November 10, 2018

2D Signed Distance Field Basics

So far we mostly used polygonal meshes to represent shapes. While meshes are the easiest to render and the most versatile, there are other ways to represent shapes in 2d and 3d. One way which is used frequently is signed distance fields(or SDF). Signed distance fields allow for cheaper raytracing, smoothly letting different shapes flow into each other and saving lower resolution textures for higher quality images. We’re going to start by generating signed distance fields with functions in 2 dimensions, but later continue by generating and using them in 3d.

November 3, 2018

Flowing River

This tutorial is a case study on how to make a river via a shader. My inspiration for the look was this post by Eris https://twitter.com/Erisdraw3D/status/1056931358185086976. The Tutorial is done via a surface shader, so if you don’t know how they work it’s best to read the tutorial on surface shaders first. Transparent Surface Shader We’ll start with a transparent surface shader, for that we’ll have to add the alpha attribute to our surface shader declaration.

October 27, 2018

Improved Toon Light

Last weeks tutorial was about making a simple toon shader, but I felt like there’s still a lot to improve about it so this weeks tutorial is too. We’ll fix a thing, and add multiple steps to the lighting as well as a specular highlight. I recommend you to read the previous tutorial if you haven’t because this one is heavily based on it and expands its code. Improved shadows for multiple lights.

October 20, 2018

Single Step Toon Light

I thought about how to make a toon shader and this is the result. There are obviously many different toon styles, so this is just one possiblity of many, but even if it’s not the result you want in your game this tutorial can give you some insight in how I work and how to do stuff with shaders. The main advantage for me to use this toon shader in opposition to one that reads from ramp texures is that I can dynamically change the parameters without editing a texture first.

October 13, 2018

Baking Shaders into Textures

Calculating everything ony the fly in the shader gives us the most flexibility and is even needed for many effects, but if we don’t need the noise to be dynamic we can save it to a texture to save a lot of performance in the shader. You can bake all shader output into textures as long as it doesn’t depend on external parameters like object position or lighting. We’re going to make a little editor tool in this tutorial that can be used to bake any shader output into a texture, but I’ll work with noise functions for now, because they can be kinda expensive and are easily repeatable which allows us to use smaller textures.

October 6, 2018

Tiling Noise

So far we generated noise that goes on forever. But in some cases we want noise that repeats itself after a certain distance though, mainly when we’re baking noise into a texture. In this tutorial I’ll show you how to make noise repeat and how to use uv coordinates instead of worldspace positions for noise generation. I use the layered perlin noise and voronoi noise to show the theory behind tiling noise, but it’s possible to use those patterns with many different types of noise and other shaders as well.

September 29, 2018

Voronoi Noise

Summary Another form of noise is voronoi noise. For voronoi noise we need a bunch of points, then we generate a pattern based on which point is the closest. This specific implementation of voronoi noise will work based on cells just like most of the previous noise types we explored, this makes it relatively cheap and easy to repeat. To understand this tutorial I recommend you to have at least understood the basics of shaders in unity and how to generate random values in shaders.

September 22, 2018

Layered Noise

Layered Noise So far the noise we generated always looked either very soft, or very noisy. We can improve that by layering multiple layers of noise on top of each other. That way we get the structure of the soft noise as well as the interresting details of the more high frequency noise. Layering noise works well for value noise as well as perlin noise. While layering noise might give you patterns that are closer to what you intend to see, you also have to be careful if you worry about performance because each layer of noise you add costs you about as much performance as the first.

September 15, 2018

Perlin Noise

Perlin Noise One of other common form of noise is perlin noise. Perlin noise is one implementation of so called “gradient noise” similarly to value noise it’s based on cells so it can be easily repeated and looks smooth. What differentiates it from value noise is that instead of interpolating the values, the values are based on inclinations. Because noise in general is a pretty complex topic I recommend you to read the tutorials on white noise and value noise first.

September 8, 2018

Value Noise

Summary In the last tutorial we learned how to generate random numbers in a shader. In this one we’ll go into interpolating between random numbers to generate noise that’s smoother and gradually changes. Because we need random values to interpolate between for value noise, you should know how to generate random values in shaders before doing this tutorial. Value noise is similar to perlin noise, but different because we always interpolate between the center of the cells, perlin noise will be explained in a later tutorial.