How do I make an algorithm to zig-zag fill a grid at any size as shown in the image below?
Here is my algorithm which doesn't work. (Starting bottom left to top right corner instead):
x1 = 0;
y1 = grid_h-1;
var a = 0;
put(x1,y1);
while(!((x1 = grid_w-1) and (y1 = 0))) { //If it isn't at the top right corner
if a = 2 {
x1 += 1;
put(x1,y1);
while(x1 != grid_w-1) { //While x1 isn't at the right
//Go diagonally down
x1 += 1;
y1 += 1;
put(x1,y1);
}
y1 -= 1;
put(x1,y1);
while(y1 != 0) { //While y1 isn't at the top
//Go diagonally up
x1 -= 1;
y1 -= 1;
put(x1,y1);
}
} else if a = 1 {
while(x1 != grid_w-1) { //While x1 isn't at the right
//Go diagonally down
x1 += 1;
y1 += 1;
put(x1,y1);
}
y1 -= 1;
put(x1,y1);
while(y1 != 0) { //While y1 isn't at the top
//Go diagonally up
x1 -= 1;
y1 -= 1;
put(x1,y1);
}
x1 += 1;
put(x1,y1);
} else {
y1 -= 1;
if (y1 = 0) { a = 1; } //At top?
put(x1,y1);
while(y1 != grid_h-1) { //While y1 isn't at the bottom
//Go diagonally down
x1 += 1;
y1 += 1;
put(x1,y1);
}
x1 += 1;
put(x1,y1);
while(x1 != 0) { //While x1 isn't at the left
//Go diagonally up
x1 -= 1;
y1 -= 1;
put(x1,y1);
if (y1 = 0) { a = 2; } //At top?
}
}
}
Any simpler way to do this?