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POBall Randomly Slowing Down
primarykey
Id
13903302
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
4
CommunityOwnedDate
CreationDate
2012-12-16T16:38:32.527
FavoriteCount
0
LastActivityDate
2012-12-20T01:33:47.510
LastEditDate
2012-12-20T01:33:47.510
LastEditorUserId
620249
OwnerUserId
1748364
ParentId
0
PostTypeId
1
Score
0
ViewCount
74
LastEditorDisplayName
text
Body
Currently, I have a program that has a ball, bouncing back and forth. In order to find out how fast it's bouncing, I made this: <pre><code>b2Vec2 velocity = blueCircleBody->GetLinearVelocity(); float constantSpeed = velocity.Length(); NSLog(@"%.f", constantSpeed); </code></pre> This is inside a tick: function. Every second, I want to see how fast the ball is moving. As I notice in the Output window, the ball seems to slow down after few minutes. <pre><code>2012-12-16 11:29:10.458 Bubble Fill V1[31623:c07] 30 2012-12-16 11:29:11.474 Bubble Fill V1[31623:c07] 30 2012-12-16 11:29:12.475 Bubble Fill V1[31623:c07] 30 2012-12-16 11:29:13.492 Bubble Fill V1[31623:c07] 24 2012-12-16 11:29:14.525 Bubble Fill V1[31623:c07] 24 </code></pre> Is there a reason why the ball randomly went from 30 to 24? Additionally, I have another problem. If I restart the program, with all the same data, the ball is going at a different speed for unknown reason. This means that the impulse/force I use doesn't dictate how fast it's going. Here's some more information on the ball: <pre><code> blueCircle = [CCSprite spriteWithFile:@"blueCircle.png"]; blueCircle.position = ccp(winSize.width/4, winSize.height/4); blueCircle.tag = 2; [self addChild:blueCircle]; blueCircleBodyDef.type = b2_dynamicBody; //Find a way to make the BoundingBox/GroundBox to not be affected by the Force of the Walls blueCircleBodyDef.position.Set(winSize.width/4/PTM_RATIO, winSize.height/4/PTM_RATIO); //blueCircleBodyDef.position.Set(blueCircle.position.x/PTM_RATIO, blueCircle.position.y/PTM_RATIO); blueCircleBodyDef.userData = blueCircle; blueCircleBody = world->CreateBody(&blueCircleBodyDef); float blueCircleRadius = blueCircle.contentSize.width/2 * blueCircle.scale; blueCircleShape.m_radius = blueCircleRadius/PTM_RATIO; blueCircleFixtureDef.shape = &blueCircleShape; blueCircleFixtureDef.density = 1.0f; blueCircleFixtureDef.friction = 0.0f; blueCircleFixtureDef.restitution = 1.0f; blueCircleBody->CreateFixture(&blueCircleFixtureDef); force.Set(0, 140); //blueCircleBody ->ApplyLinearImpulse(force, blueCircleBodyDef.position); //blueCircleBody->SetLinearVelocity(force); blueCircleBody->SetGravityScale(0); blueCircleBody->SetLinearVelocity(force); </code></pre>
Tags
<cocos2d-iphone><box2d><circle><physics-engine>
Title
Ball Randomly Slowing Down
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USSergiu Dumitriu
UserOwnerUserId
1. USWei Pan
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 POBall Randomly Slowing Down
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTClose
CommentsPostId

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