# GLCore

**Repository Path**: Storm_rain/GLCore

## Basic Information

- **Project Name**: GLCore
- **Description**: 基于OpenGL及OptiX的渲染框架，供个人实现算法使用，详细介绍见Markdown
- **Primary Language**: C++
- **License**: GPL-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-10-13
- **Last Updated**: 2022-03-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: Rendering, Opengl, Optix, PathTracing, Irradiance

## README

# GLCore
GLCore 是一个基于 OpenGL 及 OptiX 的渲染框架，供个人实现算法使用。<br/>

现因Gitee不支持LFS，新仓库地址[https://world-tree.coding.net/public/GLCore/GLCore/git/files](https://world-tree.coding.net/public/GLCore/GLCore/git/files)<br/>

## 21 Features
- 延迟渲染 (Deferred rendering) <details>
  <summary> by multi render targets framebuffer named GBuffer </summary>
  <img src="doc/Introduction/GBuffer.png"/>
</details>

- 全阶段着色器支持 (Full stage shaders supported) <details>
  <summary> by glsl tess control, tess evaluation, geometry, compute shaders </summary>
  <img src="doc/Introduction/AllStageShaders.png"/>
</details>

- 着色器头文件包含 (Shading language include) <details>
  <summary> by GL_ARB_shading_language_include and GLCore's File utility </summary>
  <img src="doc/Introduction/ShaderInclude.png"/>
</details>

- Debug标签 (Renderdoc event and resource label) <details>
  <summary> by glPushDebugGroup()... and glObjectLabel() to locate Graphics resources </summary>
  <img src="doc/Introduction/DebugLabel.png"/>
</details>

- 交叉编译 (Compile to SPIR-V) <details>
  <summary> by GL_SHADER_BINARY_FORMAT_SPIR_V and shaderc to compile glsl or hlsl to SPIR-V </summary>
  <img src="doc/Introduction/CompileToSPIR-V.png"/>
</details>

- 光线追踪管线 (Ray tracing pipeline) <details>
  <summary> by OptiX raygen, hitgroup(intersect, closesthit, anyhit), miss shaders </summary>
  <img src="doc/Introduction/RayTracingPipeline.png"/>
</details>

- 多材质路径追踪 (Multi materials path tracing) <details>
  <summary> by OptiX shaders and CUDA texture, surface object </summary>
  <img src="doc/Introduction/MultiMaterialsPT.png"/>
</details>

- DDGI (Dynamic diffuse Global Illumination) <details>
  <summary> by probes trace radiance, depth and convolution to tetra atlas and sample volume atlas </summary>
  <img src="doc/Introduction/DDGI.png"/>
</details>

- OptiX降噪器 (OptiX AI denoiser) <details>
  <summary> by OptixDenoiser and CUDA OpenGL interoperation </summary>
  <img src="doc/Introduction/OptiXDenoiser.gif"/>
</details>

- 无绑定纹理及图像 (Bindless texture and image) <details>
  <summary> by GL_ARB_bindless_texture and glGetImageHandleARB()... </summary>
  <img src="doc/Introduction/BindlessTexture.png"/>
</details>

- 间接绘制 (Indirect drawing) <details>
  <summary> by glMultiDrawArraysIndirect()... and indirect buffer </summary>
  <img src="doc/Introduction/IndirectDrawing.png"/>
</details>

- 各向异性过滤 (Anisotropic filtering) <details>
  <summary> by trilinear filtering and GL_TEXTURE_MAX_ANISOTROPY </summary>
  <img src="doc/Introduction/AnisotropicFilter.png"/>
</details>

- 压缩纹理 (Compressed texture) <details>
  <summary> by GL_COMPRESSED_RGBA_S3TC_DXT5_EXT... and manually load and flip DDS blocks </summary>
  <img src="doc/Introduction/CompressedTexture.png"/>
</details>

- FBX场景读取 (Load FBX scene) <details>
  <summary> by FBX sdk and GLCore's Model, Material, Light components </summary>
  <img src="doc/Introduction/LoadFBX.png"/>
</details>

- PBR材质 (PBR material) <details>
  <summary> by BaseColor, Normal, Roughness, Metallic, AO maps and Albedo, RMA render targets </summary>
  <img src="doc/Introduction/PBRMaterial.png"/>
</details>

- HDR工作流 (HDR workflow) <details>
  <summary> by sRGB gamma correction, linear space compute and result tone mapping </summary>
  <img src="doc/Introduction/IBL.png"/>
</details>

- Shadertoy框架 (Shadertoy framework) <details>
  <summary> by imple shadertoy's whole input uniforms and GLCore's Renderpass </summary>
  <img src="doc/Introduction/Shadertoy.png"/>
</details>

- 组件式封装 (Encapsule as components) <details>
  <summary> by minimizing include files in header and treat Graphics concepts as individuals </summary>
  <img src="doc/Introduction/Encapsule.png"/>
</details>

