Option for not combining buffers

The purpose of this option is to support simpler downstream
processing.

bin/obj2gltf.js

@@ -67,6 +67,11 @@ const argv = yargs
       type: "boolean",
       default: defaults.separateTextures,
     },
+    noCombineBuffers: {
+      describe: "Do not combine data buffers.",
+      type: "boolean",
+      default: defaults.noCombineBuffers,
+    },
     checkTransparency: {
       describe:
         "Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel. By default textures are considered to be opaque.",
@@ -205,6 +210,7 @@ const options = {
   binary: binary,
   separate: argv.separate,
   separateTextures: argv.separateTextures,
+  noCombineBuffers: argv.noCombineBuffers,
   checkTransparency: argv.checkTransparency,
   secure: argv.secure,
   packOcclusion: argv.packOcclusion,

lib/createGltf.js

@@ -108,7 +108,7 @@ function createGltf(objData, options) {
     });
   }
 
-  addBuffers(gltf, bufferState, name, options.separate);
+  addBuffers(gltf, bufferState, name, options.separate, options.noCombineBuffers);
 
   if (options.specularGlossiness) {
     gltf.extensionsUsed.push("KHR_materials_pbrSpecularGlossiness");
@@ -289,7 +289,7 @@ function addSeparateBuffers(gltf, bufferState, name) {
   );
 }
 
-function addBuffers(gltf, bufferState, name, separate) {
+function addBuffers(gltf, bufferState, name, separate, noCombineBuffers) {
   const buffers = bufferState.positionBuffers.concat(
     bufferState.normalBuffers,
     bufferState.uvBuffers,
@@ -301,8 +301,8 @@ function addBuffers(gltf, bufferState, name, separate) {
     buffersByteLength += buffers[i].length;
   }
 
-  if (separate && buffersByteLength > createGltf._getBufferMaxByteLength()) {
-    // Don't combine buffers if the combined buffer will exceed the Node limit.
+  if ((separate && buffersByteLength > createGltf._getBufferMaxByteLength()) || noCombineBuffers) {
+    // Don't combine buffers if the combined buffer will exceed the Node limit, or the user asked for it.
     addSeparateBuffers(gltf, bufferState, name);
   } else {
     addCombinedBuffers(gltf, bufferState, name);

lib/obj2gltf.js

@@ -20,6 +20,7 @@ module.exports = obj2gltf;
  * @param {Boolean} [options.binary=false] Convert to binary glTF.
  * @param {Boolean} [options.separate=false] Write out separate buffer files and textures instead of embedding them in the glTF.
  * @param {Boolean} [options.separateTextures=false] Write out separate textures only.
+ * @param {Boolean} [options.noCombineBuffers=false] Do not combine buffers,
  * @param {Boolean} [options.checkTransparency=false] Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
  * @param {Boolean} [options.secure=false] Prevent the converter from reading textures or mtl files outside of the input obj directory.
  * @param {Boolean} [options.packOcclusion=false] Pack the occlusion texture in the red channel of the metallic-roughness texture.
@@ -50,6 +51,7 @@ function obj2gltf(objPath, options) {
   options.separateTextures =
     defaultValue(options.separateTextures, defaults.separateTextures) ||
     options.separate;
+  options.noCombineBuffers = defaultValue(options.noCombineBuffers, defaults.noCombineBuffers);
   options.checkTransparency = defaultValue(
     options.checkTransparency,
     defaults.checkTransparency
@@ -173,6 +175,12 @@ obj2gltf.defaults = {
    * @default false
    */
   separateTextures: false,
+  /**
+   * Gets or sets whether to use different buffers for different meshes.
+   * @type Boolean
+   * @default false
+   */
+  noCombineBuffers: false,
   /**
    * Gets or sets whether the converter will do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
    * @type Boolean

lib/writeGltf.js

@@ -36,7 +36,7 @@ function writeGltf(gltf, options) {
     if (separate) {
       promises.push(writeSeparateBuffers(gltf, options));
     } else if (!binary) {
-      writeEmbeddedBuffer(gltf);
+      writeEmbeddedBuffers(gltf);
     }
 
     const binaryBuffer = gltf.buffers[0].extras._obj2gltf.source;
@@ -158,20 +158,23 @@ function writeSeparateTextures(gltf, options) {
   );
 }
 
-function writeEmbeddedBuffer(gltf) {
-  const buffer = gltf.buffers[0];
-  const source = buffer.extras._obj2gltf.source;
+function writeEmbeddedBuffers(gltf) {
+  const buffersLength = gltf.buffers.length;
+  for (let i = 0; i < buffersLength; ++i) {
+    const buffer = gltf.buffers[i];
+    const source = buffer.extras._obj2gltf.source;
 
-  // Buffers larger than ~192MB cannot be base64 encoded due to a NodeJS limitation. Source: https://github.com/nodejs/node/issues/4266
-  if (source.length > 201326580) {
-    throw new RuntimeError(
-      "Buffer is too large to embed in the glTF. Use the --separate flag instead."
-    );
+    // Buffers larger than ~192MB cannot be base64 encoded due to a NodeJS limitation. Source: https://github.com/nodejs/node/issues/4266
+    if (source.length > 201326580) {
+      throw new RuntimeError(
+        "Buffer is too large to embed in the glTF. Use the --separate flag instead."
+      );
+    }
+
+    buffer.uri = `data:application/octet-stream;base64,${source.toString(
+      "base64"
+    )}`;
   }
-
-  buffer.uri = `data:application/octet-stream;base64,${source.toString(
-    "base64"
-  )}`;
 }
 
 function writeEmbeddedTextures(gltf) {