From cda1278efed3f759661e0764ac4556de2571e674 Mon Sep 17 00:00:00 2001
From: AZhan <njktsmshh@163.com>
Date: Thu, 3 Mar 2022 17:41:16 +0800
Subject: [PATCH] fix: ignore scale (#670)

* fix: camera ignore scale
---
 packages/core/src/Camera.ts | 52 ++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/Camera.ts b/packages/core/src/Camera.ts
index 9b4baf5ef2..a089b1c64f 100644
--- a/packages/core/src/Camera.ts
+++ b/packages/core/src/Camera.ts
@@ -1,4 +1,4 @@
-import { BoundingFrustum, MathUtil, Matrix, Ray, Vector2, Vector3, Vector4 } from "@oasis-engine/math";
+import { BoundingFrustum, MathUtil, Matrix, Quaternion, Ray, Vector2, Vector3, Vector4 } from "@oasis-engine/math";
 import { Logger } from "./base";
 import { deepClone, ignoreClone } from "./clone/CloneManager";
 import { Component } from "./Component";
@@ -35,6 +35,52 @@ export class Camera extends Component {
   private static _inverseProjectionMatrixProperty = Shader.getPropertyByName("u_projInvMat");
   private static _cameraPositionProperty = Shader.getPropertyByName("u_cameraPos");
 
+  /**
+   * Compute the inverse of the rotation translation matrix.
+   * @param rotation - The rotation used to calculate matrix
+   * @param translation - The translation used to calculate matrix
+   * @param out - The calculated matrix
+   */
+  private static _rotationTranslationInv(rotation: Quaternion, translation: Vector3, out: Matrix) {
+    const oe = out.elements;
+    const { x, y, z, w } = rotation;
+    let x2 = x + x;
+    let y2 = y + y;
+    let z2 = z + z;
+
+    let xx = x * x2;
+    let xy = x * y2;
+    let xz = x * z2;
+    let yy = y * y2;
+    let yz = y * z2;
+    let zz = z * z2;
+    let wx = w * x2;
+    let wy = w * y2;
+    let wz = w * z2;
+
+    oe[0] = 1 - (yy + zz);
+    oe[1] = xy + wz;
+    oe[2] = xz - wy;
+    oe[3] = 0;
+
+    oe[4] = xy - wz;
+    oe[5] = 1 - (xx + zz);
+    oe[6] = yz + wx;
+    oe[7] = 0;
+
+    oe[8] = xz + wy;
+    oe[9] = yz - wx;
+    oe[10] = 1 - (xx + yy);
+    oe[11] = 0;
+
+    oe[12] = translation.x;
+    oe[13] = translation.y;
+    oe[14] = translation.z;
+    oe[15] = 1;
+
+    out.invert();
+  }
+
   /** Shader data. */
   readonly shaderData: ShaderData = new ShaderData(ShaderDataGroup.Camera);
 
@@ -191,10 +237,10 @@ export class Camera extends Component {
    * View matrix.
    */
   get viewMatrix(): Readonly<Matrix> {
-    // Remove scale
     if (this._isViewMatrixDirty.flag) {
       this._isViewMatrixDirty.flag = false;
-      Matrix.invert(this._transform.worldMatrix, this._viewMatrix);
+      // Ignore scale.
+      Camera._rotationTranslationInv(this._transform.worldRotationQuaternion, this._transform.worldPosition, this._viewMatrix);
     }
     return this._viewMatrix;
   }