Problem with rotating actors

[Freddy]

Ive tried making a game were a cannon points to the mouse, and fires when you click. The bullet (or whatever you would call it) is created relative to the actor at 0, 0. It aslo is created to have a directional velocity moving towards were the crosshair was. The problem is, when the bullet is created, it is usually located outside the barrel. It only works properly if you point it just right. How can I get around this?

[edh]

You may need to know what angle the cannon is aiming at and then start it at a position relative to the barrel. Or you could start the bullet from a position not at 0,0 but something near the middle of the cannon actor. I don't think 0,0 is in the center of the actor.

[Freddy]

Or you could start the bullet from a position not at 0,0 but something near the middle of the cannon actor.

If I were to do this, would the bullet actor be created relative to the cannon's current frame? For example, say the bullet was created at 0, 25. If the cannon pointed left, would that effect the starting point of the bullet?

[DilloDude]

No, it wouldn't. You need to add that bit in yourself.

[Freddy]

Darn. How could I do that?

[DilloDude]

Add this to global code:

Code: Select all

double xdist(double angsize, double dist)
{
    return cos(degtorad(angsize)) * dist;
}

double ydist(double angsize, double dist)
{
    return sin(degtorad(angsize)) * -dist;
}

To get the x coordinate (relative to the centre):

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xdist(<angle you want to use>, <radius of circle>);

y coordinate is the same, with ydist instead. So, it might be

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double xpos = xdist(dir, 100);
double ypos = ydist(dir, 100);
CreateActor("bullet"...  xpos, ypos, false);

or something like that. You may need to add some to those values if the centre of rotation is not the centre of the actor. Also, if the cannon rotates with an eliptical path (because of some isometric angle to the camera or something) use different values for the distances in xdist and ydist.