Removed g_UseFixedFunctionVertexShader, as it never changes from true anymore.

Also removed related code that's no longer required either :
host D3DDevice calls to SetTransform and SetLightEnable,
and the EmuXB2PC_D3DTS tooling function.

src/core/hle/D3D8/Direct3D9/Direct3D9.cpp

@@ -6858,11 +6858,7 @@ void CxbxImpl_SetTransform
     LOG_INIT
 
 	d3d8TransformState.SetTransform(State, pMatrix);
-
-	auto d3d9State = EmuXB2PC_D3DTS(State);
-
-    HRESULT hRet = g_pD3DDevice->SetTransform(d3d9State, pMatrix);
-    DEBUG_D3DRESULT(hRet, "g_pD3DDevice->SetTransform");    
+	// Note : SetTransform is handled in our fixed function shader  - see UpdateFixedFunctionVertexShaderState()
 }
 
 // MultiplyTransform should call SetTransform, we'd like to know if it didn't
@@ -7742,7 +7738,7 @@ void CxbxUpdateHostVertexShaderConstants()
 	// So we can skip updates
 	static bool isXboxConstants = false;
 
-	if (g_Xbox_VertexShaderMode == VertexShaderMode::FixedFunction && g_UseFixedFunctionVertexShader) {
+	if (g_Xbox_VertexShaderMode == VertexShaderMode::FixedFunction) {
 		// Write host FF shader state
 		// TODO dirty tracking like for Xbox constants?
 		UpdateFixedFunctionVertexShaderState();
@@ -8546,12 +8542,7 @@ xbox::hresult_xt WINAPI xbox::EMUPATCH(D3DDevice_LightEnable)
 	xbox::hresult_xt hRet = XB_TRMP(D3DDevice_LightEnable)(Index, bEnable);
 
 	d3d8LightState.EnableLight(Index, bEnable);
-#ifdef CXBX_USE_D3D11
-	// Under D3D11, LightEnable relies on our fixed function shader (see if (g_Xbox_VertexShaderMode == VertexShaderMode::FixedFunction && g_UseFixedFunctionVertexShader) {
-#else
-	HRESULT hRet_host = g_pD3DDevice->LightEnable(Index, bEnable);
-	DEBUG_D3DRESULT(hRet_host, "g_pD3DDevice->LightEnable");
-#endif
+	// Note : LightEnable is handled in our fixed function shader  - see UpdateFixedFunctionVertexShaderState()
 
     return hRet;
 }

src/core/hle/D3D8/Direct3D9/TextureStates.cpp

@@ -33,7 +33,7 @@
 #include "EmuShared.h"
 #include "core/hle/Intercept.hpp"
 #include "RenderStates.h"
-#include "core/hle/D3D8/XbVertexShader.h" // For g_UseFixedFunctionVertexShader, g_Xbox_VertexShaderMode and VertexShaderMode::FixedFunction
+#include "core/hle/D3D8/XbVertexShader.h" // For g_Xbox_VertexShaderMode and VertexShaderMode::FixedFunction
 #include "core/hle/D3D8/Direct3D9/Direct3D9.h" // For g_pD3DDevice
 #include <optional>
 

src/core/hle/D3D8/XbConvert.h

@@ -94,32 +94,6 @@ else
     CxbxrAbortEx(LOG_PREFIX_D3DCVT, "Unknown Transform State Type (%d)", State);
 //*/
 
-// convert from xbox to pc texture transform state types
-inline D3DTRANSFORMSTATETYPE EmuXB2PC_D3DTS(xbox::X_D3DTRANSFORMSTATETYPE State)
-{
-    // Handle Xbox -> D3D State mapping
-    switch (State) {
-	case xbox::X_D3DTS_VIEW: return D3DTS_VIEW;
-    case xbox::X_D3DTS_PROJECTION: return D3DTS_PROJECTION;
-    case xbox::X_D3DTS_TEXTURE0: return D3DTS_TEXTURE0;
-    case xbox::X_D3DTS_TEXTURE1: return D3DTS_TEXTURE1;
-    case xbox::X_D3DTS_TEXTURE2: return D3DTS_TEXTURE2;
-    case xbox::X_D3DTS_TEXTURE3: return D3DTS_TEXTURE3;
-    case xbox::X_D3DTS_WORLD: return D3DTS_WORLD;
-    case xbox::X_D3DTS_WORLD1: return D3DTS_WORLD1;
-    case xbox::X_D3DTS_WORLD2: return D3DTS_WORLD2;
-    case xbox::X_D3DTS_WORLD3: return D3DTS_WORLD3;
-    }
-
-    // Handle World Matrix offsets
-    if (State >= 256 && State <= 511) {
-		return D3DTS_WORLDMATRIX(State - 256);
-    }
-
-    CxbxrAbortEx(LOG_PREFIX_D3DCVT, "Unknown Transform State Type (%d)", State);
-    return (D3DTRANSFORMSTATETYPE)0;
-}
-
 // convert from xbox to pc blend ops
 inline D3DBLENDOP EmuXB2PC_D3DBLENDOP(xbox::X_D3DBLENDOP Value)
 {

src/core/hle/D3D8/XbVertexShader.cpp

@@ -62,7 +62,6 @@ extern XboxRenderStateConverter XboxRenderStates; // Declared in Direct3D9.cpp
  xbox::X_VERTEXATTRIBUTEFORMAT g_Xbox_SetVertexShaderInput_Attributes = { 0 }; // Read by GetXboxVertexAttributes when g_Xbox_SetVertexShaderInput_Count > 0
 
 VertexShaderMode g_Xbox_VertexShaderMode = VertexShaderMode::FixedFunction;
-bool g_UseFixedFunctionVertexShader = true;
 
                 xbox::dword_xt g_Xbox_VertexShader_Handle = 0;
 #ifdef CXBX_USE_GLOBAL_VERTEXSHADER_POINTER // TODO : Would this be more accurate / simpler?

src/core/hle/D3D8/XbVertexShader.h

@@ -100,7 +100,6 @@ enum class VertexShaderMode {
 };
 
 extern VertexShaderMode g_Xbox_VertexShaderMode;
-extern bool g_UseFixedFunctionVertexShader;
 
 // Intermediate vertex shader structures