Question

Hi i need to shoot my sprite..i use below code

-(void)shooter
{
LHSprite* laserSprite = [lh newPhysicalSpriteWithUniqueName:@"ball_1" ];
b2Body* laserBody = [laserSprite body];
[self addChild:laserSprite z:10]; 
NSAssert(laserSprite!=nil, @"Couldn't find devil1"); 

[laserSprite transformPosition:_hero.position];
b2Vec2 ballvel = laserBody->GetLinearVelocity();
ballvel.x = 16;
laserBody->SetLinearVelocity(ballvel);
}

above code shoots the sprite right side,

but i need to shoot left side..even if i change ballvel.x = 16; to ballvel.x = -16; its still shooting towards right side..please help

I am new to box2d so please be gentle 🙂

Answer 1

Syntax is like this:

//1. First calculate angle of move.
//2. Calculate power(strength) of hit.

b2Vec2 force;

force.x = cos(angle * M_PI / 180) * power;
force.y = sin(angle * M_PI / 180) * power;

laserBody->ApplyLinearImpulse(force, laserBody->GetPosition()); //or SetLinearVelocity