rj-action-library/Runtime/Procedural/Parametric/Tube/TubeGeometry.cs

using Godot;
using Rokojori;
using System.Collections.Generic;

namespace Rokojori
{  
 
  public class TubeGeometry
  {
    public SplineCurve curve;    
    public TubeShape[] shapes = [];

    public TubeGeometrySettings settings;

    public MeshGeometry CreateMesh()
    {
      int splineSegments = settings.fixedSplineSegmentDivisions;

      if ( TubeSegmentMode.Fixed_Division != settings.segmentMode )
      {
        splineSegments = Mathf.CeilToInt( curve.ComputeLength( curve.points.Count * 3 ) / settings.splineSegmentLength );

        if ( TubeSegmentMode.Maximum_Of_Both == settings.segmentMode )
        {
          splineSegments = Mathf.Max( splineSegments, settings.fixedSplineSegmentDivisions );
        } 
        if ( TubeSegmentMode.Minimum_Of_Both == settings.segmentMode )
        {
          splineSegments = Mathf.Min( splineSegments, settings.fixedSplineSegmentDivisions );
        }
      }

      var shapesList = new List<TubeShape>();

      if ( shapes != null && shapes.Length > 0 )
      {
        shapesList.AddRange( shapes );
        Lists.Sort( shapesList, s => s.tubePosition );

        shapesList.ForEach( s => s.ClearCache() );
        
      }

      System.Func<Vector2,Pose> uvFunction = ( Vector2 uv ) =>
        {
          var t = settings.undistortSplineSegments ? curve.ComputeTforNormalizedCurveLength( uv.Y, splineSegments ) : uv.Y;
          var index = curve.NormalizedToPointIndex( t );
          var pose = curve.PoseAt( t );        
          // RJLog.Log( "Pose at t:", t, "rot:",  pose.rotation, "pos", pose.position );
          var radiusSize = settings.radius * ( settings.radiusSizeCurve == null ? 1 : settings.radiusSizeCurve.Sample( t ) );
          var sizeX = radiusSize;
          var sizeY = radiusSize;
          var twistOffset = 0f;

          if ( settings.radiusWidthCurve != null )
          {
            sizeX *= settings.radiusWidthCurve.Sample( t );
          }

          if ( settings.radiusHeightCurve != null )
          {
            sizeY *= settings.radiusHeightCurve.Sample( t );
          }

          if ( settings.scaleRadiusByPathTransforms )
          {
            
            var splineScale = curve.SmoothStepScaleByPointIndex( index );

            if ( settings.scaleRadiusByPathTransforms )
            {
              sizeX *= splineScale.X;
              sizeY *= splineScale.Y;
            }
          }

          if ( settings.twistCurve != null )
          {
            twistOffset = Mathf.DegToRad( settings.twistCurve.Sample( t ) );
          }

          twistOffset += Mathf.DegToRad( curve.SmoothStepTwistByPointIndex( index ) * 360 );

          var twistRotation = Math3D.RotateZ( twistOffset ).Normalized();

          var scale = new Vector3( sizeX, sizeY, 0 );

          if ( shapesList.Count > 0 )
          { 
            if ( shapesList.Count == 1 )
            {
              return shapesList[ 0 ].GetPose( settings.undistortSplineSegments, splineSegments, settings.radialSegments, pose, uv, scale, twistRotation );
            }

            var lerpResult = Lists.LerpIndex( shapesList, uv.Y, s => s.tubePosition );


            var closestShape = shapesList[ lerpResult.closestIndex ];
            var secondShape  = shapesList[ lerpResult.secondIndex ];

            var closestPose = closestShape.GetPose( settings.undistortSplineSegments, splineSegments, settings.radialSegments, pose, uv, scale, twistRotation );
            var secondPose  = secondShape.GetPose( settings.undistortSplineSegments, splineSegments, settings.radialSegments, pose, uv, scale, twistRotation );

            var smoothLerp = Mathf.SmoothStep( 0f, 1f, lerpResult.lerpAmount );
            return Pose.Lerp( closestPose, secondPose, smoothLerp );
            
          }          
          else 
          {
            var angle = uv.X * 2f * Mathf.Pi * ( sizeX / sizeY );
            var circlePose = Pose.Create( Vector3.Zero, pose.rotation * Math3D.RotateZ( angle ) );
        

            circlePose.rotation = circlePose.rotation.Normalized();
            var circleStart = Vector3.Up * radiusSize * scale;

            

            var positionOnCircle = circlePose.Apply( circleStart );

            return Pose.Create( positionOnCircle + pose.position, circlePose.rotation );
          }

        };
      
      var mg = MeshGeometry.CreateFromUVFunction( uvFunction, 
        settings.radialSegments, splineSegments, settings.useFullUVQuads 
      );

      if ( TubeGeometrySettings.CapType.Flat == settings.startCapType )
      {
        var startCapMG = MeshGeometry.CreateCapUVFunction( uvFunction, settings.radialSegments, true );
        mg.Add( startCapMG );
      }

      if ( TubeGeometrySettings.CapType.Flat == settings.endCapType )
      {
        var endCapMG = MeshGeometry.CreateCapUVFunction( uvFunction, settings.radialSegments, false );
        mg.Add( endCapMG );
      }

      return mg;
    }
  }
}