From 07ada7b4210d24f3b3c68d06b2fac8254516f32b Mon Sep 17 00:00:00 2001
From: Robert Kolner <robert.kolner@gmail.com>
Date: Thu, 15 Mar 2012 21:10:45 +0100
Subject: [PATCH] Simple AI.

---
 index.html        |  5 ++-
 tetris-ai.js      | 94 +++++++++++++++++++++++++++++++++++++++++++++++
 tetris-control.js | 10 ++---
 tetris.js         | 28 +++++++++++---
 4 files changed, 123 insertions(+), 14 deletions(-)
 create mode 100644 tetris-ai.js

diff --git a/index.html b/index.html
index b1d28d1..dce1ef3 100755
--- a/index.html
+++ b/index.html
@@ -4,7 +4,8 @@
 		<script src="utils.js"></script>
 		<script src="tetris-canvas.js"></script>
 		<script src="tetris.js"></script>
-		<script src="tetris-control.js"></script>
+<!--		<script src="tetris-control.js"></script>-->
+		<script src="tetris-ai.js"></script> 
 		
 		<style>
 			#tetris-board {
@@ -18,7 +19,7 @@
 	<body>
 		<div><canvas id="tetris-board" height="720" width="480" /></div>
 
-		<div>
+		<div style="display:none;">
 			<ul style>Controls:
 				<li>a,d - left/right</li>
 				<li>w - rotate</li>
diff --git a/tetris-ai.js b/tetris-ai.js
new file mode 100644
index 0000000..391f61b
--- /dev/null
+++ b/tetris-ai.js
@@ -0,0 +1,94 @@
+var ACTION_LEFT = 1;
+var ACTION_RIGHT = 2;
+var ACTION_ROTATE = 3;
+var ACTION_DROP = 4;
+
+var game;
+
+function getAllPossibleDropLocations(brickId) {
+	var dropLocations = [[game.width/2,game.height+1,0]];
+
+	// Go as far down as possible:
+	var goDown = function(x, y, rot) {
+		var counter = 0;
+		while (game.isValidBrickLoc(brickId, [x, y - counter], rot)) {
+			counter++;
+		}
+		dropLocations.push([x,y - counter+1,rot]);
+	}
+
+	// For each of the four rotations:
+	for (var i = 0; i < 4; i++) {
+		// Try to go as far left as possible:
+		var counter = 0;
+		while(game.isValidBrickLoc(brickId, [game.currentBrickLoc[0]-counter,game.currentBrickLoc[1], i], i)) {
+			goDown(game.currentBrickLoc[0]-counter, game.currentBrickLoc[1], i);
+			counter++;
+		}
+
+		// Try to go as far right as possible:
+		var counter = 0;
+		do {
+			goDown(game.currentBrickLoc[0]+counter, game.currentBrickLoc[1], i);
+			counter++;
+		} while(game.isValidBrickLoc(brickId, [game.currentBrickLoc[0]+counter,game.currentBrickLoc[1], i], i));
+	}
+
+	return dropLocations;
+}
+
+function chooseDropLocation(brickId) {
+	var dropLocations = getAllPossibleDropLocations(brickId);
+
+	/* Just find the lowest location possible: */
+	var best = 0;
+	for (var i = 0; i < dropLocations.length; i++) {
+		if (dropLocations[i][1] < dropLocations[best][1]) {
+			best = i;
+		}
+	}
+
+	return dropLocations[best];
+}
+
+function chooseAction(dropLocation) {
+	var dx = dropLocation[0] - game.currentBrickLoc[0];
+	var dy = dropLocation[1] - game.currentBrickLoc[1];
+	var dr = (dropLocation[2] - game.currentBrickRot + 4) % 4;
+
+	if (dr != 0) return [ACTION_ROTATE, dr];
+	if (dx <  0) return [ACTION_LEFT, -dx];
+	if (dx >  0) return [ACTION_RIGHT, dx];
+	return [ACTION_DROP, -dy];
+}
+
+function doAction(action) {
+	if (action[1] == 0) {
+		return;
+	}
+
+	if (action[0] == ACTION_LEFT) {
+		game.moveCurrentBrickHorizontally(-1);
+	} else if (action[0] == ACTION_RIGHT) {
+		game.moveCurrentBrickHorizontally(1);
+	} else if (action[0] == ACTION_ROTATE) {
+		game.rotateCurrentBrick();
+	} else if (action[0] == ACTION_DROP) {
+		game.hardDrop();	
+		/* do nothing. */
+	}
+}
+
+function startAI() {
+	var dropLocation = chooseDropLocation(game.currentBrickId);
+	var action = chooseAction(dropLocation);
+	doAction(action);
+
+	window.setTimeout(startAI, 100);
+}
+
+$(document).ready(function() {
+	game = new TetrisGame("tetris-board");
+	game.startGame();
+	startAI();
+});
diff --git a/tetris-control.js b/tetris-control.js
index 5877c3d..d60340f 100644
--- a/tetris-control.js
+++ b/tetris-control.js
@@ -1,15 +1,10 @@
 var game = null;
 var wasRecentlyRotated = false;
 
-function doTurn() {
+function initControls() {
 	document.onkeypress = onKeyPressed;
 	document.onkeydown = onKeyDown;
 	document.onkeyup = onKeyUp;
-	if (game.doTurn()) {
-		window.setTimeout(doTurn, 333);
-	} else {
-		alert('You lost!');
-	}
 }
 
 function onKeyDown(e) {
@@ -50,6 +45,7 @@ function onKeyUp(e) {
 }
 
 $(document).ready(function() {
+	initControls();
 	game = new TetrisGame("tetris-board");
-	doTurn();
+	game.startGame();
 });
diff --git a/tetris.js b/tetris.js
index b77f074..d2d72bf 100644
--- a/tetris.js
+++ b/tetris.js
@@ -27,6 +27,8 @@ function TetrisGame(id) {
 	/**************/
 	/* Variables: */
 	/**************/
+	this.gameIsOver = false;
+
 	this.width = 10;
 	this.height = 15;
 	this.canvas = new TetrisCanvas(id, this.width, this.height);
@@ -68,11 +70,13 @@ function TetrisGame(id) {
 	}
 	
 	this.resetCurrentBrick = function() {
-		this.currentBrickId = this.getRandomBrick();
-		this.currentBrickRot = 0;
-		this.currentBrickLoc = this.getBrickStartingLocation(this.currentBrickId);
-
-		this.redraw();
+		if (! this.gameIsOver) {
+			this.currentBrickId = this.getRandomBrick();
+			this.currentBrickRot = 0;
+			this.currentBrickLoc = this.getBrickStartingLocation(this.currentBrickId);
+	
+			this.redraw();
+		}
 	}
 	
 	this.brickShape = function(brickId, brickRot) {
@@ -176,6 +180,7 @@ function TetrisGame(id) {
 			var y = this.currentBrickLoc[1]+shape[i][1];
 
 			if (y >= this.height) {
+				this.gameIsOver = true;
 				return false;
 			}
 
@@ -254,6 +259,19 @@ function TetrisGame(id) {
 		return true;
 	}
 
+	this.loop = function(game) {
+		if (! game.doTurn()) {
+			return false;
+		}
+			
+		window.setTimeout(game.loop, 333, game);
+		
+	}
+
+	this.startGame = function() {
+		this.loop(this);
+	}
+
 	/****************/
 	/* Constructor: */
 	/****************/