Question

我一直在使用Scenekit中的GameplayKit（和ARKit，尽管这对这个问题并不重要）应用程序。

具体来说，我一直在使用实体，组件和行为代理，除了一件事以外，它一直都很好用。

我已经设法在组件内部使用GKAgent来移动场景，并避免使用其他对象。这一切似乎都有效。但是，我只能使GKAgent位置工作，而不是“旋转”属性。

import Foundation
import SceneKit
import GameplayKit

class MoveComponent: GKScnComponent, GKAgentDelegate {

   //this class is abbreviated for perfunctory sakes   

   func agentWillUpdate(_ agent: GKAgent) {
    guard let visualComponent = entity?.component(ofType: self.visualType) as? VisualComponent else {
      return
    }

     //works with just "position", but turns possessed with both rotation and position
    agentSeeking.rotation = convertToFloat3x3(float4x4: visualComponent.parentMostNode.simdTransform)
    agentSeeking.position = visualComponent.parentMostNode.simdPosition
  }

  func agentDidUpdate(_ agent: GKAgent) {
    guard let visualComponent = entity?.component(ofType: self.visualType) as? VisualComponent else {
      return
    }

    //works with just "position", but turns possessed with both rotation and position
    visualComponent.parentMostNode.simdPosition = agentSeeking.position
    visualComponent.parentMostNode.simdTransform = convertToFloat4x4(float3x3: agentSeeking.rotation)
  }

}

由于这个问题，我在3x3矩阵和4x4矩阵之间编写了一些转换代码： Converting matrix_float3x3 rotation to SceneKit

import Foundation
import GameplayKit

func convertToFloat3x3(float4x4: simd_float4x4) -> simd_float3x3 {
  let column0 = convertToFloat3 ( float4: float4x4.columns.0 )
  let column1 = convertToFloat3 ( float4: float4x4.columns.1 )
  let column2 = convertToFloat3 ( float4: float4x4.columns.2 )

  return simd_float3x3.init(column0, column1, column2)
}

func convertToFloat3(float4: simd_float4) -> simd_float3 {
  return simd_float3.init(float4.x, float4.y, float4.z)
}

func convertToFloat4x4(float3x3: simd_float3x3) -> simd_float4x4 {
  let column0 = convertToFloat4 ( float3: float3x3.columns.0 )
  let column1 = convertToFloat4 ( float3: float3x3.columns.1 )
  let column2 = convertToFloat4 ( float3: float3x3.columns.2 )
  let identity3 = simd_float4.init(x: 0, y: 0, z: 0, w: 1)

  return simd_float4x4.init(column0, column1, column2, identity3)
}

func convertToFloat4(float3: simd_float3) -> simd_float4 {
  return simd_float4.init(float3.x, float3.y, float3.z, 0)
}

我对这一切都有点新意，而且我不是线性代数大师，所以如果我的矩阵转换功能完全按照他们应该做的那样做，我不是百分之百确定。

当我只使用代理的“position”属性时，一切都很好，但是当我从代理添加旋转/转换到节点时，一切都开始被占有。

任何想法/指示/帮助我做错了什么？

Answer 1

我明白了。矩阵乘法是实现这一目标的关键。任何有3D游戏开发经验的人都可能告诉我没有任何精神上的努力：）

func agentWillUpdate(_ agent: GKAgent) {
    guard let visualComponent = entity?.component(ofType: self.visualType) as? VisualComponent else {
      return
    }

    agentSeeking.position = visualComponent.parentMostNode.simdPosition

    let rotation = visualComponent.parentMostNode.rotation
    let rotationMatrix = SCNMatrix4MakeRotation(rotation.w, rotation.x, rotation.y, rotation.z)
    let float4x4 = SCNMatrix4ToMat4(rotationMatrix)

    agentSeeking.rotation = convertToFloat3x3(float4x4: float4x4)
  }


func agentDidUpdate(_ agent: GKAgent) {
    guard let visualComponent = entity?.component(ofType: self.visualType) as? VisualComponent else {
      return
    }

//    visualComponent.parentMostNode.simdPosition = agentSeeking.position
    let rotation3x3 = agentSeeking.rotation
    let rotation4x4 = convertToFloat4x4(float3x3: rotation3x3)
    let rotationMatrix = SCNMatrix4FromMat4(rotation4x4)
    let position = agentSeeking.position

    let translationMatrix = SCNMatrix4MakeTranslation(position.x, position.y, position.z)
    let transformMatrix = SCNMatrix4Mult(rotationMatrix, translationMatrix)

    visualComponent.parentMostNode.transform = transformMatrix
  }

我希望有人觉得这很有用。

GameplayKit + SceneKit，GKAgent旋转转换

1 个答案: