Add CutTube class

visionforge-solid/src/commonMain/kotlin/space/kscience/visionforge/solid/CutTube.kt

@@ -0,0 +1,154 @@
+package space.kscience.visionforge.solid
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import space.kscience.visionforge.MutableVisionContainer
+import space.kscience.visionforge.VisionBuilder
+import space.kscience.visionforge.setChild
+import kotlin.math.abs
+import kotlin.math.cos
+import kotlin.math.sin
+
+/**
+ * A tube section cut with two planes.
+ * The centers of the two sections are positioned
+ * along the central axis of the tube, at the top
+ * and at the bottom.
+ *
+ * The default segment number is 32.
+ */
+@Serializable
+@SerialName("solid.cutTube")
+public class CutTube(
+    public val outerRadius: Float,
+    public val innerRadius: Float,
+    public val height: Float,
+    public val phiStart: Float = 0f,
+    public val phi: Float = PI2,
+    public val nTop: Float32Vector3D,
+    public val nBottom: Float32Vector3D,
+) : SolidBase<CutTube>(), GeometrySolid {
+
+    init {
+        require(innerRadius >= 0) { "Tube inner radius must be non-negative" }
+        require(outerRadius >= 0) { "Tube outer radius must not be less than its inner radius" }
+        require(height >= 0) { "Tube height must be non-negative" }
+        //TODO implement more "subtle" section checks
+        require(abs(nTop.z) > 1e-5) { "Top section is almost vertical" }
+        require(abs(nBottom.z) > 1e-5) { "Bottom section is almost vertical" }
+        //require(phiStart >= 0)
+        require(phi in (0f..(PI2)))
+    }
+
+    override fun <T : Any> toGeometry(geometryBuilder: GeometryBuilder<T>) {
+        val segments = detail ?: 32
+        require(segments >= 4) { "The number of segments in the tube is too small" }
+        val angleStep = phi / (segments - 1)
+
+        fun section(r: Float, z: Float, n: Float32Vector3D): List<Float32Vector3D> = (0 until segments).map { i ->
+            val x = r * cos(phiStart + angleStep * i)
+            val y = r * sin(phiStart + angleStep * i)
+            Float32Vector3D(x, y, (n.z * z - n.x * x - n.y * y) / n.z)
+        }
+
+        geometryBuilder.apply {
+            //creating top and bottom sections of the tube:
+            //shapes in planes defined with (0, 0, +-z) points and normal vectors
+            //TODO check for an intersection of the sections
+            val topOuterPoints = section(outerRadius, height / 2, nTop)
+            val bottomOuterPoints = section(outerRadius, -height / 2, nBottom)
+
+
+            //outer face
+            for (it in 1 until segments) {
+                face4(bottomOuterPoints[it - 1], bottomOuterPoints[it], topOuterPoints[it], topOuterPoints[it - 1])
+            }
+            if (phi == PI2) {
+                face4(bottomOuterPoints.last(), bottomOuterPoints[0], topOuterPoints[0], topOuterPoints.last())
+            }
+
+            if (innerRadius == 0f) {
+                val zeroBottom = Float32Vector3D(0f, 0f, -height / 2)
+                val zeroTop = Float32Vector3D(0f, 0f, height / 2)
+                (1 until segments).forEach {
+                    face(bottomOuterPoints[it - 1], zeroBottom, bottomOuterPoints[it])
+                    face(topOuterPoints[it - 1], topOuterPoints[it], zeroTop)
+                }
+                if (phi == PI2) {
+                    face(bottomOuterPoints.last(), zeroBottom, bottomOuterPoints[0])
+                    face(topOuterPoints.last(), topOuterPoints[0], zeroTop)
+                } else {
+                    face4(zeroTop, zeroBottom, bottomOuterPoints[0], topOuterPoints[0])
+                    face4(zeroTop, zeroBottom, bottomOuterPoints.last(), topOuterPoints.last())
+                }
+            } else {
+                val topInnerPoints = section(innerRadius, height / 2, nTop)
+                val bottomInnerPoints = section(innerRadius, -height / 2, nBottom)
+                // inner face
+                (1 until segments).forEach {
+                    // inner surface
+                    face4(
+                        bottomInnerPoints[it],
+                        bottomInnerPoints[it - 1],
+                        topInnerPoints[it - 1],
+                        topInnerPoints[it]
+                    )
+                    //bottom cup
+                    face4(
+                        bottomInnerPoints[it - 1],
+                        bottomInnerPoints[it],
+                        bottomOuterPoints[it],
+                        bottomOuterPoints[it - 1]
+                    )
+                    //upper cup
+                    face4(
+                        topInnerPoints[it],
+                        topInnerPoints[it - 1],
+                        topOuterPoints[it - 1],
+                        topOuterPoints[it]
+                    )
+                }
+                if (phi == PI2) {
+                    face4(bottomInnerPoints[0], bottomInnerPoints.last(), topInnerPoints.last(), topInnerPoints[0])
+                    face4(
+                        bottomInnerPoints.last(),
+                        bottomInnerPoints[0],
+                        bottomOuterPoints[0],
+                        bottomOuterPoints.last()
+                    )
+                    face4(topInnerPoints[0], topInnerPoints.last(), topOuterPoints.last(), topOuterPoints[0])
+                } else {
+                    face4(bottomInnerPoints[0], bottomOuterPoints[0], topOuterPoints[0], topInnerPoints[0])
+                    face4(
+                        bottomOuterPoints.last(),
+                        bottomInnerPoints.last(),
+                        topInnerPoints.last(),
+                        topOuterPoints.last()
+                    )
+                }
+            }
+        }
+    }
+}
+
+
+@VisionBuilder
+public inline fun MutableVisionContainer<Solid>.cutTube(
+    outerRadius: Number,
+    innerRadius: Number,
+    height: Number,
+    startAngle: Number = 0f,
+    angle: Number = PI2,
+    topNormal: Float32Vector3D,
+    bottomNormal: Float32Vector3D,
+    name: String? = null,
+    block: CutTube.() -> Unit = {},
+): CutTube = CutTube(
+    outerRadius = outerRadius.toFloat(),
+    innerRadius = innerRadius.toFloat(),
+    height = height.toFloat(),
+    phiStart = startAngle.toFloat(),
+    phi = angle.toFloat(),
+    nTop = topNormal,
+    nBottom = bottomNormal
+).apply(block).also { setChild(name, it) }

visionforge-solid/src/commonMain/kotlin/space/kscience/visionforge/solid/Solids.kt

@@ -45,6 +45,7 @@ public class Solids(meta: Meta) : VisionPlugin(meta), MutableVisionContainer<Sol
             subclass(SolidLabel.serializer())
             subclass(Sphere.serializer())
             subclass(SphereLayer.serializer())
+            subclass(CutTube.serializer())
 
             subclass(AmbientLightSource.serializer())
             subclass(PointLightSource.serializer())