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interaction [2020/05/25 11:36] – [In Viewport] admininteraction [2020/11/06 09:23] – [Input-Controller] admin
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 ====== Interaction ====== ====== Interaction ======
  
-In the following the implementation of mouse and keyboard interaction with default FMX methods will be described.+In the following the implementation of mouse, keyboard and gesture interaction with default FMX methods will be described.
  
 In case you'll need extended features, have a look at the InputController implementation: [[inputpolling|Input Polling]] In case you'll need extended features, have a look at the InputController implementation: [[inputpolling|Input Polling]]
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 To make your mouse move events available all over the viewport, you have to set HitTest of each object inside of the viewport to FALSE. To make your mouse move events available all over the viewport, you have to set HitTest of each object inside of the viewport to FALSE.
  
-Another solution is to include rotation behaviour in each object related mouse-move event.+Another solution is to include rotation behaviour in each object related mouse-move event, or to use TGorillaInputController with global mouse hooks ([[inputpolling|Input Polling]]).
 ==== On components ==== ==== On components ====
  
 +Like described above, it sometimes is necessary to detect mouse events on components itself.
 +For TControl3D instances like a TGorillaCube or TSphere, different kind of events will be called.
 +
 +  * TMouseEvent3D
 +  * TMouseMoveEvent3D
 +
 +Those callback events have a different method signature and should be defined like that:
 +
 +<file pascal>
 +procedure TForm1.DoOnCubeMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single;
 +  RayPos, RayDir: TVector3D);
 +begin
 +  FIsMoving  := true;
 +  FLastPoint := PointF(X, Y);
 +end;
 +
 +procedure TForm1.DoOnCubeMouseUp(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Single;
 +  RayPos, RayDir: TVector3D);
 +begin
 +  FIsMoving := false;
 +end;
 +
 +procedure TForm1.DoOnCubeMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Single; 
 +  RayPos, RayDir: TVector3D);
 +var LDiff : TPointF;
 +begin
 +  if FIsMoving then
 +  begin
 +    if (ssLeft in AShiftState) then
 + begin
 +      LDiff := PointF(X, Y) - FLastPoint;
 +      Dummy1.RotationAngle.Y := Dummy1.RotationAngle.Y + LDiff.X;
 + end;
 +
 +    FLastPoint := PointF(X, Y);
 +  end;
 +end;
 +</file>
 ==== HitTest Property ==== ==== HitTest Property ====
  
 +The HitTest property is a very important value for user interaction and for performance. Because Firemonkey checks all controls on the form each time the mouse moves, many operations are caused. Especially ray cast operations on 3D objects are very costly!
 +
 +So our intention should be, to reduce those operations to a minimum. Any object that is not important for user interaction or ray-casting, should be disabled for intersection tests.
 +
 +<file pascal>
 +GorillaCube1.HitTest := false;
 +</file>
 +
 +But remember, if you disable intersection tests, no mouse events on that object will be called anymore!
 +
 +==== Bounding-Volume-History ====
 +
 +Gorilla3D offers an optimization for fast raycast intersection tests. This optimization is only available for derived classes of TGorillaMesh with a valid "Def" (TMeshDef) property.
 +Take a further read for Bounding volume hierarchy at: [[https://en.wikipedia.org/wiki/Bounding_volume_hierarchy|https://en.wikipedia.org/wiki/Bounding_volume_hierarchy]]
 +
 +<file pascal>
 +procedure TForm1.FormCreate(Sender: TObject); 
 +var LMeshDef : TMeshDef;
 +begin
 +  [...]
 +  // setup bounding volume hierarchy
 +  LMeshDef := GorillaMesh1.Def as TMeshDef;
 +  LMeshDef.AcquireBVH();
 +end;
 +</file>
 +
 +To destroy a bounding volume hierarchy again, we have to call ReleasBVH().
 +<file pascal>
 +var LMeshDef : TMeshDef;
 +begin
 +  // destroy bounding volume hierarchy
 +  LMeshDef := GorillaMesh1.Def as TMeshDef;
 +  LMeshDef.ReleaseBVH();
 +end;
 +</file>
 +
 +Because setting up a bounding volume hierarchy causes some overhead data you should keep in mind to use this optimization only where it's useful. 
 ===== Keyboard Interaction ===== ===== Keyboard Interaction =====
  
