Initial commit for first version of project

GasTankAR/Views/TankAR/TankHighlightFactory.swift

@@ -0,0 +1,69 @@
+//
+//  TankHighlightFactory.swift
+//  GasTankAR
+//
+//  Created by Dennis Nemec on 28.08.26.
+//
+
+import RealityKit
+import UIKit
+
+/// Baut die Auswahl-Markierung um den Tank: ein (ansonsten unsichtbarer) Quader, dessen
+/// acht Ecken mit kräftig gefärbten Winkeln hervorgehoben werden – deutlich sichtbar,
+/// ohne den Tank selbst zu verdecken.
+@MainActor
+enum TankHighlightFactory {
+    /// Name der Markierungs-Entity (zum Ein-/Ausblenden bei Auswahl).
+    static let name = "TankSelectionHighlight"
+
+    private static let color = UIColor.systemTeal
+
+    /// Erzeugt die Eck-Winkel passend zur Bounding-Box (im Koordinatensystem des Containers).
+    static func makeHighlight(for bounds: BoundingBox) -> Entity {
+        let root = Entity()
+        root.name = name
+
+        let extents = bounds.extents
+        let smallestEdge = min(extents.x, min(extents.y, extents.z))
+        let armLength = max(0.05, smallestEdge * 0.3)
+        let thickness = max(0.008, smallestEdge * 0.05)
+
+        var material = UnlitMaterial(color: color)
+        material.faceCulling = .none
+
+        for x in [bounds.min.x, bounds.max.x] {
+            for y in [bounds.min.y, bounds.max.y] {
+                for z in [bounds.min.z, bounds.max.z] {
+                    let corner = SIMD3(x, y, z)
+                    // Vorzeichen: Winkel zeigt von der Ecke nach innen (zur Boxmitte).
+                    let signX: Float = (x == bounds.min.x) ? 1 : -1
+                    let signY: Float = (y == bounds.min.y) ? 1 : -1
+                    let signZ: Float = (z == bounds.min.z) ? 1 : -1
+
+                    root.addChild(beam(
+                        size: SIMD3(armLength, thickness, thickness),
+                        center: corner + SIMD3(signX * armLength / 2, 0, 0),
+                        material: material
+                    ))
+                    root.addChild(beam(
+                        size: SIMD3(thickness, armLength, thickness),
+                        center: corner + SIMD3(0, signY * armLength / 2, 0),
+                        material: material
+                    ))
+                    root.addChild(beam(
+                        size: SIMD3(thickness, thickness, armLength),
+                        center: corner + SIMD3(0, 0, signZ * armLength / 2),
+                        material: material
+                    ))
+                }
+            }
+        }
+        return root
+    }
+
+    private static func beam(size: SIMD3<Float>, center: SIMD3<Float>, material: UnlitMaterial) -> ModelEntity {
+        let beam = ModelEntity(mesh: .generateBox(size: size), materials: [material])
+        beam.position = center
+        return beam
+    }
+}