cocos2d 环绕已知点移动一圈

 

答案1：

问题解决 
将step改为如下即可
-(void)step:(ccTime)dt
{
    if (rotate == 360) {
        rotate = 0;
    }
    rotate += 5;
    float fradian = rotate * PI / 180;
    NSLog(@"%f  %f",rotate,fradian);
    id ac0 = [CCMoveTo actionWithDuration:0.01 
                                 position:*****(centerx + radius * sinf(fradian),
                                              centery + radius * cosf(fradian))];
    id ac1 = [CCRotateTo actionWithDuration:0.01 angle:(int)(rotate)];
    [sparrowhead runAction:[CCSpawn actions:ac0,ac1,nil]];
}

答案2：

根据算法，写成一个cocos2d的action

 

1. /** Round circle a CCNode object clockwise a number of degrees by modiying it's rotation attribute.
2. */
3. @interface CCRoundBy : CCActionInterval <NSCopying>
4. {
5.     BOOL turn;// Forward or Reverse round
6.     float startAngle;// default
7.     float radius;// Round circle radius
8.     CGPoint center;// Round circle center point
9. }
10. /** creates the action */
11. +(id) actionWithDuration:(ccTime)duration turn:(BOOL)a center:(CGPoint)point radius:(float)r;
12. /** initializes the action */
13. -(id) initWithDuration:(ccTime)duration turn:(BOOL)a center:(CGPoint)point radius:(float)r;
14. @end

 

1. //
2. // CCRoundBy
3. //
4. #pragma mark -
5. #pragma mark CCRoundBy
6.  
7. @implementation CCRoundBy
8. +(id) actionWithDuration: (ccTime) t turn:(BOOL) a center:(CGPoint)point radius:(float)r
9. {    
10.     return [[[self alloc] initWithDuration:t turn:a center:point radius:r] autorelease];
11. }
12.  
13. -(id) initWithDuration: (ccTime) t turn:(BOOL) a center:(CGPoint)point radius:(float)r
14. {
15.     if( (self=[super initWithDuration: t]) ) {
16.         turn = a;
17.         radius = r;
18.         center = point;
19.     }
20.     return self;
21. }
22.  
23. -(id) copyWithZone: (NSZone*) zone
24. {
25.     CCAction *copy = [[[self class] allocWithZone: zone] initWithDuration: [self duration] turn: turn center:center radius:radius];
26.     return copy;
27. }
28.  
29. -(void) startWithTarget:(id)aTarget
30. {
31.     [super startWithTarget:aTarget];
32.     startAngle = [target_ rotation];
33.     if (turn) {
34.         ((CCNode *)target_).position = *****Add(center, *****(-radius, 0));
35.     }
36.     else {
37.         ((CCNode *)target_).position = *****Add(center, *****(radius, 0));
38.     }    
39. }
40.  
41. -(void) update: (ccTime) t
42. {    
43.     // XXX: shall I add % 360
44.     float rotate =  (startAngle + 360.0f * t );
45.     if (turn) {
46.         rotate *= -1;
47.     }
48.     [target_ setRotation:rotate];
49.     
50.     float fradian = rotate * M_PI / 180.0f;
51.     CGPoint pos = *****(center.x + radius * sinf(fradian),
52.                       center.y + radius * cosf(fradian));
53.     [target_ setPosition: pos];
54. }
55.  
56. -(CCActionInterval*) reverse
57. {    
58.     BOOL result = !turn;
59.     return [[self class] actionWithDuration:duration_ turn:result center:center radius:radius];
60. }
61.  
62. @end

 

 

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