Shader containers (.shaderbin)

Each shader family (environment, uber_road, terr_mega, glass, uber_water, …) is a .shaderbin, a Grub bundle, plus one compiled DXIL container per permutation and light scenario. World families are in <track>\bin.zip → shaders\_0xNN\<family>.shaderbin; the car families are in media\Cars\_library\shaders\<family>.zip; the engine’s compute and post shaders are in media\ShadersDXIL.zip. Observed The hashed _0xNN folder and family names of a bin.zip are mapped to their source paths by its asset manifest. Proven A permutation file is named like _Standard…_ST…\environmentGBufferLightScenario_I.pcdxil.pso; the .pso files are plain shader containers that carry no depth, raster or blend state. Observed Disassembling them works with a current DXC (dxc -dumpbin); the 2020 SDK build crashes on them. Observed

Counts about the Tokyo track Brio here are from a recorded census, no longer re-checkable. Observed Counts about the install (build 25588841) come from reading all 987 .shaderbin files (of the world, car and library zips) with the rules below, which refuse any byte they do not account for; none is refused. Proven · all 987 shaderbins

Blobs

Blob	Holds	Confidence
PARM	every material parameter the family declares, with its hash	Observed
DFPR	the family’s default parameter values (the end of every material chain)	Observed
VARS	the uber-shader name, the switch names with hashes and one record per compiled variant	Observed
CBMP	parameter hash → byte offset in the material constant buffer	Observed
TXMP	parameter hash → texture slot	Observed
SPMP	parameter hash → sampler register	Observed
CBEX	the material constant buffer size	Observed

Every shaderbin holds exactly one each of PARM 1.2, CBMP, TXMP and SPMP (3.1), CBEX 1.0 and DFPR 2.1. Proven · all 987 shaderbins

PARM, written as the tag bytes MRAP, is u32 count then count × { u32 name hash, varint name length, name, u32 key hash, u8 n, n bytes }. Walking records this way ends exactly at the blob’s end (environment: 328 records, 15,003 bytes); a parser that assumes n = 0 stops halfway. Proven · all 19,539 records of 987 shaderbins The first u32 is the CRC32 of the name on every record. Proven · all 19,539 records The second hash, the one a material’s parameter, a CBMP, TXMP or SPMP entry and a DFPR default carry, equals the CRC32 of the name in only 3,362 of the 19,539 records and differs in 16,177: it is a key of its own, not a name hash. Proven · all 19,539 records n is 0 on 19,162 records; on the other 377 it is between 2 and 40 and the bytes are not understood. Proven · all 19,539 records Unknown

CBMP, TXMP and SPMP (version 3.1) are u16 count; count × { u32 parameter hash; u16 value; u8 guid[16] }, 22 bytes each, so the blob size is 2 + 22 n. Proven · all 18,492 entries of 987 shaderbins: 13,192 CBMP, 4,440 TXMP, 860 SPMP Every one of those parameter hashes is the key hash of a PARM record of the same shaderbin. Proven · all 18,492 entries CBEX is one u16, the constant buffer size. Proven · all 987 shaderbins DFPR (version 2.1) is a u16 count and parameters in the layout of a material’s (Materials), without a trailer; it holds 19,539 parameters in all, 16,588 of them flagged, and the flag hash of every flagged one equals the CRC32 of the name of the PARM record with the parameter’s hash. Proven · all 987 shaderbins The three DFPR parameters of type 8 (a gradient) are particle defaults. Observed VARS and the other blobs are not read. Unknown

Choosing a permutation

The VARS blob (tag bytes SRAV) holds the uber-shader name, the switch names with their hashes (43 for environment), then one record per compiled variant (1,540 for environment): name, 12 bytes, "DefaultOrTerrain", then 1 + 43 bytes where byte i+1 is switch i: 1 on, 0 off, 2 don’t care. A material’s switch values are its merged type-4 parameters (int 1 is on), with unset switches taken from the shader’s DFPR defaults. In a Tokyo area, 6,052 of 6,059 materials match exactly one variant and every matched variant exists in bin.zip. Observed

Two refinements hold for every world family: a switch absent from the whole chain (instance, parents, defaults) matches any value, and a switch with the same value in every compiled variant is fixed by the shader and ignored. Under this rule 4,037 summer materials over three test areas each map to exactly one shipped variant; the 68 misses are unshipped winter-only permutations. Observed

Name suffixes of environment variants: _B Blend2, _L Lightmap, _M Modulate, _ST SwatchTint, _WM WetnessMask, _D Deposits, _MS MegaSkirt, _TPNAO TriPlanarNormalAO, TriPlanar (implies Modulate and WetnessMask), DualUv prefix. The most common is _StandardRCSM_ShadowsTriPlanar_ST_TPNAO_D. Observed

The rural road families uber_megaroad and uber_megaroad_edge cannot be matched this way: none of the family’s 493 compiled variants matches any of the 574 census materials, and its VARS table carries an extra name list (WinterRoads, TerrainNoise, RoadParallax, RoadDetail, UseMegaTex...) that presumably maps material switches to variant switches and is not decoded. Observed

How a draw reaches its material

World families read their material from a bindless constant block: a parameter’s register is its CBMP byte offset ÷ 16 (component = offset % 16 ÷ 4), and texture indices are dwords in the same block at a family-specific base plus the TXMP value: 188 for environment, 124 for window_linecastroom (whose CBEX says 33 registers, so the base is not always four times the register count), 88 for uber_rock_array and 76 for uber_rock. Observed Per draw one packed integer X locates the material: constants at row (X >> 16) + CBMP offset / 16, textures at index-buffer entry (X & 0xFFFF) + (TXMP offset − 16). environmentdeferreddecal and projection_lod keep their texture indices in parameter rows from register 9, anim_flag from 12 and environment_plot from 27. Observed The road decal families uber_roaddecal and uber_roaddecalretro keep theirs in row 0 of the material’s block, which the compiled code reaches as (X >> 2) & 0x3FFF rather than through the two-part X above. Observed · read in all 35 GBuffer permutations of the two families

Car families use classic bound registers instead: the CBMP value is the byte offset in the material buffer cb0 (register = value ÷ 16), the TXMP value is the t register (t16 to t33 for car_standard), and SPMP the sampler register; CBEX is 528 bytes for car_standard. Observed

Outputs

The main pass of the world families writes a G-buffer: RT0.rgb linear albedo, RT0.w metalness, RT1.w perceptual roughness, RT2.xyz the world-space normal in the game frame (a raw signed vector to normalise when consumed) and RT1.xyz the light scenario seed (emissive and local lights). Observed The forward light loop uses GGX D = a⁴ / (π((n·h)²(a⁴ − 1) + 1)²) with a = max(sat(r), 0.05), Smith-Schlick k = r²/2, Burley diffuse with F90 = 0.5 + 2 r (l·h)² and F0 = lerp(0.04, albedo, metal). Observed In dry weather every wetness term is the identity (rain constant cb7[2].x = 0; randomising the wet-only globals leaves all outputs bit-identical). Observed

Per-family formulas are on Environment shaders, Other world families, Rock and animated props, Spline deform and Car materials; water is on Water.