ollis66 You can't use an implicit form of equation like this in a shader. You'll need to turn it into an explicit form where y is expressed in terms of x, in other words you need to solve for y. Unfortunately, the equation of type y=sin(x+y) belongs into category of transcendental equations and cannot be solved algebraically. You could probably solve it numerically if your math skills are up to a par. Maybe Mathematica or Wolfram Alpha can help you.
But why bother when you could patch one period of a similarly shaped curve from a couple of smoothstepped segments in the shader. Or simpler yet, take a regular sine and linearly skew it.
