Kazen

Kazen Con 2022-Q2 总结

2022-07-10T00:00:00+00:00

1. Core Feature

New samplers.
1. stratified
2. correlated
3. pmj02-bn
Geometric shadow terminator : remove the shadow-line artifact cause by geometry.
Fire fly reduction: increase roughness per bounce.
Configurable ray bias for reduce ray intersection computations error (floating point error).
Light primary visibility : toggle light visibility.

2. Sampler Compare

stratified
correlated
pmj02-bn

2.1 Stratified Sampling

分层采样 (stratified sampling) 将域划分为离散数量的层，并且在每个层上独立得到一个采样点。相比随机采样，通常会减少采样点的聚簇的现象，所以会有更好的收敛性。

Figure x: 256spp indenpendent (left) | stratified (right). For a full screen comparison, click here.

2.2 Correlated multi-jittered sampling

Figure 3: 256spp stratified (left) | correlated (right). For a full screen comparison, click here.

2.3 Progressive multi-jittered sampling wtih blue nose

Figure 5: 256spp stratified (left) | pmj02 (right). For a full screen comparison, click here.

3. Geometric shadow terminator

Figure x: Geometric shadow terminator 问题

这个问题是由于：着色法线 (shading normal) 与 几何法线 (geometric normal) 不一致导致的。尤其在底模的情况下非常明显。

一般来说，光线追踪过程中，要得到光滑的表面，需要对顶点法线进行插值。计算方法是：进行相交检测获得三角形的重心坐标，然后根据重心坐标进行插值。这个法线叫做着色法线 (shading normal)。

根据图x来看，在计算光源遮挡的时候，插值出来的着色法线与 shadowray 的夹角小于 90°，所以开始进行几何体相交检测，发现着色点被遮挡，那么可以认为这个点处于阴影中。通常是整个三角形被更靠近光源的三角形遮挡住，导致了带棱角的阴影瑕疵。

Figure x: shadowray 检测

这次实现的是 Johannes Hanika 提出的一种方法。简单来说：计算一个着色点上方的位置，作为 shadowray 的 origin 位置。其实这也很好理解：我们希望得到一个光滑的效果，也可以认为其实是对几何体构造了一个虚拟的光滑表面，这个表面顶点是沿着几何法线位移了一些，类似于曲面细分。效果如图x。

Figure x: xxxx

添加 geometric shadow terminator 的对比图

Figure 3: 256spp stratified (left) | correlated (right). For a full screen comparison, click here.

4. Firefly reduction

Firefly 产生的原因可以看 Matt Pharr 在《Ray Tracing Gems》的第 17 章的 Ignoring the Inconvenient When Tracing Rays，介绍的比较全面。

简单来说：根据距离平方反比定律，一个小光源想要照亮场景的话就需要很大的能量值，比如说 radiance = 500 这样。从某个像素发出的路径，在非常小的概率下击中光源，导致 throughput 过大。一个像素的值范围是 [0, 1]，如果要消除这个很大的值，就需要后面非常多的采样才能平滑掉。

这次实现了 Yuriy O’Donnell 提出的方法：每一次弹射光线与场景相交，就累加一个粗糙度偏移值 (roughness bias)，然后将这个值累加给当前材质的粗糙度上。这样，随着光线深度的增加，材质累加的粗糙度会越来越大。

// https://twitter.com/YuriyODonnell/status/1199253959086612480
float oldRoughness = payload.roughness;
payload.roughness = min(1.0, payload.roughness + roughnessBias);
roughnessBias += oldRoughness *  0.2;

作者原来的实现是: roughnessBias += oldRoughness * 0.75; 但是 0.75 这个乘数过大，导致金属和地面交接处的焦散消失了。所以我们将这个系数暴露出来: accumulatedRoughnessCoff，使得我们可以在外面手动调节这个参数。下面的例子是 accumulatedRoughnessCoff 为 0.2 的效果。

Figure x: Naive (left) | Roughness accumulated (right).
accumulatedRoughnessCoff 为 0.2 的对比效果 click here.

这里可以看到，accumulated a roughness 后的 Firefly 明显减少，但会使金属材质变得更亮了，效果错误。因为在金属之间的弹射 SS 路径，累加粗糙度似乎不正确，或许这种方法只适合 SDS 路径？

后续需要阅读 Path Space Regularization for Holistic and Robust Light Transport 来寻找答案，文中提到了一种更加通用的 Vertex Connection and Merging 方法。

5. Ray epsilon

由于在路径追踪过程中的数值精度问题，会出现类似 “self shadowing” 的渲染瑕疵。

这是由于反射射线与被反射的表面相交。为了避免这个问题，反射光并不是从相交点开始，而是从离表面一定距离的地方开始，我们用 $\epsilon$ rayEpsilon 表示这个距离，单位是米。例如，如果射线的 $\epsilon$ 为 0.1，那么偏移量为 0.1 米 (=10厘米)。

一般来说，我们希望让射线的 $\epsilon$ 变得非常小。根据经验，它大约是摄像机 <===> 物体距离的 1 / 100000 ~ 1 / 1000。在大多数“现实场景”的尺度范围内 ( 对象尺寸为 0.1 米 ~ 100 米 )，默认值 0.001 应该就可以了。

Figure x: rayEpsilon=0.00001 (left) | rayEpsilon=0.001 (right).
左侧比右侧暗，这是因为自阴影导致反射光线被截断了。另外，也能看到背景物体上明显的线条瑕疵。增加 rayEpsilon 就可以去除这类渲染瑕疵 (self-shadowing, dark lines, etc.) click here.

在 integrator 中的 shadowRay 和 bsdf 生成新的 ray 都需要重新设置一下 rayEpsilon。例如：

/* Apply ray epsilon to shadow ray. */
lRec.shadowRay.mint = m_rayEpsilon;
lRec.shadowRay.maxt -= m_rayEpsilon;

/* Apply ray epsilon to trace ray. */
ray = Ray3f(its.p, its.toWorld(bRec.wo));
ray.mint = m_rayEpsilon;

6. Final result

Figure x: 1920x1080 | 16384 spp | 1.1 h. Stormtrooper (by ScottGraham) License: CC BY 3.0

Reference

[1] Stochastic Sampling in Computer Graphics ROBERT L. COOK. 1986

[2] Correlated Multi-Jittered Sampling Andrew Kensler. 2013

[3] Andrew Kensler’s permute() Andrew Helmer. 2021

[4] Progressive Multi-Jittered Sample Sequences Per Christensen, Andrew Kensler and Charlie Kilpatrick. 2015

[5] Physically Based Rendering v4: from theory to implementation Matt Pharr, Wenzel Jakob and Greg Humphreys. 2023

[6] Hacking the Shadow Terminator Johannes Hanika. 2021

[7] Accumulate a roughness bias based on roughness of hitting surface Yuriy O’Donnell. 2019

[8] Ray Tracing Denoisinge Alain Galvan. 2020

使用 Rez 作为包管理工具开发 c++

2022-05-23T00:00:00+00:00

Rez 是什么
- rez 是什么?
- 包管理是什么
安装 Rez
- wsl2 安装开发
写一个简单的 Rez package
- cmake / python 基础知识推荐视频
- rp 中的 cmake / python 基本套路
什么是pkg-config

简单理解，pkg-config根据.pc结尾的文件做依赖配置。找到.pc文件周，解析其内容，然后对底层构建工具（C/C++编译器、链接器）或高层构建工具（automake?, cmake）提供具体配置项目。

通常是在POSIX系统（Linux，MacOS等）使用pkg-config，解决第三方依赖项配置问题。

近些年来随着CMake的越发流行，原本用pkg-config的很多软件包提供了cmake的配置作为替代；少部分仍然提供.pc文件作为兼容考虑；还有另外一小部分的软件包，即使基于cmake构建了，对外提供依赖配置时仍然只有.pc文件。

这就导致一个问题：虽然我学会了cmake在大部分时候都能解决依赖问题，但个别格楞子软件包还是要用pkg-config来搞。

Building Packages

rez包可以使用rez-build工具来构建和本地安装。这个工具有以下操作：
- 遍历一个包的变体
- 构建环境
- 在此环境中运行构建系统
每一个构建都来自构建的目录路径。（通常是构建的子目录或构建下的变体特定子目录）例如一个包含两个基本python变体的程序包：

ENV cmake

Operator to read environment variables.

Use the syntax $ENV{VAR} to read environment variable VAR.

To test whether an environment variable is defined, use the signature if(DEFINED ENV{<name>}) of the if() command.

See the set() and unset() commands to see how to write or remove environment variables.

CMAKE_PREFIX_PATH

Semicolon-separated list of directories specifying installation prefixes to be searched by the find_package(), find_program(), find_library(), find_file(), and find_path() commands. Each command will add appropriate subdirectories (like bin, lib, or include) as specified in its own documentation.

By default this is empty. It is intended to be set by the project.

Build Environment Variables

https://github.com/AcademySoftwareFoundation/rez/wiki/Environment-Variables

These are variables that rez generates within a build environment, in addition to those listed here.
- REZ_BUILD_ENV - Always present in a build, has value 1.
- REZ_BUILD_INSTALL - Has a value of 1 if an installation is taking place (either a rez-build -i or rez-release), otherwise 0.
- REZ_BUILD_INSTALL_PATH - Installation path, if an install is taking place.
- REZ_BUILD_PATH - Path where build output goes.
- REZ_BUILD_PROJECT_DESCRIPTION - Equal to the description attribute of the package being built.
- REZ_BUILD_PROJECT_FILE - The filepath of the package being built (typically a package.py file).
- REZ_BUILD_PROJECT_NAME - Name of the package being built.
- REZ_BUILD_PROJECT_VERSION - Version of the package being built.
- REZ_BUILD_REQUIRES - Space-separated list of requirements for the build - comes from the current package’s requires, build_requires and private_build_requires attributes, including the current variant’s requirements.
- REZ_BUILD_REQUIRES_UNVERSIONED - Equivalent but unversioned list to REZ_BUILD_REQUIRES.
- REZ_BUILD_SOURCE_PATH - Path containing the package.py file.
- REZ_BUILD_THREAD_COUNT - Number of threads being used for the build.
- REZ_BUILD_TYPE - One of local or central. Value is central if a release is occurring.
- REZ_BUILD_VARIANT_INDEX - Zero-based index of the variant currently being built. For non-varianted packages, this is “0”.
- REZ_BUILD_VARIANT_REQUIRES - Space-separated list of runtime requirements of the current variant. This does not include the common requirements as found in REZ_BUILD_REQUIRES. For non-varianted builds, this is an empty string.
- REZ_BUILD_VARIANT_SUBPATH - Subdirectory containing the current variant. For non-varianted builds, this is an empty string.
- tbb 包生成
- 测试 tbb
  - target 名字是 TBB::tbb，可以在 kazen\packages\tbb\2021.2.0\platform-linux\arch-x86_64\lib\cmake\TBB\TBBTargets.cmake
阶段总结

写一个复杂库的 Rez package
- embree3
- 测试 embree 3 功能
写一个纯头文件库的 Rez package
- tinyobjloader
- 测试 tinyobjloader 功能
写一个自己的启动环境，测试开发
- vfx platform 介绍
Rez 优缺点分析
阶段总结

c++ 开发环境搭建 (wsl2)

