我正在尝试使用Scene Kit通过鼠标/触摸板拖动棋子。所有对象(棋盘和棋子)都是从Collada文件加载的根节点的子级。
我在Stack Overflow上找到了一个有用的过程描述(其他地方)。使用该描述,我编写了下面代码的初始版本。我的问题是点击坐标和棋子节点位置之间的差异——它们的坐标数量级不同。我仍然不清楚如何将它们匹配起来,使它们处于“同一宇宙”中。我尝试了许多苹果论坛上的建议以及自己的想象。
这是我目前的尝试,大部分基于上面链接的原始版本,并记录了沿途的坐标值。结果是拖动棋子会导致其突然跳出屏幕:
我在Stack Overflow上找到了一个有用的过程描述(其他地方)。使用该描述,我编写了下面代码的初始版本。我的问题是点击坐标和棋子节点位置之间的差异——它们的坐标数量级不同。我仍然不清楚如何将它们匹配起来,使它们处于“同一宇宙”中。我尝试了许多苹果论坛上的建议以及自己的想象。
这是我目前的尝试,大部分基于上面链接的原始版本,并记录了沿途的坐标值。结果是拖动棋子会导致其突然跳出屏幕:
- (NSPoint)
viewPointForEvent: (NSEvent *) event_
{
NSPoint windowPoint = [event_ locationInWindow];
NSPoint viewPoint = [self.view convertPoint: windowPoint
fromView: nil];
return viewPoint;
}
- (SCNHitTestResult *)
hitTestResultForEvent: (NSEvent *) event_
{
NSPoint viewPoint = [self viewPointForEvent: event_];
CGPoint cgPoint = CGPointMake (viewPoint.x, viewPoint.y);
NSArray * points = [(SCNView *) self.view hitTest: cgPoint
options: @{}];
return points.firstObject;
}
- (void)
mouseDown: (NSEvent *) theEvent
{
SCNHitTestResult * result = [self hitTestResultForEvent: theEvent];
SCNVector3 clickWorldCoordinates = result.worldCoordinates;
log output: clickWorldCoordinates x 208.124578, y -12827.223365, z 3163.659073
SCNVector3 screenCoordinates = [(SCNView *) self.view projectPoint: clickWorldCoordinates];
log output: screenCoordinates x 245.128906, y 149.335938, z 0.985565
// save the z coordinate for use in mouseDragged
mouseDownClickOnObjectZCoordinate = screenCoordinates.z;
selectedPiece = result.node; // save selected piece for use in mouseDragged
SCNVector3 piecePosition = selectedPiece.position;
log output: piecePosition x -18.200000, y 6.483060, z 2.350000
offsetOfMouseClickFromPiece.x = clickWorldCoordinates.x - piecePosition.x;
offsetOfMouseClickFromPiece.y = clickWorldCoordinates.y - piecePosition.y;
offsetOfMouseClickFromPiece.z = clickWorldCoordinates.z - piecePosition.z;
log output: offsetOfMouseClickFromPiece x 226.324578, y -12833.706425, z 3161.309073
}
- (void)
mouseDragged: (NSEvent *) theEvent;
{
NSPoint viewClickPoint = [self viewPointForEvent: theEvent];
SCNVector3 clickCoordinates;
clickCoordinates.x = viewClickPoint.x;
clickCoordinates.y = viewClickPoint.y;
clickCoordinates.z = mouseDownClickOnObjectZCoordinate;
log output: clickCoordinates x 246.128906, y 0.000000, z 0.985565
log output: pieceWorldTransform =
m11 = 242.15889219510001, m12 = -0.000045609300002524833, m13 = -0.00000721691076126, m14 = 0,
m21 = 0.0000072168760805499971, m22 = -0.000039452697396149999, m23 = 242.15890446329999, m24 = 0,
m31 = -0.000045609300002524833, m32 = -242.15889219510001, m33 = -0.000039452676995750002, m34 = 0,
m41 = -4268.2349924762348, m42 = -12724.050221935429, m43 = 4852.6652710104272, m44 = 1)
SCNVector3 newPiecePosition;
newPiecePosition.x = offsetOfMouseClickFromPiece.x + clickCoordinates.x;
newPiecePosition.y = offsetOfMouseClickFromPiece.y + clickCoordinates.y;
newPiecePosition.z = offsetOfMouseClickFromPiece.z + clickCoordinates.z;
log output: newPiecePosition x 472.453484, y -12833.706425, z 3162.294639
selectedPiece.position = newPiecePosition;
}
到目前为止,我收到了许多有趣和有用的评论和建议。但是我意识到,为了向前发展,我可能需要一个工作代码示例,展示允许点击和矢量存在于“同一宇宙”中的秘密酱汁。