Volumetric Rendering: Surface Shading

This third instalment on Volumetric Rendering will explain how to shade volumes in a realistic fashion. This essential step is what gives three-dimensionality to the flat, unlit shapes that have been generated so far with raymarching.

Introduction
Step 1. Lambertian Reflectance
Step 2. Normal Estimation
Step 3. The Shading
Step 4. Specular Reflections
Conclusion

You can find here all the other posts in this series:

The full Unity package is available at the end of this article. 📦

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Physically Based Rendering and lighting models in Unity3D

Part 1, Part 2, Part 3, Part 4, Part 5, [download the Unity3D package]

Why is it colder at the poles and hotter on the equator? This question, which seems completely unrelated to shaders, is actually fundamental to understand how lighting models work. As explained in the previous part of this tutorial, surface shaders use a mathematical model to predict how light will reflect on triangles. Generally speaking, Unity supports two types of shading techniques, one for matte and one for specular materials. The former ones are perfect for opaque surfaces, while the latter ones simulate objects which reflections. The Maths behind these lighting models can get quite complicated, but understanding how they work is essential if you want to create your own, custom lighting effect. Up to Unity4.x, the default diffuse lighting model was based on the Lambertian reflectance. Continue reading →

Surface shaders in Unity3D

Part 1, Part 2, Part 3, Part 4, Part 5

This is the second part of a series of posts on Unity3D shaders, and it will focus on surface shaders. As previously mentioned, shaders are special programs written in a language called Cg / HLSL which is executed by GPUs. They are used to draw triangles of your 3D models on the screen. Shaders are, in a nutshell, the code which represents how different materials are rendered. Surface shaders are introduced in Unity3D to simplify the way developers can define the look of their materials.

Surface shader Continue reading →