HTML and CSS Reference
In-Depth Information
When the tank is not moving, we know that we must be at the center of the current node. This
requires us to calculate how and where to move the tank to the next node and what angle it
should be rotated in.
iif
(
!
finishedPath
) {
iif
(
nextNode
.
x
>
currentNode
.
x
) {
colDelta
=
1
;
}
else
else iif
(
nextNode
.
x
<
currentNode
.
x
) {
colDelta
=-
1
}
else
else
{
colDelta
=
0
}
iif
(
nextNode
.
y
>
currentNode
.
y
) {
rowDelta
=
1
;
}
else
else iif
(
nextNode
.
y
<
currentNode
.
y
) {
rowDelta
=-
1
}
else
else
{
rowDelta
=
0
}
angleInRadians
=
Math
.
atan2
(
colDelta
,
rowDelta
);
tankMoving
=
true
true
;
}
If the
x
value of
nextNode
is greater than the
x
value of
currentNode
, the tank will need to
move to the right. If the opposite is true, the tank will move to the left. If the
x
values are
equal, there will be no movement on the x-axis.
If the
y
value of
nextNode
is greater than the
y
value of
currentNode
, the tank will need to
move down. If the opposite is true, the tank will move up. If the
y
values are equal, there will
be no movement on the y-axis.
After we have calculated the
rowDelta
and
colDelta
values, we can use those to find the
angle to rotate the tank. This is accomplished by passing them into the
Mathy.atan2
func-
tion. Notice that we swap the normal
y
,
x
(row, col) in the
atan2
function with
x
,
y
(col,row)
to match the screen coordinates for our tile map rather than the
astar.search()
returned co-
ordinates.Thisgoesbacktothetilemapbeinglaidoutinrowsofcolumnsratherthancolumns
of rows (the way the
graph.as
uses them).
Finally, if the tank has not finished its path, we need to add the
colDelta
value to
the
tankX
position and the
rowDelta
value to the
tankY
position:
tankX
+=
colDelta
;
tankY
+=
rowDelta
;
