Function ImportGltf

source/asset_importer.cpp:179–467

// ***********************************************************************

bool ImportGltf(Arena* pArena, lua_State* L, u8 format, String source) {
	// Load file
	String fileContents;
    fileContents.pData = ReadWholeFile(source, &fileContents.length, pArena);

	// @todo: if first few bytes is "gltf" in ascii, then it's a binary, glb file, you can verify this with the extension
	
	// ParseJson
    JsonValue parsed = ParseJsonFile(pArena, fileContents);

	// validate gltf
	bool validGltf = parsed["asset"]["version"].ToString() == "2.0";
    if (!validGltf) {
		Log::Info("File %s is not a valid gltf file for us to import", source);
        return 1;
	}


	lua_newtable(L); // top level table for gltf
	lua_newtable(L); // scene table

	// -------------------------------------
	// Import Scene

	// note that the nodelist in the top level scene does not include child nodes
	// so they are not included in this list, but will be parsed recursively
	JsonValue& topLevelNodeList = parsed["scenes"][0]["nodes"];
	i32 topLevelNodesCount = topLevelNodeList.Count();
    for (int i = 0; i < topLevelNodesCount; i++) {
		i32 nodeId = topLevelNodeList[i].ToInt();
		ParseJsonNodeRecursively(L, parsed, nodeId);
	}

	lua_setfield(L, -2, "scene");


	// -------------------------------------
	// Load buffer data

    ResizableArray<GltfBuffer> rawDataBuffers(pArena);
    JsonValue& jsonBuffers = parsed["buffers"];
    for (int i = 0; i < jsonBuffers.Count(); i++) {
        GltfBuffer buf;
        buf.byteLength = jsonBuffers[i]["byteLength"].ToInt();

        String encodedBuffer = jsonBuffers[i]["uri"].ToString();
		// @todo: the substr 37 tells us which type of gltf file this is, glb, bin as separate file, or base 64
		// these should be the options:
		// data:dontcaretext;base64,
			// this of course is what we have here, a base64 encoded string, embedded in the uri
		// filename.bin
			// this will be another file to load, with the binary data directly there
		// no entry other than byte length, then it is glb and the binary is in the next chunk or chunks
        String decoded = DecodeBase64(pArena, SubStr(encodedBuffer, 37));
        buf.pBytes = (u8*)decoded.pData;

        rawDataBuffers.PushBack(buf);
    }