If you're developing new effects, debugging with RenderDoc is insanely useful. It looks more intimidating than it is:

It's freeware and you can download the windows version from https://renderdoc.org/builds

After installation, ...

• if you're using the stand alone version, you will need to use an IDE:
  • Install Visual Studio, Rider or Visual Studio Code
  • Clone the source code / main branch
• in your IDE (Rider or Visual Studio)...
  • Switch the build configuration from Release to Debug
  • use Build → Build Solution
  • In TiXL you'll need to enable Settings -> Project -> Shader Debugging
• Exit T3.exe or TiXL.exe, if it's running
• Start RenderDoc
• Find the "Launch Application" tab
• Setup the Executable Path and Working directory. For me this looks like:

Press [Launch]. TiXL should start in its window. Notice the RenderDoc overlay in the top left corner:

Press CTRL+F12 to capture a frame. (Use the CTRL key to avoid switching to Focus mode) Then find and select the tab called "t3 [PID 12334]" and double click the screenshot of the frame capture:

Select the "Texture Viewer" Tab and then explore the render steps on the left:

The Pipeline state will the give you a detailed overview of what PRECISELY the graphics card did for this frame:

• You can analyze and download(!) all textures
• See and debug all shaders
• Check if an effect was called with the parameters you expected
• Check and analyze and download all relevant structure buffers