Fix DX on VK (#40)

This could probably be a little neater, as at the moment it conflates dxvk with being not on windows, but I think that if anyone wants to use dxvk on Windows they can cope with improving this

CMakeLists.txt

@@ -18,22 +18,24 @@ option(SLANG_RHI_BUILD_SHARED "Build shared library" OFF)
 option(SLANG_RHI_BUILD_TESTS "Build tests" ON)
 
 # Determine available backends
-set(SLANG_RHI_HAS_D3D11 OFF)
-set(SLANG_RHI_HAS_D3D12 OFF)
-set(SLANG_RHI_HAS_VULKAN OFF)
-set(SLANG_RHI_HAS_METAL OFF)
-set(SLANG_RHI_HAS_CUDA OFF)
 if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
-    set(SLANG_RHI_HAS_D3D11 ON)
-    set(SLANG_RHI_HAS_D3D12 ON)
-    set(SLANG_RHI_HAS_VULKAN ON)
-    set(SLANG_RHI_HAS_CUDA ON)
+    option(SLANG_RHI_HAS_D3D11 ON)
+    option(SLANG_RHI_HAS_D3D12 ON)
+    option(SLANG_RHI_HAS_VULKAN ON)
+    option(SLANG_RHI_HAS_METAL OFF)
+    option(SLANG_RHI_HAS_CUDA ON)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    set(SLANG_RHI_HAS_VULKAN ON)
-    set(SLANG_RHI_HAS_CUDA ON)
+    option(SLANG_RHI_HAS_D3D11 OFF)
+    option(SLANG_RHI_HAS_D3D12 OFF)
+    option(SLANG_RHI_HAS_VULKAN ON)
+    option(SLANG_RHI_HAS_METAL OFF)
+    option(SLANG_RHI_HAS_CUDA ON)
 elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-    set(SLANG_RHI_HAS_VULKAN ON)
-    set(SLANG_RHI_HAS_METAL ON)
+    option(SLANG_RHI_HAS_D3D11 OFF)
+    option(SLANG_RHI_HAS_D3D12 OFF)
+    option(SLANG_RHI_HAS_VULKAN ON)
+    option(SLANG_RHI_HAS_METAL ON)
+    option(SLANG_RHI_HAS_CUDA OFF)
 endif()
 
 # Backend options

src/d3d/d3d-util.cpp

@@ -615,7 +615,11 @@ Result D3DUtil::compileHLSLShader(
 
 SharedLibraryHandle D3DUtil::getDxgiModule()
 {
-    const char* const libName = SLANG_ENABLE_DXVK ? "dxvk_dxgi" : "dxgi";
+#if SLANG_WINDOWS_FAMILY
+    const char* const libName = "dxgi";
+#else
+    const char* const libName = "libdxvk_dxgi.so";
+#endif
 
     static SharedLibraryHandle s_dxgiModule = [&]()
     {

src/d3d11/d3d11-device.cpp

@@ -48,7 +48,11 @@ Result DeviceImpl::initialize(const Desc& desc)
 
     // Rather than statically link against D3D, we load it dynamically.
     SharedLibraryHandle d3dModule;
-    const char* libName = SLANG_ENABLE_DXVK ? "dxvk_d3d11" : "d3d11";
+#if SLANG_WINDOWS_FAMILY
+    const char* const libName = "d3d11";
+#else
+    const char* const libName = "libdxvk_d3d11.so";
+#endif
     if (SLANG_FAILED(loadSharedLibrary(libName, d3dModule)))
     {
         fprintf(stderr, "error: failed to load '%s'\n", libName);

src/d3d12/d3d12-device.cpp

@@ -442,7 +442,7 @@ Result DeviceImpl::initialize(const Desc& desc)
 #if SLANG_WINDOWS_FAMILY
     const char* libName = "d3d12";
 #else
-    const char* libName = "vkd3d-proton-d3d12";
+    const char* libName = "libvkd3d-proton-d3d12.so";
 #endif
     if (SLANG_FAILED(loadSharedLibrary(libName, d3dModule)))
     {