Changeset 93 for trunk/UTrack.pas

Timestamp:

Sep 26, 2022, 10:39:03 PM (20 months ago)

Author:

chronos

Message:

• Added: Support for train carriages.
• Added: City support implementation preparation.

File:

• trunk/UTrack.pas (modified) (3 diffs)

trunk/UTrack.pas

@@ -4 +4 @@
 
 uses
-  Classes, SysUtils, Math, Generics.Collections;
+  Classes, SysUtils, Math, Generics.Collections, UGeometric;
 
 type
   TTrack = class;
+  TTrackPoint = class;
   TTrackPoints = class;
   TTrackLink = class;
   TTrackLinks = class;
+
+  { TTrackPosition }
+
+  TTrackPosition = record
+    BaseTrackPoint: TTrackPoint;
+    RelPos: Double;
+    function GetVector: TVector;
+    procedure Move(Distance: Double);
+  end;
 
   { TTrackPoint }
@@ -93 +103 @@
 implementation
 
-uses
-  UGeometric;
-
 resourcestring
   SAlreadyConnectedTrackPoint = 'Trying to connect already connected track point';
   SAlreadyDisconnectedTrackPoint = 'Trying to disconnect not connected track point';
   STrackPointNotFound = 'Track point %d not found';
+
+{ TTrackPosition }
+
+function TTrackPosition.GetVector: TVector;
+var
+  D: Integer;
+  UpPoint: TTrackPoint;
+begin
+  Result.Position := Point(0, 0);
+  if Assigned(BaseTrackPoint) then
+  with BaseTrackPoint do begin
+    UpPoint := BaseTrackPoint.GetNeighUp;
+    if Assigned(UpPoint) then begin
+      D := Distance(UpPoint.Position, Position);
+      if D > 0 then begin
+        Result.Direction := SubPoint(UpPoint.Position, Position);
+        Result.Position := Point(Trunc(Position.X + Result.Direction.X * RelPos / D),
+          Trunc(Position.Y + Result.Direction.Y * RelPos / D));
+      end;
+    end;
+  end;
+end;
+
+procedure TTrackPosition.Move(Distance: Double);
+var
+  Direction: Integer;
+begin
+  Direction := Sign(Distance);
+  Distance := Abs(Distance);
+  while Distance > 0 do begin
+    if Direction > 0 then begin
+      if RelPos + Distance < BaseTrackPoint.GetDistance then begin
+        RelPos := RelPos + Distance;
+        Distance := 0;
+      end else begin
+        if Assigned(BaseTrackPoint.GetNeighUp) then begin
+          Distance := Distance - (BaseTrackPoint.GetDistance - RelPos);
+          BaseTrackPoint := BaseTrackPoint.GetNeighUp;
+          RelPos := 0;
+        end else
+          // Reverse direction at the end of track
+          Direction := -Direction;
+      end;
+    end else
+    if Direction < 0 then begin
+      if RelPos - Distance >= 0 then begin
+        RelPos := RelPos - Distance;
+        Distance := 0;
+      end else begin
+        if Assigned(BaseTrackPoint.GetNeighDown) then begin
+          Distance := Distance - RelPos;
+          BaseTrackPoint := BaseTrackPoint.GetNeighDown;
+          RelPos := BaseTrackPoint.GetDistance;
+        end else
+        // Reverse direction at the end of track
+        Direction := -Direction;
+      end;
+    end;
+  end;
+end;
 
 { TTrackLinks }
@@ -349 +416 @@
 begin
   Index := Track.Points.IndexOf(Self);
-  Result := Distance(Track.Points[Index + 1].Position, Track.Points[Index].Position);
+  if Index + 1 < Track.Points.Count then begin
+    Result := Distance(Track.Points[Index + 1].Position, Track.Points[Index].Position);
+  end else Result := 0;
 end;