make PMREM blur order consistent (#28166)

* make blur order consistent

* fix format

src/extras/PMREMGenerator.js

@@ -49,16 +49,16 @@ const INV_PHI = 1 / PHI;
 // Vertices of a dodecahedron (except the opposites, which represent the
 // same axis), used as axis directions evenly spread on a sphere.
 const _axisDirections = [
-	/*@__PURE__*/ new Vector3( 1, 1, 1 ),
-	/*@__PURE__*/ new Vector3( - 1, 1, 1 ),
-	/*@__PURE__*/ new Vector3( 1, 1, - 1 ),
-	/*@__PURE__*/ new Vector3( - 1, 1, - 1 ),
-	/*@__PURE__*/ new Vector3( 0, PHI, INV_PHI ),
-	/*@__PURE__*/ new Vector3( 0, PHI, - INV_PHI ),
-	/*@__PURE__*/ new Vector3( INV_PHI, 0, PHI ),
-	/*@__PURE__*/ new Vector3( - INV_PHI, 0, PHI ),
+	/*@__PURE__*/ new Vector3( - PHI, INV_PHI, 0 ),
 	/*@__PURE__*/ new Vector3( PHI, INV_PHI, 0 ),
-	/*@__PURE__*/ new Vector3( - PHI, INV_PHI, 0 ) ];
+	/*@__PURE__*/ new Vector3( - INV_PHI, 0, PHI ),
+	/*@__PURE__*/ new Vector3( INV_PHI, 0, PHI ),
+	/*@__PURE__*/ new Vector3( 0, PHI, - INV_PHI ),
+	/*@__PURE__*/ new Vector3( 0, PHI, INV_PHI ),
+	/*@__PURE__*/ new Vector3( - 1, 1, - 1 ),
+	/*@__PURE__*/ new Vector3( 1, 1, - 1 ),
+	/*@__PURE__*/ new Vector3( - 1, 1, 1 ),
+	/*@__PURE__*/ new Vector3( 1, 1, 1 ) ];
 
 /**
  * This class generates a Prefiltered, Mipmapped Radiance Environment Map
@@ -444,12 +444,13 @@ class PMREMGenerator {
 		const renderer = this._renderer;
 		const autoClear = renderer.autoClear;
 		renderer.autoClear = false;
+		const n = this._lodPlanes.length;
 
-		for ( let i = 1; i < this._lodPlanes.length; i ++ ) {
+		for ( let i = 1; i < n; i ++ ) {
 
 			const sigma = Math.sqrt( this._sigmas[ i ] * this._sigmas[ i ] - this._sigmas[ i - 1 ] * this._sigmas[ i - 1 ] );
 
-			const poleAxis = _axisDirections[ ( i - 1 ) % _axisDirections.length ];
+			const poleAxis = _axisDirections[ ( n - i - 1 ) % _axisDirections.length ];
 
 			this._blur( cubeUVRenderTarget, i - 1, i, sigma, poleAxis );