Game Development Reference

In-Depth Information

3. We use
point in direcion ()
to make the sprite face left; fill in value
-90
.

4. Then we add a
repeat ()
loop that will run
500
imes.

5. This patern requires a slower horizontal speed, so we
move speed / () steps

each cycle of the loop.

The finished script will look like the following screenshot:

Now we get to the interesing part. We will use a sine wave formula to determine the

verical posiion of the sprite based on its horizontal posiion. This is why we needed to

slow down the horizontal movement. At regular speed, the movement would be way too

fast and bouncy.

1. So after moving horizontally, we use
set y to ()
. This slot will be filled with a formula

that is constructed from different parts.

2. First, we take the x posiion and place it in the let slot of the
() * ()
block. In the

right slot, we enter the value as
0.5
. The resuling number determines how

frequently the sprite completes a full wave (up-down and back to center). The

higher the number, the shorter the wave.

3. Then we take this result and muliply it by
4
(using
muliply
). This number

determines the overall speed of the wave moion. It's an opional number.

It's not necessary to complete the formula, but it gives us more control.

4. Then we use the mathemaical
sin
funcion on this result. This is what efecively

causes the wavy patern.

5. Finally, we muliply the whole by
150
(using
muliply
). This part determines the

amount by which the wave deviates from the center line. This number is literally

the maximum verical distance from the center line.