libobs-d3d11: Don't depend on specific D3DCompiler

I do not want the D3D11 library to depend on a specific compiler
version.  This way, I do not have to distribute D3D Compiler libraries
with the program (proprietary binary blobs).  Any particular version
works because the API for the D3DCompiler function appears to be the
same; the only things that change are other features and additions
mostly (at least as far as I can tell).  Using any version available on
the system should be more than sufficient rather than depending on some
specific D3D compiler version.

If the user doesn't have it, a download of the latest D3D distributables
should be fine, though it should work with the ones that come with
windows 7+ as well.

libobs-d3d11/CMakeLists.txt

@@ -29,7 +29,6 @@ set_target_properties(libobs-d3d11
 target_link_libraries(libobs-d3d11
 	libobs
 	d3d11
-	dxgi
-	d3dcompiler)
+	dxgi)
 
 install_obs_core(libobs-d3d11)

libobs-d3d11/d3d11-shader.cpp

@@ -180,8 +180,8 @@ void gs_shader::Compile(const char *shaderString, const char *file,
 	if (!shaderString)
 		throw "No shader string specified";
 
-	hr = D3DCompile(shaderString, strlen(shaderString), file, NULL, NULL,
-			"main", target,
+	hr = device->d3dCompile(shaderString, strlen(shaderString), file, NULL,
+			NULL, "main", target,
 			D3D10_SHADER_OPTIMIZATION_LEVEL1, 0,
 			shader, errorsBlob.Assign());
 	if (FAILED(hr)) {

libobs-d3d11/d3d11-subsystem.cpp

@@ -135,6 +135,31 @@ gs_swap_chain::gs_swap_chain(gs_device *device, const gs_init_data *data)
 	Init(data);
 }
 
+void gs_device::InitCompiler()
+{
+	char d3dcompiler[40] = {};
+	int ver = 49;
+
+	while (ver > 30) {
+		sprintf_s(d3dcompiler, 40, "D3DCompiler_%02d.dll", ver);
+
+		HMODULE module = LoadLibraryA(d3dcompiler);
+		if (module) {
+			d3dCompile = (pD3DCompile)GetProcAddress(module,
+					"D3DCompile");
+			if (d3dCompile) {
+				return;
+			}
+
+			FreeLibrary(module);
+		}
+
+		ver--;
+	}
+
+	throw "Could not find any D3DCompiler libraries";
+}
+
 void gs_device::InitFactory(uint32_t adapterIdx, IDXGIAdapter1 **padapter)
 {
 	HRESULT hr;
@@ -423,6 +448,7 @@ gs_device::gs_device(const gs_init_data *data)
 		curSamplers[i] = NULL;
 	}
 
+	InitCompiler();
 	InitFactory(data->adapter, adapter.Assign());
 	InitDevice(data, adapter);
 	device_set_render_target(this, NULL, NULL);

libobs-d3d11/d3d11-subsystem.hpp

@@ -605,6 +605,8 @@ struct gs_device {
 	ID3D11BlendState            *curBlendState;
 	D3D11_PRIMITIVE_TOPOLOGY    curToplogy;
 
+	pD3DCompile                 d3dCompile;
+
 	gs_rect                     viewport;
 
 	vector<mat4float>           projStack;
@@ -613,6 +615,7 @@ struct gs_device {
 	matrix4                     curViewMatrix;
 	matrix4                     curViewProjMatrix;
 
+	void InitCompiler();
 	void InitFactory(uint32_t adapterIdx, IDXGIAdapter1 **adapter);
 	void InitDevice(const gs_init_data *data, IDXGIAdapter *adapter);