Each row is one game texture. Columns: original, then each upscaler. Every cell shows the whole texture and a 2× crop of its centre. A red frame marks an output flagged for drift (SSIM < 0.8 or ΔE > 6). Scroll to zoom, drag to pan.
Same model, pose and lighting in every tile; only the textures differ. Order: original, lanczos, seedvr2, ultrasharp2 / pbrify4, klein, qwen.
Tiling check for terrain: each texture is repeated 2×2 so a seam at the wrap edge would show as a cross. Original first, then each variant.
What this is
MU Online's textures are mostly 64–256 px. We upscaled 188 of them (Lorencia, Devias and a set of character, item and monster models) 4× with five image models and two controls, packed each set as an overlay on unchanged game data, and photographed the exact same frame in two clients: the original and the variant. A saved scene snapshot (clock, camera, characters, animation phase, grass, light) is loaded into both clients, so every difference you see comes from the textures alone.
Verdict
Key findings
- Resolution decides whether HD textures can show. At 1024×768 the original Lorencia terrain is already ~0.8 texels per screen pixel, so ¾ of a 4× texture's detail cannot be displayed. At 2560×1440 the close Devias camera shows the full 4×. Judge at Enhanced, 2560×1440.
- Classic shimmers with HD textures. The Classic renderer has no mipmaps, so 4× textures alias when minified (that is why Classic SSIM is much lower). The Enhanced renderer (mipmaps + 8× anisotropic filtering) keeps them stable.
- Cost: UltraSharpV2 is 40× faster than Qwen (2.3 vs 99.8 GPU-minutes for 188 textures) and needs 5 GB of VRAM instead of 28 GB.
- Klein's brightness is measurable: mean colour error ΔE 8.9, 127 of 188 outputs flagged. A colour transfer back to the source would likely fix it; not tried.
How much each variant changes the frame
Mean SSIM of the world region against the original, over all 11 scenes (+0 gear). This measures how much a variant changes the picture, not how good it is.
Per-texture metrics
Method
- All variants run at 4× through ComfyUI. Qwen and Klein used the prompt
Restore and upscale this image. Same image, higher resolution, sharper, cleaner. Change nothing else.
- Tiling textures are wrap-padded; every variant shares one alpha path. Generative models run at a 1024 px longer side and are scaled to 4× with Lanczos.
- 11 scenes per shot set (8 Lorencia, 3 Devias), hero alone, UI hidden, two loadouts (+0 and +11 glow); Classic and Enhanced renderers at 1024×768, Enhanced at 2560×1440 — 462 shot pairs, none failed.
- Images on this page are WebP at quality 92 (visually lossless); the comparisons were measured on the original PNGs.
Work in progress from the MUnolith project. MU Online is © Webzen; game art is shown for comparison only.