orklev2-pbr

name	orklev2-pbr
description	Answer questions about orkid's PBR material system, GfxMaterial hierarchy, PBRMaterial texture channels (albedo/normal/metallic-roughness/emissive), FreestyleMaterial, IBL/environment maps, BRDF integration, lightmaps, XGM serialization, FxPipeline, shader technique selection, and Python material bindings. Use when the user asks about PBR, materials, IBL, environment maps, or material rendering.
user-invocable	false

Orkid PBR Material System Reference

When answering questions about PBR materials, shading, or IBL in orkid, consult the files below. All under ork.lev2/.

Key Files

Component	Header/File
GfxMaterial Base	inc/ork/lev2/gfx/gfxmaterial.h
PBRMaterial	inc/ork/lev2/gfx/material_pbr.inl
FreestyleMaterial	inc/ork/lev2/gfx/material_freestyle.h
IBL/Radiance	inc/ork/lev2/gfx/renderer/NodeCompositor/pbr_common.h
Drawable Integration	inc/ork/lev2/gfx/renderer/drawable.h
Model/XGM	inc/ork/lev2/gfx/gfxmodel.h
PBR Main Impl	src/gfx/material/material_pbr.cpp
PBR I/O (XGM)	src/gfx/material/material_pbr_io.cpp
PBR Images/Textures	src/gfx/material/material_pbr_image.cpp
PBR Lightmaps	src/gfx/material/material_pbr_lightmaps.cpp
BRDF Generation	src/gfx/material/material_pbr_gen.cpp
Pipeline/Techniques	src/gfx/material/material_pbr_pipeline.cpp
Depth Prepass	src/gfx/material/material_pbr_depthprepass.cpp
Picking	src/gfx/material/material_pbr_pick.cpp
Unlit	src/gfx/material/material_pbr_unlit.cpp
Misc Techniques	src/gfx/material/material_pbr_misc.cpp
Python Bindings	pyext/src/pyext_gfx_material.cpp

Class Hierarchy

ork::Object
└── GfxMaterial (abstract, gfxmaterial.h:113)
    ├── PBRMaterial (material_pbr.inl:36)
    └── FreestyleMaterial (material_freestyle.h:20)

GfxMaterial Base (gfxmaterial.h)

• mMaterialName, miNumPasses — identity and pass count
• _rasterstate — blend, depth, cull state
• _varmap — dynamic parameter storage (VarMap)
• _variant — CRC32 variant identifier for technique override
• _state_lambdas — per-frame parameter binding callbacks
• _bound_params — fxparam → value bindings

PBRMaterial

Full physically-based rendering material with metallic-roughness workflow.

FreestyleMaterial

Generic shader wrapper — wraps an FxShader* with techniques/parameters. Used internally by PBRMaterial (_as_freestyle member).

PBR Texture Channels

Channel	Image Member	Texture Member	Description
Color/Albedo	_image_color	_texColor	Base color (RGBA)
Normal	_image_normal	_texNormal	Tangent-space normal map
Metallic+Roughness	_image_mtlruf	_texMtlRuf	Packed metallic/roughness
Emissive	_image_emissive	_texEmissive	Emissive glow map
Ambient Occlusion	_image_ambocc	_texAmbOcc	AO map
Light Map	—	_texLightMap	Pre-baked lighting

All textures are packed into _texArrayCNMREA (TextureArray) via assignImages() — images are conformed to the same dimensions and converted to RGBA8.

PBR Scalar Parameters

Parameter	Default	Description
_metallicFactor	0.0	Metallic weight
_roughnessFactor	1.0	Roughness weight
_baseColor	(1,1,1,1)	Base color tint
_alphaCutoff	0.0	Alpha test threshold
_alphaMode	0	0=OPAQUE, 1=MASK, 2=BLEND
_doubleSided	false	Two-sided rendering
_shaderpath	"orkshader://pbr"	Shader asset path

IBL / Environment Maps

RadianceMaps (pbr_common.h:51–64)

struct RadianceMaps {
  texturearray_ptr_t _filtenvSpecularMapArray;  // Roughness-stratified specular
  texture_ptr_t _filtenvDiffuseMap;             // Diffuse irradiance
  texture_ptr_t _brdfIntegrationMapGGX;         // GGX BRDF LUT
  texture_ptr_t _brdfIntegrationMapVelvet;      // Velvet BRDF LUT
  texture_ptr_t _brdfIntegrationMapGGXRIM;      // GGX+rim BRDF LUT
  texture_ptr_t _brdfIntegrationMapBlinn;       // Blinn BRDF LUT
  texture_ptr_t _brdfIntegrationMapPhong;       // Phong BRDF LUT
  std::vector<float> _specularRoughnessValues;
  int _numRoughnessLevels;
};

CommonStuff (pbr_common.h:68–159)

Per-scene IBL state including:

• _radiance_maps, _environmentIntensity (default 1.0)
• _environmentMipBias, _environmentMipScale
• _diffuseLevel, _specularLevel, _ambientLevel, _skyboxLevel
• _roughnessPower
• SSAO parameters: _ssaoRadius, _ssaoBias, _ssaoWeight, _ssaoPower, _ssaoNumSamples, _ssaoNumSteps

