global illumination in unity 5japan.unity3d.com/unite/unite2015/files/day1_1400_room1_jesper.pdf ·...

COPYRIGHT 2014 @ UNITY TECHNOLOGIES

GLOBAL ILLUMINATION IN UNITY 5

Jesper Mortensen

Software Engineer, Unity CPH


Text Styles

key to switch

between levels

24 pt.

Level 2 = Bullet 24 pt.



To get bullet / plain text

list

GLOBAL ILLUMINATION IN UNITY 5


VIDEO – Unity Shrine by Alex Lovett


Text Styles

key to switch

between levels

24 pt.





list

AGENDA

• What is Enlighten?

• How does Enlighten work?

• Realtime Reflections

• What’s next?

• Questions

COPYRIGHT 2014 @ UNITY TECHNOLOGIESCOPYRIGHT 2014 @ UNITY TECHNOLOGIES

WHAT IS ENLIGHTEN?


Text Styles

key to switch

between levels

24 pt.





list

WHAT IS ENLIGHTEN?

• Middleware for computing Global Illumination (GI)

• Developed by Geomerics/ARM based in Cambridge

• Supports all modern platforms (including mobile)

• Used for several successful AAA titles

• Enlighten 2.22 is integrated into Unity 5.0


Text Styles

key to switch

between levels

24 pt.





list

ENLIGHTEN GI OUTPUTS

• Following a precompute phase

• Realtime lightmaps

• Realtime light probes

• Realtime cubemaps (coming in 5.x)

• Following an additional baking phase

• Baked lightmaps

• Baked light probes


Text Styles

key to switch

between levels

24 pt.





list

REALTIME GI OUTPUTS

• Realtime lightmaps/probes contain only indirect light

• Indirect light is generally low frequency

• Hence they can be low res

• It is radiosity only, so no specular bounce

• Light probes are L1 spherical harmonics

• Cubemaps for reflections – low res (coming in 5.x)


Text Styles

key to switch

between levels

24 pt.





list

BAKED GI OUPUTS

• High resolution baked lightmaps

• Direct lighting

• AO

• Indirect lighting

• Optional directional information for specular

• Relatively cheap

• But all lighting is static


Text Styles

key to switch

between levels

24 pt.





list

WHAT DOES REALTIME GI MEAN

• Freely change all light properties in the player• Add/remove lights• Change light properties

• Freely modify material reflectance properties• Customized shader pass

• Freely change emission properties of static geometry• Customized shader pass

• Freely change the environment lighting (skybox)


Text Styles

key to switch

between levels

24 pt.





list

WHAT CAN YOU DO WITH THIS?

• Dynamic time of day• Glowy things• Attached lights

• Flashlights• Car headlights• Flaming swords• Lights that can be shot out• Explosions

• Mood lighting

Ghost of a Tale – Time of day tests in U5


Text Styles

key to switch

between levels

24 pt.





list


Text Styles

key to switch

between levels

24 pt.





list

Blacksmith – with indirect lighting


Text Styles

key to switch

between levels

24 pt.





list

Blacksmith – without indirect lighting


Text Styles

key to switch

between levels

24 pt.





list


Text Styles

key to switch

between levels

24 pt.





list

WHAT CAN YOU *NOT* DO NOW

• Dynamic geometry cannot bounce light

• Dynamic geometry cannot emit light

• The majority of your scene must be static

• The precompute/bake phases are Editor only

• No fully procedurally generated worlds

• However, we intend to fix these in 5.x!


Text Styles

key to switch

between levels

24 pt.





list

SMOKE AND MIRRORS™ – THE TRICKS• Add glow by attaching lights to dynamic objects

• Realtime transparency is upcoming in 5.x

• Support destruction with realtime transparency

• Support doors etc. with realtime transparency

• Use invisible emissive static geometry for glow


HOW DOES ENLIGHTEN WORK?


Text Styles

key to switch

between levels

24 pt.





list


• Enlighten has one purpose

• Compute indirect lighting fast

• It does that extremely well

• Everything else is built on top of that


Text Styles

key to switch

between levels

24 pt.





list


• Solves an approximation to the rendering equation


Text Styles

key to switch

between levels

24 pt.





list


• Assume finite elements

• Assume diffuse transport


Text Styles

key to switch

between levels

24 pt.





list


• Well the radiosity of an element depends on the

radiosity of all the other elements!

