CD-ROM Shader: Diffraction Grating – Part 1

This post will guide you through the creation of a shader that reproduces the rainbow reflections that can be seen on CD-ROMs and DVDs. This tutorial is part of a longer series on physically based iridescence.

You can find the complete series here:

A link to download the Unity project used in this series is also provided at the end of the page.

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Fast Subsurface Scattering in Unity (Part 1)

Most (if not all) optical phenomena that materials exhibit can be replicated by simulating how the individual rays of light propagate and interact. This approach is referred in the scientific literature as ray tracing, and it is often too computationally expensive for any real-time application. Most modern engines rely on massive simplifications that, despite being unable to reproduce photorealism, can produce a believable approximation. This tutorial introduces a fast, cheap and convincing solution that can be used to simulate translucent materials which exhibit subsurface scattering.

This is a two part series:

At the end of this post, you will find a link to download the Unity project.

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Understanding Diffraction Grating

The first post in this series, The Nature of Light, introduced the dual nature of light, exhibiting behaviours which are typical of both waves and particles. In this part, we will see how those two aspects are both necessary for iridescence to arise.

You can find the complete series here:

A link to download the Unity project used in this series is also provided at the end of the page.

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Improving the Rainbow – Part 2

In the previous part of this tutorial, Improving the Rainbow – Part 1, we have seen different techniques to reproduce the colours of the rainbow procedurally. Solving this problem efficiently will allow us to simulate physically based reflections with a much higher fidelity.

The purpose of this post is to introduce a novel approach that yields better results than any of the previous solutions, without using any branching.

You can find the complete series here:

A link to download the Unity project used in this series is also provided at the end of the page.

Continue reading