avoid possible error when polynomial faces do not get populated due to unsupported format

src/Tools/babylon.dds.ts

@@ -332,7 +332,7 @@
         }
 
         private static _ExtractLongWordOrder(value: number): number {
-            if (value === 0 ||value === 255 || value === -16777216) {
+            if (value === 0 || value === 255 || value === -16777216) {
                 return 0;
             }
 
@@ -373,8 +373,8 @@
         }
 
         public static UploadDDSLevels(engine: Engine, gl: WebGLRenderingContext, arrayBuffer: any, info: DDSInfo, loadMipmaps: boolean, faces: number, lodIndex = -1, currentFace?: number) {
-            var sphericalPolynomialFaces:Nullable<Array<ArrayBufferView>> = null;
-            if(info.sphericalPolynomial){
+            var sphericalPolynomialFaces: Nullable<Array<ArrayBufferView>> = null;
+            if (info.sphericalPolynomial) {
                 sphericalPolynomialFaces = new Array<ArrayBufferView>();
             }
             var ext = engine.getCaps().s3tc;
@@ -457,7 +457,7 @@
             let rOffset = DDSTools._ExtractLongWordOrder(header[off_RMask]);
             let gOffset = DDSTools._ExtractLongWordOrder(header[off_GMask]);
             let bOffset = DDSTools._ExtractLongWordOrder(header[off_BMask]);
-            let aOffset = DDSTools._ExtractLongWordOrder(header[off_AMask]);            
+            let aOffset = DDSTools._ExtractLongWordOrder(header[off_AMask]);
 
             if (computeFormats) {
                 format = engine._getWebGLTextureType(info.textureType);
@@ -487,13 +487,13 @@
                             if (engine._badOS || engine._badDesktopOS || (!engine.getCaps().textureHalfFloat && !engine.getCaps().textureFloat)) { // Required because iOS has many issues with float and half float generation
                                 if (bpp === 128) {
                                     floatArray = DDSTools._GetFloatAsUIntRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i);
-                                    if(sphericalPolynomialFaces && i == 0){
+                                    if (sphericalPolynomialFaces && i == 0) {
                                         sphericalPolynomialFaces.push(DDSTools._GetFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i));
                                     }
                                 }
                                 else if (bpp === 64) {
                                     floatArray = DDSTools._GetHalfFloatAsUIntRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i);
-                                    if(sphericalPolynomialFaces && i == 0){
+                                    if (sphericalPolynomialFaces && i == 0) {
                                         sphericalPolynomialFaces.push(DDSTools._GetHalfFloatAsFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i));
                                     }
                                 }
@@ -505,12 +505,12 @@
                             else {
                                 if (bpp === 128) {
                                     floatArray = DDSTools._GetFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i);
-                                    if(sphericalPolynomialFaces && i == 0){
+                                    if (sphericalPolynomialFaces && i == 0) {
                                         sphericalPolynomialFaces.push(floatArray);
                                     }
                                 } else if (bpp === 64 && !engine.getCaps().textureHalfFloat) {
                                     floatArray = DDSTools._GetHalfFloatAsFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i);
-                                    if(sphericalPolynomialFaces && i == 0){
+                                    if (sphericalPolynomialFaces && i == 0) {
                                         sphericalPolynomialFaces.push(floatArray);
                                     }
 
@@ -519,7 +519,7 @@
                                     internalFormat = engine._getRGBABufferInternalSizedFormat(info.textureType);
                                 } else { // 64
                                     floatArray = DDSTools._GetHalfFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i);
-                                    if(sphericalPolynomialFaces && i == 0){
+                                    if (sphericalPolynomialFaces && i == 0) {
                                         sphericalPolynomialFaces.push(DDSTools._GetHalfFloatAsFloatRGBAArrayBuffer(width, height, dataOffset, dataLength, arrayBuffer, i));
                                     }
                                 }
@@ -565,7 +565,7 @@
                     break;
                 }
             }
-            if(sphericalPolynomialFaces){
+            if (sphericalPolynomialFaces && sphericalPolynomialFaces.length > 0) {
                 info.sphericalPolynomial = CubeMapToSphericalPolynomialTools.ConvertCubeMapToSphericalPolynomial({
                     size: header[off_width],
                     right: sphericalPolynomialFaces[0],
@@ -578,6 +578,8 @@
                     type: Engine.TEXTURETYPE_FLOAT,
                     gammaSpace: false,
                 });
+            } else {
+                info.sphericalPolynomial = undefined;
             }
         }
     }