From cde48d1750c7f7579fa40d506f963ea6ed8f9130 Mon Sep 17 00:00:00 2001
From: minggo <nudtzxm@gmail.com>
Date: Wed, 17 Apr 2024 14:00:59 +0800
Subject: [PATCH] add Vec2.toVec3() and Vec3.toVec2() (#16906)

* add Vec2.toVec3() and Vec3.toVec2()
---
 cocos/core/math/vec2.ts      | 10 ++++++++++
 cocos/core/math/vec3.ts      | 12 ++++++++++++
 tests/core/math/vec2.test.ts | 15 +++++++++++++++
 tests/core/math/vec3.test.ts | 13 +++++++++++++
 4 files changed, 50 insertions(+)

diff --git a/cocos/core/math/vec2.ts b/cocos/core/math/vec2.ts
index a05053c5d2e..0ca486914a8 100644
--- a/cocos/core/math/vec2.ts
+++ b/cocos/core/math/vec2.ts
@@ -834,6 +834,16 @@ export class Vec2 extends ValueType {
         this.y = matrix.m01 * x + matrix.m05 * y + matrix.m13;
         return this;
     }
+
+    /**
+     * @en Converts the current Vec2 object to a Vec3 object by adding a z-component of 0.
+     * @zh 将当前的Vec2对象转换为一个z分量为0的Vec3对象。
+     * @returns Vec3 @en A new Vec3 object created from the current Vec2 object with z-component set to 0.
+     * @zh 从当前的Vec2对象创建一个新的Vec3对象，其中z分量设置为0。
+     */
+    public toVec3 (): Vec3 {
+        return new Vec3(this.x, this.y, 0);
+    }
 }
 
 CCClass.fastDefine('cc.Vec2', Vec2, { x: 0, y: 0 });
diff --git a/cocos/core/math/vec3.ts b/cocos/core/math/vec3.ts
index 8a2cb04b91e..0a9f3b32c79 100644
--- a/cocos/core/math/vec3.ts
+++ b/cocos/core/math/vec3.ts
@@ -23,6 +23,7 @@
  THE SOFTWARE.
 */
 
+import type { Vec2 }  from './vec2';
 import { CCClass } from '../data/class';
 import { ValueType } from '../value-types/value-type';
 import { Mat4 } from './mat4';
@@ -1237,6 +1238,17 @@ export class Vec3 extends ValueType {
         this.z = (matrix.m02 * x + matrix.m06 * y + matrix.m10 * z + matrix.m14) * rhw;
         return this;
     }
+
+    /**
+     * @en Converts the current Vec3 object to a Vec2 object by adding a z-component of 0.
+     * @zh 将当前的Vec3对象转换为一个z分量为0的Vec3对象。
+     * @returns Vec2 @en A new Vec2 object created from the current Vec3 object with z-component ignored.
+     * @zh 从当前的Vec3对象创建一个新的Vec2对象，丢弃z分量。
+     */
+    public toVec2 (): Vec2 {
+        // eslint-disable-next-line
+        return new legacyCC.Vec2(this.x, this.y);
+    }
 }
 
 CCClass.fastDefine('cc.Vec3', Vec3, { x: 0, y: 0, z: 0 });
diff --git a/tests/core/math/vec2.test.ts b/tests/core/math/vec2.test.ts
index 68cab7a03c2..bfaeb687d43 100644
--- a/tests/core/math/vec2.test.ts
+++ b/tests/core/math/vec2.test.ts
@@ -103,6 +103,21 @@ describe('Test Vec2', () => {
             t(v1, v2(v1Angle + 280.0001), 280.0001 - 360);
         }
     });
+
+    test(`toVec3`, () => {
+        const vec2 = new Vec2(1, 2);
+        const vec3 = vec2.toVec3();
+        expect(vec3.x).toBe(1);
+        expect(vec3.y).toBe(2);
+        expect(vec3.z).toBe(0);
+
+        // vec2 will not affect vec3.
+        vec2.x = 2;
+        vec2.y = 3;
+        expect(vec3.x).toBe(1);
+        expect(vec3.y).toBe(2);
+        expect(vec3.z).toBe(0);
+    });
 });
 
 function polar(angle: number, length: number) {
diff --git a/tests/core/math/vec3.test.ts b/tests/core/math/vec3.test.ts
index fe0674eb07d..63b0d2881fd 100644
--- a/tests/core/math/vec3.test.ts
+++ b/tests/core/math/vec3.test.ts
@@ -330,4 +330,17 @@ describe('Test Vec3', () => {
             return result;
         }
     });
+
+    test(`toVec2`, () => {
+        const vec3 = new Vec3(1, 2, 3);
+        const vec2 = vec3.toVec2();
+        expect(vec2.x).toBe(1);
+        expect(vec2.y).toBe(2);
+
+        // vec3 will not affect vec2.
+        vec3.x = 2;
+        vec3.y = 3;
+        expect(vec2.x).toBe(1);
+        expect(vec2.y).toBe(2);
+    });
 });
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