- 好用的ImGUI (Friendly ImGUI) <details>
  <summary> by C17 std::variant and lambda, functional to introduce SHeader and SWidget </summary>
  <img src="doc/Introduction/FriendlyImGUI.png"/>
</details>

- 四元数相机 (Quaternion camera) <details>
  <summary> by user euler angle interface and inner quaternion rotation </summary>
  <img src="doc/Introduction/QuaternionCamera.png"/>
</details>

- 屏幕文本绘制 (Screen text drawing) <details>
  <summary> by bindless texture(renderdoc can't debug) or texture2D array with times.ttf </summary>
  <img src="doc/Introduction/DrawText.png"/>
</details>

## Built-in RenderPasses
- 前向渲染SimplePass<br/>&emsp;
输入需要显示的各模型名，输出漫反射结果到当前帧缓冲
- 延迟渲染GBufferPass<br/>&emsp;
输入GBuffer需要的各模型名，输出Position，Normal，Albedo，RMA等纹理
- 局部光照BlinnPhongPass<br/>&emsp;
输入GBuffer各纹理名，输出Lambert漫反射，BlinnPhong镜面反射，常量环境光的局部光照纹理
- 天空盒SkyboxPass<br/>&emsp;
输入立方体贴图路径或纹理名，输出天空盒到当前帧缓冲
- 辐照度卷积EnvironmentMapConvolutionPass<br/>&emsp;
输入各环境立方体贴图名，输出各环境辐照度立方体贴图
- 屏幕四边形ScreenQuadPass<br/>&emsp;
输入需要全屏显示的纹理名，禁用深度测试输出到当前帧缓冲
- 色调映射ToneMappingPass<br/>&emsp;
输入HDR纹理名，输出经过ACES映射后的SDR纹理
- 本地版ShadertoyPass<br/>&emsp;
输入Shadertoy的片段着色器路径，输出运行结果
- 文本绘制DrawTextPass<br/>&emsp;
输入文本及位置，颜色，大小等属性，输出屏幕文本到当前帧缓冲
- 模型描边OutlinePass<br/>&emsp;
输入需要描边的各模型名及颜色，输出描边结果到当前帧缓冲
- 对象选取SelectObjectPass<br/>&emsp;
输入需要监控的资源，如模型，灯光，通过接口返回被鼠标选取对象
<br/><br/>

## Experiments && Examples
### Shadertoy框架光线步进
![Ray Marcing](doc/Introduction/RayMarching.gif)
<br/><br/>

### 符号距离场建场及可视化
![Visual SDF](doc/Introduction/VisualSDF.png)
<br/><br/>

### 双抛物面点光源阴影贴图
![Duel Paraboloid](doc/Introduction/DuelParaboloid.png)
<br/><br/>

### 康奈尔盒DDGI
![IBL](doc/Introduction/DDGI.png)
<br/><br/>

### 基于图像的光照
![IBL](doc/Introduction/IBL.png)
<br/><br/>

### 辐照度球谐编码
![IBL](doc/Introduction/SH.png)
<br/><br/>

### 分布式光线追踪
![IBL](doc/Introduction/DistributionRayTracing.png)
<br/><br/>

### 可视化场景材质ID
![IBL](doc/Introduction/MaterialId.png)
<br/><br/>

### 多材质路径追踪
![IBL](doc/Introduction/PathTracing.png)
<br/><br/>

## Dependencies
安装CUDA Toolkit<br/>
部分模型如[Bistro](https://developer.nvidia.com/orca/amazon-lumberyard-bistro)酒馆未上传至仓库
 <details>
  <summary> ... </summary>
之前通过nuget管理第三方库，但每项目需要独立配置过于繁琐，现通过#pragma comment预编译导入lib，新项目只需添加包含目录<br/>
因为用到了C17 filesystem 提供的符号链接为GLSL扩展的语法补全提供支持。管理员打开VS运行一次该项目，即可让扩展找到Shader头文件
</details><br/>

## Additional
### 为何要自己写？
为了**自由和简单**。直接用Godot，Unity，UE等游戏引擎难以直接操作图形API。而直接用其他渲染框架如[G3D](https://casual-effects.com/g3d/www/index.html)，[Falcor](https://github.com/NVIDIAGameWorks/Falcor)文档复杂，修改困难。

### 为什么用OpenGL和OptiX？
Vulkan，DX12等现代API通过将部分驱动层的概念暴露给用户，来获得对硬件更细致的掌控，进而提高运行效率。但API复杂且**学习资料少**，不利于前期学习。光追支持可通过Vulkan扩展，DXR和OptiX获得，因为选择了最简单的OpenGL，对应的通过基于CUDA的OptiX来支持。

### 为什么要做DDGI？
因为毕设准备做**探针**相关的全局光照算法。