Reproduction for https://github.com/castle-engine/castle-engine/issues/295

position_on_viewport_early.lpr

// -*- compile-command: "castle-engine simple-compile position_on_viewport_early.lpr && ./position_on_viewport_early" -*-
{ Reproduction for https://github.com/castle-engine/castle-engine/issues/295 . }

uses SysUtils,
  CastleWindow, CastleViewport, CastleVectors, CastleFilesUtils, CastleTransform,
  CastleLog, CastleKeysMouse, CastleScene;

var
  Viewport: TCastleViewport;

procedure TestQueryPosition(const ScreenPos: TVector2);
var
  CameraPlaneResult, RayOrigin, RayDirection, WorldPlaneResult: TVector3;
  Pos2D: TVector2;
begin
  WritelnLog('Testing on ', ScreenPos.ToString);

  Viewport.PositionToRay(ScreenPos, true, RayOrigin, RayDirection);
  WritelnLog('  PositionToRay test: %s %s', [RayOrigin.ToString, RayDirection.ToString]);

  if Viewport.PositionToCameraPlane(ScreenPos, true, 2, CameraPlaneResult) then
    WritelnLog('  PositionToCameraPlane test: %s', [CameraPlaneResult.ToString])
  else
    WritelnLog('  PositionToCameraPlane test: none');

  if Viewport.PositionToWorldPlane(ScreenPos, true, -10, WorldPlaneResult) then
    WritelnLog('  PositionToWorldPlane test: %s', [WorldPlaneResult.ToString])
  else
    WritelnLog('  PositionToWorldPlane test: none');

  Pos2D := Viewport.PositionTo2DWorld(ScreenPos, true);
  WritelnLog('  PositionTo2DWorld test: ', Pos2D.ToString);
end;

procedure Press(Container: TUIContainer; const Event: TInputPressRelease);
begin
  if Event.IsKey(keyS) then
  begin
    TestQueryPosition(Vector2(100, 100));
    TestQueryPosition(Vector2(Container.Width / 2, Container.Height / 2));
  end;
end;

var
  Window: TCastleWindowBase;
  Box: TCastleBox;
begin
  InitializeLog;

  Window := TCastleWindowBase.Create(Application);
  Window.OnPress := @Press;
  Window.Width := 300;
  Window.Height := 300;
  Window.Open;

  Viewport := TCastleViewport.Create(Application);
  Viewport.FullSize := true;

  // too early to use
  // TestQueryPosition(Vector2(100, 100));
  // TestQueryPosition(Vector2(Window.Width / 2, Window.Height / 2));

  Window.Controls.InsertFront(Viewport);

  TestQueryPosition(Vector2(100, 100));
  TestQueryPosition(Vector2(Window.Width / 2, Window.Height / 2));

  Box := TCastleBox.Create(Application);
  Viewport.Items.Add(Box);

  Application.Run;
end.