From 81fbf4bcc93407149613fff723e860c7f3b43d08 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Thu, 20 Aug 2020 15:18:45 +0100
Subject: [PATCH] Fix some dodgy memcpy calls

---
 renderdoc/driver/vulkan/vk_shaderdebug.cpp | 47 +++++++---------------
 renderdoc/maths/vec.h                      | 47 +++++++++++++++++++---
 2 files changed, 57 insertions(+), 37 deletions(-)

diff --git a/renderdoc/driver/vulkan/vk_shaderdebug.cpp b/renderdoc/driver/vulkan/vk_shaderdebug.cpp
index 54a007351..ae70fe169 100644
--- a/renderdoc/driver/vulkan/vk_shaderdebug.cpp
+++ b/renderdoc/driver/vulkan/vk_shaderdebug.cpp
@@ -484,34 +484,17 @@ public:
       const DerivativeDeltas &deriv = location_derivatives[location];
 
       DerivativeDeltas ret;
-      if(component == 0)
+
+      RDCASSERT(component < 4, component);
+
+      // rebase from component into [0]..
+
+      for(uint32_t src = component, dst = 0; src < 4; src++, dst++)
       {
-        ret = deriv;
-      }
-      else if(component == 1)
-      {
-        memcpy(&ret.ddxcoarse.x, &deriv.ddxcoarse.y, sizeof(Vec3f));
-        memcpy(&ret.ddxfine.x, &deriv.ddxfine.y, sizeof(Vec3f));
-        memcpy(&ret.ddycoarse.x, &deriv.ddycoarse.y, sizeof(Vec3f));
-        memcpy(&ret.ddyfine.x, &deriv.ddyfine.y, sizeof(Vec3f));
-      }
-      else if(component == 2)
-      {
-        memcpy(&ret.ddxcoarse.x, &deriv.ddxcoarse.z, sizeof(Vec2f));
-        memcpy(&ret.ddxfine.x, &deriv.ddxfine.z, sizeof(Vec2f));
-        memcpy(&ret.ddycoarse.x, &deriv.ddycoarse.z, sizeof(Vec2f));
-        memcpy(&ret.ddyfine.x, &deriv.ddyfine.z, sizeof(Vec2f));
-      }
-      else if(component == 3)
-      {
-        ret.ddxcoarse.x = deriv.ddxcoarse.w;
-        ret.ddxfine.x = deriv.ddxfine.w;
-        ret.ddycoarse.x = deriv.ddycoarse.w;
-        ret.ddyfine.x = deriv.ddyfine.w;
-      }
-      else
-      {
-        RDCERR("Unexpected component %u", component);
+        ret.ddxcoarse.fv[dst] = deriv.ddxcoarse.fv[src];
+        ret.ddxfine.fv[dst] = deriv.ddxfine.fv[src];
+        ret.ddycoarse.fv[dst] = deriv.ddycoarse.fv[src];
+        ret.ddyfine.fv[dst] = deriv.ddyfine.fv[src];
       }
 
       return ret;
@@ -4284,11 +4267,11 @@ ShaderDebugTrace *VulkanReplay::DebugPixel(uint32_t eventId, uint32_t x, uint32_
 
       const size_t sz = sizeof(Vec4f) - sizeof(uint32_t) * comp;
 
-      memcpy(((uint32_t *)&var.value.uv) + comp, &value[i], sz);
-      memcpy(((uint32_t *)&deriv.ddxcoarse.x) + comp, &ddxcoarse[i], sz);
-      memcpy(((uint32_t *)&deriv.ddycoarse.x) + comp, &ddycoarse[i], sz);
-      memcpy(((uint32_t *)&deriv.ddxfine.x) + comp, &ddxfine[i], sz);
-      memcpy(((uint32_t *)&deriv.ddyfine.x) + comp, &ddyfine[i], sz);
+      memcpy(&var.value.uv[comp], &value[i], sz);
+      memcpy(&deriv.ddxcoarse.fv[comp], &ddxcoarse[i], sz);
+      memcpy(&deriv.ddycoarse.fv[comp], &ddycoarse[i], sz);
+      memcpy(&deriv.ddxfine.fv[comp], &ddxfine[i], sz);
+      memcpy(&deriv.ddyfine.fv[comp], &ddyfine[i], sz);
     }
 
     ret = debugger->BeginDebug(apiWrapper, ShaderStage::Pixel, entryPoint, spec,
diff --git a/renderdoc/maths/vec.h b/renderdoc/maths/vec.h
index 2d849964c..f0cfaaffc 100644
--- a/renderdoc/maths/vec.h
+++ b/renderdoc/maths/vec.h
@@ -27,6 +27,11 @@
 
 #include <stdint.h>
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4201)
+#endif
+
 struct Vec2f
 {
   Vec2f(float X = 0.0f, float Y = 0.0f)
@@ -34,8 +39,15 @@ struct Vec2f
     x = X;
     y = Y;
   }
-  float x;
-  float y;
+
+  union
+  {
+    struct
+    {
+      float x, y;
+    };
+    float fv[2];
+  };
 };
 
 class Vec3f
@@ -57,7 +69,14 @@ public:
     z /= l;
   }
 
-  float x, y, z;
+  union
+  {
+    struct
+    {
+      float x, y, z;
+    };
+    float fv[3];
+  };
 };
 
 struct FloatVector;
@@ -74,7 +93,14 @@ struct Vec4f
   Vec4f(const FloatVector &v);
   operator Vec3f() const { return Vec3f(x, y, z); }
   operator FloatVector() const;
-  float x, y, z, w;
+  union
+  {
+    struct
+    {
+      float x, y, z, w;
+    };
+    float fv[4];
+  };
 };
 
 inline Vec3f operator*(const Vec3f &a, const float b)
@@ -150,5 +176,16 @@ struct Vec4u
     z = Z;
     w = W;
   }
-  uint32_t x, y, z, w;
+  union
+  {
+    struct
+    {
+      uint32_t x, y, z, w;
+    };
+    uint32_t uv[4];
+  };
 };
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif