ShaderGen: Implement pixel ubershaders

Source/Core/VideoCommon/PixelEngine.cpp

@@ -18,6 +18,7 @@
 #include "VideoCommon/CommandProcessor.h"
 #include "VideoCommon/Fifo.h"
 #include "VideoCommon/PixelEngine.h"
+#include "VideoCommon/PixelShaderManager.h"
 
 namespace PixelEngine
 {
@@ -231,6 +232,7 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
   {
     mmio->Register(base | (PE_BBOX_LEFT + 2 * i), MMIO::ComplexRead<u16>([i](u32) {
                      BoundingBox::active = false;
+                     PixelShaderManager::SetBoundingBoxActive(false);
                      return g_video_backend->Video_GetBoundingBox(i);
                    }),
                    MMIO::InvalidWrite<u16>());