Cocos2d 3.0 + Chipmunk + CCAnimation: moving physics body with animated object. How? - ios

Question

I have a boat with attached physics body. This boat is static physics body. Boat moving with CCAnimateMoveTo from left to right. When I tap on screen my character fall down. I detect collisions well. But I want that after collision my character just fall on boat and keep moving with it. Character is dynamic body. Link to sample video: Sample video
Here I create a boat:
- (void)createBoat
{
currentBoat = [CCSprite spriteWithImageNamed:#"Boat.png"];
currentBoat.position = ccp(0 - currentBoat.boundingBox.size.width, winSize.height * 0.2);
// currentBoat.physicsBody = [CCPhysicsBody bodyWithRect:(CGRect){0, 0, currentBoat.contentSize.width, currentBoat.contentSize.height * 0.5} cornerRadius:0];
CGPoint shape[6];
shape[0] = ccp(0, 30);
shape[1] = ccp(64, 10);
shape[2] = ccp(128, 30);
shape[3] = ccp(128, 0);
shape[4] = ccp(0, 0);
shape[5] = ccp(0, 30);
currentBoat.physicsBody = [CCPhysicsBody bodyWithPolylineFromPoints:shape count:6 cornerRadius:0 looped:NO];
currentBoat.physicsBody.type = CCPhysicsBodyTypeStatic;
currentBoat.physicsBody.collisionGroup = #"BoatGroup";
currentBoat.physicsBody.collisionType = #"BoatCollision";
[physicsWorld addChild:currentBoat z:PHYSICS_Z+3];
id actionMoveBoat = [[CCActionMoveTo alloc] initWithDuration:5.0f position:ccp(winSize.width + currentBoat.boundingBox.size.width, currentBoat.position.y)];
id actionMethod = [CCActionCallFunc actionWithTarget:self selector:#selector(createBoat)];
[currentBoat runAction:[CCActionSequence actions:actionMoveBoat, [[CCActionRemove alloc] init], actionMethod, nil]];
}
Character creation:
- (void)createCharacter
{
if (needCharacter)
{
CCSprite *newCharacter = [CCSprite spriteWithImageNamed:#"Character.png"];
newCharacter.opacity = 0;
newCharacter.position = ccp(winSize.width * 0.5, winSize.height * 0.76);
newCharacter.physicsBody = [CCPhysicsBody bodyWithRect:(CGRect){CGPointZero, newCharacter.contentSize} cornerRadius:0];
newCharacter.physicsBody.affectedByGravity = NO;
newCharacter.physicsBody.allowsRotation = YES;
newCharacter.physicsBody.collisionGroup = #"playerGroup";
newCharacter.physicsBody.collisionType = #"playerCollision";
[physicsWorld addChild:newCharacter z:PHYSICS_Z+4];
id actionFadeIn = [[CCActionFadeIn alloc] initWithDuration:0.5];
[newCharacter runAction:actionFadeIn];
[allCharacters addObject:newCharacter];
needCharacter = false;
touchDone = false;
}
}
Then detection touch and collision:
- (void)touchBegan:(UITouch *)touch withEvent:(UIEvent *)event
{
CCNode *lastCharacter = [allCharacters lastObject];
if (!touchDone)
{
[lastCharacter.physicsBody applyImpulse:ccp(0, 300)];
lastCharacter.physicsBody.type = CCPhysicsBodyTypeDynamic;
lastCharacter.physicsBody.affectedByGravity = YES;
touchDone = true;
}
}
- (BOOL)ccPhysicsCollisionBegin:(CCPhysicsCollisionPair *)pair playerCollision:(CCNode *)currentCharacterC BoatCollision:(CCNode *)currentBoatC {
currentCharacterC.physicsBody.collisionType = #"tmpCollision";
CCLOG(#"score++");
if ([allCharacters containsObject:currentCharacterC])
{
score++;
[scores setString:[NSString stringWithFormat:#"%d", score]];
[allCharacters removeAllObjects];
if (lives != 0)
{
needCharacter = true;
[self createCharacter];
}
}
CCLOG(#"allCharacters = %#", allCharacters);
return YES;
}

Answer 1

well I too faced the same problem, tried increasing the friction/surface velocity etc, it didn't really work well.
Finally had to resolve it my own way, whenever player lands on any body, you keep a pointer to that body as say _bodyUnderFeet of the player object.
Now, in the update loop add the velocity of the _bodyUnderFeet to the players calculated velocity. See the use of zeroVel_x
Sample code is here:
void Player::update(float dt)
{
float zeroVel_x = 0;
if(_bodyUnderFeet != NULL)
{
zeroVel_x = _bodyUnderFeet->v.x;
}
cpBody *bd = getCPBody();
assert(bd);
//log("Body angle %f", bd->a);
//check forward backward or at rest
float accel = _accelGround;
if(_onGroundBoost < UP_BOOST)
{
accel = _accelAir;
}
if(_touchPressedB)
{
if(!isFlippedX())
{
setFlippedX(true);
}
//cpBodySetVel(bd, cpv(cpBodyGetVel(bd).x - accel*0.25, 0));
cpVect bdv = cpBodyGetVel(bd);
bdv.x = bdv.x - zeroVel_x;
if(bdv.x > 0) bdv.x = 0;
if(bdv.x > -_maxVelocity.x)
cpBodySetVel(bd, cpv(zeroVel_x + bdv.x - accel*0.25, bdv.y));
}
else if(_touchPressedF)
{
if(isFlippedX())
{
setFlippedX(false);
}
//cpBodySetVel(bd, cpv(cpBodyGetVel(bd).x + accel*0.25, 0));
cpVect bdv = cpBodyGetVel(bd);
bdv.x = bdv.x - zeroVel_x;
if(bdv.x < 0) bdv.x = 0;
if(bdv.x < _maxVelocity.x)
cpBodySetVel(bd, cpv(zeroVel_x+bdv.x + accel*0.25, bdv.y));
}
else
{
cpFloat bd_x = cpBodyGetVel(bd).x;
bd_x = bd_x - zeroVel_x;
if(bd_x>0)
{
if(bd_x > accel*0.25)
{
cpBodySetVel(bd, cpv(zeroVel_x+bd_x - accel*0.25, cpBodyGetVel(bd).y));
}
else
{
cpBodySetVel(bd, cpv(zeroVel_x+0, cpBodyGetVel(bd).y));
}
}
else if(bd_x < 0)
{
if(bd_x < accel*0.25)
{
cpBodySetVel(bd, cpv(zeroVel_x+bd_x + accel*0.25, cpBodyGetVel(bd).y));
}
else
{
cpBodySetVel(bd, cpv(zeroVel_x+0, cpBodyGetVel(bd).y));
}
}
}
//check jump
if(_touchPressedJ)
{
if(_onGroundBoost)
{
cpVect bdv = cpBodyGetVel(bd);
if(bdv.y < 0) bdv.y = 0;
if((bdv.y + _accelUp) < _maxVelocity.y)
{
cpBodySetVel(bd, cpv(bdv.x, bdv.y + _accelUp));
--_onGroundBoost;
}
else
{
cpBodySetVel(bd, cpv(bdv.x, _maxVelocity.y));
_onGroundBoost = 0;
}
}
}
//check shots
if(_touchPressedS)
{
if(!_bulletFired)
{
}
}
//check home
if(_touchPressedH)
{
}
boundRotation(bd);
}

Answer 2

I think,
you can increase the friction between man and boat after he fall down. and reduce the elasticity . then the boat can 'take' the man go together...
just a trick.