Ball.m

/* TouchesTest (c) Valentin Milea 2009
 */
#import "Ball.h"
#import "Paddle.h"

@implementation Ball

@synthesize velocity;

- (float)radius
{
	return self.texture.contentSize.width / 2;
}

+ (id)ballWithTexture:(CCTexture2D *)aTexture
{
	return [[[self alloc] initWithTexture:aTexture] autorelease];
}

- (void)move:(ccTime)delta
{
	self.position = ccpAdd(self.position, ccpMult(velocity, delta));
	
	if (self.position.x > 320 - self.radius) {
		[self setPosition: ccp( 320 - self.radius, self.position.y)];
		velocity.x *= -1;
	} else if (self.position.x < self.radius) {
		[self setPosition: ccp(self.radius, self.position.y)];
		velocity.x *= -1;
	}
}

- (void)collideWithPaddle:(Paddle *)paddle
{
	CGRect paddleRect = paddle.rect;
	paddleRect.origin.x += paddle.position.x;
	paddleRect.origin.y += paddle.position.y;
	
	float lowY = CGRectGetMinY(paddleRect);
	float midY = CGRectGetMidY(paddleRect);
	float highY = CGRectGetMaxY(paddleRect);
	
	float leftX = CGRectGetMinX(paddleRect);
	float rightX = CGRectGetMaxX(paddleRect);
	
	if (self.position.x > leftX && self.position.x < rightX) {
	
		BOOL hit = NO;
		float angleOffset = 0.0f; 
		
		if (self.position.y > midY && self.position.y <= highY + self.radius) {
			self.position = CGPointMake(self.position.x, highY + self.radius);
			hit = YES;
			angleOffset = (float)M_PI / 2;
		}

		else if (self.position.y < midY && self.position.y >= lowY - self.radius) {
			self.position = CGPointMake(self.position.x, lowY - self.radius);
			hit = YES;
			angleOffset = -(float)M_PI / 2;
		}
		
		if (hit) {
			float hitAngle = ccpToAngle(ccpSub(paddle.position, self.position)) + angleOffset;
			
			float scalarVelocity = ccpLength(velocity) * 1.05f;
			float velocityAngle = -ccpToAngle(velocity) + 0.5f * hitAngle;
			
			velocity = ccpMult(ccpForAngle(velocityAngle), scalarVelocity);
		}
	}	
}

@end