June 10, 2018

Polygon Clipping

Summary Of course everything we render so far is made of polygons, but someone asked me how to clip a polygon shape based on a list of points in a shader so I’ll explain how to do that now. I will explain how to do that with a single shader pass in a fragment shader, a different way would be to actually generate triangles based on your polygon and use stencil buffers to clip, but I won’t explain that in this tutorial.

June 2, 2018

Custom Lighting

Summary Surface shaders are wonderful and being able to use the Standard PBR model is very powerful. But we don’t always want the PBR light. Sometimes we want to change the way we treat lighting to get a different, often more cartoonish, look. Custom lighting functions allow us to do exactly that. This tutorial is about a surface shader specific feature, while the basics of lighting are the same in all shaders, you need a lot more code to archieve the same result from a non-surface shader and I won’t explain it in this tutorial.

May 26, 2018

Fresnel

Summary A common effect people use in shaders in a fresnel effect. With a fresnel you can darken, lighten or color the outline of your objects, increasing the sense of depth. For this tutorial we will make a surface shader, so if you follow it directly you should know the basics of surface shaders. You can find a explanation of them here. But you can also use a fresnel effect for unlit shaders, giving your objects some smoothness and tangibility without having to implement expensive lighting.

May 18, 2018

Checkerboard Pattern

Summary For me, one of the most interresting things to do with shaders is procedural images. To get started with that, we’re going to create a simple Checkerboard pattern. This tutorial will build on the simple shader with only properties, but as always, you can also use the technique to generate colors in more complex shaders. Stripes I will take the world position of the surface to generate the chessboard texture, that way we can later move and rotate the model around and the generated patterns will fit together.

May 11, 2018

Triplanar Mapping

Summary I made a tutorial about planar mapping previously. The biggest disadvantage of the technique is that it only works from one direction and breaks when the surface we’re drawing isn’t oriented towards the direction we’re mapping from (up in the previous example). A way to improve automatic uv generation is that we do the mapping three times from different directions and blend between those three colors. This tutorial will build upon the planar mapping shader which is a unlit shader, but you can use the technique with many shaders, including surface shaders.

May 3, 2018

Color Interpolation

Summary Often you have more than one color going into the output you want to draw to the screen. A simple way of combining two colors is to interpolate between them based on other parameters. This tutorial will build on the simple textured shader, but you can use this technique with any shader including surface shaders. Interpolate Colors The first version of this shader we’re exploring will just interpolate between two plain colors based on a value.

April 23, 2018

Planar Mapping

Summary Sometimes you don’t have texture coordinates on your object, you want to make the Textures of multiple Objects align or you have a different reason to generate your own UV coordinates… In this tutorial we’ll start with the simplest way to generate your own coordinates, planar mapping. This tutorial will build on the simple textured shader, but you can use the technique with any shader including surface shaders. Basics We start by removing the uv coordinates from the input struct as we’ll generate our own texture coordinates.

April 13, 2018

Sprite Shaders

Summary In unity the way sprites are rendered is very similar to the way 3d objects are rendered. Most of the work is done by the sprite renderer component. I’ll go a bit over what the component is doing and how we can change our shader to do some of the stuff the default sprite renderer is doing. This tutorial will build on the transparent shader we made previously so it’s best that you understand that one first.

April 6, 2018

Basic Transparency

Summary In addition to just painting color onto the screen, we can also preserve some of the color that was on the screen previously, making the object seem see-through. I’ll explain how we can archieve this effect in a basic shader without lighting. To understand how to implement transparency, I recommend you know the basics of writing shaders, in this tutorial I’ll start with the result of the tutorial for implementing textures.

March 30, 2018

Surface Shader Basics

Summary In addition to writing shaders almost from the ground up, unity also allows us to define some parameters and let unity generate the code which does the complex light calculations. Those shaders are called “surface shaders”. To understand surface shaders, it’s good to get to know basic unlit shaders first, I have a tutorial on them here. Conversion to simple Surface Shader When using surface shaders we don’t have to do a few things we have to do otherwise, because unity will generate them for us.