- Add RHIDescriptorSet base class with Update/UpdateSampler/GetNativeHandle
- Add RHIDescriptorPool with AllocateSet/FreeSet methods
- Add SetGraphicsDescriptorSets/SetComputeDescriptorSets to RHICommandList
- Implement D3D12DescriptorSet using descriptor heap allocation
- Implement OpenGLDescriptorSet using TextureUnitAllocator
- Add CreateDescriptorPool/CreateDescriptorSet factory methods to RHIDevice
- Fix unit test SetVertexBuffer -> SetVertexBuffers API
- Add SetVertexBuffer convenience method for D3D12 backward compatibility
- Update CMakeLists.txt with new source files
- Remove void* parameters from RHICommandList abstract interface
- TransitionBarrier, SetVertexBuffer, SetIndexBuffer, SetRenderTargets,
ClearRenderTarget, ClearDepthStencil, CopyResource now use RHIResourceView*
- SetPipelineState now uses RHIPipelineState* instead of void*
- Simplified SetVertexBuffer to 3 params, SetIndexBuffer to 2 params
- Add internal D3D12 APIs for native type support (low-level escape hatch)
- Fix OpenGL SetRenderTargets to call glDrawBuffers for MRT support
- Update tests to match new interface signatures
All 289 RHI tests pass (158 unit + 64 OpenGL backend + 58 D3D12 backend + 8 integration + 1 disabled)
- Add RHITestFixture with RHI_BACKEND env var support for backend selection
- Add unit tests for: Device, Buffer, Texture, SwapChain, CommandList, CommandQueue, Shader, Fence, Sampler
- Tests can run against D3D12 or OpenGL backends via RHI_BACKEND env var
- Add integration folder placeholder for future integration tests
