WBVector

WBVector.h

@interface WBVector : NSObject <NSCopying> {
  CGFloat _x;
  CGFloat _y;
  CGFloat _z;
}

@property (nonatomic) CGFloat x;
@property (nonatomic) CGFloat y;
@property (nonatomic) CGFloat z;

+ (WBVector *)vectorWithX:(CGFloat)x;
+ (WBVector *)vectorWithX:(CGFloat)x Y:(CGFloat)y;
+ (WBVector *)vectorWithX:(CGFloat)x Y:(CGFloat)y Z:(CGFloat)z;
+ (CGFloat)distanceFromVector:(WBVector *)v1 vector:(WBVector *)v2;

- (WBVector *)initWithX:(CGFloat)x;
- (WBVector *)initWithX:(CGFloat)x Y:(CGFloat)y;
- (WBVector *)initWithX:(CGFloat)x Y:(CGFloat)y Z:(CGFloat)z;

- (void)add:(WBVector *)v;
- (void)sub:(WBVector *)v;
- (void)mult:(id)v;
- (void)multByFloat:(CGFloat)f;
- (void)div:(id)v;
- (void)divByFloat:(CGFloat)f;
- (void)normalize;
- (void)limit:(CGFloat)max;
- (CGFloat)dist:(WBVector *)v;
- (CGFloat)mag;

@end

WBVector.m

#import "WBVector.h"

@implementation WBVector

@synthesize x = _x, y = _y, z = _z;

+ (WBVector *)vectorWithX:(CGFloat)x {
  return [[[WBVector alloc] initWithX:x Y:0 Z:0] autorelease];
}

+ (WBVector *)vectorWithX:(CGFloat)x Y:(CGFloat)y {
  return [[[WBVector alloc] initWithX:x Y:y Z:0] autorelease];
}

+ (WBVector *)vectorWithX:(CGFloat)x Y:(CGFloat)y Z:(CGFloat)z {
  return [[[WBVector alloc] initWithX:x Y:y Z:z] autorelease];
}

+ (CGFloat)distanceFromVector:(WBVector *)v1 vector:(WBVector *)v2 {
  return [v1 dist:v2];
}

- (WBVector *)initWithX:(CGFloat)x Y:(CGFloat)y Z:(CGFloat)z {
  _x = x;
  _y = y;
  _z = z;
  return self;
}

- (WBVector *)initWithX:(CGFloat)x Y:(CGFloat)y {
  return [self initWithX:x Y:y Z:0];
}

- (WBVector *)initWithX:(CGFloat)x {
  return [self initWithX:x Y:0 Z:0];
}

- (id)copyWithZone:(NSZone *)zone {
  return [[[WBVector alloc] initWithX:_x Y:_y Z:_z] autorelease];
}

// add the passed in vector to the vector
- (void)add:(WBVector *)v {
  _x += v.x;
  _y += v.y;
  _z += v.z;
};

// subtract the passed in vector from the vector
- (void)sub:(WBVector *)v {
  _x -= v.x;
  _y -= v.y;
  _z -= v.z;
};

// multiply the vector by the passed in vector
- (void)mult:(WBVector *)v {
  _x *= v.x;
  _y *= v.y;
  _z *= v.z;
};

- (void)multByFloat:(CGFloat)f {
  [self mult:[WBVector vectorWithX:f Y:f Z:f]];
}

// divide the vector by the passed in vector
- (void)div:(WBVector *)v {
  _x /= v.x;
  _y /= v.y;
  _z /= v.z;
};

// divide the vector by the passed in float
- (void)divByFloat:(CGFloat)f {
  [self div:[WBVector vectorWithX:f Y:f Z:f]];
}

// calculate the distance between two vectors
- (CGFloat)dist:(WBVector *)v {
  CGFloat dx = v.x - _x;
  CGFloat dy = v.y - _y;
  CGFloat dz = v.z - _z;
  return sqrt(dx*dx + dy*dy + dz*dz);
};

// limit the magnitude of the vector
- (void)limit:(CGFloat)max {
  if ([self mag] > max) {
    [self normalize];
    [self multByFloat:max];
  }
};

// calculate the magnitude (distance from the origin) of the vector
- (CGFloat)mag {
  return sqrt(_x*_x + _y*_y + _z*_z);
};

// normalize the vector (convert to a unit vector)
- (void)normalize {
  CGFloat mag = [self mag];
  [self divByFloat:mag];  
};

@end