Bullets from a sprite?

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Dec 10th, 2002, 12:15 PM
raoul85

Bullets from a sprite?

Im making an action game in a 2d environment with 2d characters. The charcter(man), holding a gun, is all one image or sprite. So I use the page flipping method in directdraw to animated him walking. Im having problem as how would I make him shoot a bullet from the tip of the nozzle of the gun. Because the gun keeps moving and is not in the same place everytime. Is there a way to get its x,y coordinate?
Dec 10th, 2002, 12:27 PM
NoteMe

I'm not sure if it is an easy way to do that. But if you want to do it you could always record wich "picture" is showing and hardcode the X,Y coordinates for the gun and add the left and top coordinates of your man....
Dec 10th, 2002, 12:47 PM
Machaira

Use an array of points that matches the animation frames, similar to what NoteMe posted. Hopefully the gun still points in a direction that makes sense to shot at. If the gun points down in one frame and you let him shoot then, it will look pretty silly if the bullet flies out horizontally.
Dec 10th, 2002, 12:48 PM
NoteMe

Quote:

Originally posted by Machaira
Use an array of points that matches the animation frames, similar to what NoteMe posted. Hopefully the gun still points in a direction that makes sense to shot at. If the gun points down in one frame and you let him shoot then, it will look pretty silly if the bullet flies out horizontally.

...hehehe...lol....yes...that would look silly...
Dec 10th, 2002, 01:18 PM
raoul85

well......thats tideous work but looks like i have no choice..thanks for the advice!
Dec 10th, 2002, 01:22 PM
alkatran

hmmm
Assuming I understand what you mean..

You want a man to be able to rotate around (360 degrees or just u/d/r/l...)

Anyways, my suggestion is to have a variable keeping track of his rotation, and to use that angle to move bullet... so:
VB Code:
```
sub shoot
BulletDir = AngleOfPerson:BulletX = XofPerson':lalalalalla
'ok so MAYBE im leaving a bit out...
end sub
 
sub move(Ref X,Ref Y,Ref speed,Ref angle)
'All the above should be referenced, I'm not sure if it's written correctly.
X = X + Speed * Sin(Angle)
Y = Y + Speed * Cos(Angle)
End sub
```
That move code is INCREDIBLY usefull, it lets you move things in all directions, by changing the angle variable (0-360, 361 = 1 duh)
Dec 10th, 2002, 01:24 PM
NoteMe

Re: hmmm
Quote:
Originally posted by alkatran
Assuming I understand what you mean..

You want a man to be able to rotate around (360 degrees or just u/d/r/l...)

Anyways, my suggestion is to have a variable keeping track of his rotation, and to use that angle to move bullet... so:

VB Code:

sub shoot
BulletDir = AngleOfPerson:BulletX = XofPerson':lalalalalla
'ok so MAYBE im leaving a bit out...
end sub

sub move(Ref X,Ref Y,Ref speed,Ref angle)
'All the above should be referenced, I'm not sure if it's written correctly.
X = X + Speed * Sin(Angle)
Y = Y + Speed * Cos(Angle)
End sub

That move code is INCREDIBLY usefull, it lets you move things in all directions, by changing the angle variable (0-360, 361 = 1 duh)
If that was what you ment..then I think I and Machaira may have miss understodd you...are you rotating 360degrees or is it a one man walking in 2D game (left right)...???
Dec 10th, 2002, 01:36 PM
raoul85

MY game is supposed 2d, ie. moving left and right only
Dec 10th, 2002, 01:38 PM
NoteMe

Then I think alkatran missunderstood...and you would have to do it the hard way..;)
Dec 10th, 2002, 01:43 PM
alkatran

Well

Damn, stupid inferior games!! ;)

But anyways, make a frame where he shoots, problem solved, always in same spot.
Dec 10th, 2002, 01:46 PM
NoteMe

Re: Well

Quote:

Originally posted by alkatran
Damn, stupid inferior games!! ;)

But anyways, make a frame where he shoots, problem solved, always in same spot.

Thats the best idea I have heard all day....hheheeh....
Dec 11th, 2002, 11:50 AM
/\/\isanThr0p

basically I am with alcatran, why would he shoot on every walking frame... I doubt you actually shoot standing on the tips of one foot :)
well what I wanted to say is that you might want to check out Statemachines for that
a good explanation can be found on www.ur.co.nz
Dec 11th, 2002, 12:35 PM
cyborg

Re: hmmm
Quote:

Originally posted by raoul85
MY game is supposed 2d, ie. moving left and right only

Well, that would be 1d....moving in only one direction...
Quote:
Originally posted by alkatran

VB Code:

X = X + Speed * Sin(Angle)
Y = Y + Speed * Cos(Angle)
shouldnt it be like this?
VB Code:
```
X = X + Speed * Sin(Angle * (Pi / 180))
Y = Y + Speed * Cos(Angle * (Pi / 180))
```
Dec 11th, 2002, 02:02 PM
/\/\isanThr0p

well only if he has his angle stored in degree what wouldn't really help to much