 +In case you'll need keyboard interaction, best performance will be reached when key events are declared in the form itself.
 +In the following example we setup a physics demo with a sphere. When cursor keys are down, an impulse will be applied to the sphere rigid body, which moves the object in space.
 +
 +<file pascal>
 +uses
 +  [...],
 +  Gorilla.Sphere, Gorilla.Physics;
 +  
 +type
 +TForm1 = class(TForm)
 +  GorillaSphere1: TGorillaSphere;
 +  GorillaPhysicsSystem1: TGorillaPhysicsSystem;
 +    
 +  procedure FormKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char;
 +    Shift: TShiftState);
 +  
 +  [...]
 +end;
 +
 +[...]
 +  
 +procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; var KeyChar: Char;
 +  Shift: TShiftState);
 +var LImpulse : TPoint3D;
 +    LBody : TQ3Body;
 +begin
 +  if (Key = vkLEFT) then
 +    LImpulse := TPoint3D.Create(-1, 0, 0)
 +  else if (Key = vkRIGHT) then
 +    LImpulse := TPoint3D.Create(1, 0, 0)
 +  else if (Key = vkUP) then
 +    LImpulse := TPoint3D.Create(0, 0, 1)
 +  else if (Key = vkDOWN) then
 +    LImpulse := TPoint3D.Create(0, 0, -1);
 +
 +  // apply impulse on sphere
 +  GorillaPhysicsSystem1.RemoteBodyImpulse(GorillaSphere1, LImpulse);
 +end;
 +</file>
 +
 +The usage of form key events is very rudimentary and may reach its limits very fast.
 +
 +===== Gesture Interaction =====
 +
 +Gesture handling is supported for Gorilla3D viewport. To allow gesture management you will need a TGestureManager component on your form and you have to link it to the TGorillaViewport component.
 +
 +In the example below it is described, how to rotate and zoom a model. Therefor we use the interactive gestures: ZOOM and PAN.
 +In the //OnGesture// event of our GorillaViewport1 we setup a callback procedure to handle gesture input. Simple check for the supplied interactive gesture event: //igiZoom// or //igiPan// and execute the very simple //DoZoom// and //DoRotate// sub-routines.
 +
 +<file pascal>
 +type
 +  TForm1 = class(TForm)
 +    GorillaViewport1: TGorillaViewport;
 +    GestureManager1: TGestureManager;
 +    GorillaModel1: TGorillaModel;
 +    
 +    procedure GorillaViewport1Gesture(Sender: TObject;
 +      const EventInfo: TGestureEventInfo; var Handled: Boolean);
 +      
 +    protected
 +      FLastPos : TPointF;
 +      
 +    [...]
 +  end;
 +  
 +procedure TForm1.FormCreate(Sender : TObject);
 +begin
 +  GorillaViewport1.Touch.GestureManager := GestureManager1;
 +  GorillaViewport1.Touch.InteractiveGestures := [Zoom, Pan];
 +  GorillaViewport1.OnGesture := GorillaViewport1Gesture;
 +  [...]
 +end;
 +
 +procedure TForm1.GorillaViewport1Gesture(Sender: TObject;
 +  const EventInfo: TGestureEventInfo; var Handled: Boolean);
 +
 +  procedure DoZoom();
 +  var LScale : Single;
 +  begin
 +    if not (TInteractiveGestureFlag.gfBegin in EventInfo.Flags)
 +    and not (TInteractiveGestureFlag.gfEnd in EventInfo.Flags) then
 +    begin
 +      LScale := EventInfo.Distance / 100;
 +      GorillaModel1.Scale.Point := Point3D(LScale, LScale, LScale);
 +    end;
 +  end;
 +
 +  procedure DoRotate();
 +  var LDist : Single;
 +      LDiff,
 +      LNew,
 +      LPos  : TPointF;
 +  begin
 +    LNew := EventInfo.Location;
 +
 +    if not Assigned(GorillaModel1) then
 +    begin
 +      FLastPos := LNew;
 +      Exit;
 +    end;
 +
 +    if not (TInteractiveGestureFlag.gfBegin in EventInfo.Flags)
 +    and not (TInteractiveGestureFlag.gfEnd in EventInfo.Flags) then
 +    begin
 +      LPos := EventInfo.Location;
 +      LDiff := FLastPos - LPos;
 +
 +      LDist := LDiff.X / 5;
 +
 +      GorillaModel1.RotationAngle.Y := GorillaModel1.RotationAngle.Y + LDist;
 +    end;
 +
 +    FLastPos := LNew;
 +  end;
 +
 +begin
 +  // just a dirty and quick solution for gesture handling
 +  case EventInfo.GestureID of
 +    igiZoom :
 +      begin
 +        // zoom
 +        DoZoom();
 +        Handled := true;
 +      end;
 +
 +    igiPan :
 +      begin
 +        // rotate model
 +        DoRotate();
 +        Handled := true;
 +      end;
 +
 +    else
 +      begin
 +        Handled := false;
 +      end;
 +  end;
 +end;
 +</file>
 +===== GamePad Interaction =====
 +
 +Interacting with gamepads in Firemonkey is not possible out of the box. But of course you can build your own component.
 +
 +But before bothering, have a look at the TGorillaInputController of Gorilla3D, which already provides support for gamepads. It is very easy to use and allows combinations of mouse and keyboard input.
 +
 +Read more: [[inputpolling|Input Polling]]
 +===== Input-Controller =====
 +
 +Because most games and applications use mouse and keyboard in combination, it can be become complex very fast. It's also a bad idea to handle inputs in mainthread an reduce rendering performance by that.
 +Besides that, it's very often a hassle to manage lots of hotkeys or input-sequences. Take a further read on the TGorillaInputController to learn how you could handle those things much easier.
 +
 +Read more: [[inputpolling|Input Polling]]
 +
 +Next step: [[charactercontrolling|CharacterControlling]]
Except where otherwise noted, content on this wiki is licensed under the following license: Public Domain


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