https://github.com/netpyoung/bs.physically_based_shader_develop_for_unity

:books:🌔책공부. 유니티 물리 기반 셰이더 개발
https://github.com/netpyoung/bs.physically_based_shader_develop_for_unity
bs shader urp
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:books:🌔책공부. 유니티 물리 기반 셰이더 개발
Host: GitHub
URL: https://github.com/netpyoung/bs.physically_based_shader_develop_for_unity
Owner: netpyoung
Created: 2021-02-04T04:15:25.000Z (over 4 years ago)
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Last Pushed: 2021-03-04T22:31:48.000Z (about 4 years ago)
Last Synced: 2025-02-13T21:45:00.701Z (3 months ago)
Topics: bs, shader, urp
Language: ShaderLab
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Metadata Files:
- Readme: README.md
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README

        # 유니티 물리 기반 쉐이더 개발

![./physically-based-shader-dev-for-unity-2017.jpg](./physically-based-shader-dev-for-unity-2017.jpg)

- [번역판](http://www.acornpub.co.kr/book/physically-unity-shader)

- [source](https://github.com/Apress/physically-based-shader-dev-for-unity-2017)

Legacy(Built-in)쉐이더로 작성되어있는데, 어차피 Legacy사용법도 잘 모르고 URP로 곧바로 연습해 보도록 하자.

## URP (Universal Render Pipeline)

- [Dev Weeks: URP 기본 구성과 흐름](https://www.youtube.com/watch?v=QRlz4-pAtpY)

- [Dev Weeks: URP 셰이더 뜯어보기](https://www.youtube.com/watch?v=9K1uOihvNyg)

``` tree

Packages/

|-- Core RP Library/

|  |-- ShaderLibrary/

|  |  |-- SpaceTransform.hlsl - 공간변환 행렬. Tangent<->World행렬

|  |  |-- Common.hlsl - 각종 수학. 텍스쳐 유틸, 뎁스 계산 ..

|  |  |-- >>> EntityLighting.hlsl - SH, ProveVolume, Lightmap계산 ???

|  |  |-- ImageBasedLighting - IBL관련 부분(GGX, Anisotropy, ImportanceSample)

|-- Universal RP/

|  |-- ShaderLibrary/

|  |  |-- Core.hlsl - 버텍스 인풋 구조체, 스크린UV계산,Fog계산

|  |  |-- Lighting.hlsl - 라이트 구조체, diffuse, specular, GI

|  |  |-- Shadows.hlsl - 쉐도우맵 샘플링, 캐스케이드 계산, ShadowCoord계산 , Shadow Bias계산

|  |-- Shaders/

```

## 1장. 셰이더 개발 과정

### Forward

``` ruby

for object in objects

    for light in lights

        FrameBuffer = LightModel(object, light);

    end

end

for light in lights

    for object in GetObjectsAffectedByLight(light)

        FrameBuffer += LightModel(object, light);

    end

end

```

![./forward-v2.png](./forward-v2.png)

라이트 갯수 증가> 연산량 증가

### Deferred

``` ruby

for object in objects:

  GBuffer = GetLightingProperties(object)

end

for light in lights

  Framebuffer += LightModel(GBuffer, light)

end

```

![./deferred-v2.png](./deferred-v2.png)

- 반투명 불가

- URP - 현재(10.3.1) deferred 지원 안함.

  - [URP 로드맵](https://portal.productboard.com/8ufdwj59ehtmsvxenjumxo82/tabs/3-universal-render-pipeline)

- [블라인드 렌더러 -  새로운 기법 != 새 장난감](https://kblog.popekim.com/2012/02/blog-post.html)

## 2장. 첫 유니티 셰이더

- [Built-in vs URP](https://docs.unity3d.com/Packages/[email protected]/manual/universalrp-builtin-feature-comparison.html)

``` txt

Create> Rendering> Universal Render Pipeline> Pipeline Asset(Forward Renderer)

Assets/

|-- UniversalRenderPipelineAsset.asset

|-- UniversalRenderPipelineAsset_Renderer.asset

Project Settings> Graphics> Scriptable Render Pipeline Settings> UniversalRenderPipelineAsset.asset

UniversalRenderPipelineAsset.asset> Quality> HDR check

Project Settings> Player> Other Settings> Color Space> Linear

