MORE RE-ORGANIZING

spikes/flutter-scene-spike/lib/card_geometry.dart

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+import 'dart:math' as math;
+import 'dart:typed_data';
+
+import 'package:flutter_scene/scene.dart';
+import 'package:vector_math/vector_math.dart' as vm;
+
+const cardWidth = 2.8571428571;
+const cardHeight = 4.0;
+const cardThickness = 0.0181405896;
+const cardCornerRadius = 0.1269841270;
+const _cornerSegments = 12;
+
+List<vm.Vector2> _roundedPerimeter() {
+  final points = <vm.Vector2>[];
+  final halfWidth = cardWidth / 2;
+  final halfHeight = cardHeight / 2;
+  final centers = [
+    vm.Vector2(halfWidth - cardCornerRadius, halfHeight - cardCornerRadius),
+    vm.Vector2(-halfWidth + cardCornerRadius, halfHeight - cardCornerRadius),
+    vm.Vector2(-halfWidth + cardCornerRadius, -halfHeight + cardCornerRadius),
+    vm.Vector2(halfWidth - cardCornerRadius, -halfHeight + cardCornerRadius),
+  ];
+
+  for (var corner = 0; corner < centers.length; corner++) {
+    final startAngle = corner * math.pi / 2;
+    for (var step = 0; step <= _cornerSegments; step++) {
+      final angle = startAngle + step / _cornerSegments * math.pi / 2;
+      points.add(
+        centers[corner] +
+            vm.Vector2(math.cos(angle), math.sin(angle)) * cardCornerRadius,
+      );
+    }
+  }
+  return points;
+}
+
+MeshGeometry buildCardFaceGeometry({
+  required bool front,
+}) {
+  final perimeter = _roundedPerimeter();
+  final z = front ? -cardThickness / 2 : cardThickness / 2;
+  final positions = <double>[0, 0, z];
+  final normals = <double>[0, 0, front ? -1 : 1];
+  final texCoords = <double>[0.5, 0.5];
+
+  for (final point in perimeter) {
+    positions.addAll([point.x, point.y, z]);
+    normals.addAll([0, 0, front ? -1 : 1]);
+    final u = front
+        ? point.x / cardWidth + 0.5
+        : 0.5 - point.x / cardWidth;
+    texCoords.addAll([u, 0.5 - point.y / cardHeight]);
+  }
+
+  final indices = <int>[];
+  for (var index = 0; index < perimeter.length; index++) {
+    final current = index + 1;
+    final next = (index + 1) % perimeter.length + 1;
+    if (front) {
+      indices.addAll([0, next, current]);
+    } else {
+      indices.addAll([0, current, next]);
+    }
+  }
+
+  return MeshGeometry.fromArrays(
+    positions: Float32List.fromList(positions),
+    normals: Float32List.fromList(normals),
+    texCoords: Float32List.fromList(texCoords),
+    indices: indices,
+  );
+}
+
+MeshGeometry buildCardEdgeGeometry() {
+  final perimeter = _roundedPerimeter();
+  final positions = <double>[];
+  final normals = <double>[];
+  final indices = <int>[];
+
+  for (var index = 0; index < perimeter.length; index++) {
+    final current = perimeter[index];
+    final next = perimeter[(index + 1) % perimeter.length];
+    final normal = (current + next).normalized();
+    final base = positions.length ~/ 3;
+    positions.addAll([
+      current.x,
+      current.y,
+      -cardThickness / 2,
+      current.x,
+      current.y,
+      cardThickness / 2,
+      next.x,
+      next.y,
+      cardThickness / 2,
+      next.x,
+      next.y,
+      -cardThickness / 2,
+    ]);
+    for (var vertex = 0; vertex < 4; vertex++) {
+      normals.addAll([normal.x, normal.y, 0]);
+    }
+    indices.addAll([
+      base,
+      base + 2,
+      base + 1,
+      base,
+      base + 3,
+      base + 2,
+    ]);
+  }
+
+  return MeshGeometry.fromArrays(
+    positions: Float32List.fromList(positions),
+    normals: Float32List.fromList(normals),
+    indices: indices,
+  );
+}