2022-05-22T00:00:00+00:00

1. 适用于 Linux 的 Windows 子系统 (wsl)

https://docs.microsoft.com/zh-cn/windows/wsl/

1.1 安装

$ wsl --list --online

以下是可安装的有效分发的列表。
请使用“wsl --install -d <分发>”安装。

NAME            FRIENDLY NAME
Ubuntu          Ubuntu
Debian          Debian GNU/Linux
kali-linux      Kali Linux Rolling
openSUSE-42     openSUSE Leap 42
SLES-12         SUSE Linux Enterprise Server v12
Ubuntu-16.04    Ubuntu 16.04 LTS
Ubuntu-18.04    Ubuntu 18.04 LTS
Ubuntu-20.04    Ubuntu 20.04 LTS

安装 Ubuntu 20.04 LTS 版本

$ wsl --install -d Ubuntu-20.04

1.2 卸载

检查已经安装的 wsl2 系统

$ wsl --list

适用于 Linux 的 Windows 子系统分发版:
Ubuntu-20.04

卸载 Ubuntu-20.04

$ wsl --unregister Ubuntu-20.04

2. Ubuntu-20.04 软件源更新

默认情况下Ubuntu 的apt下载源是国外的仓库，我们可以将它的默认下载地址切换到国内环境下，例如阿里云的镜像地址。

2.1 备份

$ sudo cp /etc/apt/sources.list /etc/apt/sources.list.bakup

2.2 修改

$ sudo vim /etc/apt/sources.list

将 sources.list 文件内容替换成下面的

deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse

2.3 更新

$ sudo apt-get update

2.4 升级

$ sudo apt-get upgrade

3. 安装 zsh

zsh 是 Z shell 的简称。用于交互式登录的 shell 及脚本编写的命令解释器，可以拓展一些功能丰富的第三方插件和主题，提高 shell 使用效率。

3.1 安装

$ sudo apt-get install zsh

3.2 检查

$ cat /etc/shells

# /etc/shells: valid login shells
/bin/sh
/bin/bash
/usr/bin/bash
/bin/rbash
/usr/bin/rbash
/bin/dash
/usr/bin/dash
/usr/bin/tmux
/usr/bin/screen
/bin/zsh
/usr/bin/zsh

3.3 启动 zsh

输入命令

$ zsh

可以看到第一次运行 zsh 时会进入如下的配置引导页面：

This is the Z Shell configuration function for new users,
zsh-newuser-install.
You are seeing this message because you have no zsh startup files
(the files .zshenv, .zprofile, .zshrc, .zlogin in the directory
~).  This function can help you with a few settings that should
make your use of the shell easier.

You can:

(q)  Quit and do nothing.  The function will be run again next time.

(0)  Exit, creating the file ~/.zshrc containing just a comment.
     That will prevent this function being run again.

(1)  Continue to the main menu.

--- Type one of the keys in parentheses ---

这里我们选择 q 直接退出。

4. 安装 oh-my-zsh

由于 zsh 配置较为复杂，推荐使用配置管理工具来配置 zsh。下面介绍使用 oh-my-zsh 来修改 zsh 的主题和安装常用的插件。

4.1 安装

获取源码

$ git clone https://gitee.com/mirrors/oh-my-zsh.git

执行安装命令

$ sh oh-my-zsh/tools/install.sh

完成后可以看到如下界面

Cloning Oh My Zsh...
remote: Enumerating objects: 1295, done.
remote: Counting objects: 100% (1295/1295), done.
remote: Compressing objects: 100% (1249/1249), done.
remote: Total 1295 (delta 26), reused 1250 (delta 26), pack-reused 0
Receiving objects: 100% (1295/1295), 1.06 MiB | 3.69 MiB/s, done.
Resolving deltas: 100% (26/26), done.
From https://github.com/ohmyzsh/ohmyzsh
 * [new branch]      master     -> origin/master
Branch 'master' set up to track remote branch 'master' from 'origin'.
Already on 'master'
/home/kazen/oh-my-zsh/tools

Looking for an existing zsh config...
Using the Oh My Zsh template file and adding it to ~/.zshrc.

