Part2?following previous article

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????In last article,we use 'raw' code to do sdf box style quadratic bezier spline.I want to wrap things up,pack code into a function,so the user-side code would be clean.

????However, HLSL?is not a quite "High Level" Shader Language to me, because it doesn't?support dynamic length array?as function parameter(Because we want an arbitrary number of keys points in the spline).Although one can use 'StructuredBuffer' as a dynamic length array, but use?StructuredBuffer means unnecessary transfer of data from CPU to GPU if our spline data is static.

????In the end, I broke down the function logic to 'atom' function, and use a for loop to do it from head to tail, finally wrap them all in a 'MACRO Function'.It feels like a little 'functional programming'? in there to me.Here is the MACRO Function code:

You can see from the following image, how I defined the projection info, and updated the info to get the min dis along the whole body.

The idea of 'Projection Info' is designed to?

1. hold extra information.

2. allow the latency?of calculating SDF.(like I do with the spline head and tail)

e.g.，the head and tail of spline's SDF is not calculated here:

With the design of 'Projection Info' and the structure of SDFSpline function below, we can easliy change the style of the body,head,tail:

And you can see it's not?coupling with quadBezier,you can easliy provide any type of spline's head/body/tail info in this function, and the the boxed style 3D SDF of it.

End

????Finally,the user-code is very clean and can be changed easily:

Acutally, since the user-end code is very neat, I can do some 'Automatic Generation Of?SDF HLSL Code' work, to transform an editor scene to a full SDF-Rendered scene, which is? very exciting to me.