From 95a6f13730b11e9d2d2994887a652d40f35f6d6e Mon Sep 17 00:00:00 2001
From: Jake Turner <jake@evansturner.co.uk>
Date: Tue, 11 Nov 2025 15:07:26 +1300
Subject: [PATCH] Fix DXIL Debugger support for structs in the input structure

i.e. matrices

Fixed incorrect asserts in LoadInput
Fixed source variable mapping
Fixed input data copying from fetcher results
---
 renderdoc/driver/d3d12/d3d12_dxil_debug.cpp  | 44 ++++++++++++++------
 renderdoc/driver/d3d12/d3d12_shaderdebug.cpp | 11 +++--
 renderdoc/driver/shaders/dxil/dxil_debug.cpp | 10 +++--
 3 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/renderdoc/driver/d3d12/d3d12_dxil_debug.cpp b/renderdoc/driver/d3d12/d3d12_dxil_debug.cpp
index 2f49fc475..baeac5fab 100644
--- a/renderdoc/driver/d3d12/d3d12_dxil_debug.cpp
+++ b/renderdoc/driver/d3d12/d3d12_dxil_debug.cpp
@@ -642,17 +642,20 @@ D3D12APIWrapper::D3D12APIWrapper(WrappedID3D12Device *device, const DXIL::Progra
           v.members[r].type = v.type;
           v.members[r].name = StringFormat::Fmt("[%u]", r);
         }
+        v.rows = 0;
+        v.columns = 0;
+        v.type = VarType::Struct;
       }
 
-      SourceVariableMapping inputMapping;
-      inputMapping.name = v.name;
-      inputMapping.type = v.type;
-      inputMapping.rows = sig.rows;
-      inputMapping.columns = sig.cols;
-      inputMapping.variables.reserve(sig.cols);
-      inputMapping.signatureIndex = i;
-      if(v.rows <= 1)
+      if(v.rows == 1)
       {
+        SourceVariableMapping inputMapping;
+        inputMapping.name = v.name;
+        inputMapping.type = v.type;
+        inputMapping.rows = sig.rows;
+        inputMapping.columns = sig.cols;
+        inputMapping.variables.reserve(sig.cols);
+        inputMapping.signatureIndex = i;
         inputMapping.variables.reserve(sig.cols);
         for(uint32_t c = 0; c < sig.cols; ++c)
         {
@@ -662,15 +665,30 @@ D3D12APIWrapper::D3D12APIWrapper(WrappedID3D12Device *device, const DXIL::Progra
           ref.component = c;
           inputMapping.variables.push_back(ref);
         }
+        m_SourceVars.push_back(inputMapping);
       }
       else
       {
-        DebugVariableReference ref;
-        ref.type = DebugVariableType::Input;
-        ref.name = inStruct.name + "." + v.name;
-        inputMapping.variables.push_back(ref);
+        // Make a mapping per element
+        for(const ShaderVariable &member : v.members)
+        {
+          SourceVariableMapping inputMapping;
+          inputMapping.name = v.name + member.name;
+          inputMapping.type = member.type;
+          inputMapping.rows = 1;
+          inputMapping.columns = member.columns;
+          inputMapping.signatureIndex = -1;
+          for(uint32_t c = 0; c < member.columns; ++c)
+          {
+            DebugVariableReference ref;
+            ref.type = DebugVariableType::Input;
+            ref.name = inStruct.name + "." + v.name + member.name;
+            ref.component = c;
+            inputMapping.variables.push_back(ref);
+          }
+          m_SourceVars.push_back(inputMapping);
+        }
       }
-      m_SourceVars.push_back(inputMapping);
     }
 
     // Make a single source variable mapping for the whole input struct
diff --git a/renderdoc/driver/d3d12/d3d12_shaderdebug.cpp b/renderdoc/driver/d3d12/d3d12_shaderdebug.cpp
index 97545e889..f65fd1fa9 100644
--- a/renderdoc/driver/d3d12/d3d12_shaderdebug.cpp
+++ b/renderdoc/driver/d3d12/d3d12_shaderdebug.cpp
@@ -3370,10 +3370,15 @@ ShaderDebugTrace *D3D12Replay::DebugPixel(uint32_t eventId, uint32_t x, uint32_t
         }
         else
         {
-          if(invar.rows <= 1)
-            rawout = &invar.value.s32v[outElement];
-          else
+          if(invar.rows == 0)
+          {
+            RDCASSERT(input.array < invar.members.count(), input.array, invar.members.count());
             rawout = &invar.members[input.array].value.s32v[outElement];
+          }
+          else
+          {
+            rawout = &invar.value.s32v[outElement];
+          }
 
           memcpy(rawout, input.data, input.numwords * 4);
         }
diff --git a/renderdoc/driver/shaders/dxil/dxil_debug.cpp b/renderdoc/driver/shaders/dxil/dxil_debug.cpp
index f5171f3af..5016b2323 100644
--- a/renderdoc/driver/shaders/dxil/dxil_debug.cpp
+++ b/renderdoc/driver/shaders/dxil/dxil_debug.cpp
@@ -1838,11 +1838,13 @@ bool ThreadState::ExecuteInstruction(const rdcarray<ThreadState> &workgroup)
             uint32_t rowIdx = arg.value.u32v[0];
             RDCASSERT(GetShaderVariable(inst.args[3], opCode, dxOpCode, arg));
             uint32_t colIdx = arg.value.u32v[0];
+
             const ShaderVariable &var = m_Input.members[inputIdx];
-            RDCASSERT(rowIdx < var.rows, rowIdx, var.rows);
-            RDCASSERT(colIdx < var.columns, colIdx, var.columns);
-            ShaderVariable &a = (var.rows <= 1) ? m_Input.members[inputIdx]
-                                                : m_Input.members[inputIdx].members[rowIdx];
+            if(var.rows == 0)
+              RDCASSERT(rowIdx < var.members.size(), rowIdx, var.members.size());
+
+            const ShaderVariable &a = (var.rows != 0) ? var : var.members[rowIdx];
+            RDCASSERT(colIdx < a.columns, colIdx, a.columns);
             const uint32_t c = colIdx;
 
 #undef _IMPL