(* This program does not work anymore, because
   it uses the old sprite routines with 16x16 sprites.
   It is only included for historical reasons.
   *)
program XmasAnimation;
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;
		changed:boolean;
		frame:array [0..3] of SpritePixels;
	end;

var pic:PictData;
    filename:string;
    infile:file;
    ch:char;
    santaSprite: Sprite;
    deerSprite: Sprite;
    ohDeerSprite: Sprite;
    rudolfSprite: Sprite;
    smokeSprite: 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 * 128);
	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;
    ydelta:integer;
    oldX,oldY:integer;
begin
	ydelta := aSprite.ydelta;
	frameIndex := aSprite.curFrame;
	frameTime := aSprite.frameTime;
	frameLeft := aSprite.frameLeft;
	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;

		if frameIndex = 1 then
		begin
			ydelta := - ydelta;
			aSprite.ydelta := ydelta;
		end;
		aSprite.y := aSprite.y + ydelta;
	end;

	aSprite.frameLeft := frameLeft;

	aSprite.x := aSprite.x + aSprite.xdelta;
	if aSprite.x > 620 then aSprite.x := 0;	
end;

procedure animate;
var i:integer;
    ydelta:integer;
    frameIndex:integer;
    frameTime:integer;
    oldX,oldY:integer;
begin
	santaSprite.x := 0;
	santaSprite.y := 60;
	santaSprite.frameTime := 10;
	santaSprite.xdelta := 2;
	santaSprite.ydelta := 1;

	smokeSprite.x := 434;
	smokeSprite.y := 252;
	smokeSprite.frameTime := 20;

	deerSprite.x := 18;
	deerSprite.y := 60;
	deerSprite.frameTime := 10;
	deerSprite.xdelta := 2;
	deerSprite.ydelta := 1;

	ohDeerSprite.x := 33;
	ohDeerSprite.y := 61;
	ohDeerSprite.frameTime := 10;
	ohDeerSprite.xdelta := 2;
	ohDeerSprite.ydelta := 1;

	rudolfSprite.x := 49;
	rudolfSprite.y := 60;
	rudolfSprite.frameTime := 10;
	rudolfSprite.xdelta := 2;
	rudolfSprite.ydelta := 1;

	ydelta := 1;

	frameTime := santaSprite.frameTime;

	while not ConAvail do
	begin
		frameIndex := santaSprite.curFrame;
		oldX := santaSprite.x; oldY := santaSprite.y;
		PutSprite(oldX, oldY, santaSprite.frame[frameIndex]);
		i := i + 1;
		frameTime := frameTime - 1;
		if frameTime = 0 then
		begin
			frameTime := santaSprite.frameTime;
			santaSprite.curFrame := frameIndex + 1;
			if frameIndex >= santaSprite.frameCount
			then
				santaSprite.curFrame := 0;

			if frameIndex = 0 then ydelta := - ydelta;
			santaSprite.y := santaSprite.y + ydelta;
		end;
		santaSprite.x := santaSprite.x + 2;
		if santaSprite.x > 620 then santaSprite.x := 0;

		PutSprite(deerSprite.x, deerSprite.y,
			deerSprite.frame[deerSprite.curFrame]);

		PutSprite(ohDeerSprite.x, ohDeerSprite.y,
			ohDeerSprite.frame[ohDeerSprite.curFrame]);

		PutSprite(rudolfSprite.x, rudolfSprite.y,
			rudolfSprite.frame[rudolfSprite.curFrame]);

		PutSprite(smokeSprite.x, smokeSprite.y,
			smokeSprite.frame[smokeSprite.curFrame]);

		animateSprite(deerSprite);
		animateSprite(ohDeerSprite);
		animateSprite(rudolfSprite);
		animateSprite(smokeSprite);

		Delay(10);
		WaitVSync;

		UndrawSprite(oldX, oldY, pic.pixeldata);
		UndrawSprite(deerSprite.oldX, deerSprite.oldY, pic.pixeldata);
		UndrawSprite(ohDeerSprite.oldX, ohDeerSprite.oldY, pic.pixeldata);
		UndrawSprite(rudolfSprite.oldX, rudolfSprite.oldY, pic.pixeldata);
		UndrawSprite(smokeSprite.oldX, smokeSprite.oldY, 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, 'sprites.sprt', ModeReadOnly);
	loadSpriteFrame(santaSprite, 0, infile, 0);
	loadSpriteFrame(santaSprite, 1, infile, 1);

	loadSpriteFrame(deerSprite, 0, infile, 5);
	loadSpriteFrame(deerSprite, 1, infile, 6);
	loadSpriteFrame(deerSprite, 2, infile, 7);

	loadSpriteFrame(ohDeerSprite, 0, infile, 7);
	loadSpriteFrame(ohDeerSprite, 1, infile, 5);
	loadSpriteFrame(ohDeerSprite, 2, infile, 6);

	loadSpriteFrame(rudolfSprite, 0, infile, 3);
	loadSpriteFrame(rudolfSprite, 1, infile, 4);
	loadSpriteFrame(rudolfSprite, 2, infile, 2);
	
	loadSpriteFrame(smokeSprite, 0, infile, 8);
	loadSpriteFrame(smokeSprite, 1, infile, 9);
	loadSpriteFrame(smokeSprite, 2, infile, 10);
	loadSpriteFrame(smokeSprite, 3, infile, 11);
	
	close(infile);

	animate;
end.