SoftGLRender

Tiny C++ software renderer/rasterizer that implements the main steps of the GPU rendering pipeline, including point, line and polygon rasterization, texture mapping, depth testing, color blending, etc., and emulates vertex shaders and fragment shaders using C++, 3D models (GLTF) are loaded by Assimp, and using GLM as math library. The project also adds OpenGL and Vulkan renderers implementation, you can switch between them (Software/OpenGL/Vulkan) in real time while running.

The purpose of this project is to provide a starting point for developers who want to learn about modern graphics programming.

Examples

Features

Software Renderer

Pipeline

Vertex shading
View Frustum culling (line & triangle)
Perspective Correct Interpolation
Back-Front face culling
Point/Line/Triangle rasterization
Fragment Shading
Shader derivative dFdx dFdy
Depth test & Alpha blending
Early Z test & Reversed Z
MSAA 4x

Texture Mapping

Mipmaps generation and sampling
Sample parameters: Lod, Bias, Offset
All kinds of texture filtering & wrapping mode
Image storage tiling and swizzling
- Linear: pixel values are stored line by line, commonly used as image RGBA buffer
- Tiled: block base storage, inside the block pixels are stored as Linear
- Morton: block base storage, inside the block pixels are stored as morton pattern (similar to zigzag)

Optimization

Multi-Threading: rasterization is block based with multi-threading support
SIMD: barycentric coordinate calculation, shader's varying interpolation, etc.

Viewer

Config panel based on imgui
Orbit camera controller
Blinn-Phong shading
PBR & IBL shading
Skybox cubeMap & equirectangular
Shadow mapping
FXAA anti-aliasing
RenderDoc in-application frame capture

Renderer abstraction

All renderers (Software/OpenGL/Vulkan) are implemented based on this abstract renderer class:

class Renderer {
 public:
  // framebuffer
  std::shared_ptr<FrameBuffer> createFrameBuffer(bool offscreen);

  // texture
  std::shared_ptr<Texture> createTexture(const TextureDesc &desc);

  // vertex
  std::shared_ptr<VertexArrayObject> createVertexArrayObject(const VertexArray &vertexArray);

  // shader program
  std::shared_ptr<ShaderProgram> createShaderProgram();

  // pipeline states
  std::shared_ptr<PipelineStates> createPipelineStates(const RenderStates &renderStates);

  // uniform
  std::shared_ptr<UniformBlock> createUniformBlock(const std::string &name, int size);
  std::shared_ptr<UniformSampler> createUniformSampler(const std::string &name, const TextureDesc &desc);

  // pipeline
  void beginRenderPass(std::shared_ptr<FrameBuffer> &frameBuffer, const ClearStates &states);
  void setViewPort(int x, int y, int width, int height);
  void setVertexArrayObject(std::shared_ptr<VertexArrayObject> &vao);
  void setShaderProgram(std::shared_ptr<ShaderProgram> &program);
  void setShaderResources(std::shared_ptr<ShaderResources> &uniforms);
  void setPipelineStates(std::shared_ptr<PipelineStates> &states);
  void draw();
  void endRenderPass();
};

Getting Started

Prerequisites

To build the project, you must first install the following tools:

CMake 3.10 or higher
Compiler environment with C++11 support

If you want to run the vulkan renderer, you need to install vulkan library as follows:

Download the Vulkan SDK from the official website: https://vulkan.lunarg.com/sdk/home
Install the SDK on your system. The installation process may vary depending on your operating system.
Set the environment variable VULKAN_SDK/VK_ICD_FILENAMES/VK_LAYER_PATH to the path where you installed the SDK.

Getting the Code

To get the code for this library, you can clone the GitHub repository using the following command:

git clone https://github.com/keith2018/SoftGLRender.git

Alternatively, you can download the source code as a ZIP file from the GitHub repository.

Building the Project

To build the project, navigate to the root directory of the repository and run the following commands:

mkdir build
cmake -B ./build -DCMAKE_BUILD_TYPE=Release
cmake --build ./build --config Release

This will generate the executable file and copy assets to directory bin, which you can run by executing the following command:

cd bin/Release
./SoftGLRender

Directory structure

assets: GLTF models and skybox textures, assets.json is the index of all model & skybox materials
src: Main source code directory
- Base: Basic utility classes like file, hash, timer, etc.
- Render: Renderer abstraction, include vertex, texture, uniform, framebuffer, etc.
  - Software: Software renderer implementation
  - OpenGL: OpenGL renderer implementation
  - Vulkan: Vulkan renderer implementation
- Viewer: GLTF loading (based on Assimp), camera & controller, config panel, and render pass management
  - Shader/GLSL: GLSL shader code, for OpenGL & Vulkan renderer
  - Shader/Software: C++ simulation of vertex shaders and fragment shaders
third_party: External libraries and assets

Third Party Libraries

assimp https://github.com/assimp/assimp
glfw https://github.com/glfw/glfw
glm https://github.com/g-truc/glm
glslang https://github.com/KhronosGroup/glslang
imgui https://github.com/ocornut/imgui
json11 https://github.com/dropbox/json11
stb_image https://github.com/nothings/stb
vma https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator

Contributing

If you would like to contribute to the project, you are welcome to submit pull requests with bug fixes, new features, or other improvements. Please ensure that your code is well-documented and adheres to the project's coding standards.

License

This code is licensed under the MIT License (see LICENSE).

samuelhsw / GLRender