```

- [URP unlit basic shader](https://docs.unity3d.com/Packages/[email protected]/manual/writing-shaders-urp-basic-unlit-structure.html)

``` hlsl

Tags { "RenderType" = "Opaque" "RenderPipeline" = "UniversalPipeline" }

Tags { "LightMode" = "SRPDefaultUnlit" } // 라이트 모드 태그 기본값

```

- [URP ShaderLab Pass tags](https://docs.unity3d.com/Packages/[email protected]/manual/urp-shaders/urp-shaderlab-pass-tags.html)

| LightMode            | URP Support |

|----------------------|-------------|

| UniversalForward     | O           |

| UniversalGBuffer     | O           |

| UniversalForwardOnly | O           |

| Universal2D          | O           |

| ShadowCaster         | O           |

| DepthOnly            | O           |

| Meta                 | O           |

| SRPDefaultUnlit      | O(기본값)   |

| Always               | X           |

| ForwardAdd           | X           |

| PrepassBase          | X           |

| PrepassFinal         | X           |

| Vertex               | X           |

| VertexLMRGBM         | X           |

| VertexLM             | X           |

## 3장. 그래픽스 파이프라인

``` cs

// #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

// |-- #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"

// Core RP Library/ShaderLibrary/SpaceTransforms.hlsl

// UNITY_MATRIX_M * (UNITY_MATRIX_VP * positionOS)

float4 TransformObjectToHClip(float3 positionOS)

{

    // More efficient than computing M*VP matrix product

    return mul(GetWorldToHClipMatrix(), mul(GetObjectToWorldMatrix(), float4(positionOS, 1.0)));

}

```

## 4장. 좌표 공간 변환

| Space |                        |

|-------|------------------------|

| WS    | world space            |

| VS    | view space             |

| OS    | object space           |

| CS    | Homogenous clip spaces |

| TS    | tangent space          |

| TXS   | texture space          |

| built-in(legacy)         | URP                          |

|--------------------------|------------------------------|

| UnityObjectToWorldDir    | TransformObjectToWorldDir    |

| UnityObjectToWorldNormal | TransformObjectToWorldNormal |

| UnityWorldSpaceViewDir   | TransformWorldToViewDir      |

| UnityWorldSpaceLightDir  | x                            |

``` hlsl

float4x4 GetObjectToWorldMatrix() UNITY_MATRIX_M;

float4x4 GetWorldToObjectMatrix() UNITY_MATRIX_I_M;

float4x4 GetWorldToViewMatrix()   UNITY_MATRIX_V;

float4x4 GetWorldToHClipMatrix()  UNITY_MATRIX_VP;

float4x4 GetViewToHClipMatrix()   UNITY_MATRIX_P;

```

| built-in(legacy)     | URP                    |

|----------------------|------------------------|

| UnityObjectToClipPos | TransformObjectToHClip |

| UnityWorldToClipPos  | TransformWorldToHClip  |

| UnityViewToClipPos   | TransformWViewToHClip  |

- 

- 

## 5장. 최초 라이팅 셰이더

``` hlsl

// #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

struct Light

{

    half3   direction;

    half3   color;

    half    distanceAttenuation;

    half    shadowAttenuation;

};

Light GetMainLight()

    light.direction = _MainLightPosition.xyz;

Light GetMainLight(float4 shadowCoord)

// #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Macros.hlsl"

#define TRANSFORM_TEX(tex, name) ((tex.xy) * name##_ST.xy + name##_ST.zw)

// #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/API/D3D11.hlsl"

#define SAMPLE_TEXTURE2D(textureName, samplerName, coord2)                               textureName.Sample(samplerName, coord2)

```

- [URP - Drawing a texture](https://docs.unity3d.com/Packages/[email protected]/manual/writing-shaders-urp-unlit-texture.html)

## 6장. 스펙큘러 구현

- TODO 더 많은 광원 지원하기(2 Directional Light)

- 

## 7장. 서피스 셰이더

- Surface는 URP에서 안쓸꺼라서 Vert/Frag로 구현

  - 2개 Albedo를 lerp시키는것.

