javascript - Running into "Maximum call stack" errors on a recursive function -
i'm making height map editor. grid of numbers can change location +/- 1. editor makes sure there can difference of 1 between of touching 8 tiles.
i'm doing recursive function. looking @ it's 8 neighbors , adjusting them needed. if adjusted, call function on 8 neighbors.
i uncaught rangeerror: maximum call stack size exceeded errors after messing around awhile , can't see coming from. i'm doing checks make sure don't try access non-exsiting grid locations...
the function this:
var movedown = function (x, y) { var updated = false; if (x-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y]) > 1) { grid[x-1][y] -= 1; updated = true; } if (x-1 < size && math.abs(grid[x][y] - grid[x+1][y]) > 1) { grid[x+1][y] -= 1; updated = true; } if (y-1 >= 0 && math.abs(grid[x][y] - grid[x][y-1]) > 1) { grid[x][y-1] -= 1; updated = true; } if (y+1 < size && math.abs(grid[x][y] - grid[x][y+1]) > 1) { grid[x][y+1] -= 1; updated = true; } if (x-1 >= 0 && y-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y-1]) > 1) { grid[x-1][y-1] -= 1; updated = true; } if (x-1 >= 0 && y+1 < size && math.abs(grid[x][y] - grid[x-1][y+1]) > 1) { grid[x-1][y+1] -= 1; updated = true; } if (x+1 < size && y-1 >= 0 && math.abs(grid[x][y] - grid[x+1][y-1]) > 1) { grid[x+1][y-1] -= 1; updated = true; } if (x+1 < size && y+1 < size && math.abs(grid[x][y] - grid[x+1][y+1]) > 1) { grid[x+1][y+1] -= 1; updated = true; } if (updated) { if (x-1 >= 0) { movedown(x-1, y); } if (x+1 < size) { movedown(x+1, y); } if (y-1 >= 0) { movedown(x, y-1); } if (y+1 < size) { movedown(x, y+1); } if (x-1 >= 0 && y-1 >= 0) { movedown(x-1, y-1); } if (x-1 >= 0 && y+1 < size) { movedown(x-1, y+1); } if (x+1 < size && y-1 >= 0) { movedown(x+1, y-1); } if (x+1 < size && y+1 < size) { movedown(x+1, y+1); } } } i have fiddle here. , looks can inline it, did too.
var size = 15 var grid; var active = {x: -1, y: -1}; var movedown = function (x, y) { var updated = false; if (x-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y]) > 1) { grid[x-1][y] -= 1; updated = true; } if (x-1 < size && math.abs(grid[x][y] - grid[x+1][y]) > 1) { grid[x+1][y] -= 1; updated = true; } if (y-1 >= 0 && math.abs(grid[x][y] - grid[x][y-1]) > 1) { grid[x][y-1] -= 1; updated = true; } if (y+1 < size && math.abs(grid[x][y] - grid[x][y+1]) > 1) { grid[x][y+1] -= 1; updated = true; } if (x-1 >= 0 && y-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y-1]) > 1) { grid[x-1][y-1] -= 1; updated = true; } if (x-1 >= 0 && y+1 < size && math.abs(grid[x][y] - grid[x-1][y+1]) > 1) { grid[x-1][y+1] -= 1; updated = true; } if (x+1 < size && y-1 >= 0 && math.abs(grid[x][y] - grid[x+1][y-1]) > 1) { grid[x+1][y-1] -= 1; updated = true; } if (x+1 < size && y+1 < size && math.abs(grid[x][y] - grid[x+1][y+1]) > 1) { grid[x+1][y+1] -= 1; updated = true; } if (updated) { if (x-1 >= 0) { movedown(x-1, y); } if (x+1 < size) { movedown(x+1, y); } if (y-1 >= 0) { movedown(x, y-1); } if (y+1 < size) { movedown(x, y+1); } if (x-1 >= 0 && y-1 >= 0) { movedown(x-1, y-1); } if (x-1 >= 0 && y+1 < size) { movedown(x-1, y+1); } if (x+1 < size && y-1 >= 0) { movedown(x+1, y-1); } if (x+1 < size && y+1 < size) { movedown(x+1, y+1); } } } var moveup = function (x, y) { var updated = false; if (x-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y]) > 