CRT filters for iPhone and iPad emulators

Choose the display, then the strength

Nearest-pixel presentation keeps the original pixel boundaries clear. CRT treatments use scanlines, masks and edge shading; LCD treatments add a pixel or subpixel structure. These choices change the presentation, not the underlying game resolution.

• Start with the unfiltered picture as a reference.
• Check small text, bright edges and dark areas, not only the title screen.
• Judge the result at the size and orientation you actually play.

No integer-scale requirement

Integer scaling maps each game pixel to a whole number of display pixels. It can be useful for crisp nearest-pixel output, but may leave extra unused space. Retropa advanced filters account for the actual output area, so their display structure is not restricted to a 2x, 3x or other whole-number multiple. You can retain the game's aspect ratio while using a viewport that fits your phone or skin.

• CRT V4 reconstructs beam coverage and analytically filters phosphor structure using the output-pixel footprint.
• Trinitron uses integrated scanline beams and band-limited aperture-grille harmonics.
• DMG integrates liquid-crystal cell coverage instead of simply point-sampling a grid.

More than a scanline overlay

Basic CRT Lite, LCD Grid and Scanline presets offer lighter display treatments. Advanced presets model more of the display itself: beam width, phosphor transmission or reflective liquid-crystal material. Directly sampled grids can become uneven at fractional scales; output-aware integration helps unresolved detail blend naturally. This is not a claim that every conventional filter needs integer scaling, or that every device and preset will be artifact-free.

What the browser comparison shows

The television previews basic filters plus native-informed CRT V4, Trinitron V1 and DMG. The advanced modes adapt selected native formulas, including pixel-footprint integration, with one shared presentation curve. The web renderer omits temporal persistence, the full multi-pass bloom chain and native color management. It demonstrates display characteristics, not pixel-identical Metal output or real gameplay footage.

Import RetroArch shader presets

A .slangp preset can reference several shader passes, textures and parameter values. Keep those dependencies together when importing. A preset file on its own may be incomplete; a .slang file describes a shader rather than an entire collection.

• Use packages intended for the supported shader workflow.
• If a preset cannot load, check referenced files and compatibility before changing the game.
• Try a lighter preset if a complex chain affects frame pacing or battery use.

Picture quality has a performance cost

A multi-pass filter can need more GPU work than nearest-pixel output. Performance depends on the device, emulator core, output resolution and preset. Retropa does not promise that every imported shader runs equally well on every iPhone. Advanced filters require Plus; confirm the available choices in the app.