Lab 07 - Smoke with Unity's Shader Graph

Let's continue practicing with Unity's shader graph to make a smoke shader based on this presentation by Simon Trumpler.

Introduction

You will create a Unity project and make within it a Shader Graph shader to turn a cylinder mesh into a cloud of smoke. Make sure it's the Universal Render Pipeline version so you don't need to import the shader graph package.

When you create the project, you should import at least the cylinder OBJ file provided below. You should also follow these steps to make a custom shader graph:

• Right click -> Create -> Shader Graph -> BuiltIn -> Unlit

When you open the shader graph editor, you should also make sure the shader uses transparency by going to:

• Graph Inspector -> Graph Settings -> Surface Type -> Transparent

What’s provided:

We have a few assets that you can use in the project:

• A mesh on which to use your smoke material.
• A Perlin noise generator you can use to make a tiled noise texture to sample when displacing your vertices. Check the Color option to make a texture with different values for R, G, and B so that you can displace differently along the X, Y, and Z axes. For an even smokier look, try making several different noise textures with different frequencies, and animate them at different speeds.
• A black-white gradient texture you may use to adjust the intensity of your vertex displacement and/or alter your mesh's transparency.

Lab Puzzle:

Your goal is to mimic as closely as you can the techniques described in the game dev tech talk to create a smoke cloud. Your smoke should have the following attributes:

• Displace your vertices by adding to them the mesh's surface normals that have themselves been added to a Perlin noise texture
• The Perlin noise texture should apply a positive and negative displacement; this means you'll need to use some math nodes to remap the RGB value to the range [-1, 1]
• The vertex displacement should be minimal at the bottom of the cylinder and extreme at the top of the cylinder
• The smoke should animate over time
• The fragment output of your shader should be opaque when viewed at a glancing angle and transparent when viewed head-on.
• The smoke should fade into transparency at its top

Hints

Here are the nodes we used to complete our implementation. You are free to implement the shader however you choose, but these might help you:

• Time
• Multiply
• Add
• Subtract
• Dot Product
• One Minus
• Vector 2
• Tiling and Offset
• Sample Texture 2D LOD (This kind of sampler must be used when using a texture to affect vertex position)
• Sample Texture 2D (This kind of sampler must be used when using a texture to affect fragment color)
• Normal Vector (object space)
• Position (object space)

Extra Credit:

• Make the smoke follow the motion of the cylinder's base

Submission:

• Create a pull request against this repository
• In your readme, add a GIF or video of your results!