Project training of Software College of Shandong University rendering engine system basic renderer (V)

Preface

This project hopes to implement a basic renderer , At the same time, it can support the use of precomputing . This article focuses on PathTracer Specific path tracking process code .
Project address

One 、 Basic logic

Same as the previous article , To calculate the contribution of the path corresponding to each pixel , We first initialize the path . Depending on the corresponding pixel from VBuffer After reading the hit point information in , For this hit point , We first calculate the contribution of direct illumination . Because we support multiple importance sampling , So we need to sample the light source when calculating the direct illumination contribution , For different light sources , We distinguish between different ways of calculating contributions , This contribution is then superimposed on this ray result . Of course , If the sampled light source does not actually contribute to the hit point , Then we will ignore it .

After calculating the contribution of direct illumination , We generate and track scattered rays , The direction of the light is determined by BRDF Sampling acquisition of . For tracking the hit results , We saved it . If we don't hit the object in the scene , Then we sample the ambient light directly and add its contribution to the path . If we hit , Then update the current path throughput, After that, take the new hit point as the starting point to continue the tracking similar to the above .

Two 、 Main function code

1、 Body tracking framework

2、 about Diffuse and Glossy Object sampling direct light

3、 Generate Glossy Scattered light

4、 Generate Diffuse Scattered light

5、 Generate Glass Scattered light

6、 Generate Mirror Scattered light

7、 Tracking scattered light

8、Gloosy Scattered light hits an object

9、Gloosy The scattered light missed the object

10、Diffuse The scattered light missed the object

11、Specular Scattered light hits an object

12、Specular The scattered light missed the object

summary

It mainly shows PathTracer The main code for the specific implementation of the function , That is, the relevant code of the specific path tracking process .