Using a Sprite in a Canvas Project

This example demonstrates the use of inbuilt TW3Buttons to control the position and orientation of a sprite. We make use of George Wright's GroundEnemy.png from TowerOfArcher for the background image of the sprite.

The Spartacus and Zen Sky demonstrations supplied with Smart Mobile Studio show how you can use a TW3Sprite3D on a form, and they compile with Version 3.0.

If you do not see the demonstration, your school security system might have blocked it. Click here to try it on a separate page.

Smart Pascal Code

This code compiles to the functional demonstration above with Smart Mobile Studio Version 2.1.1.2435. It also compiles with Versions 2.2 Beta 5 (and 3.0 with SmartCL.Graphics.Types added to the uses clause), showing the sprite and buttons but without the buttons having any effect. We temporarily changed the code Btn.OnMouseDown := lambda Pressed := True; end; to Btn.OnMouseDown := lambda Btn.Caption := 'OK'; end;. This showed the buttons themselves to be working with Version 2.2 Beta 5 but not with Version 3.0. Inserting the line RotatingZ := True; at the start of the PaintView procedure caused the sprite to rotate with Version 3.0 but not with Version 2.2 Beta 5!

unit Unit1;

interface

uses
  System.Types, SmartCL.System, SmartCL.Components, SmartCL.Application, SmartCL.Game,
  SmartCL.GameApp, SmartCL.Graphics, SmartCL.Touch, SmartCL.Controls.Button, SmartCL.Sprite3D;

type
  TCanvasProject = class(TW3CustomGameApplication)
  private
    const SCENE_WIDTH = 300;
    const SCENE_HEIGHT = 250;
    const X_SPEED = 2;
    const Y_SPEED = 2;
    const SPRITE_SCALE_FACTOR = 0.9;
    Mob: TW3Sprite;
    Scene: TRect;
    btnLeft, btnRight, btnUp, btnDown, btnRotX, btnRotY, btnRotZ: TW3Button;
  protected
    procedure SetupGameButton(Btn: TW3Button; Capt: string;
                              W, L, T: integer; var Pressed: Boolean);
    procedure ApplicationStarting; override;
    procedure ApplicationClosing; override;
    procedure PaintView(Canvas: TW3Canvas); override;
  end;

implementation

var
  MovingLeft, MovingRight, MovingUp, MovingDown, RotatingX, RotatingY, RotatingZ: Boolean;


procedure TCanvasProject.SetupGameButton(Btn: TW3Button; Capt: string;
                                         W, L, T: integer; var Pressed: Boolean);
begin
  Pressed := False;
  Btn.Caption := Capt;
  Btn.Width := W;
  Btn.Left := L;
  Btn.Top := T;
  Btn.OnMouseDown := lambda Pressed := True; end;
  btn.OnMouseUp := lambda Pressed := False; end;
  btn.OnTouchBegin := lambda Pressed := True; end;
  btn.OnTouchEnd := lambda Pressed := False; end;
end;

procedure TCanvasProject.ApplicationStarting;
begin
  inherited;
  GameView.Delay := 5;
  Scene := TRect.CreateSized(0, 0, SCENE_WIDTH, SCENE_HEIGHT);

  Mob := TW3Sprite.Create(Document);
  Mob.Background.fromURL('res/GroundEnemy.png');
  Mob.Width := 72;
  Mob.Height := 70;
  Mob.X := 50;
  Mob.Y := 50;
  Mob.SetTransformFlags(CNT_USE_POS or CNT_USE_ROTX or CNT_USE_ROTY or
                        CNT_USE_ROTZ or CNT_USE_SCALE);

  btnLeft := TW3Button.Create(Document);
  SetupGameButton(btnLeft, '←', 40, 5, SCENE_HEIGHT + 5, MovingLeft);
  btnRight := TW3Button.Create(Document);
  SetupGameButton(btnRight, '→', 40, 55, SCENE_HEIGHT + 5, MovingRight);
  btnUp := TW3Button.Create(Document);
  SetupGameButton(btnUp, '↑', 40, 105, SCENE_HEIGHT + 5, MovingUp);
  btnDown := TW3Button.Create(Document);
  SetupGameButton(btnDown, '↓', 40, 155, SCENE_HEIGHT + 5, MovingDown);
  btnRotX := TW3Button.Create(Document);
  SetupGameButton(btnRotX, 'RotateX', 80, SCENE_WIDTH + 5, 0, RotatingX);
  btnRotY := TW3Button.Create(Document);
  SetupGameButton(btnRotY, 'RotateY', 80, SCENE_WIDTH + 5, 50, RotatingY);
  btnRotZ := TW3Button.Create(Document);
  SetupGameButton(btnRotZ, 'RotateZ', 80, SCENE_WIDTH + 5, 100, RotatingZ);
  GameView.StartSession(False);
end;

procedure TCanvasProject.ApplicationClosing;
begin
  GameView.EndSession;
  inherited;
end;

procedure TCanvasProject.PaintView(Canvas: TW3Canvas);
begin
  // Clear background of scene
  Canvas.FillStyle := 'rgb(0, 0, 99)';
  Canvas.FillRectF(Scene);
  // Move mob if button pressed and if a move would not take it outside the scene
  if MovingLeft and (Mob.X > X_SPEED) then
    Mob.MoveX(-X_SPEED)
  else if MovingRight and (Mob.X + Mob.Width + X_SPEED < SCENE_WIDTH) then
    Mob.MoveX(X_SPEED)
  else if MovingUp and (Mob.Y > Y_SPEED) then
     Mob.MoveY(-Y_SPEED)
  else if MovingDown and (Mob.Y + Mob.Height + Y_SPEED < SCENE_HEIGHT)  then
    Mob.MoveY(Y_SPEED);
  if RotatingX then
    Mob.RotateX(1);
  if RotatingY then
    Mob.RotateY(1);
  if RotatingZ then
    Mob.RotateZ(-1);
  Mob.Scale(SPRITE_SCALE_FACTOR);
  Mob.Update3D;
end;

end.