- Qt 5.5
- Qt Quick
- QML Advanced Tutorial 3 - Implementing the Game Logic
- samegame.js Example File
- Qt 5.5.1 Reference Documentation

# samegame.js Example File

tutorials/samegame/samegame3/samegame.js

    /* This script file handles the game logic */
    var maxColumn = 10;
    var maxRow = 15;
    var maxIndex = maxColumn * maxRow;
    var board = new Array(maxIndex);
    var component;

    //Index function used instead of a 2D array
    function index(column, row) {
        return column + (row * maxColumn);
    }

    function startNewGame() {
        //Calculate board size
        maxColumn = Math.floor(gameCanvas.width / gameCanvas.blockSize);
        maxRow = Math.floor(gameCanvas.height / gameCanvas.blockSize);
        maxIndex = maxRow * maxColumn;

        //Close dialogs
        dialog.hide();

        //Initialize Board
        board = new Array(maxIndex);
        gameCanvas.score = 0;
        for (var column = 0; column < maxColumn; column++) {
            for (var row = 0; row < maxRow; row++) {
                board[index(column, row)] = null;
                createBlock(column, row);
            }
        }
    }

    function createBlock(column, row) {
        if (component == null)
            component = Qt.createComponent("Block.qml");

        // Note that if Block.qml was not a local file, component.status would be
        // Loading and we should wait for the component's statusChanged() signal to
        // know when the file is downloaded and ready before calling createObject().
        if (component.status == Component.Ready) {
            var dynamicObject = component.createObject(gameCanvas);
            if (dynamicObject == null) {
                console.log("error creating block");
                console.log(component.errorString());
                return false;
            }
            dynamicObject.type = Math.floor(Math.random() * 3);
            dynamicObject.x = column * gameCanvas.blockSize;
            dynamicObject.y = row * gameCanvas.blockSize;
            dynamicObject.width = gameCanvas.blockSize;
            dynamicObject.height = gameCanvas.blockSize;
            board[index(column, row)] = dynamicObject;
        } else {
            console.log("error loading block component");
            console.log(component.errorString());
            return false;
        }
        return true;
    }

    var fillFound; //Set after a floodFill call to the number of blocks found
    var floodBoard; //Set to 1 if the floodFill reaches off that node

    function handleClick(xPos, yPos) {
        var column = Math.floor(xPos / gameCanvas.blockSize);
        var row = Math.floor(yPos / gameCanvas.blockSize);
        if (column >= maxColumn || column < 0 || row >= maxRow || row < 0)
            return;
        if (board[index(column, row)] == null)
            return;
        //If it's a valid block, remove it and all connected (does nothing if it's not connected)
        floodFill(column, row, -1);
        if (fillFound <= 0)
            return;
        gameCanvas.score += (fillFound - 1) * (fillFound - 1);
        shuffleDown();
        victoryCheck();
    }

    function floodFill(column, row, type) {
        if (board[index(column, row)] == null)
            return;
        var first = false;
        if (type == -1) {
            first = true;
            type = board[index(column, row)].type;

            //Flood fill initialization
            fillFound = 0;
            floodBoard = new Array(maxIndex);
        }
        if (column >= maxColumn || column < 0 || row >= maxRow || row < 0)
            return;
        if (floodBoard[index(column, row)] == 1 || (!first && type != board[index(column, row)].type))
            return;
        floodBoard[index(column, row)] = 1;
        floodFill(column + 1, row, type);
        floodFill(column - 1, row, type);
        floodFill(column, row + 1, type);
        floodFill(column, row - 1, type);
        if (first == true && fillFound == 0)
            return;     //Can't remove single blocks
        board[index(column, row)].opacity = 0;
        board[index(column, row)] = null;
        fillFound += 1;
    }

    function shuffleDown() {
        //Fall down
        for (var column = 0; column < maxColumn; column++) {
            var fallDist = 0;
            for (var row = maxRow - 1; row >= 0; row--) {
                if (board[index(column, row)] == null) {
                    fallDist += 1;
                } else {
                    if (fallDist > 0) {
                        var obj = board[index(column, row)];
                        obj.y += fallDist * gameCanvas.blockSize;
                        board[index(column, row + fallDist)] = obj;
                        board[index(column, row)] = null;
                    }
                }
            }
        }
        //Fall to the left
        var fallDist = 0;
        for (var column = 0; column < maxColumn; column++) {
            if (board[index(column, maxRow - 1)] == null) {
                fallDist += 1;
            } else {
                if (fallDist > 0) {
                    for (var row = 0; row < maxRow; row++) {
                        var obj = board[index(column, row)];
                        if (obj == null)
                            continue;
                        obj.x -= fallDist * gameCanvas.blockSize;
                        board[index(column - fallDist, row)] = obj;
                        board[index(column, row)] = null;
                    }
                }
            }
        }
    }

    function victoryCheck() {
        //Award bonus points if no blocks left
        var deservesBonus = true;
        for (var column = maxColumn - 1; column >= 0; column--)
            if (board[index(column, maxRow - 1)] != null)
            deservesBonus = false;
        if (deservesBonus)
            gameCanvas.score += 500;

        //Check whether game has finished
        if (deservesBonus || !(floodMoveCheck(0, maxRow - 1, -1)))
            dialog.show("Game Over. Your score is " + gameCanvas.score);
    }

    //only floods up and right, to see if it can find adjacent same-typed blocks
    function floodMoveCheck(column, row, type) {
        if (column >= maxColumn || column < 0 || row >= maxRow || row < 0)
            return false;
        if (board[index(column, row)] == null)
            return false;
        var myType = board[index(column, row)].type;
        if (type == myType)
            return true;
        return floodMoveCheck(column + 1, row, myType) || floodMoveCheck(column, row - 1, board[index(column, row)].type);
    }