This is a remake of https://github.com/dolphin-emu/dolphin/pull/3749
Full credit goes to phire.
Old message:
"If none of the texture registers have changed and TMEM hasn't been invalidated or changed in other ways, we can blindly reuse the old texture cache entries without rehashing.
Not only does this fix the bloom effect in Spyro: A Hero's Tail (The game abused texture cache) but it will also provide speedups for other games which use the same texture over multiple draw calls, especially when safe texture cache is in use."
Changed the pr per phire's instructions to only return the current texture(s) if none of the texture registers were changed. If any texture register was changed, fall back to the default hashing and rebuilding textures from memory.
It was only implemented in OpenGL, though the option was visible in both
backends, leading to memory leaks if you enabled it in DirectX.
And it wasn't particularly useful as a debug feature as it only showed
where in the EFB the copies were taken from, not what format it was, or
what the copy was used for, or what content was in the EFB at that point
in time.
Also, it stretched the copy regions relative to the window, so the
on-screen regions don't even line up with the window unless the game used
the full EFB (some pal games) and you game image stretched to the full
window.
Texture updates have been moved into TextureCache, while
TMEM updates where moved into bpmem. Code for handling
efb2ram updates was added to TextureCache.
There was a bug for preloaded RGBA8 textures, it only copied
half the texture. The TODO was wrong too.
Baten Kaitos allocates its XFBs from a tagged heap
structure. With the old calculation, too many lines
were being written so the tag of the allocation
after the XFB was being corrupted. Fixes crash
mentioned in this comment:
https://code.google.com/p/dolphin-emu/issues/detail?id=7734#c6
Through just returning the last written value sounds better, this crashes Paper Mario.
In my opinion, gfx issues are fine on older GPUs, but crashes should not happen.
Léo Lam