Hello,
I am working on a basic tank game. This is my very first game without a tutorial. I got the tank to move with the left and right arrow keys, and the turret to move with the up and down arrow keys. But I can not get the bullets to shoot out the end of the turret. No matter which direction the turret is facing the bullet always shots to the right. Could someone take a look at it please? Thanks a lot.
tanks5.mfa <-- Click to open/download file
Their are under 20 events so far.
You are changing the angle of the turret but when you use the built in "launch an object" thats going to take the direction of an object.
What you want to do here is completely possible ... I just would have to think a bit on how I would do this sort of thing and I am busy tonight.
Someone else might have a solution readily at hand. Some of the 360 degree shooting examples would be what I would use as research material.
A simple 360 movement is what you want here (the built-in movements tend to be too buggy for most things).
http://sdrv.ms/YdIJBW
You'll see a few variables like "XPosition", "XVelocity", etc - those are just normal alterable values that I've renamed.
Also, you'll notice that the Y-related values are often negated (eg. 0-Sin..., -1*YVelocity..., etc) - that's because the Y axis in MMF2 (and computers in general) is inverted, so that 0,0 is in the top left corner.
A couple of other things:
* Angles and directions both start with 0 pointing to the right. For that reason, it generally makes it easier if you draw things like gun barrels so that they are pointing to the right (you'll see I had to add "+90" in a few places to make the maths work - it would have been easier just to rotate the sprite image 90 degrees in the animation editor).
* Under the bullet object's properties, there's an option called "create at start". It's good to untick that for things like bullets, because you don't want them to be created until the player shoots.
Originally Posted by MuddyMole
Thanks a lot. The math is really confusing to me. But at least it works now. I don't see a "create at start" option for the bullet. I just see "visible at start". Which un-ticking makes the bullet invisible, and that would require another action to make it visible when it is shoot. Can't I just leave it outside of the play area?
Thanks again
The 'Create At Start' option should be under the active's Runtime Option, click on the Whitebox with the red arrow inside in the object's properties. If you don't have this tab then the object is a backdrop and not an active...?!
I have the tab, but that is not an option under it. This screenshot shows all available options under that tab:
runtime options.png
Maybe it is because I am using an older version of MMF2 (r253 I think). The demo has not been updated to r256.
As a work-around, you could make it so that, at the start of the frame, you destroy the bullet object.
Okay. Thanks. But is it even necessary to do that?
It's an issue with the demo right now. The option should be in the demo, but, for some reason, it isn't. So, for now, you will have to use the work-around.
I mean why is it necessary to destroy them. They are not affecting anything just sitting there outside of the play area.
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