  - NormapMap적용.

## 8장. 물리 기반 셰이딩이란?

- 빛을 측정하는 방법

|                       | 단위               | 설명                                             |

|-----------------------|--------------------|--------------------------------------------------|

| 입체각 Solid Angle    | sr(steradian)      | 단위 구로 어떠한 형상을 사영한 것.               |

| 파워 Power            | W                  | 여러 방향에서 표면을 통과해 전달되는 에너지 크기 |

| 일레디안스 Irradiance | E (W/m^2)          | 모든 광선에서 점에 전달되는 빛의 크기            |

| 레디안스 Radiance     | L_0 (W/(m^2 * sr)) | 하나의 광선에서 점에 전달되는 빛의 크기          |

- 재질을 표현하는 방법

양방향 반사 분포 함수 BRDF Bidirectional Reflectance Distribution Function

빛이 표면에서 어떻게 반사될지에 대해 정의한 함수.

| BRDF 속성              |                                                                                              |

|------------------------|----------------------------------------------------------------------------------------------|

| positivity             | BRDF값은 0이상이다                                                                           |

| symmetry (reciprocity) | 빛이 들어오는 방향과 반사되는 방향의 값은 동일하다                                           |

| conservation of energy | 나가는 빛의 양은 들어오는 빛의 양을 넘어설 수 없다(물체가 자체적으로 빛을 발산하지 않는다면) |

## 9장. 물리 기반 셰이더 제작하기

``` hlsl

half3 LightingPhong(half3 lightColor, half3 lightDir, half3 normal, half3 viewDir, half4 specularColor, half3 albedo, half shininess)

{

    half NdotL = saturate(dot(normal, lightDir));

    half3 diffuseTerm = NdotL * albedo * lightColor;

    half3 reflectionDirection = reflect(-lightDir, normal);

    half3 specularDot = max(0.0, dot(viewDir, reflectionDirection));

    half3 specular = pow(specularDot, shininess);

    half3 specularTerm = specularColor.rgb * specular * lightColor;

    return diffuseTerm + specularTerm;

}

// Lafortune and Willems (1994)

half3 LightingPhongModified(half3 lightColor, half3 lightDir, half3 normal, half3 viewDir, half4 specularColor, half3 albedo, half shininess)

{

    half NdotL = saturate(dot(normal, lightDir));

    half3 diffuseTerm = NdotL * albedo * lightColor;

    half norm = (shininess + 2) / (2 * PI);

    half3 reflectionDirection = reflect(-lightDir, normal);

    half3 specularDot = max(0.0, dot(viewDir, reflectionDirection));

    half3 specular = norm * pow(specularDot, shininess);

    half3 specularTerm = specularColor.rgb * specular * lightColor;

    return diffuseTerm + specularTerm;

}

```

## 10장. 후처리 효과

``` hlsl

// com.unity.render-pipelines.core/ShaderLibrary/API/D3D11.hlsl

#define SAMPLE_TEXTURE2D(textureName, samplerName, coord2)                               textureName.Sample(samplerName, coord2)

#define SAMPLE_DEPTH_TEXTURE(textureName, samplerName, coord2)          SAMPLE_TEXTURE2D(textureName, samplerName, coord2).r

