diff --git a/renderdoc/driver/shaders/spirv/spirv_debug.cpp b/renderdoc/driver/shaders/spirv/spirv_debug.cpp
index 45f531827..1836963c9 100644
--- a/renderdoc/driver/shaders/spirv/spirv_debug.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_debug.cpp
@@ -1570,7 +1570,7 @@ void ThreadState::StepNext(ShaderDebugState *state,
 
       result.type = resultType.scalar().Type();
 
-      if(!debugger.GetAPIWrapper()->CalculateSampleGather(opdata.op, img.GetBinding(),
+      if(!debugger.GetAPIWrapper()->CalculateSampleGather(*this, opdata.op, img.GetBinding(),
                                                           sampler.GetBinding(), uv, ddxCalc, ddyCalc,
                                                           compare, gather, operands, result))
       {
diff --git a/renderdoc/driver/shaders/spirv/spirv_debug.h b/renderdoc/driver/shaders/spirv/spirv_debug.h
index ee22914e6..7c38c3786 100644
--- a/renderdoc/driver/shaders/spirv/spirv_debug.h
+++ b/renderdoc/driver/shaders/spirv/spirv_debug.h
@@ -44,6 +44,8 @@ enum class GatherChannel : uint8_t
   Alpha = 3,
 };
 
+struct ThreadState;
+
 class DebugAPIWrapper
 {
 public:
@@ -56,7 +58,7 @@ public:
   virtual void FillInputValue(ShaderVariable &var, ShaderBuiltin builtin, uint32_t location,
                               uint32_t component) = 0;
 
-  virtual bool CalculateSampleGather(rdcspv::Op opcode, BindpointIndex imageBind,
+  virtual bool CalculateSampleGather(ThreadState &thread, rdcspv::Op opcode, BindpointIndex imageBind,
                                      BindpointIndex samplerBind, const ShaderVariable &uv,
                                      const ShaderVariable &ddxCalc, const ShaderVariable &ddyCalc,
                                      const ShaderVariable &compare, GatherChannel gatherChannel,
@@ -75,8 +77,6 @@ public:
                                          uint32_t component) = 0;
 };
 
-struct ThreadState;
-
 typedef ShaderVariable (*ExtInstImpl)(ThreadState &, const rdcarray<Id> &);
 
 struct ExtInstDispatcher
diff --git a/renderdoc/driver/vulkan/vk_shaderdebug.cpp b/renderdoc/driver/vulkan/vk_shaderdebug.cpp
index 29eeebdd9..f825eeadc 100644
--- a/renderdoc/driver/vulkan/vk_shaderdebug.cpp
+++ b/renderdoc/driver/vulkan/vk_shaderdebug.cpp
@@ -114,7 +114,7 @@ public:
     return DerivativeDeltas();
   }
 
-  bool CalculateSampleGather(rdcspv::Op opcode, BindpointIndex imageBind,
+  bool CalculateSampleGather(rdcspv::ThreadState &thread, rdcspv::Op opcode, BindpointIndex imageBind,
                              BindpointIndex samplerBind, const ShaderVariable &uv,
                              const ShaderVariable &ddxCalc, const ShaderVariable &ddyCalc,
                              const ShaderVariable &compare, rdcspv::GatherChannel gatherChannel,