GPUShaders::Common::Common_pbr Class Reference

Common pbr general shader. More...

Classes
struct	Light
	Analytic light data. Some members might only be valid for some types of lights. More...
struct	Probe
	Environment probe data. More...

Public Member Functions
vec3	F (vec3 F0, float VdotH)
vec3	iorToFresnel (vec3 internalIOR, vec3 externalIOR)
float	iorToFresnel (float internalIOR, float externalIOR)
vec3	fresnelToIor (vec3 F0)
vec3	iridescenceSensitivity (float opd, float shift)
vec3	iridescenceF0 (vec3 F0, float LdotH, float ior, float thickness, float externalIOR)
float	D (float NdotH, float alpha)
float	DAnisotropic (float NdotH, float TdotH, float BdotH, float alphaT, float alphaB)
float	DCharlie (float NdotH, float alpha)
float	V (float NdotL, float NdotV, float alpha)
float	Vfast (float NdotL, float NdotV, float alpha)
float	VAnisotropic (float NdotL, float NdotV, float TdotV, float BdotV, float TdotL, float BdotL, float alphaT, float alphaB)
float	VKelemen (float LdotH)
float	VNeubelt (float NdotL, float NdotV)
vec3	ggx (vec3 n, vec3 v, vec3 l, vec3 h, vec3 F0, float roughness)
float	ggxClearCoat (vec3 n, vec3 v, vec3 l, vec3 h, float roughness, out float clearCoatFresnel)
vec3	ggxAnisotropic (vec3 n, vec3 v, vec3 l, vec3 h, vec3 F0, Material material)
vec3	ggxSheen (vec3 n, vec3 v, vec3 l, vec3 h, Material material)
vec3	radiance (vec3 r, vec3 p, float roughness, textureCube cubeMap, Probe probe)
float	probeWeight (vec3 p, Probe probe)
vec3	applySH (vec3 wn, vec4 coeffs[9])
float	approximateSpecularAO (float diffuseAO, float NdotV, float roughness)
void	ambientLighting (Material material, vec3 worldP, vec3 viewV, mat4 inverseV, Probe probe, textureCube envmap, vec4 envSH[9], texture2D brdfLUT, out vec3 diffuse, out vec3 specular)
void	directBrdf (Material material, vec3 n, vec3 v, vec3 l, out vec3 diffuse, out vec3 specular)
bool	applyPointLight (Light light, vec3 viewSpacePos, vec3 viewSpaceN, textureCubeArray shadowMap, out vec3 l, out float shadowing)
bool	applyDirectionalLight (Light light, vec3 viewSpacePos, vec3 viewSpaceN, texture2DArray shadowMap, out vec3 l, out float shadowing)
bool	applySpotLight (Light light, vec3 viewSpacePos, vec3 viewSpaceN, texture2DArray shadowMap, out vec3 l, out float shadowing)

Detailed Description

Common pbr general shader.

See also

GPUShaders::Common::Utils, GPUShaders::Common::Constants, GPUShaders::Common::Colors, GPUShaders::Common::Geometry, GPUShaders::Common::Samplers, GPUShaders::Common::Materials, GPUShaders::Common::Shadow_maps

Member Function Documentation

ambientLighting()

void GPUShaders::Common::Common_pbr::ambientLighting ( Material  material, vec3  worldP, vec3  viewV, mat4  inverseV, Probe  probe, textureCube  envmap, vec4  envSH[9], texture2D  brdfLUT, out vec3  diffuse, out vec3  specular  )

inline

Evaluate the lighting contribution from an analytic light source.

Parameters

material	the surface point material parameters
worldP	the surface position (in world space)
viewV	the outgoing view direction (in view space)
inverseV	the transformation matrix from view to world space
probe	the environment probe parameters
envmap	the environment probe texture
envSH	the environment probe irradiance coefficients
brdfLUT	the preintegrated BRDF lookup table
diffuse	will contain the diffuse ambient contribution
specular	will contain the specular ambient contribution

applyDirectionalLight()

bool GPUShaders::Common::Common_pbr::applyDirectionalLight ( Light  light, vec3  viewSpacePos, vec3  viewSpaceN, texture2DArray  shadowMap, out vec3  l, out float  shadowing  )

inline

Compute a directional light contribution for a given scene point.