```

``` hlsl

// com.unity.render-pipelines.core/ShaderLibrary/API/Common.hlsl

// Z buffer to linear 0..1 depth (0 at near plane, 1 at far plane).

// Does NOT correctly handle oblique view frustums.

// Does NOT work with orthographic projection.

// zBufferParam = { (f-n)/n, 1, (f-n)/n*f, 1/f }

float Linear01DepthFromNear(float depth, float4 zBufferParam)

{

    return 1.0 / (zBufferParam.x + zBufferParam.y / depth);

}

// Z buffer to linear 0..1 depth (0 at camera position, 1 at far plane).

// Does NOT work with orthographic projections.

// Does NOT correctly handle oblique view frustums.

// zBufferParam = { (f-n)/n, 1, (f-n)/n*f, 1/f }

float Linear01Depth(float depth, float4 zBufferParam)

{

    return 1.0 / (zBufferParam.x * depth + zBufferParam.y);

}

// Z buffer to linear depth.

// Does NOT correctly handle oblique view frustums.

// Does NOT work with orthographic projection.

// zBufferParam = { (f-n)/n, 1, (f-n)/n*f, 1/f }

float LinearEyeDepth(float depth, float4 zBufferParam)

{

    return 1.0 / (zBufferParam.z * depth + zBufferParam.w);

}

// Z buffer to linear depth.

// Correctly handles oblique view frustums.

// Does NOT work with orthographic projection.

// Ref: An Efficient Depth Linearization Method for Oblique View Frustums, Eq. 6.

float LinearEyeDepth(float2 positionNDC, float deviceDepth, float4 invProjParam)

{

    float4 positionCS = float4(positionNDC * 2.0 - 1.0, deviceDepth, 1.0);

    float  viewSpaceZ = rcp(dot(positionCS, invProjParam));

    // If the matrix is right-handed, we have to flip the Z axis to get a positive value.

    return abs(viewSpaceZ);

}

// Z buffer to linear depth.

// Works in all cases.

// Typically, this is the cheapest variant, provided you've already computed 'positionWS'.

// Assumes that the 'positionWS' is in front of the camera.

float LinearEyeDepth(float3 positionWS, float4x4 viewMatrix)

{

    float viewSpaceZ = mul(viewMatrix, float4(positionWS, 1.0)).z;

    // If the matrix is right-handed, we have to flip the Z axis to get a positive value.

    return abs(viewSpaceZ);

}

```

|        | Built-in      | URP                   |

|--------|---------------|-----------------------|

| Camera | Camera:       | RenderPipelineManager |

|        | OnPreCull     | beginFrameRendering   |

|        | OnPreRender   | beginCameraRendering  |

|        | OnPostRender  | endCameraRendering    |

|        | OnRenderImage | endFrameRendering     |

`Create> Rendering> Universal Render Pipeline> Renderer Feature`

|                            | 자동 생성됨 |                                   |

|----------------------------|-------------|-----------------------------------|

| _CameraDepthTexture        | O           | Pipeline Settings> Depth Texture  |

| _CameraOpaqueTexture       | O           | Pipeline Settings> Opaque Texture |

| _CameraColorTexture        | ??          |                                   |

| _CameraDepthNormalsTexture | X           |                                   |

- 

``` txt

- Camera> Rendering> Post-Processing 체크

- Hierachy> Volume> Global Volume

- Global Volume> Volume> Profile> New

- Global Volume> Volume> Add Override

```

## 11장. BRDF 누가 누구인가?

- 

- 

- 

- [[ 번역 ] Physically-Based Shading at Disney](https://lifeisforu.tistory.com/350)

![./brdf_vectors.png](./brdf_vectors.png)

| 기호 | 설명                              |

|------|-----------------------------------|

| N    | 노말                              |

| H    | 하프벡터 `H = normalize( L + V )` |

| L    | 라이트(광원)                      |

| V    | 뷰(카메라)                        |

| T    | 탄젠트                            |

| Θ    | (Theta) 방위각                    |

| Φ    | (Phi)  앙각(올려본각)             |

### BRDF 종류

#### Ashikhmin Shirley 어크먼 셜리

2000 - Michael Ashikhmin & Peter Shirley - An Anisotropic Phong BRDF Model

퐁 스펙큘러

#### Cook Torrance 쿡토렌스

1982 - Robert L.Cook & Kenneth E. Torrance - A Reflectance Model For Computer Graphics

미세면이론

#### Oren Nayar 오렌네이어

1994 - Michael Oren & Shree K. Nayar - Generalization of Lambert’s Reflectance Model

디퓨즈 전용

#### Ward 알드

1992 - Gregory J. Ward - Measuring and modeling anisotropic reflection

경험적 데이터 기반, 거의 사용되지 않음.

