program animate;
uses sprites;

type PictData = record
		magic,mode:integer;
		palette: array [0..15] of integer;
		pixeldata: array [0..31999] of integer;
	end;

     Sprite = record
     	x,y:integer;
     	oldX,oldY:integer;
     	xdelta,ydelta:integer;
     	curFrame:integer;
     	frameCount:integer;
     	frameTime:integer;
     	frameLeft:integer;
     	moveTime:integer;
     	moveLeft:integer;
     	changed:boolean;
     	frame:array [0..3] of SpritePixels;
    end;

var pic:PictData;
    filename:string;
    infile:file;
    ch:char;
    stickMan:Sprite;
    rocket:Sprite;
    rocket2:Sprite;
    rocket3:Sprite;

procedure WaitVSync; external;

procedure loadPalette(var pic:PictData);
var i:integer;
begin
	for i := 0 to 15 do
		setpalette(i, pic.palette[i]);
end;

procedure showPic(var pic:PictData);
begin
	PutScreen(pic.pixeldata);
end;

procedure loadSpriteFrame(var aSprite:Sprite;spriteIndex:integer;
		var sheetFile:file;sheetIndex:integer);
begin
	seek(sheetFile, 8 + sheetIndex * 512);
	read(sheetFile, aSprite.frame[spriteIndex]);
	if aSprite.frameCount <= spriteIndex then
		aSprite.frameCount := spriteIndex + 1;

	aSprite.curFrame := 0;
	writeln('loaded sprite frame ', spriteIndex, ' from ', sheetIndex);
end;

procedure animateSprite(var aSprite:Sprite);
var frameIndex:integer;
    frameTime,frameLeft:integer;
    moveTime,moveLeft:integer;
    ydelta:integer;
    oldX,oldY:integer;
begin
	ydelta := aSprite.ydelta;
	frameIndex := aSprite.curFrame;
	frameTime := aSprite.frameTime;
	frameLeft := aSprite.frameLeft;
	moveTime := aSprite.moveTime;
	moveLeft := aSprite.moveLeft;
	oldX := aSprite.x; oldY := aSprite.y;
	aSprite.oldX := oldX; aSprite.oldY := oldY;

	frameLeft := frameLeft - 1;
	if frameLeft <= 0 then
	begin
		frameIndex := frameIndex + 1;
		frameLeft := aSprite.frameTime;
		aSprite.frameLeft := frameLeft;
		aSprite.curFrame := frameIndex;
		if frameIndex >= aSprite.frameCount then
			aSprite.curFrame := 0;
	end;

	moveLeft := moveLeft -1;
	if moveLeft <= 0 then
	begin
		aSprite.x := aSprite.x + aSprite.xdelta;
		aSprite.y := aSprite.y + aSprite.ydelta;
		moveLeft := moveTime;

		if aSprite.x > 608 then aSprite.x := 0;

		if aSprite.y < 0 then
		begin
			aSprite.y := 200;
			aSprite.x := 0;
		end;
	end;
	
	aSprite.frameLeft := frameLeft;
	aSprite.moveLeft := moveLeft;
end;

procedure animLoop;
var i:integer;
    oldX,oldY:integer;
    roldX,roldY:integer;
    r2oldX,r2oldY:integer;
    r3oldX,r3oldY:integer;
begin
	stickMan.x := 0;
	stickMan.y := 322;
	stickMan.frameTime := 6;
	stickMan.frameLeft := stickMan.frameTime;
	stickMan.curFrame := 0;
	stickMan.xdelta := 2;
	stickMan.ydelta := 0;
	stickMan.moveTime := 2;
	stickman.moveLeft := stickMan.moveTime;

	rocket.x := 0;
	rocket.y := 200;
	rocket.frameTime := 5;
	rocket.frameLeft := rocket.frameTime;
	rocket.curFrame := 0;
	rocket.xdelta := 3;
	rocket.ydelta := -1;
	rocket.moveTime := 1;
	rocket.moveLeft := rocket.moveTime;

	rocket2.x := 50;
	rocket2.y := 100;
	rocket2.frameTime := 5;
	rocket2.frameLeft := rocket2.frameTime;
	rocket2.curFrame := 0;
	rocket2.xdelta := 3;
	rocket2.ydelta := -1;
	rocket2.moveTime := 1;
	rocket2.moveLeft := rocket2.moveTime;

	rocket3.x :=100;
	rocket3.y := 50;
	rocket3.frameTime := 5;
	rocket3.frameLeft := rocket3.frameTime;
	rocket3.curFrame := 0;
	rocket3.xdelta := 3;
	rocket3.ydelta := -1;
	rocket3.moveTime := 1;
	rocket3.moveLeft := rocket3.moveTime;

	while not ConAvail do
	begin
		oldX := stickMan.x;
		oldY := stickMan.y;

		roldX := rocket.x;
		roldY := rocket.y;

		r2oldX := rocket2.x;
		r2oldY := rocket2.y;

		r3oldX := rocket3.x;
		r3oldY := rocket3.y;

		PutSprite(roldX, roldY, rocket.frame[rocket.curFrame]);
		PutSprite(r2oldX, r2oldY, rocket2.frame[rocket2.curFrame]);
		PutSprite(r3oldX, r3oldY, rocket3.frame[rocket3.curFrame]);
		PutSprite(oldX, oldY, stickMan.frame[stickMan.curFrame]);

		animateSprite(rocket);
		animateSprite(rocket2);
		animateSprite(rocket3);
		animateSprite(stickMan);

		Delay(10);
		WaitVSync;

		UndrawSprite(oldX, oldY, pic.pixeldata);
		UndrawSprite(roldX, roldY, pic.pixeldata);
		UndrawSprite(r2oldX, r2oldY, pic.pixeldata);
		UndrawSprite(r3oldX, r3oldY, pic.pixeldata);
	end;
end;

begin
	filename := 'background.pict';
	open(infile, filename, ModeReadonly);
	read(infile, pic);
	close(infile);

	writeln('magic: ', pic.magic, ' mode:', pic.mode);

	loadPalette(pic);
	showPic(pic);

	open(infile, 'walking.sprt', ModeReadOnly);
	loadSpriteFrame(stickMan, 0, infile, 0);
	loadSpriteFrame(stickMan, 1, infile, 1);
	loadSpriteFrame(stickMan, 2, infile, 2);
	loadSpriteFrame(stickMan, 3, infile, 3);
	close(infile);

	open(infile, 'rocket.sprt', ModeReadOnly);
	loadSpriteFrame(rocket, 0, infile, 0);
	loadSpriteFrame(rocket, 1, infile, 1);
	loadSpriteFrame(rocket, 2, infile, 2);
	loadSpriteFrame(rocket, 3, infile, 3);
	close(infile);

	rocket2.frame := rocket.frame;
	rocket3.frame := rocket.frame;

	animLoop;
end.