unit UGame;

{$mode objfpc}{$H+}

interface

uses
  Classes, sysutils, BGRAGraphics, BGRABitmap, BGRABitmapTypes,
  BGRAOpenGL, Controls;

const
  FrameDurationMs = 15;

type
  TTux = class;

  { TGameContext }

  TGameContext = class
  protected
    TexturesLoaded: boolean;
    LeftKey,RightKey,UpKey: boolean;
    texWalking,texGround: IBGLTexture;
    tux,smallTux: TTux;
    elapsedMs: single;
    sun: IBGLTexture;
    font, bubbleFont: IBGLRenderedFont;
    CenterOnSmallTux: boolean;
    infoTextAnimTime: single;
    procedure AddGround(x,y,w: single);
    function FindGround(x: single; var y: single): boolean;

  public
    FPS: integer;
    constructor Create(ACenterOnSmallTux: boolean);
    destructor Destroy; override;

    procedure LoadTextures({%H-}ctx: TBGLContext);
    procedure UnloadTextures({%H-}ctx: TBGLContext);
    procedure Render(ctx: TBGLContext);
    procedure Elapse(ctx: TBGLContext; ms: single);

    procedure MouseDown({%H-}Button: TMouseButton; {%H-}X,{%H-}Y: integer);
    procedure MouseMove({%H-}X,{%H-}Y: integer);
    procedure MouseUp({%H-}Button: TMouseButton);
    procedure KeyDown(var Key: Word; {%H-}Shift: TShiftState);
    procedure KeyUp(var Key: Word; {%H-}Shift: TShiftState);
  end;

  { TTextBubble }

  TTextBubble = class
  protected
    FText: string;
    FFont: IBGLFont;
  public
    constructor Create(AText: string; AFont: IBGLFont);
    procedure Draw(AXCenter, AYBottom: single);
  end;

  { TTux }

  TTux = class(TBGLSprite)
    Speed: TPointF;
    LookingLeft: boolean;
    Context: TGameContext;
    Autoplay: boolean;
    Parent: TTux;
    OnTheGround: boolean;
    Bubble,BubbleTooFar: TTextBubble;
    BubbleTime: integer;
    ShowBubbleTooFar: boolean;
    goRight,goLeft,goUp: boolean;
    waiting: integer;
    JumpStrength: single;
    procedure OnInit; override;
    procedure OnDraw; override;
    procedure OnTimer; override;
    constructor Create(ATexture: IBGLTexture; AContext: TGameContext);
    destructor Destroy; override;
  end;

  { TSmallTux }

  TSmallTux = class(TTux)
    procedure OnInit; override;
    procedure OnTimer; override;
  end;

  { TGround }

  TGround = class(TBGLSprite)
    constructor Create(ATexture: IBGLTexture; AX,AY: Single; AFrame: integer);
    procedure OnInit; override;
  end;

var
  ResourceDir : string;

implementation

uses LCLType;

{ TTextBubble }

constructor TTextBubble.Create(AText: string; AFont: IBGLFont);
begin
  FText := AText;
  FFont := AFont;
end;

procedure TTextBubble.Draw(AXCenter, AYBottom: single);
const horizMargin = 6; vertMargin = 4;
var tw,x,y,tx,ty: integer;
begin
  tw := round(FFont.TextWidth(FText));
  tx := tw+horizMargin*2;
  ty := round(FFont.TextHeight(FText))+2*vertMargin;
  x := round(AXCenter)-tx div 2;
  y := round(AYBottom)-ty;
  BGLCanvas.RoundRect(x,y,x+tx,y+ty,12,12,BGRABlack, BGRA(255,255,250));
  FFont.SetGradientColors(CSSBlack,CSSBlack,CSSDodgerBlue,CSSDodgerBlue);
  FFont.TextOut(x+horizMargin,y+vertMargin,FText, taLeftJustify, tlTop, BGRABlack);
  FFont.GradientColors := false;
end;

