This repository is Part 3 of Vercidium's Free Friday series.

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This demo uses multiple threads to stream PNG files from the disk to textures on the graphics card. It covers many aspects of OpenGL:

• Multithreading
• Fences
• PBOs
• Textures
• Pools
• Shared contexts

This project uses Silk.NET so it should be cross-platform, but I've only tested it on Windows.

There are two folders:

• boring contains code that's common across each of these Free Friday posts
• interesting contains the code you're interested in

Key files:

• Client.cs creates the window and contains the render loop
• AsyncTextureLoader.cs orchestrates the texture streaming process from disk to GPU. It does this in 3 steps:
  • Step 1: BitmapLoader.cs loads PNGs from disk, decodes them using SkiaSharp, and stores the raw image data in an RGBA array
  • Step 2: BitmapToPBO copies the raw image data to a PBO and flushes it
  • Step 3: Copies from the PBO to the texture on a shared background OpenGL context

TODO:

• Add bandwidth logs (MB/s from disk, MB/s from disk to PBO, etc)
• Add additional info here about how the background OpenGL context works

References:

• songho's PBO article and demo
• Ground texture by Cethiel