Time to change your default shell to zsh:
Do you want to change your default shell to zsh? [Y/n] y
Changing your shell to /usr/bin/zsh...
[sudo] password for kazen:
Shell successfully changed to '/usr/bin/zsh'.

         __                                     __
  ____  / /_     ____ ___  __  __   ____  _____/ /_
 / __ \/ __ \   / __ `__ \/ / / /  /_  / / ___/ __ \
/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / /
\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/
                        /____/                       ....is now installed!


Before you scream Oh My Zsh! look over the `.zshrc` file to select plugins, themes, and options.

• Follow us on Twitter: @ohmyzsh
• Join our Discord community: Discord server
• Get stickers, t-shirts, coffee mugs and more: Planet Argon Shop

4.2 配置 zsh

$ vim ~/.zshrc

**主题修改

ZSH_THEME="robbyrussell"

其中可以将 robbyrussell 改为 Theme 中的任意一种，比如 ZSH_THEME="agnoster" 。

插件配置

plugins=(git)

修改为

plugins=(git zsh-autosuggestions)

4.3 安装 autosuggestion 插件

上面我们为 zsh 配置了 autosuggestions 插件，但这个插件并不是 zsh 自带的插件，需要下载安装。

$ git clone https://github.com/zsh-users/zsh-autosuggestions ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-autosuggestions

安装完成后，重新更新配置。

$ source .zshrc

在编辑指令的时候，对于之前使用过的指令，按 → 即可快速补全。

5. c++ (cmake) 开发环境搭建

我们需要在 Windows 环境中安装 VS Code。从官网下载最新版本，直接安装：https://code.visualstudio.com/

5.1 基础软件安装

build-essential

构建基础包（build-essential）实际上是属于 Debian 的。在它里面其实并不是一个软件。它包含了创建一个 Debian 包（.deb）所需的软件包列表。这些软件包包括 libc、gcc、g++、make 等。构建基础包包含这些所需的软件包作为依赖，所以当你安装它时，你只需一个命令就能安装所有这些软件包。

$ sudo apt-get install build-essential

GDB

全称 GNU symbolic debugger，是 Linux 下常用的程序调试器。

$ sudo apt-get install gdb

CMake

是一种优秀的跨平台的构建系统，类似于 Makefile，是专为 C/C++ 开发的一套构建系统。

$ sudo apt install cmake

Remote-WSL

在 Windows 环境中安装 VS Code。官网下载最新版本并安装
在 VS Code 的插件市场，搜索 remote-wsl 插件，然后安装

5.2 测试

创建一个文件夹 test ，然后进入文件夹。

$ mkdir test
$ cd test

在文件夹中启动 vscode

$ code .

新建 main.cpp 文件，完成代码

#include <iostream>

using namespace std;
int main() {
    cout << "Hell World!" << endl;
}

新建 CMakeLists.txt 文件，完成代码

cmake_minimum_required (VERSION 3.10)
project (test)
add_executable(test main.cpp)

构建应用程序

$ cmake .
$ make

测试应用程序

$ ./test

Hell World!

Sampler 的比较

2022-05-19T00:00:00+00:00

Figure 1: indenpendent (left) | stratified (right). For a full screen comparison, click here.

Figure 2: indenpendent (left) | correlated (right). For a full screen comparison, click here.

Figure 3: stratified (left) | correlated (right). For a full screen comparison, click here.

Figure 4: 16spp stratified (left) | pmj02 (right). For a full screen comparison, click here.

Figure 5: 256spp stratified (left) | pmj02 (right). For a full screen comparison, click here.

Figure 6: test. For a full screen comparison, click here.

