Positioning Shots Problem (asked by svn)

svn

I'm making a shooter game. The shots are supposed to move to the mouse's position, but the necessary rules mean that when your character moves, and the mouse is on him, the shots stay where in the character. How can I tell it to move in a linear fashion, but it moves in a hypothetical invisible line stretching from the character to the mouse and beyond?(Sorry if this gets confusing, just play any web shooter game, like the excellent Commando 2[miniclip.com/games/commando-2/en/] , and watch how the shots move to see what I mean)

JohnPapiomitis

use vector to angle to determine the angle of the shot from the player to the mouse position, then you can use magnitude to determine how close the mouse is to the player and if its within the range you want have it so the shots dont move and stay where the character is

vector to angle expression: vectorToAngle(selfposition.x-mousepositon.x,self.position.y-mouse.position.y)

magnitude expression: magnitude(self.position.x-mouse.position.x,self.position.y-mouse.position.y)

tsb has a great video called distance between actors in the gamesalad cookbook that shows magnitude as well

svn

No, no. You're misinterpreting my query(my fault entirelly). What I want is for the bullet to shoot in a straight line, passing through the mouse's position. Should I interpolate the move behaviors to the mouse position or something? Play any 2D web shooter game to see what I mean.

JohnPapiomitis

ahh i see. All you need to do then is have a change velocity behavior in the bullet and for the direction have vectorToAngle(self.position.x-mouse.posiiton.x,self.posiiton.y-mouse.position.y)

that will have it shoot towards the mouse and keep going past it in the same direction, so it doesnt just go to the mouse and stop

svn

Thanks, John. You're a big help, man.

JohnPapiomitis

anytime

svn

Hey! What happened?! I followed JohnPapiomitis' instructions, but the bullet moves in the opposite direction and angle. What is going on?

JohnPapiomitis

thats weird, it should be workign right

you can do: -vectorToAngle(self.position.x-mouse.posiiton.x,self.posiiton.y-mouse.position.y)

since its going the opposite having the minus will make it the right way, thats still puzziling why its not working from the get go though

svn

Hey, what if.. For the "self.position.x/y- mouse.position.x/y" ,.is the self.position for the bullet itself, or the actor it should fire from? And is the mouse.position.x mean "game.mouse.position.x"?

JohnPapiomitis

no the expressions right

and i just remeber, the image of the player should be facing right to begin with, if its facing left thats why its shooting out the other side. Im refereing to the actual png you imported into gamesalad

svn

John, I just found out what went wrong! Turns out, the equation is actually "VectortoAngle(GAME.MOUSE.POSITION.X/Y- SELF.POSITION.X/Y). You wrote the numbers in the wrong order, but that was it!