Migrate to DX9

[JohnsterID]

Following on from w3dhub/OpenW3D#17, draft attempt at JohnsterID#1

Phase 1: DX8 → DX9 (Windows-only modernization)
├── Update WW3D2 core (dx8wrapper → dx9wrapper)
├── Update all tools (W3DView, WorldBuilder, etc.)
├── Update main games (Generals, Zero Hour)
└── Validate everything works

Phase 2: DX9 → Abstraction Layer
├── Create RenderDevice interface
├── Implement DX9RenderDevice
├── Refactor WW3D to use abstraction
└── Test with DX9 backend

Phase 3: Add Cross-Platform Backends
├── Implement OpenGLRenderDevice
├── Implement VulkanRenderDevice (optional)
├── Add platform-specific windowing
└── Cross-platform builds

[xezon]

My main ask here is to not break DirectX 8 while upgrading to Direct X 9. Have them selectable by compile option, or later, command line argument.

[Mauller]

There's also the need to first unify the directx 8 code between generals and zero hour, i think someone started it then stopped so far through.

I might take a look at finishing that off.

The directx9 codebase also wants to be parallel to the directx8 codebase as this can then allow switching between the two using an API Abstraction layer at a later date.

[JohnsterID]

Ok, I added an attempt at compile-time option.

[HossamAbubakr]

What benefits would the migration bring?

[fbraz3]

In my fork i've implemented the code to choose graphic engine by cmdline parameter.

I think this deepwiki can help to implement the same feature into supehackers repo.
https://deepwiki.com/search/the-windows-version-have-some_1ec57cc3-019a-4233-b258-710d1ac5dd05