///// 2016

int DirRev(int dir) {
	int bypassshields = 0;
	if ( DIR > 7 ) {
		bypassshields = 8;
		dir = dir - 8;
	}
	if ( dir == DIR_LEFT) return DIR_RIGHT + bypassshields;
	if ( dir == DIR_DOWN) return DIR_UP + bypassshields;
	if ( dir == DIR_UP) return DIR_DOWN + bypassshields;
	if ( dir == DIR_RIGHT) return DIR_LEFT + bypassshields;
	if ( dir == DIR_DOWNLEFT) return DIR_UPRIGHT + bypassshields;
	if ( dir == DIR_DOWNRIGHT) return DIR_UPLEFT + bypassshields;
	if ( dir == DIR_UPLEFT) return DIR_DOWNRIGHT + bypassshields;
	if ( dir == DIR_UPRIGHT) return DIR_DOWNLEFT + bypassshields;
}
	

int SpeedRev(int speed, int reduceinertia){
	if ( speed > 0 ) speed = ((speed * -1) + reduceiertia);
	if ( speed < 0 ) speed = ((speed * -1) - reduceinertia);
	return speed;
}

//Accepts the mass, and velocity if two objects. Determins the acceleration on impact. 
//Returns the net change that would affect both objects. 
int ImpactVelocity(int mass1, int velocity1, int mass2, int velociy2 ) { //, int time){ //time is sed here, as the amount of time that both objects are in contact.
	int momentum1 = mass1*velocity1; //mv1
	int momentum2 = mass2*velociy2; //mv2
	//int accel1;
	//int accel2;
	return momentum1 - momentum2;
}

//Accepts the mass, and velocity if two objects. Determins the acceleration on impact. 
//Returns the change of acceleration for object 'B'. 
int ImpactVelocityA(int massA, int velocityA, int massB, int velociyB ) { //, int time){ //time is sed here, as the amount of time that both objects are in contact.
	int momentumA = massA*velocityA; //mv1
	int momentumB = massB*velociyB; //mv2
	int accelA = momentumA - momentumB;
	int accelB = momentumB - momentumA;
	return momentumA;
}

//Accepts the mass, and velocity if two objects. Determins the acceleration on impact. 
//Returns the change of acceleration for object 'B'.
int ImpactVelocityB(int massA, int velocityA, int massB, int velociyB ) { //, int time){ //time is sed here, as the amount of time that both objects are in contact.
	int momentumA = massA*velocityA; //mv1
	int momentumB = massB*velociyB; //mv2
	int accelA = momentumA - momentumB;
	int accelB = momentumB - momentumA;
	return momentumB;
}

//Accepts the mass, and velocity if two weapons. Determins the acceleration on impact. 
//Changes the Step of both to reflect their mass on collision. 
void ImpactVelocity(lweapon a, eweapon b, int massA, int velocityA, int massB, int velociyB ) { //, int time){ //time is sed here, as the amount of time that both objects are in contact.
	int momentumA = massA*velocityA; //mv1
	int momentumB = massB*velociyB; //mv2
	int accelA = momentumA - momentumB;
	int accelB = momentumB - momentumA;
	a->Step += accelA;
	b->Step += accelB;
}

void ImpactVelocityF(){} //FFC version that will change the direction, and speed of moving ffcs on collision. 

//Returns centre of lweapon, with option to include its HitXOffset
int CenterX(lweapon anLWeapon, bool trueoffset) { 
	if ( trueoffset ) return anLWeapon->X+8*anLWeapon->TileWidth + anLWeapon->HitXOffset;
	else return CenterX(anLWeapon);
}

//Returns centre of lweapon, with option to include its HitYOffset
int CenterY(lweapon anLWeapon, bool trueoffset) {
	if ( trueoffset ) return anLWeapon->Y+8*anLWeapon->TileHeight + anLWeapon->HitYOffset;
	else return CenterX(anLWeapon);
}

//Returns centre of eweapon, with option to include its HitXOffset
int CenterX(eweapon anEWeapon, bool trueoffset) { 
	if ( trueoffset ) return anEWeapon->X+8*anEWeapon->TileWidth + anEWeapon->HitXOffset;
	else return CenterX(anEWeapon);
}