{ TSmallTux }

procedure TSmallTux.OnInit;
begin
  inherited OnInit;
  Autoplay:= true;
  H := H*0.75;
  W := W*0.75;
  LookingLeft := true;
  Bubble := TTextBubble.Create('Where are my parents?',Context.bubbleFont);
  BubbleTooFar := TTextBubble.Create('Please stay close to me!',Context.bubbleFont);
  //JumpStrength := 4;
end;

procedure TSmallTux.OnTimer;
begin
  inherited OnTimer;
  if Parent = nil then
  begin
    if sqr(X-Context.tux.X)+sqr(Y-Context.tux.Y) < sqr(50) then
    begin
      Parent := Context.tux;
      FreeAndNil(Bubble);
      Bubble := TTextBubble.Create('Hey my parent!',Context.bubbleFont);
      BubbleTime := 400;
    end;
  end;
end;

{ TGameContext }

constructor TGameContext.Create(ACenterOnSmallTux: boolean);
begin
  LeftKey := false;
  RightKey := false;
  UpKey := false;
  TexturesLoaded:= false;
  CenterOnSmallTux:= ACenterOnSmallTux;
  infoTextAnimTime := 0;
end;

destructor TGameContext.Destroy;
begin
  inherited Destroy;
end;

procedure TGameContext.LoadTextures({%H-}ctx: TBGLContext);
var sunBmp: TBGLBitmap;
begin
  if TexturesLoaded then exit;
  Randomize;
  texWalking := BGLTexture(ResourceDir+'tux_walking.png');
  texWalking.SetFrameSize(64,64);

  texGround := BGLTexture(ResourceDir+'ground.png');
  texGround.SetFrameSize(32,32);

  font := BGLFont('Arial', 20, CSSLightYellow,CSSBlack, [fsBold]);
  bubbleFont := BGLFont('Arial', 16);
  bubbleFont.HorizontalAlign := taCenter;
  bubbleFont.Justify:= true;
  bubbleFont.Padding := RectF(10,10,10,10);

  AddGround(32,128,200);
  AddGround(400,128,200);
  AddGround(200,250,200);
  AddGround(-32,250,150);
  AddGround(400,380,200);
  AddGround(300,500,150);
  AddGround(-32,600-32,800+64);

  tux := TTux.Create(texWalking,self);
  tux.Location := PointF(128,128);

  smallTux := TSmallTux.Create(texWalking,self);
  smallTux.Location := PointF(450,128);

  sunBmp := TBGLBitmap.Create(100,100);
  sunBmp.FillEllipseLinearColorAntialias(50,50,49,49,BGRA(255,255,random(100)),BGRA(255,random(200),0));
  sun := sunBmp.MakeTextureAndFree;
  TBGLSprite.Create(sun,-2).Location := PointF(random(200),0);

  TexturesLoaded:= true;
end;

procedure TGameContext.Render(ctx: TBGLContext);
const infoText = 'Welcome to this demo showing how to use BGRABitmap with OpenGL';
var ofsX,ofsY,h: single;
  r:TRectF;
  alpha: byte;
begin
  ctx.Canvas.FillRectLinearColor(Rect(0,0,ctx.Width,ctx.Height),
       CSSSkyBlue,CSSSkyBlue,MergeBGRA(CSSSkyBlue,CSSBlue),MergeBGRA(CSSSkyBlue,CSSBlue));

  if CenterOnSmallTux then
  begin
    ofsX := smallTux.X;
    ofsY := smallTux.Y;
  end else
  begin
    ofsX := tux.X;
    ofsY := tux.Y;
  end;
  ofsX -= ctx.Width div 2;
  ofsY -= ctx.Height div 2;
  if ofsX > 800-ctx.Width then ofsX := 800-ctx.Width;
  if ofsY > 600-ctx.Height then ofsY := 600-ctx.Height;
  if ofsX < 0 then ofsX := 0;
  if ofsY < 0 then ofsY := 0;

  ctx.Canvas.Translate(-ofsX,-ofsY);
  ctx.Sprites.OnDraw;
  ctx.Canvas.Translate(ofsX,ofsY);

  if infoTextAnimTime <= 500 then
    alpha := round(infoTextAnimTime*255/500)
  else if infoTextAnimTime <= 3500 then
    alpha := 255
  else if infoTextAnimTime <= 4000 then
    alpha := round((4000-infoTextAnimTime)*255/500)
  else
    alpha := 0;

