TextureCache: Don't re-use pooled textures within the same frame

This is an issue because a driver may have to maintain two copies of a
texture if it batches all uploads together at the start of a frame.

In the Vulkan backend, we do something similar to avoid breaking out of a
render pass to copy a texture from the streaming buffer to the destination
image.

This was causing issues in the sms-bubbles fifolog, where an EFB copy to
the same address of a previously-used texture caused the previous texture
to be re-used again for a different image later on in the frame, causing
the original contents to be discarded.

Source/Core/VideoCommon/TextureCacheBase.cpp

@@ -1353,7 +1353,7 @@ void TextureCacheBase::CopyRenderTargetToTexture(u32 dstAddr, unsigned int dstFo
 TextureCacheBase::TCacheEntryBase*
 TextureCacheBase::AllocateTexture(const TCacheEntryConfig& config)
 {
-  TexPool::iterator iter = texture_pool.find(config);
+  TexPool::iterator iter = FindMatchingTextureFromPool(config);
   TextureCacheBase::TCacheEntryBase* entry;
   if (iter != texture_pool.end())
   {
@@ -1373,6 +1373,19 @@ TextureCacheBase::AllocateTexture(const TCacheEntryConfig& config)
   return entry;
 }
 
+TextureCacheBase::TexPool::iterator
+TextureCacheBase::FindMatchingTextureFromPool(const TCacheEntryConfig& config)
+{
+  // Find a texture from the pool that does not have a frameCount of FRAMECOUNT_INVALID.
+  // This prevents a texture from being used twice in a single frame with different data,
+  // which potentially means that a driver has to maintain two copies of the texture anyway.
+  auto range = texture_pool.equal_range(config);
+  auto matching_iter = std::find_if(range.first, range.second, [](const auto& iter) {
+    return iter.second->frameCount != FRAMECOUNT_INVALID;
+  });
+  return matching_iter != range.second ? matching_iter : texture_pool.end();
+}
+
 TextureCacheBase::TexCache::iterator
 TextureCacheBase::GetTexCacheIter(TextureCacheBase::TCacheEntryBase* entry)
 {

Source/Core/VideoCommon/TextureCacheBase.h

@@ -193,6 +193,7 @@ private:
   static void CheckTempSize(size_t required_size);
 
   static TCacheEntryBase* AllocateTexture(const TCacheEntryConfig& config);
+  static TexPool::iterator FindMatchingTextureFromPool(const TCacheEntryConfig& config);
   static TexCache::iterator GetTexCacheIter(TCacheEntryBase* entry);
 
   // Removes and unlinks texture from texture cache and returns it to the pool