macos - SceneKit 从动画 SCNNode 中获取当前 SCNNode 位置

Question

我想从动画 SCNNode 获取当前节点位置我知道 presentationNode 并且我尝试从那里提取位置形式，但没有运气

这是我的代码

SCNNode * pelvis = [_unit childNodeWithName:@"Bip01_Pelvis" recursively:YES];
SCNNode * present = pelvis.presentationNode;



SCNVector3 position = [self convertPosition:present.position toNode:self.parentNode];

我的位置是在应用CAAnimation之前处于“休息”模式的SCNNode的位置。

如何从“presentationNode”获取位置等属性？

编辑

类本身相关部分:

@interface UndeadSimple : RepresentationNode <CAAnimationDelegate>
{
    //Animations
    SCNNode * _undead;

    CAAnimation * _currentAnimation;
    NSString    * _currAnimationkey;

    CAAnimation * _death1;
    ...

    SCNNode        * _audioNode;
    SCNAudioSource * _deathSource;
    SCNAudioPlayer * _player;
}

初始化:

NSString * sceneName = @ZOMBIE;
SCNScene *scene2 = [SCNScene sceneNamed:sceneName];

_undead = [SCNNode node];
for(SCNNode * node in scene2.rootNode.childNodes)
{
    [_undead addChildNode:node];
    [node removeAllAnimations];
}
[_undead setScale:(SCNVector3Make(0.024, 0.02, 0.024))];

[self addChildNode:_undead];
[_undead removeAllAnimations];

_currentAnimation = _idleAnimation;
_currAnimationkey = @"resting";

[_undead addAnimation:_currentAnimation forKey:_currAnimationkey];

动画和事件:

SCNAnimationEvent * event2 = [SCNAnimationEvent animationEventWithKeyTime:0.9 block:^(CAAnimation * _Nonnull animation, id  _Nonnull animatedObject, BOOL playingBackward)
{
    [self.delegate finishedDeathAnimation];
}];

_death1 = anims.death1.mutableCopy;
[_death1 setDelegate:self];
[_death1 setFillMode:kCAFillModeForwards];
_death1.removedOnCompletion = NO;
[_death1 setAnimationEvents:@[event2]];

动画调用:

- (void)die
{

    if([_currAnimationkey isEqualToString:@"dead"])
    {
        return;
    }

   [_undead removeAllAnimations];
   CAAnimation * death = nil;



    int anim = arc4random_uniform(3);
    if(anim < 1)
    {
        death = _death1;
    }
    else if(anim < 2)
    {
        death = _death2;
    }
    else
    {
        death = _death3;
    }

    _currAnimationkey = @"dead";
    _currentAnimation = death;

}

//获取展示节点的Helper方法

- (SCNNode *)getSnapNode
{
    SCNNode * repNode = [_undead presentationNode];
    _undead.transform = repNode.transform;
    repNode = _undead.clone;
    return repNode;
}

//回调调用并尝试获取位置:

- (void)finishedDeathAnimation
{
    SCNPlane * bloodgeometry = [SCNPlane planeWithWidth:4 height:4];
    bloodgeometry.firstMaterial.diffuse.contents = [NSImage imageNamed:@"blood"];

    SCNNode * bloodNode = [SCNNode node];
    [bloodNode setEulerAngles:SCNVector3Make(-M_PI_2, 0, 0)];
    bloodNode.geometry = bloodgeometry;

    //Bip01_Pelvis
    SCNNode * deadBody = [_unit getSnapNode];

    SCNNode * pelvis = [deadBody childNodeWithName:@"Bip01_Pelvis" recursively:YES];

    SCNNode * present = pelvis.presentationNode;
    SCNVector3 position = [self convertPosition:present.position toNode:self.parentNode];

   NSLog(@"pelvis position %lf,%lf,%lf", present.position.x, present.position.y, present.position.z); //Always {0,0,0}


    bloodNode.position = SCNVector3Make(position.x, 0.0001, position.z);

    [self.parentNode addChildNode:bloodNode];

    [self removeFromParentNode];
}

编辑 2

我也尝试简化一下:

另一个辅助方法:

//不死族/单位类别

- (SCNVector3)getPosition
{
    SCNNode * repNode = [[_undead childNodeWithName:@"Bip01_Pelvis" recursively:YES] presentationNode];
    return repNode.position;
}

回调时:

- (void)finishedDeathAnimation
{
    position = [_unit getPosition];
    NSLog(@"pelvis position %lf,%lf,%lf", position.x, position.y, position.z); //Alway 0,0,0 as well :(
}

Answer 1

很少有人像我一样仍然相信 Objective C 而不是 swift，这就是为什么我想提供全面的帮助。

我在从 Blender 导出作为 Collada 的动画时遇到了这个问题，但经过几次尝试后成功获得了实际位置。

使用presentationNode是正确的方法，但你需要在制作动画时从子节点获取它，例如，这是如何为名为_monkey的节点运行动画，请注意，在最后的代码中，我从子节点获取了_present。 presentationNode 不是来自 _monkey.presentationNode 也必须在枚举期间而不是之后获取

所以首先我需要定义

NSNode * _present; 

然后我播放动画

   [_monkey enumerateChildNodesUsingBlock:^(SCNNode *child, BOOL *stop)
     {
         for(NSString *key in child.animationKeys)
         {               // for every animation key
             CAAnimation *animation = [child animationForKey:key]; // get the animation
             animation.usesSceneTimeBase = NO;                     // make it system time based
             animation.repeatCount = FLT_MAX;                      // make it repeat forever
             animation.speed = 0.2;
             [child addAnimation:animation forKey:key];            // animations are copied upon addition, so we have to replace the previous animation
         }
         _present = child.presentationNode;
     }];

然后在渲染下我可以检查随着动画移动而变化的结果(此外，如果您使用过 iOS11，您可以检查 worldPosition 而不是位置，它也可以提供很好的结果)。

- (void)renderer:(id <SCNSceneRenderer>)renderer didSimulatePhysicsAtTime:(NSTimeInterval)time
{
     NSLog(@" Location X:%f Y:%f Z:%f", _present.position.x, _present.position.y, _present.position.z);

}

最后是结果

Y:-2.505034 Z:4.426160
2017-10-11 04:42:19.700435+0200 monkey[547:137368]  Location X:-5.266642 Y:-2.480119 Z:4.427162
2017-10-11 04:42:19.720763+0200 monkey[547:137368]  Location X:-5.215315 Y:-2.455228 Z:4.428163
2017-10-11 04:42:19.740449+0200 monkey[547:137346]  Location X:-5.163589 Y:-2.430143 Z:4.429171
2017-10-11 04:42:19.760397+0200 monkey[547:137368]  Location X:-5.112190 Y:-2.405216 Z:4.430173
2017-10-11 04:42:19.780557+0200 monkey[547:137346]  Location X:-5.060925 Y:-2.380355 Z:4.431173
2017-10-11 04:42:19.800418+0200 monkey[547:137342]  Location X:-5.008560 Y:-2.355031 Z:4.432024

这给了我很好的结果。希望它能与您合作。