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当我们想将骨骼绘制到 XNA 中时（使用 KnectSDK 和 C#），您必须计算两个关节之间的差异并在它们之间绘制骨骼。这是绘制骨骼的函数：

private void DrawBone(JointCollection joints, JointType startJoint, JointType endJoint)
    {
        Vector2 start = this.mapMethod(joints[startJoint].Position);
        Vector2 end = this.mapMethod(joints[endJoint].Position);
        Vector2 diff = end - start;
        Vector2 scale = new Vector2(1.0f, diff.Length() / this.boneTexture.Height);

        float angle = (float)Math.Atan2(diff.Y, diff.X) - MathHelper.PiOver2;

        Color color = Color.LightGreen;
        if (joints[startJoint].TrackingState != JointTrackingState.Tracked ||
            joints[endJoint].TrackingState != JointTrackingState.Tracked)
        {
            color = Color.Gray;
        }

        this.SharedSpriteBatch.Draw(this.boneTexture, start, null, color, angle, this.boneOrigin, scale, SpriteEffects.None, 1.0f);
    }

我只是想了解计算角度的方式以及角度公式的工作原理

谢谢

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1 回答 1

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这是计算两个向量之间角度的代码（代码下方的解释）：

    public class Angles
    {
    public double AngleBetweenTwoVectors(Vector3D vectorA, Vector3D vectorB)
        {
            double dotProduct = 0.0;
            dotProduct = Vector3D.DotProduct(vectorA, vectorB);

            return (double)Math.Acos(dotProduct)/Math.PI*180;
        }

        public double[] GetVector(Skeleton skeleton)
        {
            Vector3D ShoulderCenter = new Vector3D(skeleton.Joints[JointType.ShoulderCenter].Position.X, skeleton.Joints[JointType.ShoulderCenter].Position.Y, skeleton.Joints[JointType.ShoulderCenter].Position.Z);
            Vector3D RightShoulder = new Vector3D(skeleton.Joints[JointType.ShoulderRight].Position.X, skeleton.Joints[JointType.ShoulderRight].Position.Y, skeleton.Joints[JointType.ShoulderRight].Position.Z);
            Vector3D LeftShoulder = new Vector3D(skeleton.Joints[JointType.ShoulderLeft].Position.X, skeleton.Joints[JointType.ShoulderLeft].Position.Y, skeleton.Joints[JointType.ShoulderLeft].Position.Z);
            Vector3D RightElbow = new Vector3D(skeleton.Joints[JointType.ElbowRight].Position.X, skeleton.Joints[JointType.ElbowRight].Position.Y, skeleton.Joints[JointType.ElbowRight].Position.Z);
            Vector3D LeftElbow = new Vector3D(skeleton.Joints[JointType.ElbowLeft].Position.X, skeleton.Joints[JointType.ElbowLeft].Position.Y, skeleton.Joints[JointType.ElbowLeft].Position.Z);
            Vector3D RightWrist = new Vector3D(skeleton.Joints[JointType.WristRight].Position.X, skeleton.Joints[JointType.WristRight].Position.Y, skeleton.Joints[JointType.WristRight].Position.Z);
            Vector3D LeftWrist = new Vector3D(skeleton.Joints[JointType.WristLeft].Position.X, skeleton.Joints[JointType.WristLeft].Position.Y, skeleton.Joints[JointType.WristLeft].Position.Z);

           /* ShoulderCenter.Normalize();
            RightShoulder.Normalize();
            LeftShoulder.Normalize();
            RightElbow.Normalize();
            LeftElbow.Normalize();
            RightWrist.Normalize();
            LeftWrist.Normalize();

            if (skeleton.Joints[JointType.ShoulderCenter].TrackingState == JointTrackingState.Tracked) { 

            }
            */

            double AngleRightElbow = AngleBetweenTwoVectors(RightElbow - RightShoulder, RightElbow - RightWrist);
            double AngleRightShoulder = AngleBetweenTwoVectors(RightShoulder - ShoulderCenter, RightShoulder - RightElbow);
            double AngleLeftElbow = AngleBetweenTwoVectors(LeftElbow - LeftShoulder, LeftElbow - LeftWrist);
            double AngleLeftShoulder = AngleBetweenTwoVectors(LeftShoulder - ShoulderCenter, LeftShoulder - LeftElbow);

            double[] Angles = {AngleRightElbow, AngleRightShoulder, AngleLeftElbow, AngleLeftShoulder};
            return Angles;
        }
}

首先我们来看看方法GetVector(Skeleton skeleton)。在这种方法中，我们首先定义我们的 Vector3D（用于您选择的关节）。然后我们调用该方法AngleBetweenTwoVectors并给它两个参数。

但是注意。如果我们只给它关节向量，我们将不会得到正确的角度。我们首先必须从 Vector 中减去周围的 Vectors（我们想要从中获取角度的 Vector）。然后我们将这两个向量传递给方法AngleBetweenTwoVectors。

在这种方法中，我们首先必须计算点积。有关点积的更多信息，请单击此处。使用点积，我们可以计算角度。为此，我们只需要使用该arcos()方法。

我挣扎的另一件事是：集会。您需要导入：

using System.Windows.Media;
using Microsoft.Kinect;
using Microsoft.Kinect.Toolkit.Fusion;
using System.Windows.Media.Media3D;

要获得 [...].Toolkit.Fusion 程序集，请转到“添加引用”并点击“浏览”。然后，您将从 MicrosoftSDK 的/Kinect/Developer Toolkit v1.8.0/Assemblies 引导至程序集目录。导入程序集并将其添加到您的项目中。

于 2014-12-26T14:04:44.213 回答