Emulation Shader Visual Comparator – CRT, LCD & Scanlines

A CRT shader digitally recreates the visual characteristics of cathode-ray tube displays. It simulates scanlines (horizontal gaps between electron beam passes), RGB phosphor dot patterns, barrel distortion from curved screens, and edge vignetting. These effects combine to produce the warm, nostalgic look of vintage televisions and arcade monitors.

Retro games were designed with CRT characteristics in mind. The natural blur and scanlines of CRTs smooth pixel edges, create perceived anti-aliasing, and blend colors in ways that artists exploited. CRT subpixel rendering also adds texture and depth that flat modern displays lack, making sprites appear more organic and detailed.

Aperture grille CRTs (like Sony Trinitron) use vertical RGB phosphor stripes with fine horizontal stabilizing wires, producing brighter images with distinct vertical lines. Shadow mask CRTs use a perforated metal sheet with RGB dots in triangular delta patterns, offering better corner sharpness but lower brightness. Both produce recognizable scanline patterns.

Scanlines create alternating bright and dark horizontal rows that reduce visible pixelation while preserving detail. The dark gaps between scanlines enhance perceived contrast and sharpness. At typical viewing distances, the eye blends scanlines with the image, producing a smoother appearance — a key reason retro games look crisp on CRT but blocky on modern displays.

An LCD shader simulates liquid crystal display characteristics: rectangular pixel grids with visible gaps, RGB subpixel stripe arrangements, uniform backlight, and no scanlines. LCD pixels are sharply defined squares, unlike CRT's organic phosphor glow. LCD shaders often add subtle grid patterns and slight color fringing at subpixel level.

Barrel distortion is the subtle outward bowing of the image toward the edges, caused by the curved surface of CRT tubes. It's most noticeable near screen corners and creates the characteristic "bulging" look. While technically a flaw, it became part of the authentic retro viewing experience and contributes to the immersive feel of CRT emulation.

Yes! The techniques demonstrated here — scanline overlays, RGB masking, and barrel distortion — are the same principles used in emulator shaders like CRT-Royale, CRT-Geom, and LCD-3x. For real-time gaming, these shaders are typically GPU-accelerated via GLSL/HLSL. This tool lets you preview the aesthetic before applying similar settings in RetroArch, MAME, or other emulators.

The Arcade CRT preset is ideal for classic arcade emulation, featuring strong scanlines, pronounced RGB phosphor masking, and moderate vignette — closely matching the look of 1990s arcade cabinets. For fighting games and shmups, combine it with slight barrel distortion for authentic cabinet realism. The Professional Monitor preset suits text-heavy or strategy games.