Multipass Shaders (& inverted Hull outlines)

So far we only ever wrote a color to the screen once per shader (or let unity generate multiple passes for us via surface shaders). But we have the possibility to draw our mesh multiple times in a single shader. A great way to use this is to draw outlines. First we draw our object as usual and then we draw it again, but we change the vertices a bit so it’s only visible around the original object, drawing a outline.

To understand this Tutorial it’s best if you understood surface shaders: https://ronja-tutorials.tumblr.com/post/172421924392/surface-shader-basics

The first version of this shader will be based on the simple unlit shader: https://ronja-tutorials.tumblr.com/post/172173911737/textures