Update for OPENRNDR segment and path generalizations

orx-shapes/src/commonMain/kotlin/blend/Path3DBlend.kt

@@ -0,0 +1,37 @@
+package org.openrndr.extra.shapes.blend
+
+import org.openrndr.extra.shapes.rectify.RectifiedContour
+import org.openrndr.extra.shapes.rectify.RectifiedPath3D
+import org.openrndr.extra.shapes.rectify.rectified
+import org.openrndr.shape.Path3D
+import org.openrndr.shape.ShapeContour
+
+/**
+ * ContourBlend holds two rectified contours with an equal amount of segments
+ */
+class Path3DBlend(val a: RectifiedPath3D, val b: RectifiedPath3D) {
+    fun mix(blendFunction: (Double) -> Double): Path3D {
+        return a.mix(b, blendFunction)
+    }
+
+    fun mix(blend: Double): Path3D {
+        return a.mix(b) { blend }
+    }
+}
+
+/**
+ * Create a [ContourBlend] for contours [a] and [b]
+ *
+ * Finding the pose that minimizes the error between [a] and [b] is not part of this function's work.
+ *
+ */
+fun Path3DBlend(a: Path3D, b: Path3D): Path3DBlend {
+    val ra = a.rectified()
+    val rb = b.rectified()
+    val sa = ra.splitForBlend(rb)
+    val sb = rb.splitForBlend(ra)
+    require(sa.path.segments.size == sb.path.segments.size) {
+        "preprocessing for contours failed to produce equal number of segments. ${sa.path.segments.size}, ${sb.path.segments.size}"
+    }
+    return Path3DBlend(sa, sb)
+}