Kazen Con 2022-Q1 总结

2022-04-01T00:00:00+00:00

1. Core Feature

Monte Carlo unbiased path tracing
multiple importance sample
Material ：kazen initial standard surface ( kiss )
1. diffuse ：Disney diffuse with Retro-Reflective
2. specular ：GGX-Smith BRDF with VNDF
3. clearcoat ：GGX-Smith BRDF with VNDF
4. sheen ：Disney sheen
Textures and simple textures ops ( nested blend, ramp color, scale uv )
OIIO texture system
Normal mapping
Camera : Perspective / Thin Lens
Light : mesh light, basic environment ( Blinn/Newell Latitude Mapping )

2. KISS PBR shading model

KISS (kazen initial standard surface) , is a linear blend of a metallic BSDF and a dielectric BSDF, see Figure 1. Currently we only support opaque dielectric BSDF and it can be used as materials like plastics, wood, or stone.

Figure 1: Structure of the KISS PBR Shading Model.

KISS blend metallic and dielectric BSDFs based on parameters metallic.

Figure 2: The KISS BRDF is a blend of metallic and dielectric BRDF models based on a metallic shader parameter.

For sampling the BRDF, I first use Russian-roulette to decide between sampling the diffuse lobe or the specular lobes with the following ratio:

$$ ratio_{diffuse} = \frac{1 - metallic}{2} $$

For non-metallic materials, 1/2 the samples are sampled with cosine weighted hemisphere sampling, the 1/2 with specular sampling described below. For metallic materials, all samples are sampled using specular sampling.

The specular samples are divided into sampling the GGX (specular lobe) and GGX (clearcoat lobe) distribution with the following ratio:

$$ ratio_{GGX} = \frac{1}{1 + clearcoat} $$

For materials with no clearcoat, samples are only sampled using the GGX distribution, for materials with 100% clearcoat, 1/2 the samples are directed to either of the distributions.

// diffuse weight
float ratioDiffuse = (1.0f - metallic) / 2;

// specular weight
float ratioGGX = 1.0f / (1.0f + clearcoat);

These following images shows material parameters support by KISS:

2.1 roughness

0.0	0.5

0.0	1.0

2.2 metallic

0.0	0.5

0.0	1.0

2.3 specular

0.0	0.5

0.0	1.0

2.4 specularTint

0.0	0.5

0.0	1.0

2.5 clearcoat

0.0	0.5

0.0	1.0

2.6 clearcoatRoughness

0.0	0.5

0.0	1.0

2.7 sheen

0.0	0.5

0.0	1.0

2.8 sheenTint

0.0	0.5

0.0	1.0

3. Debug Error

Figure 3: Firefly error and incorrect color bleeding in shadow | 4096 spp.

This error occurred when we set integrator maxDepth to a very high value, so the light path will be terminated only by russian roulette. The scenario is the light will bounce between floor and sphere forever, and make the shadow part look aweful.

Althrought, kill light path by maxDepth without compensation will cause statistics bias.

Figure 4: maxDepth=5 (left) and maxDepth=1024 (right). For a full screen comparison, click here.

maxDepth parameter is found when I check cycles render setting : Light path, by default it sets maxBounces to 4.
So the take-away is : Reverse thinking code logic by ground truth (cycles) results, not just debug through code.

4. Look-dev

This shows the cycles shading graph.

Figure 5: The shading graph for creating the look.

The corresponding nano-Kazen material scene graph:

<bsdf type="normalmap">
    <texture type="imagetexture">
        <string name="filename" value="textures/MSMC_Brass_Hammered_Normal.jpg"/>
        <float name="scale" value="1.0"/>
        <string name="colorspace" value="linear"/>
    </texture>
    <bsdf type="kazenstandard">
        <texture type="blend" id="baseColor">
            <string name="blendmode" value="mix"/>
            <texture type="constanttexture" id="input1">
                <color name="color" value="0.887923 0.351533 0.002125"/>
            </texture>
            <texture type="constanttexture" id="input2">
                <color name="color" value="0.982251 0.822786 0.62396"/>
            </texture>
            <texture type="imagetexture" id="mask">
                <string name="filename" value="textures/MSMC_Circle_Outline_Grid.jpg"/>
                <float name="scale" value="1.0"/>
                <string name="colorspace" value="linear"/>
            </texture>
        </texture>
        <texture type="constanttexture" id="roughness">
            <color name="color" value="0.166233 0.166233 0.166233"/>
        </texture>
        <texture type="imagetexture" id="metallic">
            <string name="filename" value="textures/MSMC_Circle_Outline_Grid.jpg"/>
            <float name="scale" value="1.0"/>
            <string name="colorspace" value="srgb"/>
        </texture>
        <float name="anisotropy" value="0.0"/>
        <float name="specular" value="0.5"/>
        <float name="specularTint" value="0.0"/>
        <float name="clearcoat" value="0.0"/>
        <float name="clearcoatRoughness" value="0.0"/>
        <float name="sheen" value="0.0"/>
        <float name="sheenTint" value="0.0"/>
    </bsdf>
</bsdf>

Figure 6: 1920x1080 | 4096 spp | 11.7 min.

5. Final result

Figure 7: 3840x2160 | 10000 spp | 3.4 h.

Compare with Blender render result.

Figure 8: nano-Kazen: 3840x2160 | 10000 spp | 3.4 h (left) and cycles: 1920x1080 | 2500 spp | 4.47 min (right). For a full screen comparison, click here.

Reference

[1] Physically Based Shading at Disney Brent Burley. 2012

[2] Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering Brent Burley. 2015

[3] Simon Kallweit’s project report Simon Kallweit. 2015

[4] Microfacet Models for Refraction through Rough Surfaces Bruce Walter. 2007

[5] Understanding the Masking-Shadowing Function in Microfacet-Based BRDFs Eric Heitz. 2014

[6] Sampling the GGX Distribution of Visible Normals Eric Heitz. 2018

[7] Robust monte carlo methods for light transport simulation Eric Veach. 1997

[8] Physically Based Rendering: from theory to implementation Matt Pharr, Wenzel Jakob and Greg Humphreys. 2016

[9] Mitsuba 2: Physically Based Renderer Wenzel Jakob

[10] Embree 3: High Performance Ray Tracing Intel

[11] OpenImageIO: a library for reading and writing images, and a bunch of related classes, utilities, and applications Larry Gritz

[12] Greyscalegorilla: modern surface material collection Greyscalegorilla. 2021

Kazen

Kazen Con 2022-Q2 总结

1. Core Feature

2. Sampler Compare

2.1 Stratified Sampling

2.2 Correlated multi-jittered sampling

2.3 Progressive multi-jittered sampling wtih blue nose

3. Geometric shadow terminator

4. Firefly reduction

5. Ray epsilon

6. Final result

Reference

使用 Rez 作为包管理工具开发 c++

什么是pkg-config

Building Packages

ENV cmake

CMAKE_PREFIX_PATH

Build Environment Variables

c++ 开发环境搭建 (wsl2)

1. 适用于 Linux 的 Windows 子系统 (wsl)

1.1 安装

1.2 卸载

2. Ubuntu-20.04 软件源更新

2.1 备份

2.2 修改

2.3 更新

2.4 升级

3. 安装 zsh

3.1 安装

3.2 检查

3.3 启动 zsh

4. 安装 oh-my-zsh

4.1 安装

4.2 配置 zsh

4.3 安装 autosuggestion 插件

5. c++ (cmake) 开发环境搭建

5.1 基础软件安装

5.2 测试

Sampler 的比较

Kazen Con 2022-Q1 总结

1. Core Feature

2. KISS PBR shading model

2.1 roughness

2.2 metallic

2.3 specular

2.4 specularTint

2.5 clearcoat

2.6 clearcoatRoughness

2.7 sheen

2.8 sheenTint

3. Debug Error

4. Look-dev

5. Final result

Reference