shape static method

Implementation

static void shape(
  sim.Shape shape,
  vm.Matrix4 transform, {
  vm.Vector4? color,
  int segments = 16,
}) {
  vm.Vector3 at(double x, double y, double z) =>
      transform.transform3(vm.Vector3(x, y, z));

  switch (shape) {
    case sim.SphereShape(:final radius):
      for (var axis = 0; axis < 3; axis++) {
        _ring(at, radius, 0, axis, segments, color);
      }
    case sim.BoxShape(:final halfExtents):
      final e = halfExtents;
      final corners = [
        for (final sx in const [-1.0, 1.0])
          for (final sy in const [-1.0, 1.0])
            for (final sz in const [-1.0, 1.0])
              at(e.x * sx, e.y * sy, e.z * sz),
      ];
      for (final (i, j) in _boxEdges) {
        line(corners[i], corners[j], color: color);
      }
    case sim.CapsuleShape(:final radius, :final halfHeight):
      _ring(at, radius, halfHeight, 1, segments, color);
      _ring(at, radius, -halfHeight, 1, segments, color);
      _cap(at, radius, halfHeight, 1, segments, color);
      _cap(at, radius, -halfHeight, -1, segments, color);
      _sides(at, radius, halfHeight, color);
    case sim.CylinderShape(:final radius, :final halfHeight):
      _ring(at, radius, halfHeight, 1, segments, color);
      _ring(at, radius, -halfHeight, 1, segments, color);
      _sides(at, radius, halfHeight, color);
    case sim.TriMeshShape(:final vertices, :final indices):
      for (var i = 0; i + 2 < indices.length; i += 3) {
        final a = indices[i] * 3;
        final b = indices[i + 1] * 3;
        final c = indices[i + 2] * 3;
        final va = at(vertices[a], vertices[a + 1], vertices[a + 2]);
        final vb = at(vertices[b], vertices[b + 1], vertices[b + 2]);
        final vc = at(vertices[c], vertices[c + 1], vertices[c + 2]);
        line(va, vb, color: color);
        line(vb, vc, color: color);
        line(vc, va, color: color);
      }
    case sim.ConvexHullShape(:final points):
      // The hull's topology is the backend's, so mark the input points.
      for (var i = 0; i + 2 < points.length; i += 3) {
        final v = at(points[i], points[i + 1], points[i + 2]);
        for (final axis in _unitAxes) {
          line(v - axis * 0.02, v + axis * 0.02, color: color);
        }
      }
    case sim.CompoundShape(:final children):
      for (final child in children) {
        DebugDraw.shape(
          child.shape,
          transform.multiplied(child.localPose),
          color: color,
          segments: segments,
        );
      }
    case sim.HeightFieldShape():
      // TODO(debug-draw): stride the heightfield grid into a wire mesh.
      break;
  }
}