#### Disney 디즈니

SIGGRAPH 2012 - Brent Burley - Physically Based Shading at Disney

여러 파라미터

## 12장. BRDF 구현하기

- 참고

  - [[NDC19] 모바일에서 사용가능한 유니티 커스텀 섭스턴스 PBR 셰이더 만들기](https://www.slideshare.net/dongminpark71/ndc19-pbr-143928930)

### 레퍼런스 BRDF

#### Cook Torrance 레퍼런스

|                                                                                      |                                                                    |

|--------------------------------------------------------------------------------------|--------------------------------------------------------------------|

| Physics and Math of Shading by Naty Hoffman                                          | SIGGRAPH every year from 2012 to 2015                              |

| Real Shading in Unreal Engine 4 by Brian Karis                                       | SIGGRAPH, 2013                                                     |

| BRDF Explorer (GLSL) - CookTorrance BRDF                                             |                                                                    |

| Specular BRDF Reference on Brian Karis’ blog                                         |  |

| Introduction to BRDF Models by Daniël Jimenez Kwast                                  |                                                                    |

| A Reflectance Model for Computer Graphics from 1981                                  |                                                                    |

| Understanding the Masking-Shadowing Function in Microfacet-Based BRDFs by Eric Heitz | SIGGRAPH, 2014 - 미세면이해 추천                                   |

| Microfacet Models for Refraction through Rough Surfaces                              | EGSR, 2017                                                         |

#### Disney 레퍼런스

|                                                                           |                                                                                    |

|---------------------------------------------------------------------------|------------------------------------------------------------------------------------|

| Physically Based Shading at Disney                                        | SIGGRAPH, 2012, by Brent Burley                                                    |

| BRDF Explorer (GLSL) - Disney BRDF                                        |                                                                                    |

| Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering | SIGGRAPH, 2015, by Brent Burley                                                    |

| Moving Frostbite to Physically Based Rendering                            | SIGGRAPH, 2015, by Sébastien Lagarde and Charlesde Rousiers (only for the Diffuse) |

### 이론 BRDF

#### Cook Torrance 이론

미세면 이론

|   |                                |              | 관여 벡터 |       |                                                                   |

|---|--------------------------------|--------------|-----------|-------|-------------------------------------------------------------------|

| D | Normal `Distribution` Function | 정규분포함수 | (H)       | 양수  | 크기, 밝기, 스펙큘러 모양                                         |

| F | Fresnel                        | 프레넬       | (L, H)    | 0 ~ 1 | 보는 각도에 따른 반사율과 굴절율                                  |

| G | Geometry                       | 기하함수     | (L, V, H) |       | 면이 서로 겹쳐서 빛을 차단하는 정도의 근사치를 통계적으로 구한다. |

- NDF (Normal `Distribution` Function)

  - Beckmann

  - Phong

  - GGX

책의 구현에서는

|   |                      |

|---|----------------------|

| D | Trowbridge-Reitz GGX |

| F | Fresnel-Schlick      |

| G | Smith's Schlick-GGX  |

#### Disney 이론

### 구현 BRDF

#### Cook Torrance 구현

#### Disney 구현

## 13장. 표준 셰이더 후킹

- 16장. 복잡도와 우버셰이더 참조.

``` hlsl

// com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl

struct BRDFData

{

    half3 albedo;

    half3 diffuse;

    half3 specular;

    half reflectivity;

    half perceptualRoughness;

    half roughness;

    half roughness2;

    half grazingTerm;

    // We save some light invariant BRDF terms so we don't have to recompute

    // them in the light loop. Take a look at DirectBRDF function for detailed explaination.

    half normalizationTerm;     // roughness * 4.0 + 2.0

    half roughness2MinusOne;    // roughness^2 - 1.0

};

