[英]Javascript canvas draw rect not working, trying to make a game board
因此,我編寫了一個程序,該程序可以使用筆觸rect或繪制img來制作空白的2d游戲板。 這是(使用筆觸矩形):
window.onload = function() {
//set up the canvas items
var canvas = document.getElementById("paper");
var emptySquare = canvas.getContext("2d");
var player = canvas.getContext("2d");
var background = canvas.getContext("2d");
//An empty game board, with basic stats
var boardArray = [];
var rowNum = 7;
var colNum = 7;
//Makes the board with the empty squares
for (i = 0; i < colNum; i++) {
for (x = 0; x < rowNum; x++) {
boardArray.push([colNum*10, rowNum*10]);
}
}
//This is the png of an empty board part of an array
var emptySquareImg = new Image();
emptySquareImg.src = "border.png";
function displayBoard() {
background.fillStyle = "rgb(0, 0, 0)";
background.fillRect(0, 0, canvas.width, canvas.height);
for (x = 0; x < boardArray.length; x++) {
for (y = 0; y < x.length; y++) {
emptySquare.beginPath();
emptySquare.lineWidth = "4";
emptySquare.strokeStyle = "rgb(200, 34, 22)";
emptySquare.rect(boardArray[x], boardArray[y], 10, 10)
emptySquare.stroke();
}
}
}
displayBoard();
}
除黑色背景外,它不顯示任何其他內容。 它也不會拋出任何錯誤,這很奇怪。 感謝您的幫助,我很快就能開始制作小型棋盤游戲!
循環和正方形數組的生成存在一些問題。 在javascript中設置for循環時,請記住使用var
關鍵字。 否則,該變量將不在本地范圍內,並且您可能無法獲得期望的結果。 特別是對於x
,因為它在兩個循環中使用。
window.onload = function() {
var canvas = document.getElementById("paper");
var emptySquare = canvas.getContext("2d");
var player = canvas.getContext("2d");
var background = canvas.getContext("2d");
var boardArray = [];
var rowNum = 7;
var colNum = 7;
// probably worth defining the width and height of cells here
var width = 10;
var height = 10;
// remember to include the keyword "var"
for (var i = 0; i < rowNum; i++) {
// add a new row to boardArray
boardArray.push([]);
for (var x = 0; x < colNum; x++) {
// add your values for this square within this row
boardArray[i].push([i*width, x*height]);
}
}
//console.log(boardArray);
var emptySquareImg = new Image();
emptySquareImg.src = "border.png";
function displayBoard() {
background.fillStyle = "rgb(0, 0, 0)";
background.fillRect(0, 0, canvas.width, canvas.height);
for (var x = 0; x < boardArray.length; x++) {
// get the row here and then iterate through it
var row = boardArray[x];
for (var y = 0; y < row.length; y++) {
// now row[y] will give you your square
emptySquare.beginPath();
emptySquare.lineWidth = "4";
emptySquare.strokeStyle = "rgb(200, 34, 22)";
// use row[y][0] and row[y][1] to position the rect
emptySquare.rect(row[y][0], row[y][1], width, height);
emptySquare.stroke();
}
}
}
displayBoard();
}
這是經過調整的循環的代碼。 boardArray.push([colNum*10, rowNum*10]);
更改為boardArray.push([i*10, x*10]);
。 boardArray[x], boardArray[y]
更改為arr[0], arr[1]
。
window.onload = function() { //set up the canvas items var canvas = document.getElementById("paper"); var emptySquare = canvas.getContext("2d"); var player = canvas.getContext("2d"); var background = canvas.getContext("2d"); //An empty game board, with basic stats var boardArray = []; var rowNum = 7; var colNum = 7; //Makes the board with the empty squares for (i = 0; i < colNum; i++) { for (x = 0; x < rowNum; x++) { boardArray.push([i*10, x*10]); } } //This is the png of an empty board part of an array var emptySquareImg = new Image(); emptySquareImg.src = "border.png"; function displayBoard() { background.fillStyle = "rgb(0, 0, 0)"; background.fillRect(0, 0, canvas.width, canvas.height); for (x = 0; x < colNum; x++) { for (y = 0; y < rowNum; y++) { emptySquare.beginPath(); emptySquare.lineWidth = "4"; emptySquare.strokeStyle = "rgb(200, 34, 22)"; var arr = boardArray[y+x*colNum]; emptySquare.rect(arr[0], arr[1], 10, 10) emptySquare.stroke(); } } } displayBoard(); }
<canvas id='paper'></canvas>
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