Wt

I am using WGLWidget to load 3D models which can be of large size. In order to speed it up, I use binary buffer option to transfer vertex buffers. Documentations tates this about using binary buffers:

Binary buffer transfers

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In bufferDatafv(), there is an additional boolean argument where you can indicate that you want the data to be transferred to the client in binary form. A WMemoryResource is created for each of these buffers. If you know all previous resources are not required in the client anymore, you can free memory with the method clearBinaryResources() (the memory is also managed, so this is not neccesary). If you want to manage these resources entirely by yourself, the following method can be used.

Using createAndLoadArrayBuffer(), you can load an array buffer in binary format from an URL. This will cause the client to fetch the given URL, and make the contents of the file available in an ArrayBuffer, which can then be used by BufferData() to bind them to an OpenGL buffer. This is ideal to load VBO buffers in a faster way, as it avoids converting floats to text strings on the server and then back to floats on the client. You can combine this with the use of WResource (e.g. WMemoryResource) to send an std::vector of vertices to the client. Note that using ArrayBuffer is not possible when you want a fall-back in the form of server-side rendering.

Everything works as expected except one thing - I set the status message as 'Ready' when the file is loaded and buffer data is updated on server side. But there is a delay between the time buffer data is set on server and the time it is sent to client and updated on client side.

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Please see the video and notice the delay between status is set to "Ready" at the bottom and the time when model is rendered - Video

My understanding is that when binary buffer is used, data is transferred as a memory resource - one per vertex buffer (vertices, normals, texture coordinates etc) . I think a signal which is emitted when all binary buffer data is available on client side will be very useful to indicate that the model is "actually" ready so that status message can be updated at the most apt time.

Or may be there is some other mechanism to handle it?

I would appreciate some input on how to handle this.

The delay increases significantly on a hosted website instead of localhost.