing the shader.

Save at the right scope

Before you apply a recommendation or save the current shader, Leaf lets you choose one of these scopes with Left and Right:

Scope	What it affects
This game	The current game with its current core. This is the default
This folder	Games launched from the same content folder with the same core
All RetroArch	Every RetroArch game. Leaf asks for confirmation because this can replace Fugazi

Leaf’s picker exposes game, folder, and global scopes. RetroArch still supports its native core scope and checks automatic presets from most specific to least specific: game, folder, core, then global. A more specific preset wins.

There is one legacy exception. RetroArch searches automatic-preset directories in order before it tries every specificity. A global preset in an earlier old or fallback directory can therefore beat a game preset in a later directory. If the result looks impossible, remove the legacy preset instead of adding more overrides.

Three saves that do different jobs

• Quitting RetroArch normally saves general RetroArch settings. It does not create an automatic shader preset. Leaf hides the Configuration File menu.
• Save Core Overrides, Save Content Directory Overrides, and Save Game Overrides store configuration changes. A config override does not carry the active shader.
• Save Game Preset, Save Content Directory Preset, Save Core Preset, and Save Global Preset under Shaders > Manage Presets create automatic presets at their matching scopes. Save Current Preset updates the loaded preset file; it does not choose a new automatic scope.

Saving a config override while a shader is visible does not save that shader. A loaded global shader also keeps returning until you remove it or save a more specific shader preset.

Turn a saved shader off

Choosing Off clears the running shader and removes the saved preset at the currently selected Leaf scope. Removing a game or folder preset does not remove a native core or global preset. A broader preset may become active after the next content launch, and Leaf explains that possibility instead of creating a fake no-shader preset.

Fugazi and global presets

Fugazi is the specialized global CRT tuner. The Leaf shader picker is the common path for recommendations; use Fugazi when you want to tune its CRT effect across every RetroArch game.

• Reset changes Fugazi’s tuner values only. It does not uninstall anything.
• Apply installs Fugazi globally. If another global preset is active, Fugazi asks before replacing it and preserves that preset as one backup.
• Remove disables Fugazi and restores the preserved preset when one exists.
• If Fugazi finds another current global preset while it still holds a backup, choose Keep current, Restore previous, or Cancel. Do not delete the files by hand.

Saving another All RetroArch shader can replace Fugazi later. If that leaves a current preset and Fugazi backup together, Fugazi shows the resolver the next time you open it.

Edit and save advanced presets

Choose Advanced RetroArch menu to open RetroArch’s native Shaders screen directly. The leaf-bundled/ folder holds the qualified advanced presets that Leaf’s recommendations reference. Everything there loads and renders correctly, but it may not suit every core or game. Choose the save scope in RetroArch while you are there; Leaf’s Left / Right scope selection does not carry into that menu.

Choose Load Preset to load a preset. If you edit its shader passes, choose Apply Changes. Then open Manage Presets and choose Save Game Preset, Save Content Directory Preset, Save Core Preset, or Save Global Preset for the automatic scope you want before you leave. Save Current Preset edits the currently loaded preset file, so use it only when that is the file you intend to maintain. Press MENU to return directly to the game. Leaf does not ask you to choose a save scope when you leave RetroArch’s shader screen.

zfast-composite remains advanced-only because its measured audio underrun was much higher than the alternatives even though its frame-rate counter stayed at 60 fps. CRT Lottes Fast also remains advanced-only after measuring about 34 fps on a lightweight test scene.

The bundle includes PT SkyWalker541 by SkyWalker541, Sharp Shimmerless by Woohyun-Kang, and lightweight CRT shaders from the libretro shader contributors.

Download the full RetroArch collection

Official does not mean qualified

The official GLSL collection is not guaranteed to be compatible or fast on every OpenGL ES driver. Leaf qualifies only leaf-recommended/ for the MLP1.

RetroArch’s Online Updater > Update GLSL Shaders downloads the complete official libretro GLSL collection into shaders_glsl/. These presets have not all passed Leaf’s MLP1 performance and visual checks. Let the download finish before browsing them.

The folders have separate owners:

• leaf-recommended/ and leaf-bundled/ are refreshed by Leaf updates.
• shaders_glsl/ is refreshed by RetroArch’s updater.
• custom/ is yours.

Leaf updates preserve the updater and custom folders. Updating GLSL shaders does not overwrite Leaf’s pinned dependencies.

Add your own shaders

Custom shader files go on the primary SD card under:

.umrk/mlp1/retroarch/.config/retroarch/shaders/custom/

With one card this is usually below /mnt/sdcard/. With two cards, Linux may mount the Leaf card at /media/sdcard1 instead. Treat the relative .umrk/ path as the real answer and do not hardcode a mount point.

Keep the dependency folder structure exactly as you found it. A .glslp file often references .glsl passes, LUT images, or other presets next to it. Copying only the .glslp file can leave the preset visible in the browser but unable to compile.

Leaf’s RetroArch build supports GLSL .glslp presets and .glsl passes. Slang/Vulkan (.slangp, .slang) and Cg (.cgp, .cg) packs do not work on MLP1. Because .umrk begins with a dot, macOS and Linux file managers hide it by default.

Leave .system/leaf/platforms/mlp1/shaders/ alone. It is Leaf’s manifest-validated source bundle and is replaced during an update. The browser, updater collection, and personal shaders live in durable .umrk/ state.

A custom or updater shader fails

First find out whether it compiled. A link failure silently falls back to the plain picture even while RetroArch still shows the preset as loaded. The Leaf picker reports that failure directly for recommendations and restores the previous shader.

For an advanced preset:

1. Confirm it is GLSL and suitable for an OpenGL ES driver.
2. Restore its complete dependency tree.
3. Reproduce it from Advanced RetroArch menu with verbose RetroArch logging enabled if support asks for evidence.

Do not replace zfast_crt_geo by hand. Use Leaf’s CRT Curved preset, which contains a guarded local compatibility patch. The same unpatched shader also fails on the stock OS, so stock is not a working fallback.

Recovery messages

Message or symptom	What to do
A recommendation is missing	Update or reinstall Leaf. Do not use the updater pack as a substitute
The shader could not compile or link	The previous shader was restored. Use another recommendation or troubleshoot the advanced preset’s driver support and dependencies
RetroArch did not confirm the shader	Reopen Shader or restart the game before saving another scope
The previous shader could not be restored	Reopen the game, then use RetroArch Settings to inspect the active shader
A shader returns after reload	Remove the saved preset at its owning scope and check Fugazi or another global preset
Fugazi says the state needs attention	Deliberately choose Keep current, Restore previous, or Cancel

The preset browser is empty

An older Leaf release may predate the shader bundle. Update Leaf first.

If the browser is still empty, check Settings > Directory > Video Shaders. It should point to the durable .umrk/mlp1/retroarch/.config/retroarch/shaders/ root, not one of its child folders. Fully exit and relaunch the game so Leaf can refresh the path after an SD mount swap.

As a last resort, Settings > Games > Reset RetroArch Config restores the default shader directory, but it also resets your other RetroArch settings.