```

- [Custom Shader GUI](https://docs.unity3d.com/2021.1/Documentation/Manual/SL-CustomShaderGUI.html)

- [ShaderGUI: Custom Material Inspectors in Unity 5+](https://www.alanzucconi.com/2016/11/07/shadergui-custom-material-inspectors-unity-5/)

## 14장. 고급 기술 구현

### 반투명 (Translucency)

반투명은 BRDF로 처리하기 곤란.

|      |                                                   |                                                |

|------|---------------------------------------------------|------------------------------------------------|

| BRDF | Bidirectional reflectance distribution function   | 는 빛이 어떤 방향으로 반사가 되는지            |

| BTDF | Bidirectional transmittance distribution function | 는 빛이 어떤 방향으로 투과가 되는지            |

| BSDF | Bidirectional scattering distribution function    | 이 둘을 합쳐 빛이 재질과 어떻게 상호작용하는지 |

- TODO 예제에서 2개의 Directional Light사용...

``` hlsl

// ref: GPG Pro 2

//Translucency

// - 노말과 라이트의 하프의 역방향에 (물체 뒷부분)

// - 뷰를 닷연산으로 묶어준다. (확산효과)

float thickness = SAMPLE_TEXTURE2D(_Thickness, sampler_Thickness, IN.uv).r;

float3 translucencyLightDir = L + N * _Distortion;

float translucencyDot = pow(saturate(dot(V, -translucencyLightDir)), _Power) * _Scale;

float3 translucency = translucencyDot * thickness * _SubsurfaceColor.rgb;

diffuse += translucency;

```

### IBL

- 

| Cubemap생성 도구                                         |             |

|----------------------------------------------------------|-------------|

| [cmftStudio](https://github.com/dariomanesku/cmftStudio) | BSD 2       |

| [Knald's Lys](https://www.knaldtech.com/lys/)            | Commercial  |

| [IBLBaker](https://github.com/derkreature/IBLBaker)      | MIT License |

| [CubeMapGen](https://gpuopen.com/archived/cubemapgen/)   | old         |

## 15장. 아티스트가 사용할 셰이더 제작

아티스트가 조작하기 편하게

1. 적절한 셋팅 갯수

2. 적절한 셋팅 네이밍

3. 상호 작용하는 셋팅값을 위한 문서화

4. 텍스쳐에 여러 정보(albedo + specular등)을 넣는 경우가 많은데, 명확하게 셋팅값과 셋팅 네이밍을 표시

5. 여러 범위 혼합사용 피하기(되도록이면 `0 ~ 1`로...)

파라미터 변화값 별로 예제 씬 있으면 좋겠네..

## 16장. 복잡도와 우버셰이더

쉐이더 하나를 이용해서 여러가지 경우를 처리하고 싶은 경우, 필요한 모든 코드를 쉐이더 하나에 집어넣게되면 그게 바로 우버셰이더.

- `if`와 같은 동적분기는 성능저하.

- `#if`와 같이 전처리기를 이용한, 정적 분기를 이용하여 처리한다.

유니티에서는 키워드를 이용 쉐이더 조합을 편리하게 해주는 기능이 있음.

- [Shader variants and keywords](https://docs.unity3d.com/2021.1/Documentation/Manual/SL-MultipleProgramVariants.html)

- 총 256개의 글로벌 키워드.

- 64개의 로컬 키워드.

- `#pragma shader_feature KEYWORD`

- `#pragma multi_compile KEYWORD`

|                | 게임빌드에 포함     |

|----------------|---------------------|

| shader_feature | 사용되는 것만       |

| multi_compile  | 조합 가능한 모든 것 |

``` txt

#pragma multi_compile A B C

#pragma multi_compile D E

조합해서 나올 수 있는 총 갯수: 6개

A+D, B+D, C+D

A+E, B+E, C+E

