IEnumerator <object> DragTangent(SplinePoint3D point, int tangentIndex)
{
var input = SceneView.Instance.Input;
Document.Current.History.BeginTransaction();
Vector3?posCorrection = null;
try {
var spline = (Spline3D)Document.Current.Container;
var viewport = spline.Viewport;
var plane = CalcPlane(spline, point.Position + GetTangent(point, tangentIndex));
var tangentsAreEqual = (point.TangentA + point.TangentB).Length < 0.1f;
while (input.IsMousePressed())
{
Document.Current.History.RevertActiveTransaction();
Utils.ChangeCursorIfDefault(MouseCursor.Hand);
var ray = viewport.ScreenPointToRay(input.MousePosition);
var distance = ray.Intersects(plane);
if (distance.HasValue)
{
var pos = (ray.Position + ray.Direction * distance.Value) * spline.GlobalTransform.CalcInverted() - point.Position;
posCorrection = posCorrection ?? GetTangent(point, tangentIndex) - pos;
Core.Operations.SetAnimableProperty.Perform(point, GetTangentPropertyName(tangentIndex), pos + posCorrection.Value);
if (input.IsKeyPressed(Key.Shift) ^ tangentsAreEqual)
{
Core.Operations.SetAnimableProperty.Perform(point, GetTangentPropertyName(1 - tangentIndex), -(pos + posCorrection.Value));
}
}
yield return(null);
}
} finally {
Document.Current.History.EndTransaction();
}
}
void DrawSplinePoint(SplinePoint3D point, Viewport3D viewport, Matrix44 splineWorldMatrix, bool selected)
{
var color = selected ? Color4.Green : Color4.Red;
var viewportToSceneFrame = viewport.CalcTransitionToSpaceOf(SceneView.Instance.Frame);
var a = (Vector2)viewport.WorldToViewportPoint(point.Position * splineWorldMatrix) * viewportToSceneFrame;
Renderer.DrawRect(a - Vector2.One * 3, a + Vector2.One * 3, color);
for (int i = 0; i < 2; i++)
{
var t = i == 0 ? point.TangentA : point.TangentB;
var b = (Vector2)viewport.WorldToViewportPoint((point.Position + t) * splineWorldMatrix) * viewportToSceneFrame;
Renderer.DrawLine(a, b, color, 1);
Renderer.DrawRect(b - Vector2.One * 1.5f, b + Vector2.One * 1.5f, color);
}
}
Vector3 GetTangent(SplinePoint3D point, int index) => index == 0 ? point.TangentA : point.TangentB;
