tooll3--t3/Operators/Lib/field/generate/sdf/ChainLinkSDF.cs

using T3.Core.DataTypes.ShaderGraph;

namespace Lib.field.generate.sdf;

[Guid("27c6aa52-7b3e-4a9a-b6e5-0359f7155cee")]
internal sealed class ChainLinkSDF : Instance<ChainLinkSDF>
,IGraphNodeOp
{
    [Output(Guid = "1ac58dd8-4393-4eaa-955b-05204c18874b")]
    public readonly Slot<ShaderGraphNode> Result = new();

    public ChainLinkSDF()
    {
        ShaderNode = new ShaderGraphNode(this);
        Result.Value = ShaderNode;
        Result.UpdateAction += Update;
    }

    private void Update(EvaluationContext context)
    {
        ShaderNode.Update(context);
    }

    public ShaderGraphNode ShaderNode { get; }

    public void GetPreShaderCode(CodeAssembleContext c, int inputIndex)
    {
        c.Globals["fChainLink"]
            = """
              float fChainLink(float3 p, float le, float r1, float r2) {
                float3 q = float3( p.x, max(abs(p.y)-le,0.0), p.z );
                return length(float2(length(q.xy)-r1,q.z)) - r2;
              }
              """;

        var n = ShaderNode;
        c.AppendCall($"f{c}.w = fChainLink(p{c}.xyz - {n}Center, {n}Length, {n}Size, {n}Thickness);");
        c.AppendCall($"f{c}.xyz = p.w < 0.5 ?  p{c}.xyz : 1;"); // save local space
    }

    public void GetPostShaderCode(CodeAssembleContext c, int inputIndex)
    {
    }

    [GraphParam]
    [Input(Guid = "02d27492-30c1-46b0-abc6-e0cd5af163d8")]
    public readonly InputSlot<Vector3> Center = new();

    [GraphParam]
    [Input(Guid = "4f0942b7-24ac-49e6-a9aa-21f0812c036b")]
    public readonly InputSlot<float> Length = new();

    [GraphParam]
    [Input(Guid = "f438eea9-ff20-482b-b5ba-c59fa189837b")]
    public readonly InputSlot<float> Size = new();

    [GraphParam]
    [Input(Guid = "6ca362c6-25d6-4bee-8e6b-37c5638414df")]
    public readonly InputSlot<float> Thickness = new();
}