```

``` hlsl

[KeywordEnum(Off, On)] _UseNormal("Use Normal Map", Float) = 0 

#pragma shader_feature _USENORMAL_OFF _USENORMAL_ON

#if _USENORMAL_ON

#endif

[Toggle] _ModifiedMode("Modified?", Float) = 0

#pragma shader_feature _MODIFIEDMODE_OFF _MODIFIEDMODE_ON

#if _MODIFIEDMODE_ON

#endif

```

## 17장. 셰이더가 정상작동하지 않을 때

### 일반적 트릭

- shader로 노말값 시각화

``` hlsl

struct Attributes

{

    float4 positionOS   : POSITION;

    float3 normalOS     : NORMAL;

    float4 tangent      : TANGENT;

    float2 uv           : TEXCOORD0;

};

struct Varyings

{

    float4 positionHCS      : SV_POSITION;

    float2 uv               : TEXCOORD0;

    float3 T                : TEXCOORD1;

    float3 B                : TEXCOORD2;

    float3 N                : TEXCOORD3;

    float3 positionWS       : TEXCOORD4;

};

// ----------

inline void ExtractTBN(in half3 normalOS, in float4 tangent, inout half3 T, inout half3  B, inout half3 N)

{

    N = TransformObjectToWorldNormal(normalOS);

    T = TransformObjectToWorldDir(tangent.xyz);

    B = cross(N, T) * tangent.w * unity_WorldTransformParams.w;

}

inline half3 CombineTBN(in half3 tangentNormal, in half3 T, in half3  B, in half3 N)

{

    return mul(tangentNormal, float3x3(normalize(T), normalize(B), normalize(N)));

}

Varyings vert(Attributes IN)

{

    //Varyings OUT;

    Varyings OUT = (Varyings)0;;

    OUT.positionHCS = TransformObjectToHClip(IN.positionOS.xyz);

    OUT.uv = TRANSFORM_TEX(IN.uv, _BumpMap);

    ExtractTBN(IN.normalOS, IN.tangent, OUT.T, OUT.B, OUT.N);

    OUT.positionWS = TransformObjectToWorld(IN.positionOS.xyz);

    return OUT;

}

// ---------------

half4 frag(Varyings IN) : SV_Target

{

#if _ENABLENORMALMAP_ON

    float3 tangentNormal = UnpackNormal(SAMPLE_TEXTURE2D(_BumpMap, sampler_BumpMap, IN.uv));

    tangentNormal.xy *= _BumpMapStrength; // BumpMap Strength.

    float3 N = CombineTBN(tangentNormal, IN.T, IN.B, IN.N);

#else

    float3 N = normalize(IN.N);

#endif

    return half4(N * 0.5 + 0.5, 1);

}

```

### 디버깅 도구

- Window> Analysis> Frame Debugger

- RenderDoc 프로그램

  - 

### 프로파일링

|                                 |  |

|---------------------------------|--|

| 배치 수                         |  |

| 드로우콜                        |  |

| SetPass                         |  |

| Vertex                          |  |

| 텍스쳐 갯수/메모리 /스위치 횟수 |  |

| Shadow Casters                  |  |

| Vertex Buffer Object            |  |

- CPU에 치중? GPU에 치중?

- Static GameObject 활용 잘하기.

## 18장. 최선 트렌드 따라잡기

### 컨퍼런스

|                 |                              |

|-----------------|------------------------------|

| GDC             | GDC Vault 구독 1년 400불정도 |

| Siggraph        | 1년 45달러                   |

| Unite           |                              |

| Digital Dragons | 영상자료 공개                |

| Eurographics    | 학술위주                     |

### 서적

어렵지만 구입해서 읽어볼 가치 있음.

|          |  |

|----------|--|

| GPU Gems |  |

| ShaderX  |  |

| GPU PRO  |  |

| GPU Zen  |  |

### 사이트

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

## etc

- [Microfacet BRDF](http://www.pbr-book.org/3ed-2018/Reflection_Models/Microfacet_Models.html#)

-
ecosyste.ms

Data

Tools

Indexes

Applications

Experiments

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https://github.com/netpyoung/bs.physically_based_shader_develop_for_unity

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