//Returns centre of eweapon, with option to include its HitYOffset
int CenterY(eweapon anEWeapon, bool trueoffset) {
	if ( trueoffset ) return anEWeapon->Y+8*anEWeapon->TileHeight + anEWeapon->HitYOffset;
	else return CenterX(anEWeapon);
}

//Returns centre of eweapon, with option to include its HitXOffset
int CenterX(npc n, bool trueoffset) { 
	if ( trueoffset ) return n->X+8*n->TileWidth + n->HitXOffset;
	else return CenterX(n);
}

//Returns centre of eweapon, with option to include its HitYOffset
int CenterY(npc n, bool trueoffset) {
	if ( trueoffset ) return n->Y+8*n->TileHeight + n->HitYOffset;
	else return CenterX(n);
}

////////////////

//Returns centre of lweapon, with option to include its HitXOffset
int CenterX(lweapon anLWeapon, bool trueoffset, bool drawoffset) { 
	int lx = anLWeapon->X+8*anLWeapon->TileWidth;
	if ( trueoffset ) lx += anLWeapon->HitXOffset;
	if ( drawoffset ) lx += anLWeapon->DrawXOffset;
	return lx;
}

//Returns centre of lweapon, with option to include its HitYOffset
int CenterY(lweapon anLWeapon, bool trueoffset, bool drawoffset) {
	int ly = anLWeapon->Y+8*anLWeapon->TileHeight;
	if ( trueoffset ) ly += anLWeapon->HitYOffset;
	if ( drawoffset ) ly += anLWeapon->DrawYOffset;
	return ly;
}

//Returns centre of eweapon, with option to include its HitXOffset
int CenterX(eweapon anEWeapon, bool trueoffset, bool drawoffset) { 
	int ex = anEWeapon->X+8*anEWeapon->TileWidth;
	if ( trueoffset ) ex += anEWeapon->HitXOffset;
	if ( drawoffset ) ex += anEWeapon->DrawXOffset;
	return ex;
}

//Returns centre of eweapon, with option to include its HitYOffset
int CenterY(eweapon anEWeapon, bool trueoffset, bool drawoffset) {
	int ey = anEWeapon->Y+8*anEWeapon->TileHeight;
	if ( trueoffset ) ey += anEWeapon->HitYOffset;
	if ( drawoffset ) ey += anEWeapon->DrawYOffset;
	return ey;
}

//Returns centre of eweapon, with option to include its HitXOffset
int CenterX(npc n, bool trueoffset, bool drawoffset) { 
	int nx = n->X+8*n->TileWidth;
	if ( trueoffset ) nx += n->HitXOffset;
	if ( drawoffset ) nx += n->DrawXOffset;
	return nx;
}

//Returns centre of eweapon, with option to include its HitYOffset
int CenterY(npc n, bool trueoffset, bool drawoffset) {
	int ny = n->Y+8*n->TileHeight;
	if ( trueoffset ) nx += n->HitYOffset;
	if ( drawoffset ) nx += n->DrawYOffset;
	return nx;
}

////////////////

int CenterLinkX(bool hitoffset) { 
	if ( hitoffset ) return Link->X + 8 * Link->TileWidth + Link->HitXOffset;
	else return Link->X + 8 * Link->TileWidth;
}

int CenterLinkY() {
	if ( hitoffset ) return Link->Y + 8 * Link->TileHeight + Link->HitYOffset;
	else return Link->Y + 8 * Link->TileHeight;
}

int CenterLinkX(bool hitoffset, bool drawoffset) { 
	int lx = Link->X + 8 * Link->TileWidth;
	if ( hitoffset ) lx += Link->HitXOffset;
	if ( drawoffset ) lx += Link->DrawXOffset;	
	return lx;
}

int CenterLinkY() {
	int ly = Link->Y + 8 * Link->TileHeight;
	if ( hitoffset ) ly += Link->HitYOffset;
	if ( drawoffset ) ly += Link->DrawYOffset;	
	return ly;
}


//Returns the direction of the vector from (0, 0) to point, in degrees from -180 to 180. (0 = right)
float Angle(int x, int y) {
  return ArcTan(x, y)*57.2958;
}