[Feature] Use librashader for .slangp (RetroArch) shader support

[mr-ke]

Summary

This PR integrates librashader as a modern shader filter backend for BizHawk, replacing the legacy Cg/GLSL shader system with support for modern slangp and glslp shader presets.

Changes

New Files

• BizHawk.Client.Common/DisplayManager/Filters/Librashader.cs - Native bindings for librashader.dll
• BizHawk.Client.Common/DisplayManager/Filters/LibrashaderFilter.cs - Filter implementation for the display pipeline

Modified Files

• BizHawk.Client.Common/DisplayManager/DisplayManagerBase.cs

  • Added LibrashaderFilter field and RefreshLibrashader() method
  • Integrated librashader into BuildDefaultChain() (TargetDisplayFilter=4)
  • Added disposal of filter resources

• BizHawk.Client.EmuHawk/config/DisplayConfig.cs

  • Added new RadioButton for librashader selection
  • Split file filters: .cgp for legacy UserFilter, .slangp/.glslp for librashader
  • Auto-select appropriate filter type based on file extension

• BizHawk.Client.EmuHawk/config/DisplayConfig.Designer.cs

  • Added UI controls for librashader option

• BizHawk.Client.EmuHawk/MainForm.Events.cs

  • Added RefreshLibrashader() call after DisplayConfig changes

Features

• Support for modern slangp and glslp shader presets via librashader
• Automatic shader chain initialization and management
• Proper OpenGL context integration
• Debug logging via Util.DebugWriteLine() (DEBUG builds only)

Requirements

• librashader.dll must be placed in dll\ directory
• OpenGL display method must be selected

Testing

Tested with various slangp shader presets (VHS, CRT effects) on NES and other cores.

Check if completed:

• I have run any relevant test suites
• I, the commit author, have read the licensing terms for contributors (last updated 2024-06-22) and am compliant

[vadosnaprimer]

WOW

What's the workflow to use of an arbitrary libretro shader with this? For example https://github.com/libretro/slang-shaders/blob/master/crt/crt-royale.slangp

[mr-ke]

WOW

What's the workflow to use of an arbitrary libretro shader with this? For example https://github.com/libretro/slang-shaders/blob/master/crt/crt-royale.slangp

Hi, good question, I guess you could follow below steps:

1. git clone https://github.com/libretro/slang-shaders.git
2. copy crt/crt-royale.slangp (preset file) and its depend *.slang into the Folder you want
3. In menu of Config->Display->display method tab->OpenGL (have not port direct3D part yet)
4. In menu of Config->Display->librashader->select, choose your presets you store as upon step
5. Start to play

[YoshiRulz]

Thank you!

[YoshiRulz]

I think this is equivalent to return (texture as OpenGLTexture2D)?.TexID ?? default;. Did you use reflection because OpenGLTexture2D is internal?

[mr-ke]

I think this is equivalent to return (texture as OpenGLTexture2D)?.TexID ?? default;. Did you use reflection because OpenGLTexture2D is internal?

If we do not use reflection to access, then InternalsVisibleTo Include="BizHawk.Client.Common" is needed for project BizHawk.Bizware.Graphics, maybe isolate this changeset without change expose charastic of BizHawk.Bizware.Graphics would be a option as better, what do you say?
Same reason apply to drawFbo

[YoshiRulz]

@CasualPokePlayer dce8e07 y/n

[CasualPokePlayer]

Don't put this librashader handling in BizHawk.Client.Common in the first place, put it in BizHawk.Bizware.Graphics. This should outright be part of the IGL so it can handle the IGL impl specific details (BizHawk.Client.Common should only be calling IGL APIs, it's not supposed to handle raw OpenGL commands).

This impl using raw OpenGL commands also means the feature is locked to the OpenGL display method, rather than also being available to the (default!) Direct3D11 display method (which librashader can support just fine).