D3D/Render: Get rid of undefined behavior in Create3DVisionTexture

pSysMem is of the type const void* -- because of this, it makes the
original delete[] call undefined behavior, as deleting a void pointer is
undefined behavior.

Also punning types into existence, like what was done for the stereo
image header is undefined behavior as well. The proper way to do this is
to either manually add all individual bytes manually, or memcpy the
struct into memory.

As we want to deallocate the memory before returning, and because
pSysMem is a const void*, we keep a unique_ptr to the data and just pass
pSysMem a raw pointer to the data.

Source/Core/VideoBackends/D3D/Render.cpp

@@ -7,6 +7,7 @@
 #include <array>
 #include <cinttypes>
 #include <cmath>
+#include <cstring>
 #include <memory>
 #include <string>
 #include <strsafe.h>
@@ -214,21 +215,25 @@ static void Create3DVisionTexture(int width, int height)
 {
   // Create a staging texture for 3D vision with signature information in the last row.
   // Nvidia 3D Vision supports full SBS, so there is no loss in resolution during this process.
-  D3D11_SUBRESOURCE_DATA sysData;
+  NVSTEREOIMAGEHEADER header;
-  sysData.SysMemPitch = 4 * width * 2;
+  header.dwSignature = NVSTEREO_IMAGE_SIGNATURE;
-  sysData.pSysMem = new u8[(height + 1) * sysData.SysMemPitch];
+  header.dwWidth = static_cast<u32>(width * 2);
-  LPNVSTEREOIMAGEHEADER header =
+  header.dwHeight = static_cast<u32>(height + 1);
-      (LPNVSTEREOIMAGEHEADER)((u8*)sysData.pSysMem + height * sysData.SysMemPitch);
+  header.dwBPP = 32;
-  header->dwSignature = NVSTEREO_IMAGE_SIGNATURE;
+  header.dwFlags = 0;
-  header->dwWidth = width * 2;
+
-  header->dwHeight = height + 1;
+  const u32 pitch = static_cast<u32>(4 * width * 2);
-  header->dwBPP = 32;
+  const auto memory = std::make_unique<u8[]>((height + 1) * pitch);
-  header->dwFlags = 0;
+  u8* image_header_location = &memory[height * pitch];
+  std::memcpy(image_header_location, &header, sizeof(header));
+
+  D3D11_SUBRESOURCE_DATA sys_data;
+  sys_data.SysMemPitch = pitch;
+  sys_data.pSysMem = memory.get();
 
   s_3d_vision_texture =
       D3DTexture2D::Create(width * 2, height + 1, D3D11_BIND_RENDER_TARGET, D3D11_USAGE_DEFAULT,
-                           DXGI_FORMAT_R8G8B8A8_UNORM, 1, 1, &sysData);
+                           DXGI_FORMAT_R8G8B8A8_UNORM, 1, 1, &sys_data);
-  delete[] sysData.pSysMem;
 }
 
 Renderer::Renderer() : ::Renderer(D3D::GetBackBufferWidth(), D3D::GetBackBufferHeight())