• Expensive ~𝑂(𝑛2)• This won’t quite work…


Text Styles

key to switch

between levels

24 pt.





list


• Observation 1: Make n small


Text Styles

key to switch

between levels

24 pt.





list


• Lightmaps are low res and tightly packed


Text Styles

key to switch

between levels

24 pt.





list


• Observation 2: Decouple emitters and receivers

• So n receivers and m emitters, where m < n


Text Styles

key to switch

between levels

24 pt.





list


• Scene is clustered

Receivers (lightmap texels) Emitters (clusters)


Text Styles

key to switch

between levels

24 pt.





list


• Observation 3: mn matrix is sparse

• Distant clusters can be merged for a given texel


Text Styles

key to switch

between levels

24 pt.





list


• Build cluster hierarchy

• Relaxation metric:

• Area

• Distance

• Normal

• Visibility

Scene root

Leaf clusters


Text Styles

key to switch

between levels

24 pt.





list


• For a given texel

• Select a hierarchy cut

• With a fixed budget

• Minimize error

Scene root

Leaf clusters


Text Styles

key to switch

between levels

24 pt.





list


• Budget is a constant k

• Complexity is 𝑂(𝑛𝑘) ≈ 𝑂(𝑛)


Text Styles

key to switch

between levels

24 pt.





list


• Phase 1: Prime clusters with direct lighting

• We have a set of points per cluster

• Evaluate direct lighting for those

• Average to get per leaf cluster direct lighting

• Push this up the cluster hierarchy


Text Styles

key to switch

between levels

24 pt.





list


• Phase 2: Read previously bounced lighting

• The cluster points has UVs mapping into output

• Read previous lighting value from output

• Average to get per leaf cluster bounced light

• Push this up the cluster hierarchy


Text Styles

key to switch

between levels

24 pt.





list


• Phase 3: Gather

• For each pixel gather new lighting from cluster cut

• Done!


Text Styles

key to switch

between levels

24 pt.





list


• Platform optimized runtimes

• Async from render loop

• Scheduling (coming in 5.x)


Text Styles

key to switch

between levels

24 pt.





list


REALTIME REFLECTIONS


Text Styles

key to switch

between levels

24 pt.





list

REFLECTION PROBES


Text Styles

key to switch

between levels

24 pt.





list

REFLECTION PROBES

• Provide approximated specular reflection

• Component on a GameObject

• A box defines:

• the influence region

• the box projection [BEHC’10]


Text Styles

key to switch

between levels

24 pt.





list

REFL. PROBE CONVOLUTION

• Needed for rough surfaces

[LAMRUG]


Text Styles

key to switch

between levels

24 pt.





list


Text Styles

key to switch

between levels

24 pt.





list

REALTIME REFL. PROBE CONVOLUTION• Runs on GPU in a pixel shader

• Seamless mipmap generation

• needs to support pre-DX10 hardware

• Accounts for projection

• sphere to cube


Text Styles

key to switch

between levels

24 pt.





list

REALTIME REFL. PROBE SCHEDULING• Time-slicing

• individual faces + 8 frames for convolution

• all faces at once + 8 frames for convolution

• all faces + convolution in one frame

• impacts framerate the most

• consistent results


Text Styles

key to switch

between levels

24 pt.





list

SCREEN SPACE REFLECTIONS


Text Styles

key to switch

between levels

24 pt.





list

SCREEN SPACE REFLECTIONS

• Image effect that extends built-in deferred shading

pipeline

• User-land scripts and shaders

• Adds mirror & glossy SSRR to emissive buffer

• Falls back to reflection probes on ray miss

• (coming in Unity 5.x)


Text Styles

key to switch

between levels

24 pt.





list

SCREEN SPACE RAYTRACING

• Depth-buffer as proxy for scene geometry

• March the ray using the depth buffer

• At an intersection

• find corresponding value in the color buffer

• use as radiance


Text Styles

key to switch

between levels

24 pt.





list

REFLECTION PROBE ONLY


Text Styles

key to switch

between levels

24 pt.





list

REFLECTION PROBE AND SSRR


WHAT’S NEXT?


Text Styles

key to switch

between levels

24 pt.





list

WHAT’S NEXT?

• Fix bugs• Improve documentation• Optimize the precompute/bake phase

• LAN Lighting Build• Cloud Lighting Build

• Level up interation speed by integrating PowerVRtechnology

• Improve mixed realtime/baked shadows


Text Styles

key to switch

between levels

24 pt.





list

QUESTIONS?

● Global Illumination:

o @pigselated (Jesper Mortensen)

o @kengelstoft (Kasper Engelstoft)

o @kubacupisz

o @JoachimAnte

● Reflection probes:

o @__ReJ__ (Renaldas Zioma)

o Tomas Dirvanauskas

o Benoit Sévigny

o @dominiclaflamme

● Screen space reflections:

o @morgan3d (Morgan McGuire)

o @mikemx7f (Michael Mara)

● Blacksmith:

o S’Holm demo team

● Unity Shrine:

o @HeliosDoubleSix

● Ghost of a Tale:

o @SeithCG

● Dioramas:

o @yezzer

● Unity Labs:

o @David_Llewelyn

o @willgoldstone

o @peteorstrike (Peet Lee)

global illumination in unity 5japan.unity3d.com/unite/unite2015/files/day1_1400_room1_jesper.pdf ·...

Documents