Refactoring legacy graphics for game remasters

Legacy Graphics Refactoring for Remasters

2015 project: textures 512×512, diffuse maps without metallic/roughness, meshes with 15,000 polygons for main character — all in Built-in Render Pipeline. Task: move to URP or HDRP, raise quality to modern PBR standards, don't break gameplay and don't increase system requirements beyond reason. This not "repaint textures" — systematic work with artistic production technical debt.

What breaks when changing render pipeline

Transition Built-in → URP — not automatic. Edit > Rendering > Render Pipeline Converter in Unity converts Standard materials to Lit (URP), but this baseline conversion. Custom shaders in GLSL or ShaderLab without Surface Shader API — need rewriting under HLSL or porting to ShaderGraph.

Main loss: Standard shader in Built-in supports Specular workflow (albedo + specular + gloss). URP Lit — only Metallic workflow (albedo + metallic + smoothness). Specular → metallic conversion not unambiguous: old materials often had physically incorrect specular values that gave "beautiful" result in old render and look wrong in PBR.

Specific situation: stone walls in 2015 game had specular color (0.2, 0.2, 0.2) with glossiness 0.3 — this gave soft gloss. After conversion metallic = 0.0, smoothness = 0.3 — walls look matte than should because F0 for dielectrics now computed physically. Needs manual smoothness tweak + Detail Normal Map addition for compensation.

Texture upscaling and reworking

Textures 512×512 in remaster for modern 1440p/4K monitors look bad. Options:

AI upscaling via Gigapixel AI or Stable Diffusion with img2img (controlnet tile for structure preservation). Gigapixel gives 4× without artifacts on tileable textures — 512 → 2048 in minutes. But for organic (character skin, plants) result unstable — needs manual refinement.

Full rework under PBR: artist creates new texture set from 4 maps (Albedo, Normal, Metallic/Roughness, AO) in Substance 3D Painter, using old texture as color reference. Right for key assets, unrealistic for whole game.

Normal maps from old geometry. If character has low-poly and high-poly versions (even in old quality) — rebake normal maps via Marmoset Toolbag or xNormal with correct cage offset. Old normal maps often baked without UV-seam separation — seams visible at edges, become more noticeable in new HDRP lighting.

Meshes: retopology vs LOD

Mesh rework for remaster depends on task. Game stays on same platform — aggressive retopology unnecessary. But if original for 7th gen consoles (PS3/Xbox 360 style), meshes often have non-functional topology: triangles everywhere, no edge flow for deformations. Adding new animations or Blend Shapes — facial animation on such topology impossible.

For remasters with updated cutscenes: retopology key characters, add blendshape-rig for facial animation, setup LOD Group with LOD0/LOD1/LOD2 — standard work.

LOD in URP/HDRP via LODGroup + SpeedTree-style billboard for far objects gives performance boost without visual degradation on near-LOD.

Shaders and visual effects

Old Particle System effects on Built-in Material — rewrite under VFX Graph (URP/HDRP). VFX Graph runs GPU, supports lit particles with normal maps and proper PBR lighting — quality jump for fire, smoke, magical effects.

ShaderGraph for custom shader rework: old 200-line Vertex-Fragment shader → visual graph with Sample Texture 2D, Normal Blend, Lerp, Fresnel Effect nodes. Debug and iterate easier, result compiles for all supported platforms.

Timelines

Cost determined after asset volume audit and remaster target platform.