TextureCacheBase: Set uninitialized XFB memory to fuchsia color

Source/Core/VideoCommon/TextureCacheBase.cpp

@@ -1878,14 +1878,21 @@ void TextureCacheBase::CopyRenderTargetToTexture(u32 dstAddr, EFBCopyFormat dstF
   }
   else
   {
-    // Hack: Most games don't actually need the correct texture data in RAM
-    //       and we can just keep a copy in VRAM. We zero the memory so we
-    //       can check it hasn't changed before using our copy in VRAM.
-    u8* ptr = dst;
-    for (u32 i = 0; i < num_blocks_y; i++)
+    if (is_xfb_copy)
     {
-      memset(ptr, 0, bytes_per_row);
-      ptr += dstStride;
+      UninitializeXFBMemory(dst, dstStride, bytes_per_row, num_blocks_y);
+    }
+    else
+    {
+      // Hack: Most games don't actually need the correct texture data in RAM
+      //       and we can just keep a copy in VRAM. We zero the memory so we
+      //       can check it hasn't changed before using our copy in VRAM.
+      u8* ptr = dst;
+      for (u32 i = 0; i < num_blocks_y; i++)
+      {
+        memset(ptr, 0, bytes_per_row);
+        ptr += dstStride;
+      }
     }
   }
 
@@ -2030,6 +2037,33 @@ void TextureCacheBase::CopyRenderTargetToTexture(u32 dstAddr, EFBCopyFormat dstF
   }
 }
 
+void TextureCacheBase::UninitializeXFBMemory(u8* dst, u32 stride, u32 bytes_per_row,
+                                             u32 num_blocks_y)
+{
+  // Originally, we planned on using a 'key color'
+  // for alpha to address partial xfbs (Mario Strikers / Chicken Little).
+  // This work was removed since it was unfinished but there
+  // was still a desire to differentiate between the old and the new approach
+  // which is why we still set uninitialized xfb memory to fuchsia
+  // (Y=1,U=254,V=254) instead of dark green (Y=0,U=0,V=0) in YUV
+  // like is done in the EFB path.
+  for (u32 i = 0; i < num_blocks_y; i++)
+  {
+    for (u32 offset = 0; offset < bytes_per_row; offset++)
+    {
+      if (offset % 2)
+      {
+        dst[offset] = 254;
+      }
+      else
+      {
+        dst[offset] = 1;
+      }
+    }
+    dst += stride;
+  }
+}
+
 TextureCacheBase::TCacheEntry* TextureCacheBase::AllocateCacheEntry(const TextureConfig& config)
 {
   std::unique_ptr<AbstractTexture> texture = AllocateTexture(config);

Source/Core/VideoCommon/TextureCacheBase.h

@@ -323,6 +323,8 @@ private:
   // Removes and unlinks texture from texture cache and returns it to the pool
   TexAddrCache::iterator InvalidateTexture(TexAddrCache::iterator t_iter);
 
+  void UninitializeXFBMemory(u8* dst, u32 stride, u32 bytes_per_row, u32 num_blocks_y);
+
   TexAddrCache textures_by_address;
   TexHashCache textures_by_hash;
   TexPool texture_pool;