[Bug Report] Chapter 8 - mainProcessing() is never fully described

[Rusettsten]

The book portion of Chapter 8 never fully describes ModelGenerator.mainProcessing() and omits the following information at the beginning of the method:

    private void mainProcessing() throws IOException {
        Logger.debug("Loading model data [{}]", modelPath);
        var modelFile = new File(modelPath);
        if (!modelFile.exists()) {
            throw new RuntimeException("Model path does not exist [" + modelPath + "]");
        }

        AIScene aiScene = aiImportFile(modelPath, FLAGS);
        if (aiScene == null) {
            throw new RuntimeException("Error loading model [modelPath: " + modelPath + "]");
        }

        String modelId = modelFile.getName();
        if (modelId.contains(".")) {
            modelId = modelId.substring(0, modelId.lastIndexOf('.'));
        }

        ModelBinData modelBinData = new ModelBinData(modelPath);

        int numMaterials = aiScene.mNumMaterials();
        Logger.debug("Number of materials: {}", numMaterials);
        List<MaterialData> matList = new ArrayList<>();
        File parentDirectory = modelFile.getParentFile();
        for (int i = 0; i < numMaterials; i++) {
            var aiMaterial = AIMaterial.create(aiScene.mMaterials().get(i));
            MaterialData material = processMaterial(aiScene, aiMaterial, modelId, parentDirectory.getPath(), i);
            matList.add(material);
        }

        int numMeshes = aiScene.mNumMeshes();
        PointerBuffer aiMeshes = aiScene.mMeshes();
        List<MeshData> meshList = new ArrayList<>();
        for (int i = 0; i < numMeshes; i++) {
            AIMesh aiMesh = AIMesh.create(aiMeshes.get(i));
            MeshData meshData = processMesh(aiMesh, matList, i, modelBinData);
            meshList.add(meshData);
        }

        var model = new ModelData(modelId, meshList, modelBinData.getVtxFilePath(), modelBinData.getIdxFilePath());