Qt 5.7 | Qt Quick | QML Advanced Tutorial 3 - Implementing the Game Logic | samegame.js Example File

Qt 5.7.1 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);
      }