parse static method

VrmNodeConstraint? parse(int index, Map<String, dynamic> node, int nodeCount)

Parses the constraint on glTF node index (its nodes[index] JSON), or returns null when it has none or it is malformed.

Implementation

static VrmNodeConstraint? parse(
  int index,
  Map<String, dynamic> node,
  int nodeCount,
) {
  final ext =
      (node['extensions'] as Map<String, dynamic>?)?['VRMC_node_constraint']
          as Map<String, dynamic>?;
  final c = ext?['constraint'] as Map<String, dynamic>?;
  if (c == null) return null;
  (int, double)? common(Map<String, dynamic>? j) {
    final source = j?['source'];
    if (source is! int || source < 0 || source >= nodeCount) return null;
    if (source == index) return null;
    return (source, ((j!['weight'] as num?) ?? 1).toDouble().clamp(0, 1));
  }

  final roll = c['roll'] as Map<String, dynamic>?;
  if (common(roll) case (final source, final weight)) {
    final axis = switch (roll!['rollAxis']) {
      'X' => Vector3(1, 0, 0),
      'Y' => Vector3(0, 1, 0),
      'Z' => Vector3(0, 0, 1),
      _ => null,
    };
    if (axis == null) return null;
    return VrmRollConstraint(
      destination: index,
      source: source,
      weight: weight,
      rollAxis: axis,
    );
  }
  final aim = c['aim'] as Map<String, dynamic>?;
  if (common(aim) case (final source, final weight)) {
    final axis = switch (aim!['aimAxis']) {
      'PositiveX' => Vector3(1, 0, 0),
      'NegativeX' => Vector3(-1, 0, 0),
      'PositiveY' => Vector3(0, 1, 0),
      'NegativeY' => Vector3(0, -1, 0),
      'PositiveZ' => Vector3(0, 0, 1),
      'NegativeZ' => Vector3(0, 0, -1),
      _ => null,
    };
    if (axis == null) return null;
    return VrmAimConstraint(
      destination: index,
      source: source,
      weight: weight,
      aimAxis: axis,
    );
  }
  final rotation = c['rotation'] as Map<String, dynamic>?;
  if (common(rotation) case (final source, final weight)) {
    return VrmRotationConstraint(
      destination: index,
      source: source,
      weight: weight,
    );
  }
  return null;
}