1) { grid[x-1][y] += 1; updated = true; } if (x-1 < size && math.abs(grid[x][y] - grid[x+1][y]) > 1) { grid[x+1][y] += 1; updated = true; } if (y-1 >= 0 && math.abs(grid[x][y] - grid[x][y-1]) > 1) { grid[x][y-1] += 1; updated = true; } if (y+1 < size && math.abs(grid[x][y] - grid[x][y+1]) > 1) { grid[x][y+1] += 1; updated = true; } if (x-1 >= 0 && y-1 >= 0 && math.abs(grid[x][y] - grid[x-1][y-1]) > 1) { grid[x-1][y-1] += 1; updated = true; } if (x-1 >= 0 && y+1 < size && math.abs(grid[x][y] - grid[x-1][y+1]) > 1) { grid[x-1][y+1] += 1; updated = true; } if (x+1 < size && y-1 >= 0 && math.abs(grid[x][y] - grid[x+1][y-1]) > 1) { grid[x+1][y-1] += 1; updated = true; } if (x+1 < size && y+1 < size && math.abs(grid[x][y] - grid[x+1][y+1]) > 1) { grid[x+1][y+1] += 1; updated = true; } if (updated) { if (x-1 >= 0) { moveup(x-1, y); } if (x+1 < size) { moveup(x+1, y); } if (y-1 >= 0) { moveup(x, y-1); } if (y+1 < size) { moveup(x, y+1); } if (x-1 >= 0 && y-1 >= 0) { moveup(x-1, y-1); } if (x-1 >= 0 && y+1 < size) { moveup(x-1, y+1); } if (x+1 < size && y-1 >= 0) { moveup(x+1, y-1); } if (x+1 < size && y+1 < size) { moveup(x+1, y+1); } } } var init = function () { $('#board').mouseleave(function () { active.x = -1; active.y = -1; }) .mousemove(function () { active.x = -1; active.y = -1; }); $('#reset').click(function () { for(var x=0; x<size; x++) { for(var y=0; y<size; y++) { grid[x][y] = 1; } } }); $(window).keydown(function (e) { if (e.keycode === 119 || e.keycode === 87) { // w grid[active.x][active.y] += 1; moveup(active.x, active.y); } if (e.keycode === 115 || e.keycode === 83) { // s grid[active.x][active.y] -= 1; movedown(active.x, active.y); } }); grid = []; for(var x=0; x<size; x++) { grid[x] = []; var row = $('<div class="row">'); for(var y=0; y<size; y++) { grid[x][y] = 1; var cell = $('<div id="c' + x + '_' + y + '" class="cell">'); cell.data('x', x).data('y', y); cell.mousemove(function (e) { var $this = $(this); active.x = $this.data('x'); active.y = $this.data('y'); e.stoppropagation(); }); row.append(cell) } $('#board').append(row); } setinterval(function () { for(var x=0; x<size; x++) { for(var y=0; y<size; y++) { $('#c' + x + '_' + y).text(grid[x][y]); } } $('#info').text('x: ' + active.x + ' y: ' + active.y); }, 100); }; init();#board { padding: 20px; z-index: -1; } .row { height: 25px; } .cell { position: relative; display: inline-block; width: 25px; height: 25px; border: 1px solid black; text-align: center; line-height: 25px; cursor: default; }<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div id="board"></div> <div id="info"></div> <p> click on board once set focus. lets keyboard work. press <strong>s</strong> make tile go down, press <strong>w</strong> make tile go up. </p> <button id="reset">reset</button>
uncaught rangeerror: maximum call stack size exceeded error occurs when there no breakpoint recursion function. when call function function or such that. execution goes caller function goes stack , callee function gets memory execution. if there no return statement or condition before recursion, processor stack gets full , throws error message.
in case, calling movedown movedown there 1 condition true , responsible calling movedown again, or same moveup.
just debug breakpoints, wrong.
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