Circle Collision inaccurate

最新推荐文章于 2022-07-31 12:43:30 发布

转载最新推荐文章于 2022-07-31 12:43:30 发布 · 420 阅读

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使用Kwigbo的碰撞检测代码，在数学上准确但在图形显示上有偏差。通过检查代码发现，两个球体之间的距离计算准确，但视觉效果不匹配。可能与锚点设置有关。

Hello,
I'm using Kwigbo's collision detection code, and what I get is an in-accurate graphical result but accurate mathematically.

OK, so I checked the collision code using the vector normalization, it took the ball like 3-4 minutes to reach the other ball.
The result is as follows:
The distance between the two centers was 27.49823, it's tremendously accurate, as the radiuses combined are only 27.5.
An image:
http://img162.imageshack.us/i/picture3m.png/

As you can see, it is not graphically accurate (more accurate than before though), although mathematically it's super accurate.
Any ideas? (Maybe Anchor points, I don't know)

Implementation in GameLayer:

- (void)checkIfOut:(ccTime)dt {

	NSMutableArray *arrayToRemove = [[NSMutableArray alloc] init];;

	for(int i = 0 ; i < [bulletArray count] ; i++){

		Bullet *b = [bulletArray objectAtIndex:i];

		if(b.outOfScreen){

			[arrayToRemove addObject:b];

			[self removeChild:b cleanup:YES];

		} else {

			if([self circle:b.position withRadius:b.radius hitsCircle:mr.position withRadius:mr.radius])

			{

				[[Director sharedDirector] stopAnimation];

			}

			else [b update:dt];

		}

		b = nil;

	}

	[bulletArray removeObjectsInArray:arrayToRemove];

	[arrayToRemove release];

}



- (BOOL)circle:(CGPoint)center1 withRadius:(float)radius1 hitsCircle:(CGPoint)center2 withRadius:(float)radius2 {

	float xdif = center2.x - center1.x;

	float ydif = center2.y - center1.y;

	float distance = sqrt(xdif*xdif + ydif* ydif);

	float minDist = radius1 + radius2;



	if(distance <= minDist)

		return kHit;

	return kNoHit;

}

Ball sprite object implementation:

- (id)init {

	if(self = [super init]){

		outOfScreen = NO;

		Sprite *spr = [Sprite spriteWithFile:@"Bullet.png"];

		self.contentSize = spr.contentSize;

		radius = self.contentSize.width /2;

		[self addChild:spr];

		self.anchorPoint = ccp(0.5, 0.5);



		self.position = ccp(168.0, 45.0);



		mass = 10;

	}

	return self;

}



- (void)update:(ccTime)dt {

	float x = self.position.x;

	float y = self.position.y;

	float width = self.contentSize.width;

	float height = self.contentSize.height;



	x += velocity.x * dt;

	y += velocity.y * dt;

	NSLog(@"x:%f y:%f", x, y);



	self.position = CGPointMake(x, y);



	if(x - width > 320.0)

		outOfScreen = YES;

	if(x + width < 0)

		outOfScreen = YES;

	if(y - height > 460)

		outOfScreen = YES;

	if(y + height < 0)

		outOfScreen = YES;

}