SoftRenderer

Introduction

A Software Rasterizer based on compute shader.

Requirements

Unity version 2021.3 or more is recommended (support compute shader variants feature).
DirectX 11

Main feature

Basic logic and render pipeline are controlled by C# scripts while computing by compute shader.
Basic rasterizer feature: z-test, frustum culling, backface culling, project correction, etc
Hard shadow && soft shadow
Blinn-Phong shading and PBR shading
Frame buffer visualization: depth buffer, shadow map buffer and color buffer
Support camera movement
Show FPS, triangles and vertices number

Rendering Overview

Bellows are using explanation whereas implementation details are as follows.

Using Explanation

Open the Unity project and click run.

If "Cannot Find kernel variants with index(0)", then your Unity version maynot support compute shader variants but that matters little.

In order to prove that the running result is rendererd by our SoftRenderer instead of Unity built-in grpahics pipeline, the scene objects' material use black as default.

You can add new GameObject to scene and bind it with Render Object script. Then the GameObject will be added to rendering queue. Every Render Object supports Blin-phong, PRB parameters and PBR Texture three materials.

Render Pipeline

The code are in file Rasterizer/Scripts/Rasterizer.cs, consist of such stages below:

Clear screen
Set Attributes
ShadowMap pass
Rasterize Pass
Update Per frame

Rasterization

Stages below:

Put every RenderObject's vertex, normal, uv to GPU buffer.
Transform every vertex to clip space by function VertexTransform.
Function RasterizeTriangles rasterize every triangle:
1. Do frustum culling in [-w, w] clip space
2. Projection division
3. Backface culling
4. Screen mapping
5. Main Rasterization Process: get every triangle's AABB and judge every pixel in AABB, calculate shading by fragment shader.