BRDF Integration Maps

• Generated via compute shader in material_pbr_gen.cpp
• Supports GGX, Blinn, Phong, Velvet, GGX-Rim models
• Cached in DataBlockCache with CRC hash
• Dimensions: 512x512

Per-Drawable Override

// drawable.h:363
pbr::radiancemaps_ptr_t _envmapOverride;  // per-drawable environment map override

Lightmap Support

• Up to kMaxLightmaps = 8 lightmaps per material
• Stored as _texLightMapArray (TextureArray), conformed to same size, RGB16 format
• setActiveLightMap(name, color) — activate and tint a named lightmap
• conformLightmaps() → assignLightmaps(ctx) pipeline

Shader Technique Naming Convention

Techniques encode their rendering configuration:

{Model}_{Content}_{Skeleton}_{Instancing}_{Stereo}

Segment	Values
Model	FWD (forward), GBU (deferred/GBuffer), PIK (picking), DPP (depth prepass)
Content	UNLIT, SKYBOX, CM (ModColor), CT (TexColor), CV (VertexColor), CF (CharFont), DB (DebugViz), EMI (Emissive)
Normal	NM (normal map), NV (vertex normal)
Skeleton	RI (rigid), SK (skinned)
Instancing	IN (instanced), NI (non-instanced)
Stereo	MO (mono), ST (stereo)

Example: _tek_FWD_CT_NM_RI_IN_MO = Forward, TexColor, NormalMapped, Rigid, Instanced, Mono

Shader Parameter Bindings

Matrices

_paramM, _paramV, _paramP, _paramVP, _paramMVP, _paramIP, _paramIV, _paramIVP Stereo: _paramVL/VR, _paramVPL/VPR, _paramMVPL/MVPR

Material

_parMetallicFactor, _parRoughnessFactor, _parRoughnessPower, _parAlphaCutoff, _parModColor, _parPickID

Environment

_parMapSpecularEnv (TextureArray), _parMapDiffuseEnv, _parMapBrdfIntegration _parEnvironmentMipBias, _parEnvironmentMipScale, _parSpecularMipBias

Lighting

_paramAmbientLevel, _paramDiffuseLevel, _paramSpecularLevel, _paramSkyboxLevel _parForwardLightBlock (SSBO, 32KB), _parInstanceBlock (SSBO for instancing)

SSAO

_paramSSAOTexture, _paramSSAOWeight, _paramSSAOPower, _paramSSAOBias, _paramSSAORadius, _paramSSAONumSteps, _paramSSAONumSamples

XGM Serialization

PBR materials are read/written via XGM model files:

// Registered in Describe():
c->annotate("xgm.reader", reader);  // material_ptr_t _xgmReader(XgmMaterialReaderContext&)
c->annotate("xgm.writer", writer);  // void _xgmWriter(XgmMaterialWriterContext&)

Reader (material_pbr_io.cpp:9): parses texture channel names, creates Image objects from embedded data, reads scalar params. Writer (material_pbr_io.cpp:114): serializes texture names/paths, scalar params, lightmap metadata.

Material Pipeline Flow

PBRMaterial._varmap
    → bindParam(fxparam, value)
    → _bound_params[fxparam] = value
    → _state_lambdas execute at render time
    → Context::FXI()->bindParam*() to GPU

Key methods:

• gpuInit(Context*) — load shader, find techniques/params
• addBasicStateLambda(pipe) — raster state setup
• addLightingLambda(pipe) — lighting parameter binding
• _doFxPipelineCache(perms) — technique selection based on permutations

Python API

from orkengine import lev2

# FreestyleMaterial (generic shader wrapper)
mtl = lev2.FreestyleMaterial(ctx, "orkshader://pbr")
tek = mtl.technique("tek_FWD_CT_NM_RI_NI_MO")
par = mtl.param("MetallicFactor")
mtl.bindParamFloat(par, 0.5)
mtl.begin(tek, rcfd)
# ... draw ...
mtl.end(rcfd)

# FxPipeline
pipeline = lev2.FxPipeline(fxcache)
pipeline.technique = tek
pipeline.bindParam(par, 0.5)
pipeline.wrappedDrawCall(rcid, lambda: draw())

# FxPipelinePermutation
permu = lev2.FxPipelinePermutation(
    rendermodel="forward",
    stereo=False,
    instanced=True,
    skinned=False
)

# Material access via model
model_drawable = lev2.ModelDrawableData("data://model.glb")
# Materials live on XgmSubMesh._material

How to Answer

1. For texture channels/params: check material_pbr.inl member declarations
2. For IBL/environment: check pbr_common.h for RadianceMaps and CommonStuff
3. For technique selection: check material_pbr_pipeline.cpp and the naming convention
4. For serialization: check material_pbr_io.cpp for XGM reader/writer
5. For lightmaps: check material_pbr_lightmaps.cpp
6. For Python: check pyext_gfx_material.cpp
7. For shader params: check the param declarations in material_pbr.inl lines 124–202