SceneKit 从动画 SCNNode 获取当前 SCNNode 位置

Question

我想从动画中获取当前节点位置SCNNode 我知道 presentationNode 并且我试图从那里提取位置，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];

我的位置是应用CAAnimation之前"rest"模式下SCNNode的位置。

如何从 'presentationNode' 中获取位置等属性？

编辑

Class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

我也试着简化了一下：

另一个辅助方法：

//在undead/unitclass

- (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

没有动画运行，至少在您向我们展示的代码中没有。在播放动画时检查演示节点的位置，可能在 renderer:updateAtTime: 中（参见 SCNRendererDelegate）。

Answer 2

很少有人像我一样仍然相信 Objective C 而不是 swift 这就是为什么我愿意提供全面帮助的原因。

对于从 Blender 作为 Collada 导出的动画，我遇到了这个问题，但在几次尝试后成功获得了实际位置。

使用 presentationNode 是正确的方法，但是你需要在制作动画时从子节点那里获取它_present 来自 child.presentationNode 不是来自 _monkey.presentationNode 也必须在枚举期间而不是在

之后获得

所以首先我需要定义

NSNode * _present;

那我就放动画

   [_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（另外，如果您使用过 iOS11，您可以检查 worldPosition 而不是 position，它也能提供很好的结果）。

- (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);

}

结果出来了

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。希望对你有用。

SceneKit 从动画 SCNNode 获取当前 SCNNode 位置

SceneKit get current SCNNode position form Animated SCNNode

macos

cocoa

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scenekit

scnnode