Geometry2D component

Contents:

1. Supported nodes

• Rectangle2D (API reference)

• Circle2D (API reference)

Note that 2D objects are just a special case of 3D objects. You can use all the 3D nodes to render 2D graphics as well.

Since various coordinates are in 3D, for 2D graphics you usually want to set the Z coordinate to a constant, like zero. By default, 2D shapes are placed at Z = 0 (but you can adjust it, to control what is visible on top of what).

2. Example in Pascal

This is an example how to construct in Pascal a scene with Rectangle2D, LineSet, and rotate it:

{ Build 2D scene with a textured Rectangle2D and outline using LineSet,
  and rotate it. }
 
uses CastleWindow, CastleViewport, CastleScene, X3DNodes, CastleFilesUtils,
  CastleColors, CastleVectors, CastleTimeUtils, CastleSceneCore;
 
var
  LifeTime: TFloatTime;
  Scene: TCastleScene;
  Transform: TTransformNode;
 
function BuildScene: TX3DRootNode;
var
  RectShape: TShapeNode;
  RectGeometry: TRectangle2DNode;
  RectTexture: TImageTextureNode;
 
  OutlineShape: TShapeNode;
  OutlineCoords: TCoordinateNode;
  OutlineGeometry: TLineSetNode;
  Material: TMaterialNode;
begin
  Transform := TTransformNode.Create;
 
  RectGeometry := TRectangle2DNode.CreateWithShape(RectShape);
  RectGeometry.Size := Vector2(200, 200);
 
  RectTexture := TImageTextureNode.Create;
  RectTexture.SetUrl(['castle-data:/face.png']);
 
  RectShape.Appearance := TAppearanceNode.Create;
  RectShape.Appearance.Texture := RectTexture;
 
  Transform.AddChildren(RectShape);
 
  OutlineCoords := TCoordinateNode.Create;
  OutlineCoords.SetPoint([
    // Z = 1 to be on top of RectShape that has Z = 0
    Vector3(-100, -100, 1),
    Vector3( 100, -100, 1),
    Vector3( 100,  100, 1),
    Vector3(-100,  100, 1),
    Vector3(-100, -100, 1)
  ]);
 
  OutlineGeometry := TLineSetNode.CreateWithShape(OutlineShape);
  OutlineGeometry.Coord := OutlineCoords;
  OutlineGeometry.SetVertexCount([OutlineCoords.FdPoint.Count]);
 
  Material := TMaterialNode.Create;
  Material.EmissiveColor := YellowRGB;
  OutlineShape.Material := Material;
 
  Transform.AddChildren(OutlineShape);
 
  Result := TX3DRootNode.Create;
  Result.AddChildren(Transform);
end;
 
procedure WindowUpdate(Container: TUIContainer);
begin
  LifeTime := LifeTime + Container.Fps.SecondsPassed;
 
  // update rotation every frame
  Transform.Rotation := Vector4(0, 0, 1, LifeTime * 2);
 
  // Note: in this case, since you just rotate whole Scene,
  // you could also rotate it like this:
  //Scene.Rotation := Vector4(0, 0, 1, LifeTime * 2);
  // There's no need for TTransformNode in this case.
end;
 
var
  Window: TCastleWindowBase;
  Viewport: TCastleViewport;
begin
  Window := TCastleWindowBase.Create(Application);
  Window.Open;
 
  Viewport := TCastleViewport.Create(Application);
  Viewport.Setup2D;
  Viewport.FullSize := true;
  Viewport.Camera.Orthographic.Height := 1000;
  Viewport.Camera.Orthographic.Origin := Vector2(0.5, 0.5);
  Window.Controls.InsertFront(Viewport);
 
  Scene := TCastleScene.Create(Application);
  Scene.Setup2D;
  Scene.Load(BuildScene, true);
  Scene.ProcessEvents := true;
 
  Viewport.Items.Add(Scene);
 
  Window.OnUpdate := @WindowUpdate;
 
  Application.Run;
end.

// This is a complete source code that you can compile. Download it!