Replacing TXST as part of swap has unintended consequences

[hakasapl]

The change in this PR: #7 sets the TXST as part of the swap. The issue is that I was assuming the lifespan of that is on each cell load. It turns out that this change is persistent and only a game restart fixes it, so you may want to revert this commit (let me know if you want me to make another PR for this).

The result of this is that when the season changes the old landscape textures remain in loaded grids until a game restart. Apologies for not spotting this earlier! It wasn't until today a user figured it out.

As community shaders reads the updated TXSTs to make sure the right PBR texture sets gets there, do you have a suggestion for how to accomplish this differently? Unfortunately, while I can read the result of the vanilla function and do see the swapped textures in the result material, those are raw textures and are not attached to any texture sets. CS needs the texture sets to get the EDIDs for additional parameter matching. Is there a way I could use/access the return value from struct GetAsShaderTextureSet in CS?

[hakasapl]

I think that something like this would work:

static RE::TESLandTexture* GetDefaultLandTXST()
{
	static const auto defaultLandTextureAddress = REL::Relocation<RE::TESLandTexture**>(RELOCATION_ID(514783, 400936));
	return *defaultLandTextureAddress;
}

static void thunk(RE::TESObjectLAND* land)
{
	if (land == nullptr || land->loadedData == nullptr) {
		return func(land);
	}

	const auto manager = SeasonManager::GetSingleton();
	if (!manager->CanSwapLandscape()) {
		return func(land);
	}

	for (uint32_t quadIndex = 0; quadIndex < 4; ++quadIndex) {
		for (uint32_t textureIndex = 0; textureIndex < 6; ++textureIndex) {
			const auto curLT = land->loadedData->quadTextures[quadIndex][textureIndex];
			if (curLT == nullptr) {
				// this is a default land texture, so use default land to check for swap
				const auto swapLT = manager->GetSwapLandTexture(GetDefaultLandTXST());
				if (swapLT) {
					land->loadedData->quadTextures[quadIndex][textureIndex] = swapLT;
				}
			} else {
				// this is a custom land texture, so use the swapped version if available
				const auto swapLT = manager->GetSwapLandTexture(curLT);
				if (swapLT) {
					land->loadedData->quadTextures[quadIndex][textureIndex] = swapLT;
				}
			}
		}
	}

	func(land);
}
static inline REL::Relocation<decltype(thunk)> func;

From my testing the TESObjectLAND object is reset every time a grid is loaded so these changes wouldn't be persistent. It also has the added advantage of not requiring any of the existing hooks in LandscapeSwap because the whole LTEX is swapped in this case so all properties goes with it. The pointer to the LTEX is swapped not the contents of the LTEX itself which keeps it from being persistent.

The problem is that this is written assuming a detour thunk, but that's going to make it incompatible with CS again because CS does the same for PBR terrain. So I guess some more RE might be needed here, ideally some place where the TESObjectLAND is initially constructed before being passed here or something. That starts to get into territory I'm less comfortable with - let me know if you have an idea, otherwise I will start learning more RE stuff.

Either way in the meantime it might be a good idea to revert PR #7 to avoid breaking seasons for everyone else while I work this out