JsGPUOpenLoader.js

class JsGPUOpenMaterialLoader {
    constructor() {
        if (JsGPUOpenMaterialLoader.instance) {
            return JsGPUOpenMaterialLoader.instance;
        }
 
        this.rootUrl = 'https://api.matlib.gpuopen.com/api';
        this.url = `${this.rootUrl}/materials`;
        this.packageUrl = `${this.rootUrl}/packages`;
        this.materials = null;
        this.materialNames = null;
 
        this.logger = console;
 
        // Cache the instance
        JsGPUOpenMaterialLoader.instance = this;
    }
    
    getMaterialList() {
        return this.materials;
    }

    getMaterialNames() {
        return this.materialNames;
    }

    async getMaterials(batchSize = 50) {
 
        /*
         * Get the materials returned from the GPUOpen material database.
         * Will loop based on the linked-list of materials stored in the database.
         * Currently, the batch size requested is 100 materials per batch.
         * @param batchSize: Number of materials to fetch per batch
         * @return: List of material lists
         */
        
        this.materials = [];
        this.materialNames = [];
 
        let url = this.url;
 
        // Get batches of materials. Start with the first N.
        let params = new URLSearchParams({
            limit: batchSize,
            offset: 0
        });
 
        // Append & parameters to url using params
        if (params) {
            url += '?' + params.toString();
        }
 
        let haveMoreMaterials = true;
        while (haveMoreMaterials) 
        {
            try {
 
                console.log('- Fetch material infoormation from url:', url)
 
                const response = await fetch(url);
 
                if (!response.ok) {
                    throw new Error(`HTTP error! status: ${response.status}`);
                }
 
                const jsonData = await response.json(); 
                this.materials.push(jsonData)   
 
                for (const material of jsonData.results) {
                    this.materialNames.push(material['title']);
                }
                
                //console.log("Number of materials fetched:", jsonData.results.length)
 
                let nextURL = jsonData.next
                if (nextURL) {
                    //console.log('Next URL: ', jsonData.next)
                    url = nextURL;
                    haveMoreMaterials = true
                }
                else
                {
                    console.log('Finished fetching materials')
                    haveMoreMaterials = false;
                    break;
                }
 
            } catch (error) {
                this.logger.info(`Error: ${error.message}`);
                haveMoreMaterials = true;
            }
        }
 
        return this.materials;
    }    

    async downloadPackage(listNumber, materialNumber, packageId = 0) {
        if (this.materials === null || this.materials.length === 0) {
            console.error('No materials available. Please fetch materials first.');
            return [null, null];
        }
 
        const jsonData = this.materials[listNumber];
        if (!jsonData) {
            console.error('Invalid list number:', listNumber);
            return [null, null];
        }
 
        let jsonResults = null;
        let jsonResult = null;
        if ('results' in jsonData) {
            jsonResults = jsonData['results'];
            if (jsonResults.length <= materialNumber) {
                console.error('Invalid material number:', materialNumber);
                return [null, null];
            } else {
                jsonResult = jsonResults[materialNumber];
            }
        }
 
        if (!jsonResult) {
            console.error('Material not found for list number:', listNumber, ' material number:', materialNumber);
            return [null, null];
        }
 
        let jsonPackages = null;
        if ('packages' in jsonResult) {
            jsonPackages = jsonResult['packages'];
        }
        if (!jsonPackages) {
            console.error('No packages found for material:', jsonResult['title']);
            return [null, null];
        }
 
        if (jsonPackages.length <= packageId) {
            console.error('Invalid package ID:', packageId, ' for material:', jsonResult['title']);
            return [null, null];
        }
        const packageIdValue = jsonPackages[packageId];
 
        if (!packageIdValue) {
            console.error('Package ID not found for material:', jsonResult['title'], ' package index:', packageId);
            return [null, null];
        }
 
        const url = `${this.packageUrl}/${packageIdValue}/download`;
        const response = await fetch(url);
        const data = await response.arrayBuffer();
        const title = jsonResult['title'];
 
        console.log(`- Loader: Downloaded package: ${title} from ${url}`);
        return [data, title];
    }

    findMaterialsByName(materialName) 
    {
        if (!this.materials) {
            return [];
        }
 
        const materialsList = [];
        let listNumber = 0;
        
        // Create a RegExp object for case-insensitive matching
        const regex = new RegExp(materialName, 'i');
        
        this.materials.forEach((materialList, materialIndex) => {
            let materialNumber = 0;
 
            materialList['results'].forEach((material) => {
 
                //console.log('testing material:', material['title'], ' with regex:', regex)
                if (regex.test(material['title'])) {
                    materialsList.push({
                        listNumber: listNumber,
                        materialNumber: materialNumber,
                        title: material['title'],
                    });
                }
                materialNumber += 1;
            });
 
            listNumber += 1;
        });
 
        return materialsList;
    }        

    async downloadPackageByExpression(searchExpr, packageId = 0) {
        const downloadList = [];
 
        const foundList = this.findMaterialsByName(searchExpr);
        if (foundList.length > 0) {
            for (const found of foundList) {
                const listNumber = found['listNumber'];
                const materialNumber = found['materialNumber'];
                const matName = found['title'];
                this.logger.info(`> Download material: ${matName} List: ${listNumber}. Index: ${materialNumber}`);
                const [data, title] = await this.downloadPackage(listNumber, materialNumber, packageId);
                downloadList.push([data, title]);
            }
        }
        return downloadList;
    }
}
 
// Export a singleton instance of the class
module.exports = new JsGPUOpenMaterialLoader();