Lighting Killzone : Shadow Fall

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3 Lighting Killzone : Shadow Fall Michal Drobot Senior Tech Programmer Guerrilla Games

4 Intro Guerrilla Games is SCEE studio based in Amsterdam Working on two Playstation 4 titles: Killzone: Shadow Fall New IP Killzone: Shadow Fall is a launch tile Annouced during Playstation 4 reveal Running on target 1080p 30fps

5 Focus Physically Based Lighting Physically Based Area Lights Rendering Pipeline

6 Motivation Killzone 3 Shipped in 2011 Matured PS3 technology Considered one of generation visual benchmark titles Killzone : Shadow Fall Next generation launch title How does it compare?

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13 Generation change

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15 Motivation Physically Based Lighting Easier to achieve hyperrealism / photorealism Consistent look in different HDR environments Simple material interface for artists Easy troubleshooting and extension

16 Theory

17 Light Flux Radiance (L) Irradiance (E) Irradiance = integrated light incoming from all directions (diffuse) Radiance = light incoming from one direction (specular reflection)

18 Image Based Lighting (IBL) Courtesy of ILM

19 Courtesy of ILM

20 Courtesy of ILM

21 Physically Based Lighting Model Physically Based Shading Model Responsible for surface response to incoming light depending on various surface physical properties Physically Based Lights Responsible for light flux calculation in the scene depending on various lights with physical properties

22 Physically Based Shading : Real life examples Specular Dominant part of visible lighting Every material exhibits specular lighting Angle dependent Material type dependant

23 Real life lighting Diffuse Specular Courtesy of John Hable

24 Real life lighting Diffuse Specular Courtesy of John Hable

25 Real life lighting Diffuse Specular Courtesy of John Hable

26 Diffuse Specular Real life lighting + Diffuse Specular Courtesy of John Hable

27 Diffuse BRDF Specular Eye

28 Fresnel Reflection Rough Refraction

29 Non metals

30 Metals

31 Roughness Smooth Rough

32 Roughness Smooth

33 Visibility / Self Shadowing

34 Non - Energy Conservative Energy Conservative

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37 Workflow 3 main parameters Albedo (RGB8) Roughness (R8) Specular Reflectance (RGB8) Material response Decoupled from Lighting Works in any light environment Review assets in different IBL lighting environments

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41 Diffuse Rough (0.0) Smooth (1.0)

42 Material properties Measured values for most materials Available in physical tables Every material can be roughly defined by those parameters We provided them as Photoshop color swatches Base for hand painted textures

43 Material Old iron plate Covered in paint Scratches Bullet holes Rust Use case

44 Thin old paint, scratched, showing off iron underneath Due weathering effects smoothened R = High Simplified Roughness texture Pure rust R = very low Rusting metal R = mixed, sparkles of medium smooth metal Bullet hole High temperature smoothens iron (due to impact energy) R = very high Pure old paint R = medium

45 Thin old paint, scratched, showing off iron underneath SR = Low Iron Simplified Specular Reflectance texture Pure rust, non metal SR = Low, non metal Rusting metal, SR = Medium, non metal, Sparkles of Low Iron Bullet hole exposes pure Iron SR = Iron Pure paint SR = Low, Medium, High non metal, Depends on paint type Old paint = Low New paint = Medium / High

46 White thin old paint, scratched, showing off iron underneath A = Dark gray (showing off metal) Simplified Albedo texture Pure rust, A = Rusty in range of old concrete Bullet hole exposes pure Iron A = Very dark (metal) White old paint A = White in albedo range of concrete (light gray)

47 Shadow Fall BRDF Based on Cook-Torrance Fresnel Smith Schlick Visiblity Function Normalization based on Specular Reflectance Roughness as Specular Importance Cone Angle Approximate translucency Density maps Translucency diffusion maps

48 IBL Point Based BRDF

49 IBL Point Based BRDF factor visualization

50 IBL Ambient BRDF factor visualization

51 IBL Ambient BRDF

52 IBL Point Based BRDF

53 IBL Ambient BRDF

54 Big step for the studio Artists had to adapt Training and workshops Production and Quality Win

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59 Physically Based Lights

60 Blinn-Phong Point Light

61 Blinn-Phong Point Light

62 Area Lights Every light source Size Shape Intensity Art Photography Light Direction

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64 Spherical Light

65 Disc Light

66 Rectangular Light

67 Texture Rectangular Light

68 Area Size and Intensity

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74 pc0 > pc1, due to d0 > d1 Result : pc0 blurier than pc1 pc0 d0 α d1 pc1 α

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78 Irradiance Integral DA : I(p,n) = Integrate(A) [L * cos(fi) * cos(fo) * da / d^2] da differential area of the light L luminance of light A Area of the light d n fo p n fi p

79 Y Radiance Integral 3D Word Space X, Y set the light frame X n p

80 Y 2D projected on light frame X

81 Y 2D projected on light frame X Area of integration

82 Y X PDF to integrate Over Area

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84 IES Light Profiles

85 IES Light Profiles

86 IES Light Profiles

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88 Lighting Pipeline Overview

89 IBL Reflection System 3 Tier Reflection Raytrace system Realtime Glossy Reflections Localized Cubemaps Skybox

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99 Localized Cubemaps

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102 Picture of pretty cubemap in cross with mips

103 Picture of pretty cubemap in cross with mips

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106 IBL Render Pass Breakdown

107 Baked Lightmaps Diffuse + Dynamic Lights Render Pass Breakdown

108 Ambient BRDF

109 Cubemaps

110 Lightmap Diffuse + Dynamic Lights + Ambient BRDF * Cubemaps

111 Real Time Glossy Reflections

112 Real Time Glossy Reflections : Mask

113 Final composite of IBL based lighting

114 Render Pass Breakdown

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116 Takeaway Physically Based Lighting Higher quality Faster asset production Asset reuse in different environments Physical Area Lights Time to say goodbye to point lights Easier workflow High quality results Real Time Reflections Important visual clue

117 We are hiring!

118 References Real Time Rendering 3 rd Edition by Tomas Akenine-Moller, Eric Haines, Naty Hoffman Physically Based Rendering, Second Edition: From Theory To Implementation by Matt Pharr Industrial Light & Magic John Hable blog -