fix: calcAverageFrameTime Remove one maximum (#7382)

Co-authored-by: lingkong <gaokun333@qq.com>
Co-authored-by: 白熱 <sonne@asaki.me>

packages/engine-render/src/basics/__tests__/performance-monitor.spec.ts

@@ -97,4 +97,15 @@ describe('performance monitor', () => {
         expect(average.averageFrameTime).toBeCloseTo(16.67, 2);
         expect(average.variance).toBe(0);
     });
+
+    it('removes only one minimum and maximum from duplicate samples', () => {
+        const average = new RollingAverage(3);
+
+        for (const frameTime of [10, 10, 20]) {
+            average.addFrameTime(frameTime);
+            average.calcAverageFrameTime();
+        }
+
+        expect(average.averageFrameTime).toBe(10);
+    });
 });

packages/engine-render/src/basics/performance-monitor.ts

@@ -265,11 +265,17 @@ export class RollingAverage {
             this._sampleCount++;
         }
 
-        // Remove one maximum and one minimum to ensure the accuracy of the average value.
-        const min = Math.min(...this._samples);
-        const max = Math.min(...this._samples);
-        const filteredData = this._samples.filter((v) => v !== max && v !== min);
-        this.averageFrameTime = filteredData.reduce((sum, value) => sum + value, 0) / filteredData.length;
+        // Once the window is full, exclude one minimum and maximum to reduce outlier bias.
+        const shouldTrimExtremes = this.isSaturated() && this._sampleCount > 2;
+        const sampleSum = this._samples.reduce((sum, value) => sum + value, 0);
+
+        if (shouldTrimExtremes) {
+            const min = Math.min(...this._samples);
+            const max = Math.max(...this._samples);
+            this.averageFrameTime = (sampleSum - min - max) / (this._sampleCount - 2);
+        } else {
+            this.averageFrameTime = sampleSum / this._sampleCount;
+        }
 
         // add new value to mean
         delta = frameDuration - this.averageFrameTime;