Finds all the points between 2 coordinates.

gistfile1.js

   // find all points between 2 pooints http://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm     
        var x1 = mouseX,
            x2 = lastX,
            y1 = mouseY,
            y2 = lastY;


        var steep = (Math.abs(y2 - y1) > Math.abs(x2 - x1));
        if (steep){
            var x = x1;
            x1 = y1;
            y1 = x;

            var y = y2;
            y2 = x2;
            x2 = y;
        }
        if (x1 > x2) {
            var x = x1;
            x1 = x2;
            x2 = x;

            var y = y1;
            y1 = y2;
            y2 = y;
        }

        var dx = x2 - x1,
            dy = Math.abs(y2 - y1),
            error = 0,
            de = dy / dx,
            yStep = -1,
            y = y1;
        
        if (y1 < y2) {
            yStep = 1;
        }

        for (var x = x1; x < x2; x++) {
            var sandX = x,
                sandY = y;
            
            if (steep) {
                sandX = y;
                sandY = x;
            }
            
            error += de;
            if (error >= 0.5) {
                y += yStep;
                error -= 1.0;
            }
            if(screenData[sandX][sandY]===0){
                screenData[sandX][sandY]=1;
            }
        }