Deferred rendering in Dying Light

Deferred Rendering in Dying Light

Agenda

Deferred shading - why?

G-Buffer

Questions?



>250K objects


>250K objects

Multiple materials


>250K objects

Multiple materials

Thousands of lights


>250K objects

Multiple materials

Thousands of lights

Day-night cycle


>250K objects

Multiple materials

Thousands of lights

Day-night cycle

Changing weather


Deferred Shading vs Forward Rendering

● Separated scene and lighting rendering

SCENE



● Separated scene and lighting rendering○ G-Buffer

SCENE



● Improved lighting rendering performance○ Scene complexity independency





○ Object material & geometry complexity independency







● Simpler rendering pipeline○ Easy light handling






● Simpler rendering pipeline○ Easy light handling

○ No material-light litght shader combinations


Not only lights

● Complex materials

● Scene overdraw

● Consistency

● Lighting model independency

● Deferred Linear Space


Not only lights


● Scene overdraw

● Consistency




Not only lights


● Scene overdraw

● Consistency




Not only lights


● Scene overdraw

● Consistency




Not only lights


● Scene overdraw

● Consistency



G-Buffer

G-Buffer

LimitationsX Y Z W

R G B A

Z-Buffer

G-Buffer

LimitationsX Y Z W

R G B A

G-Buffer

Limitations

Needs (PBR)

X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness

Human Skin Translucency Leaves

G-Buffer

How?X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


?

G-Buffer

How?

Solutions

● Lower resolution

X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


?

G-Buffer

How?

Solutions


● Spherical Normals

X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


?

G-Buffer

How?

Solutions



● YUV

X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


?

G-Buffer

How?

Solutions



● YUV

● ?

X Y Z W

R G B A

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


?

G-Buffer

● Specular & Diffuse

G-Buffer


● PBR Materials○ Metals

○ Dielectrics

Specular Diffuse

Metals brightcolorful black

Dielectrics darkmonochromatic

full rangecolorful

G-Buffer



○ Dielectrics

● Conclusions○ Metals needs only RGB

○ Dielectrics needs only RGB + Gray

○ Non-overlaping ranges

Specular Diffuse



full rangecolorful

G-Buffer



○ Dielectrics




● PBR needs (real)

Specular Diffuse



full rangecolorful

RGB Alpha

Metal specular color 0 (black)

Dielectric diffuse color Dielectric specular

G-Buffer



○ Dielectrics




● PBR needs (real)○ Lossless

Specular Diffuse



full rangecolorful

RGB Alpha

Metal specular color 0 (black)

Dielectric diffuse color Dielectric specular

G-Buffer

● Encoding

rgb = dielectric ? diffuse.rgb : specular.rgb

alpha = dielectric ? specular.g : 0.0

G-Buffer

● Encoding

rgb = dielectric ? diffuse.rgb : specular.rgb

alpha = dielectric ? specular.g : 0.0

● Decoding

Specular = (alpha > 0.0) ? alpha : rgb;

Diffuse = (alpha > 0.0) ? rgb : 0.0;

G-Buffer

Specular & Diffuse

Normal (XYZ)

Specular (RGB)

Diffuse (RGB)

Roughness


G-Buffer

Specular & Diffuse

Normal (XYZ)

Specular/Diffuse (RGB) Specular (SD)

Roughness


G-Buffer

Specular & Diffuse

RoughnessNormal (XYZ)


Roughness


G-Buffer

Specular & Diffuse

Roughness

Masks

● subsurface scattering

● dielectrics only

● binary values

● exclusive

Normal (XYZ) Roughness



G-Buffer

Diffuse/Specular alpha channel - human skinNormal (XYZ) Roughness



G-Buffer

Diffuse/Specular alpha channel - human skin

M Dielectric Specular

0 1 255

G-Buffer

Diffuse/Specular alpha channel - human skin

M Dielectric Specular H

0 1 254 255

G-Buffer

Diffuse/Specular alpha channel - translucency

● simple subsurface scattering


0 1 254 255

G-Buffer


● simple subsurface scattering● varying specular


0 1 254 255

G-Buffer


● simple subsurface scattering● varying specular● signed format?


0 1 254 255

G-Buffer


● simple subsurface scattering● varying specular● signed format?● encoding/decoding - single mad instruction (alpha * 2.0 - 1.0)

H Translucent Dielectric Specular M M Dielectric Specular H

0 1 126 127 128 129 254 255

-1.0 0.0 1.0

G-Buffer


● simple subsurface scattering● varying specular● signed format?● encoding/decoding - single mad instruction (alpha * 2.0 - 1.0)● encoded specular inversion - abs()


0 1 max min 126 127 128 129 min max 254 255

-1.0 0.0 1.0

G-Buffer

Diffuse/Specular alpha channel - leaves

● simplified lighting for tree crowns


0 1 max min 126 127 128 129 min max 254 255

-1.0 0.0 1.0

G-Buffer


● simplified lighting for tree crowns● no specular


0 1 max min 126 127 128 129 min max 254 255

-1.0 0.0 1.0

G-Buffer


L Translucent Dielectric Specular M M Dielectric Specular H

0 1 max min 126 127 128 129 min max 254 255

-1.0 0.0 1.0

Final layout (almost)Normal (XYZ) Roughness

Specular/Diffuse (RGB) M/SD/H/T/L

G-Buffer

G-Buffer

Final layoutNormal (XYZ) M/SD/H/T/L

Specular/Diffuse (RGB) Roughness

G-Buffer

Final layout - summary

● simple (en)coding Normal (XYZ) M/SD/H/T/L


G-Buffer


● simple (en)coding

● slim

Normal (XYZ) M/SD/H/T/L


G-Buffer



● slim

● lossless



G-Buffer



● slim

● lossless

● PBR correct



Questions?

Deferred rendering in Dying Light

Software