Rotational direction using cos and sin

NacMacFeegle

Using keyboard input I have achieved rotational and directional movement forward using the cos and sin functions as follows.

self.position.x+*cos(self.rotation)
self.position.y+*sin(self.rotation)

However if I take either one of the lines out it still works.

Can anybody help to point me in the direction to achieve both forward and backward rotational movement using the keyboard as the input device?

Many thanks

Regards

Chris

tatiang

Can you write your equation out all the way?

For example, are you doing Change Attribute self.position.x to self.position.x*cos(self.rotation)? You listed the operators +* which isn't making sense to me.

NacMacFeegle

Rule
On key down
Do
Move
Move in direction (equation goes here)
Move in direction (equation goes here)

What the +* should do is add the multiplied result.

Thanks

Socks

On key down
Do
Move
Move in direction (equation goes here)
Move in direction (equation goes here)

You have two move behaviours that both happen when you press your key ?

self.position.x+*cos(self.rotation)

Having a '+' & '*' together will give you an invalid expression.

tatiang

Can you post a screenshot of your rules? I was hoping for the actual behavior you are using rather than a general idea. The statement "Move in direction (equation goes here)" could represent a dozen different ways of setting up rules & behaviors in GameSalad. And stacking Move, Move in direction, Move in direction will have unusual results so I'm guessing that's not the order of your behaviors.

I'm not trying to be a pain... just trying to understand how you have it set up and then help you out.

NacMacFeegle

The utube link below shows 2 examples of achieving this type of motion, the second example is the one I have based the movement on and shows how the equations are used above.



Many thanks

tatiang

Okay, the video is helpful. At 0:57 you show the equations. Now... can you explain what you mean by "both forward and backward rotational movement"?

RThurman

Does the attached file help?

NacMacFeegle

I have zipped up how far I have got, what you should end up with is a square that rotates using the arrow keys left and right, moves forward using the up arrow key in the direction it is now pointing. It’s the back arrow key I can’t get working; I think the process is described as negating.

https://www.dropbox.com/s/mwf0s7eldphj73k/qk.zip

Thanks

Socks

. . . a square that rotates using the arrow keys left and right, moves forward using the up arrow key in the direction it is now pointing. . . .

@Chris0000

Try this:

http://www.mediafire.com/?44w9vhpmjbzsfym

NacMacFeegle

Fantastic Socks spot on and many thanks to the other posts.

Chris

Socks

Fantastic Socks spot on and many thanks to the other posts.

Chris

Glad it's the right thing for your needs ! There was no need for sin and cos and all that in the end, I'd always try the simple stuff first.