增加求2向量夹角的方法.

__test__/GeUtils/angleTo.test.ts

@@ -0,0 +1,32 @@
+import { angleTo } from '../../src/Geometry/GeUtils';
+test('俯视图', () =>
+{
+    //-0.5pi 逆时针
+    let v = angleTo(new Vector3(1, 0, 0), new Vector3(0, 1, 0), new Vector3(0, 0, 1)) //?
+    expect(v).toEqual(Math.PI * -0.5)
+
+    //-0.5pi 顺时针
+    let v2 = angleTo(new Vector3(0, 1, 0), new Vector3(1, 0, 0), new Vector3(0, 0, 1)) //?
+    expect(v2).toEqual(Math.PI * 0.5)
+});
+test('仰视', () =>
+{
+    //-0.5pi 顺时针
+    let v = angleTo(new Vector3(1, 0, 0), new Vector3(0, 1, 0), new Vector3(0, 0, -1)) //?
+    expect(v).toEqual(Math.PI * 0.5)
+});
+
+test('右视图', () =>
+{
+    let v = angleTo(new Vector3(0, 0, 1), new Vector3(0, 1, 0), new Vector3(1, 0, 0)) //?
+    expect(v).toEqual(Math.PI * 0.5)
+
+    v = angleTo(new Vector3(0, 1, 0), new Vector3(0, 0, 1), new Vector3(1, 0, 0)) //?
+    expect(v).toEqual(Math.PI * -0.5)
+});
+
+test('0向量', () =>
+{
+    let v = angleTo(new Vector3(1, 0, 0), new Vector3(0, 0, 1), new Vector3(1, 0, 0)) //?
+    expect(v).toEqual(0)
+});

src/Geometry/GeUtils.ts

@@ -37,6 +37,35 @@ export function angle(v: THREE.Vector3, an: number, dis: number)
     v.y += Math.sin(an) * dis;
 }
 
+/**
+ * 求两个向量的夹角,顺时针为正,逆时针为负
+ * 
+ * @param {THREE.Vector3} v1 
+ * @param {THREE.Vector3} v2 
+ * @param {THREE.Vector3} [ref] 参考向量,如果为世界坐标系则为0,0,1
+ * @returns 
+ */
+export function angleTo(v1: THREE.Vector3, v2: THREE.Vector3, ref: THREE.Vector3)
+{
+    if (!ref.equals(new Vector3(0, 0, 1)))
+    {
+        //任意轴坐标系. 使用相机的构造矩阵.
+        ref.multiplyScalar(-1);
+        let up = getLoocAtUpVec(ref);
+        let refOcs = new THREE.Matrix4();
+        refOcs.lookAt(cZeroVec, ref, up);
+        let refOcsInv = new THREE.Matrix4().getInverse(refOcs);
+        v1.applyMatrix4(refOcsInv);
+        v2.applyMatrix4(refOcsInv);
+        v1.z = 0;
+        v2.z = 0;
+    }
+    if (v1.equals(cZeroVec) || v2.equals(cZeroVec))
+        return 0;
+    let cv = new Vector3().crossVectors(v1, v2).normalize();
+    return -cv.z * v1.angleTo(v2);
+}
+
 export function getLoocAtUpVec(dir: THREE.Vector3): THREE.Vector3
 {
     if (dir.equals(cZeroVec))