Parameters

light	the light information
viewSpacePos	the point position in view space
viewSpaceN	the normal in view space
shadowMap	the 2D shadow maps
l	will contain the light direction for the point
shadowing	will contain the shadowing factor

Returns

true if the light contributes to the point shading

applyPointLight()

bool GPUShaders::Common::Common_pbr::applyPointLight ( Light  light, vec3  viewSpacePos, vec3  viewSpaceN, textureCubeArray  shadowMap, out vec3  l, out float  shadowing  )

inline

Compute a point light contribution for a given scene point.

Parameters

light	the light information
viewSpacePos	the point position in view space
viewSpaceN	the normal in view space
shadowMap	the cube shadow maps
l	will contain the light direction for the point
shadowing	will contain the shadowing factor

Returns

true if the light contributes to the point shading

applySH()

vec3 GPUShaders::Common::Common_pbr::applySH ( vec3  wn, vec4  coeffs[9]  )

inline

Evaluate the ambient irradiance (as SH coefficients) in a given direction.

Parameters

wn	the direction (normalized) in world space
coeffs	the SH coefficients

Returns

the ambient irradiance

applySpotLight()

bool GPUShaders::Common::Common_pbr::applySpotLight ( Light  light, vec3  viewSpacePos, vec3  viewSpaceN, texture2DArray  shadowMap, out vec3  l, out float  shadowing  )

inline

Compute a spot light contribution for a given scene point.

Parameters

light	the light information
viewSpacePos	the point position in view space
viewSpaceN	the normal in view space
shadowMap	the 2D shadow maps
l	will contain the light direction for the point
shadowing	will contain the shadowing factor

Returns

true if the light contributes to the point shading

approximateSpecularAO()

float GPUShaders::Common::Common_pbr::approximateSpecularAO ( float  diffuseAO, float  NdotV, float  roughness  )

inline

Estimate specular ambient occlusion. Based on "Moving Frostbite to Physically Based Rendering".

Parameters

diffuseAO	diffuse visbility factor
NdotV	visibility/normal angle
roughness	linear material roughness

Returns

the estimated specular visibility

D()

float GPUShaders::Common::Common_pbr::D ( float  NdotH, float  alpha  )

inline

GGX Distribution term.

Parameters

NdotH	angle between the half and normal directions
alpha	the roughness squared

Returns

the distribution term

DAnisotropic()

float GPUShaders::Common::Common_pbr::DAnisotropic ( float  NdotH, float  TdotH, float  BdotH, float  alphaT, float  alphaB  )

inline

Anisotropic GGX distribution term. Described by B. Burley in "Physically-Based Shading at Disney", 2012, (https://www.disneyanimation.com/publications/physically-based-shading-at-disney/)

Parameters

NdotH	angle between the half and normal directions
TdotH	angle between the half and tangent directions
BdotH	angle between the half and bitangent directions
alphaT	the roughness squared in the tangent direction
alphaB	the roughness squared in the bitangent direction

Returns

the distribution term

DCharlie()

float GPUShaders::Common::Common_pbr::DCharlie ( float  NdotH, float  alpha  )

inline

Sheen-specific "Charlie" distribution. Described by A.-C. Estevez and C. Kulla in "Production Friendly Microfacet Sheen BRDF", 2017, (http://www.aconty.com/pdf/s2017_pbs_imageworks_sheen.pdf)

Parameters

NdotH	angle between the half and normal directions
alpha	the roughness squared

Returns

the distribution term

directBrdf()

void GPUShaders::Common::Common_pbr::directBrdf ( Material  material, vec3  n, vec3  v, vec3  l, out vec3  diffuse, out vec3  specular  )

inline

Evaluate the lighting contribution from an analytic light source.

Parameters

material	the surface point material parameters
n	the surface normal (in view space)
v	the outgoing view direction (in view space)
l	the incoming light direction (in view space)
diffuse	will contain the diffuse direct contribution
specular	will contain the specular direct contribution

F()

vec3 GPUShaders::Common::Common_pbr::F ( vec3  F0, float  VdotH  )

inline

Fresnel approximation.

Parameters

F0	fresnel based coefficient
VdotH	angle between the half and view directions

Returns

the Fresnel term

fresnelToIor()

vec3 GPUShaders::Common::Common_pbr::fresnelToIor ( vec3  F0 )

inline

Convert a Fresnel coefficient to an internal IOR, assuming the external medium is air (IOR 1.0)

Parameters

F0	the Fresnel coefficient

Returns

the IOR

ggx()

vec3 GPUShaders::Common::Common_pbr::ggx ( vec3  n, vec3  v, vec3  l, vec3  h, vec3  F0, float  roughness  )

inline

Evaluate the GGX BRDF for a given normal, view direction and material parameters.

Parameters

n	the surface normal
v	the view direction
l	the light direction
h	the half vector between the view and light
F0	the Fresnel coefficient
roughness	the surface roughness

Returns

the BRDF value

ggxAnisotropic()

vec3 GPUShaders::Common::Common_pbr::ggxAnisotropic ( vec3  n, vec3  v, vec3  l, vec3  h, vec3  F0, Material  material  )

inline

Evaluate the anisotropic GGX BRDF for a given normal, view direction, frame and material parameters.

Parameters

n	the surface normal
v	the view direction
l	the light direction
h	the half vector between the view and light
F0	the Fresnel coefficient
material	the surface parameters

Returns

the BRDF value

ggxClearCoat()

float GPUShaders::Common::Common_pbr::ggxClearCoat ( vec3  n, vec3  v, vec3  l, vec3  h, float  roughness, out float  clearCoatFresnel  )

inline

Evaluate a simplified GGX BRDF for a given normal, view direction and material parameters.

Parameters

n	the surface normal
v	the view direction
l	the light direction
h	the half vector between the view and light
roughness	the surface roughness
clearCoatFresnel	will contain the value of the Fresnel coefficient

Returns

the BRDF value

ggxSheen()

vec3 GPUShaders::Common::Common_pbr::ggxSheen ( vec3  n, vec3  v, vec3  l, vec3  h, Material  material  )

inline

Sheen specific BRDF, with a constant Fresnel coefficient.

Parameters

n	the surface normal
v	the view direction
l	the light direction
h	the half vector between the view and light
material	the surface parameters

Returns

the BRDF value

iorToFresnel() [1/2]

float GPUShaders::Common::Common_pbr::iorToFresnel ( float  internalIOR, float  externalIOR  )

inline

Estimate the Fresnel coefficient at an interface based on the internal and external media IORs.

Parameters

internalIOR	the internal IOR
externalIOR	the external IOR

Returns

the corresponding Fresnel coefficient

iorToFresnel() [2/2]

vec3 GPUShaders::Common::Common_pbr::iorToFresnel ( vec3  internalIOR, vec3  externalIOR  )

inline

Estimate the Fresnel coefficient at an interface based on the internal and external media IORs.

Parameters

internalIOR	the internal IOR
externalIOR	the external IOR

Returns

the corresponding Fresnel coefficient

iridescenceF0()

vec3 GPUShaders::Common::Common_pbr::iridescenceF0 ( vec3  F0, float  LdotH, float  ior, float  thickness, float  externalIOR  )

inline

Evaluate the new Fresnel coefficient generated by the interferences caused by a thin film on top of a dieletric or conductor. This approximation that accounts for multiple reflections inside the thin film while accounting for spectral variations has been described by L. Belcour and P. Barla in "A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence", 2017, (https://belcour.github.io/blog/research/publication/2017/05/01/brdf-thin-film.html). Additional simplifications have been described by S. Lagarde and E. Golubev in "The Road toward Unified Rendering with Unity’s High Definition Render Pipeline", 2015, (http://advances.realtimerendering.com/s2018/index.htm#_9hypxp9ajqi).