  if alpha <> 0 then
  begin
    h := bubbleFont.TextHeight(infoText, 300)+bubbleFont.Padding.Top+bubbleFont.Padding.Bottom+4;
    if infoTextAnimTime <= 500 then
      h := h*infoTextAnimTime/500;
    r.Left := ctx.Width/2-150;
    r.Right := r.Left + 300;
    r.Top := ctx.Height/2-h/2;
    r.Bottom := r.Top + h;
    ctx.Canvas.FillRect(r, BGRA(0,0,0,alpha div 2));
    bubbleFont.Clipped:= true;
    bubbleFont.TextRect(r, infoText, BGRA(255,255,255,alpha));
    bubbleFont.Clipped:= false;
  end;

  if FPS <> 0 then
     font.TextOut(ctx.Width-5,0,inttostr(FPS)+' FPS',taRightJustify);
end;

procedure TGameContext.UnloadTextures(ctx: TBGLContext);
begin
  if TexturesLoaded then
  begin
    ctx.Sprites.Clear;
    TexturesLoaded := false;
  end;
end;

procedure TGameContext.AddGround(x, y, w: single);
begin
  TGround.Create(texGround,x,y,1);
  x += 32;
  w -= 32;
  while w > 32 do
  begin
    TGround.Create(texGround,x,y,2);
    x += 32;
    w -= 32;
  end;
  TGround.Create(texGround,x,y,3);
end;

procedure TGameContext.Elapse(ctx: TBGLContext; ms: single);
begin
  infoTextAnimTime += ms;
  elapsedMs += ms;
  while elapsedMs > FrameDurationMs do
  begin
    ctx.Sprites.OnTimer;
    elapsedMs -= FrameDurationMs;
  end;
end;

function TGameContext.FindGround(x: single; var y: single): boolean;
var
  i: Integer;
  s: TBGLSprite;
  g: TGround;
begin
  for i := 0 to BGLSpriteEngine.Count-1 do
  begin
    s := BGLSpriteEngine.Sprite[i] as TBGLSprite;
    if s is TGround then
    begin
      g := TGround(s);
      if (x >= g.X-g.W/2) and (x <= g.X+g.W/2) then
      begin
        if (y >= g.Y-4) and (Y <= g.Y-4+16) then
        begin
          result := true;
          y := g.Y-4;
          exit;
        end;
      end;
    end;
  end;
  result := false;
end;

procedure TGameContext.MouseDown(Button: TMouseButton; X, Y: integer);
begin

end;

procedure TGameContext.MouseMove(X, Y: integer);
begin

end;

procedure TGameContext.MouseUp(Button: TMouseButton);
begin

end;

procedure TGameContext.KeyDown(var Key: Word; Shift: TShiftState);
begin
  If Key = VK_LEFT then begin LeftKey := true; Key := 0; end;
  If Key = VK_RIGHT then begin RightKey := true; Key := 0; end;
  If Key = VK_UP then begin UpKey := true; Key := 0; end;
end;

procedure TGameContext.KeyUp(var Key: Word; Shift: TShiftState);
begin
  If Key = VK_LEFT then begin LeftKey := false; Key := 0; end;
  If Key = VK_RIGHT then begin RightKey := false; Key := 0; end;
  If Key = VK_UP then begin UpKey := false; Key := 0; end;
end;

{ TGround }

constructor TGround.Create(ATexture: IBGLTexture; AX, AY: Single;
  AFrame: integer);
begin
  inherited Create(ATexture, -1);
  Location := PointF(AX,AY+4);
  Frame := AFrame;
end;

procedure TGround.OnInit;
begin
  HorizontalAlign := taCenter;
  VerticalAlign := tlCenter;
end;

