Support debugging fetching input attachments

renderdoc/driver/shaders/spirv/spirv_debug.cpp

@@ -2192,6 +2192,9 @@ void ThreadState::StepNext(ShaderDebugState *state, const rdcarray<ThreadState>
       DebugAPIWrapper::TextureType texType =
           (DebugAPIWrapper::TextureType)img.value.u64v[TextureTypeVariableSlot];
 
+      // should not be sampling or fetching from subpass textures
+      RDCASSERT((texType & DebugAPIWrapper::Subpass_Texture) == 0);
+
       ShaderVariable result;
 
       result.type = resultType.scalar().Type();
@@ -2239,23 +2242,60 @@ void ThreadState::StepNext(ShaderDebugState *state, const rdcarray<ThreadState>
       ShaderVariable result;
       result.type = resultType.scalar().Type();
 
-      if(!debugger.GetAPIWrapper()->ReadTexel(img.GetBinding(), coord,
-                                              read.imageOperands.flags & ImageOperands::Sample
-                                                  ? GetSrc(read.imageOperands.sample).value.uv[0]
-                                                  : 0,
-                                              result))
-      {
-        // sample failed. Pretend we got 0 columns back
-        result.value.uv[0] = 0;
-        result.value.uv[1] = 0;
-        result.value.uv[2] = 0;
+      DebugAPIWrapper::TextureType texType =
+          (DebugAPIWrapper::TextureType)img.value.u64v[TextureTypeVariableSlot];
 
-        if(result.type == VarType::Float || result.type == VarType::Half)
-          result.value.fv[3] = 1.0f;
-        else if(result.type == VarType::Double)
-          result.value.dv[3] = 1.0;
-        else
-          result.value.uv[3] = 1;
+      if(texType & DebugAPIWrapper::Subpass_Texture)
+      {
+        // get current position
+        ShaderVariable curCoord;
+        debugger.GetAPIWrapper()->FillInputValue(curCoord, ShaderBuiltin::Position, 0, 0);
+
+        // co-ords are relative to the current position
+        coord.value.uv[0] += curCoord.value.uv[0];
+        coord.value.uv[1] += curCoord.value.uv[1];
+
+        // do it with samplegather as ImageFetch rather than a Read which caches the whole texture
+        // on the CPU for no reason (since we can't write to it)
+
+        if(!debugger.GetAPIWrapper()->CalculateSampleGather(
+               *this, Op::ImageFetch, texType, img.GetBinding(), DebugAPIWrapper::invalidBind,
+               coord, ShaderVariable(), ShaderVariable(), ShaderVariable(), GatherChannel::Red,
+               ImageOperandsAndParamDatas(), result))
+        {
+          // sample failed. Pretend we got 0 columns back
+          result.value.uv[0] = 0;
+          result.value.uv[1] = 0;
+          result.value.uv[2] = 0;
+
+          if(result.type == VarType::Float || result.type == VarType::Half)
+            result.value.fv[3] = 1.0f;
+          else if(result.type == VarType::Double)
+            result.value.dv[3] = 1.0;
+          else
+            result.value.uv[3] = 1;
+        }
+      }
+      else
+      {
+        if(!debugger.GetAPIWrapper()->ReadTexel(img.GetBinding(), coord,
+                                                read.imageOperands.flags & ImageOperands::Sample
+                                                    ? GetSrc(read.imageOperands.sample).value.uv[0]
+                                                    : 0,
+                                                result))
+        {
+          // sample failed. Pretend we got 0 columns back
+          result.value.uv[0] = 0;
+          result.value.uv[1] = 0;
+          result.value.uv[2] = 0;
+
+          if(result.type == VarType::Float || result.type == VarType::Half)
+            result.value.fv[3] = 1.0f;
+          else if(result.type == VarType::Double)
+            result.value.dv[3] = 1.0;
+          else
+            result.value.uv[3] = 1;
+        }
       }
 
       result.rows = 1;

renderdoc/driver/shaders/spirv/spirv_debug.h

@@ -74,6 +74,7 @@ public:
     SInt_Texture = 0x02,
 
     Buffer_Texture = 0x10,
+    Subpass_Texture = 0x20,
   };
 
   static const BindpointIndex invalidBind;

renderdoc/driver/shaders/spirv/spirv_debug_setup.cpp

@@ -214,6 +214,7 @@ ShaderDebugTrace *Debugger::BeginDebug(DebugAPIWrapper *apiWrapper, const Shader
       case Capability::SampleRateShading:
       case Capability::ImageRect:
       case Capability::SampledRect:
+      case Capability::InputAttachment:
       case Capability::MinLod:
       case Capability::Sampled1D:
       case Capability::Image1D:
@@ -310,13 +311,6 @@ ShaderDebugTrace *Debugger::BeginDebug(DebugAPIWrapper *apiWrapper, const Shader
       case Capability::GroupNonUniformQuad:
       case Capability::SubgroupBallotKHR:
       case Capability::SubgroupVoteKHR:
-      {
-        supported = false;
-        break;
-      }
-
-      // input attachments
-      case Capability::InputAttachment:
 
       // sparse operations
       case Capability::SparseResidency:
@@ -325,6 +319,10 @@ ShaderDebugTrace *Debugger::BeginDebug(DebugAPIWrapper *apiWrapper, const Shader
       case Capability::FragmentShaderSampleInterlockEXT:
       case Capability::FragmentShaderShadingRateInterlockEXT:
       case Capability::FragmentShaderPixelInterlockEXT:
+      {
+        supported = false;
+        break;
+      }
 
       // no plans to support these - mostly Kernel/OpenCL related or vendor extensions
       case Capability::Addresses:
@@ -832,6 +830,9 @@ ShaderDebugTrace *Debugger::BeginDebug(DebugAPIWrapper *apiWrapper, const Shader
         if(imageTypes[imgid].dim == Dim::Buffer)
           texType |= DebugAPIWrapper::Buffer_Texture;
 
+        if(imageTypes[imgid].dim == Dim::SubpassData)
+          texType |= DebugAPIWrapper::Subpass_Texture;
+
         if(imageTypes[imgid].retType.type == Op::TypeInt)
         {
           if(imageTypes[imgid].retType.signedness)
@@ -842,7 +843,7 @@ ShaderDebugTrace *Debugger::BeginDebug(DebugAPIWrapper *apiWrapper, const Shader
 
         var.value.u64v[TextureTypeVariableSlot] = texType;
 
-        if(imageTypes[imgid].sampled == 2)
+        if(imageTypes[imgid].sampled == 2 && imageTypes[imgid].dim != Dim::SubpassData)
         {
           var.type = VarType::ReadWriteResource;
           debugType = DebugVariableType::ReadWriteResource;

renderdoc/driver/vulkan/vk_shaderdebug.cpp

@@ -3473,6 +3473,7 @@ ShaderDebugTrace *VulkanReplay::DebugPixel(uint32_t eventId, uint32_t x, uint32_
   std::map<ShaderBuiltin, ShaderVariable> &builtins = apiWrapper->builtin_inputs;
   builtins[ShaderBuiltin::DeviceIndex] = ShaderVariable(rdcstr(), 0U, 0U, 0U, 0U);
   builtins[ShaderBuiltin::DrawIndex] = ShaderVariable(rdcstr(), draw->drawIndex, 0U, 0U, 0U);
+  builtins[ShaderBuiltin::Position] = ShaderVariable(rdcstr(), x, y, 0U, 0U);
 
   // If the pipe contains a geometry shader, then Primitive ID cannot be used in the pixel
   // shader without being emitted from the geometry shader. For now, check if this semantic