Parameters

F0	the base surface Fresnel coefficient
LdotH	the dot product between the light and the half vector
ior	the thin film index of refraction
thickness	the thin film thickness (in nm)
externalIOR

Returns

the updated Fresnel coefficient

iridescenceSensitivity()

vec3 GPUShaders::Common::Common_pbr::iridescenceSensitivity ( float  opd, float  shift  )

inline

Approximation of the Fourier transform of the sensitivity for iridescent materials, using four gaussian lobes. This encompasses the sensitivity resulting from all light paths with the input path difference and phase.

Parameters

opd	optical path difference
shift	phase of the signal

Returns

the sensitivty in XYZ color space

probeWeight()

float GPUShaders::Common::Common_pbr::probeWeight ( vec3  p, Probe  probe  )

inline

Compute the contribution of a probe to a given point in the scene, based on the probe effect box size, position and fading settings.

Parameters

p	the position in the scene (world space)
probe	the probe parameters

Returns

the contribution weight in [0,1]

radiance()

vec3 GPUShaders::Common::Common_pbr::radiance ( vec3  r, vec3  p, float  roughness, textureCube  cubeMap, Probe  probe  )

inline

Return the (pre-convolved) radiance for a given direction (in world space) and material parameters.

Parameters

r	the direction to query (world space)
p	the surface point (world space)
roughness	the surface roughness
cubeMap	the environment map texture
probe	the probe parameters

Returns

the radiance value

V()

float GPUShaders::Common::Common_pbr::V ( float  NdotL, float  NdotV, float  alpha  )

inline

Visibility term of GGX BRDF, V=G/(n.v)(n.l)

Parameters

NdotL	dot product of the light direction with the surface normal
NdotV	dot product of the view direction with the surface normal
alpha	squared roughness

Returns

the value of V

VAnisotropic()

float GPUShaders::Common::Common_pbr::VAnisotropic ( float  NdotL, float  NdotV, float  TdotV, float  BdotV, float  TdotL, float  BdotL, float  alphaT, float  alphaB  )

inline

Visibility term of the anisotropic GGX BRDF. Described by B. Burley in "Physically-Based Shading at Disney", 2012, (https://www.disneyanimation.com/publications/physically-based-shading-at-disney/)

Parameters

NdotL	dot product of the light direction with the surface normal
NdotV	dot product of the view direction with the surface normal
TdotV	dot product of the tangent direction with the view direction
BdotV	dot product of the bitangent direction with the view direction
TdotL	dot product of the tangent direction with the light direction
BdotL	dot product of the bitangent direction with the light direction
alphaT	squared roughness in the tangent direction
alphaB	squared roughness in the bitangent direction

Returns

the value of V

Vfast()

float GPUShaders::Common::Common_pbr::Vfast ( float  NdotL, float  NdotV, float  alpha  )

inline

Linearized visibility term of GGX BRDF, V=G/(n.v)(n.l)

Parameters

NdotL	dot product of the light direction with the surface normal
NdotV	dot product of the view direction with the surface normal
alpha	squared roughness

Returns

the value of V

VKelemen()

float GPUShaders::Common::Common_pbr::VKelemen ( float  LdotH )

inline

Simplified visibility term described by Kelemen in "A Microfacet Based Coupled Specular-Matte BRDF Model with Importance Sampling", 2001

Parameters

LdotH

dot product of the light direction and the half vector

Returns

the value of V

VNeubelt()

float GPUShaders::Common::Common_pbr::VNeubelt ( float  NdotL, float  NdotV  )

inline

Sheen-specific visibility term. Described by D. Neubelt and M. Pettineo in "Crafting a Next-Gen Material Pipeline for The Order: 1886", 2014, (https://www.gdcvault.com/play/1020162/Crafting-a-Next-Gen-Material)

Parameters

NdotL	dot product of the light direction with the surface normal
NdotV	dot product of the view direction with the surface normal

Returns

the value of V

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The documentation for this class was generated from the following file:

• resources/common/shaders/objects/common_pbr.glsl