{ TTux }

procedure TTux.OnInit;
begin
  HorizontalAlign := taCenter;
  VerticalAlign := tlBottom;
  Frame := 1;
  Speed := PointF(0,0);
  FrameLoopStart := 1;
  FrameLoopEnd := 10;
  LookingLeft:= false;
  goRight:= false;
  goLeft:= false;
  goUp := false;
  waiting := 0;
  JumpStrength:= 5;
  Parent := nil;
  Autoplay:= false;
end;

procedure TTux.OnDraw;
begin
  if lookingLeft then Texture.ToggleFlipX;
  inherited OnDraw;
  if lookingLeft then Texture.ToggleFlipX;
  if Bubble <> nil then
  begin
    if BubbleTime mod 500 > 400 then
    begin
      if ShowBubbleTooFar then
        BubbleTooFar.Draw(x,y-H)
      else
        Bubble.Draw(x,y-H);
    end;
  end;
end;

procedure TTux.OnTimer;
var curY: single;
  nearParent: boolean;
begin
  if not OnTheGround then
  begin
    //jumping
  end else
  begin
    nearParent:= false;
    if Autoplay then
    begin
      if waiting > 0 then
        dec(waiting)
      else
      begin
        goRight:= false;
        goLeft:= false;
        goUp := false;
        if Parent<> nil then
          nearParent := (abs(X-Parent.X) < 100) and (abs(Y-Parent.Y) < 150);

        ShowBubbleTooFar := (Parent <> nil) and not nearParent;
        if (Parent<> nil) and (abs(X-Parent.X) < 200) and (abs(Y-Parent.Y) < 200) then
        begin
          if BubbleTime > 500 then
          begin
            if not nearParent then
              BubbleTime := 0
            else
              BubbleTime := 500;
          end;
          if (abs(X-Parent.X) > 40) then
          begin
            waiting := random(150);
            if X > Parent.X then goLeft := true
            else goRight := true;
          end else
          if (Parent.Y < Y-40) and (Parent.Y > Y-200) then
          begin
            waiting := random(150);
            goUp := true;
            waiting := 0;
          end;
        end else
        begin
          waiting := random(300);
          case random(10) of
            0..2: goLeft:= true;
            3..5: goRight:= true;
            9: begin goUp:= true; waiting := 0; end;
          end;
        end;
      end;
      curY := Y+5;
      if goLeft and (X < 1) then
      begin
        goLeft := false;
        waiting:= 0;
      end;
      if goRight and (X > 799) then
      begin
        goRight := false;
        waiting:= 0;
      end;
      if not nearParent then
      begin
        if goLeft and not Context.FindGround(X-20,curY) then
        begin
          goLeft:= false;
          waiting:= 0;
        end;
        if goRight and not Context.FindGround(X+20,curY) then
        begin
          goRight:= false;
          waiting := 0;
        end;
      end else
      if (Parent <> nil) and (abs(X-Parent.X) < 5) then
      begin
        goLeft:= false;
        goRight:= false;
      end;
    end else
    begin
      goRight:= Context.RightKey;
      goLeft:= Context.LeftKey;
      goUp := Context.UpKey;
    end;
    if not goRight and not goLeft and not goUp then
    begin
      speed.X := speed.X*0.9;
      if abs(speed.X)<0.1 then speed.X := 0;
    end else
    begin
      //on the ground and can move
      if goRight then Speed.X += 0.1;
      if Speed.X > 1.3 then Speed.X := 1.3;
      if goLeft then Speed.X -= 0.1;
      if Speed.X < -1.3 then Speed.X := -1.3;
      if goUp then Speed.Y := -JumpStrength;

      if (Speed.X < 0) and not LookingLeft and (round(Frame) = 1) then
        lookingLeft:= true;
      if (Speed.X > 0) and LookingLeft and (round(Frame) = 1) then
        lookingLeft := false;
    end;
    if LookingLeft xor (Speed.X < 0) then
      Frame := Frame-Speed.X*0.5
    else
      Frame := Frame+Speed.X*0.5;
  end;

  Speed.Y += 0.1;
  Location := Location+Speed;
  curY := Y;
  OnTheGround:= Context.FindGround(X,curY);
  if OnTheGround then Speed.Y := 0;
  Y := curY;
  if X < 0 then X := 0;
  if X > 800 then X := 800;
  inc(BubbleTime);
end;

constructor TTux.Create(ATexture: IBGLTexture; AContext: TGameContext);
begin
  Context := AContext;
  inherited Create(ATexture, 0);
end;

destructor TTux.Destroy;
begin
  FreeAndNil(Bubble);
  FreeAndNil(BubbleTooFar);
  inherited Destroy;
end;

end.