Question about Texture Cache Color Samples

[Miksel12]

I have been updating some game INI's and was wondering about how Texture Cache accuracy works in the INI's.
First of all, I don't: 0 sample = safe, 512 samples = medium, 128 samples = fast (https://wiki.dolphin-emu.org/index.php?title=GameINI#Texture_Cache_Accuracy). I don't see the logic behind that.
Besides that, I have found some game INI's with a 'custom' setting. MySims Agents uses 4096 samples. What does that mean, the wiki states 'safe' should be used so I'm not sure if I should change it to 0 samples or keep it (some probably had a good reason to put it a 4096).

[JMC47]

4096 is faster than 0.

0 = hash the entire texture
128 = hash the first 128 bytes (I think) of the texture
512 = hash the first 512 bytes.
etc. etc.

In MySims Agents, someone manually found the point at which it started working which was 4096.

[Miksel12]

I see, that makes sense. What should I do with a case like MySims agents? The wiki states it should be set to safe but someone must have put 4096 in the INI for a reason...
I have also seen some conflicting information about Texture Cache accuracy slider position, on some wiki page configs position 1 is used and on other position 3, both indicating 'safe' so which postion is safe?

[mstreurman]

(06-09-2019, 09:16 AM)Miksel12 Wrote: I see, that makes sense. What should I do with a case like MySims agents? The wiki states it should be set to safe but someone must have put 4096 in the INI for a reason...
I have also seen some conflicting information about Texture Cache accuracy slider position, on some wiki page configs position 1 is used and on other position 3, both indicating 'safe' so which postion is safe?

How about you try if the game works correctly if you delete that line from the INI?
But ofcourse I can imagine that you don't own it

[mimimi]

Yeah, 0 ist just a special setting that makes it so that all of the data is used to create the hashes. And for the other ones, it takes x samples, which means it hashes x times 4 or 8 bytes of the texture. If i remember correctly, it's 8 bytes per sample.

4096 is a custom setting that hashes 8 times more data than the medium setting(512), which means it hashes up to 32 KB per texture, fully hashing all textures smaller than 32KB. The maximum texture size should be around 1024x1024x4 (x4 for the colors), so 4MB, which means that the 4096 is 128 times faster than the medium setting for this texture. New Super Mario Bros has a texture like that, which contains 32 times 32 smaller images. Since the samples for the texture cache hashing are spread evenly, the medium setting(512) results in only hashing 1 sample of every 2nd of those sub-textures, while the 4096 setting results in hashing 4 samples of each sub-texture. Well, this texture is a special case, since it contains the coins, blocks and stuff, which are handled by the partial texture updates now(they are created by efb copies...), which is why Dolphin doesn't need to properly hash the whole texture anymore.

Anyways, if you turn on dumping textures on the game, i'm sure you'll find a really big texture, which would not properly hashed with the medium(512) setting.

For a long time i was considerung to add another setting to the texture cache, making it hash more data, the bigger a texture is. But that would be just a hack on top of a hack, for only a little gain. The are enough other hacks related to the texture cache already. The 4096er setting should work for >90% of the games that "need" the safe setting.

[Miksel12]

Thanks for your answer!
Another question unrelated to texture cache (not willing to make a new thread for one question): Scaled EFB does nothing when IR = 1, right? That means that all problems with scaled EFB (like this one: https://wiki.dolphin-emu.org/index.php?title=SpongeBob_SquarePants:_Battle_for_Bikini_Bottom) should be in enhancements, correct?