2D Shooter Help

[Spartan117]

This should just be basic trig but for some reason I can't get it to work right. I'm trying to make a bullet shoot from the player position towards the mouse position like a 2D shooter but something is wrong. It works out fine on paper I just don't know whats wrong here. When I have the mouse somewhere above the player and "shoot" it seems to work fine until i move my mouse down around 45 degrees or so then it shoots off in one position until i move the mouse back up. It's weird...here's the gist of it:

[cpp]
static public void Shoot()
{

...

Point mouse = Mouse.MousePosition;
Point offset = new Point(mouse.X - position.X, mouse.Y - position.Y);

angle = Math.Atan(offset.Y / offset.X);

if (offset.X > 0 && offset.Y < 0) quadrant = 0;
else if (offset.X > 0 && offset.Y > 0) quadrant = 1;
else if (offset.X < 0 && offset.Y > 0) quadrant = 2;
else if (offset.X < 0 && offset.Y < 0) quadrant = 3;

bullets[i].Create(bulletSurface, angle, position, 15, quadrant);

...

}

class Bullet
{
public void Create(Surface newSurface, double angle, Point newPosition, double speed, int quadrant)
{

...

velocity.X = (int)((Math.Cos(angle) * speed) + 0.5);
velocity.Y = (int)((Math.Sin(angle) * speed) + 0.5);
if(quadrant == 2 || quadrant == 3)
{
velocity.X = -velocity.X;
velocity.Y = -velocity.Y;
}

...

}

}
[/cpp]

[iPope]

Why not use vectors instead of trig?

[Sporbie]

[cpp]float ang=atan2 (mousey - posy , mousex - posx);
float bulletxvel=cos(ang) * BULLET_VELOCITY;
float bulletyvel=sin(ang) * BULLET_VELOCITY;
[/cpp]

atan2 replaces all your ifs.

[Spartan117]

[QUOTE=Sporbie;15982428][cpp]float ang=atan2 (mousey - posy , mousex - posx);
float bulletxvel=cos(ang) * BULLET_VELOCITY;
float bulletyvel=sin(ang) * BULLET_VELOCITY;
[/cpp]

atan2 replaces all your ifs.[/QUOTE]

Oh wow, thank you so much. That fixed everything :D

[Cathbadh]

[QUOTE=Spartan117;15981236]
[cpp]
static public void Shoot()
{

...

Point mouse = Mouse.MousePosition;
Point offset = new Point(mouse.X - position.X, mouse.Y - position.Y);

angle = Math.Atan(offset.Y / offset.X);

if (offset.X > 0 && offset.Y < 0) quadrant = 0;
else if (offset.X > 0 && offset.Y > 0) quadrant = 1;
else if (offset.X < 0 && offset.Y > 0) quadrant = 2;
else if (offset.X < 0 && offset.Y < 0) quadrant = 3;

bullets[i].Create(bulletSurface, angle, position, 15, quadrant);

...

}
[/cpp][/QUOTE]
Wow, you must be leaking memory like an anus and a stack of fat-free pringles. Try not to use the 'new' operator when you don't need variables beyond that certain scope.

[VoiDeD]

[QUOTE=Cathbadh;16041551]Wow, you must be leaking memory like an anus and a stack of fat-free pringles. Try not to use the 'new' operator when you don't need variables beyond that certain scope.[/QUOTE]

Luckily, it's C# so none of that matters. :buddy: