After changing the 75 to a 25 (which still generates very much ores), there are much less lag spikes. Thank you! ^^

 

Now, there is only 1 thing left:

Is there a way, that the TESR renders the ItemStack, too?

I saw a method ForgeHooksClient#registerTESRItemStack, but I can't get it working (and it's deprecated and should have been removed in 1.9?)

You should use custom IBakedModels for your items if you need something complex, and forge's animation api if you need your items animated. That method only exists to allow rendering of tile entities as items (vanilla examples - chests, mob skulls, banners, etc.). And as you've pointed out yourself it is clearly marked for deletion.

I tried to figure out, how Chests are rendered and saw, that the chest has got an item-model-file, whose parent is "builtin/entity".

I did that for the black ore, too, but then the item is just invisible.

Then I saw the function TileEntityItemStackRenderer#renderByItem.

The interesting part there, is this line:

net.minecraftforge.client.ForgeHooksClient.renderTileItem(itemStackIn.getItem(), itemStackIn.getMetadata());

Well, then i looked into ForgeHooksClient#renderTileItem, but then I saw, that I should register my item with the function, which is very deprecated...

Should I use this one then? it would work though

What exactly are you trying to achieve? Most likely you can just create a standart json model, bind it in your blockstates file and let standart model rendering take things from there.

Well, this was a silly question

Got it working by adjusting the blockstates-json, thank you very much

21 hours ago, V0idWa1k3r said:

WorldGenMinable already offsets the positions for you so no need to do the +rand.nextInt(16).

Minable's offset is a fixed +8 +8 to move away from the problematic north and west edges (south and east always have neighbors already, so it's ok for ores to push into them). Minable does not randomize, so a mod still needs to do that.

 

Some mods don't use WorldGenMinable (perhaps because they must do other work or make other decisions) . Those are the mods that must beware of runaway worldgen and produce their own offset to avoid generating anything along the north or west edge of the given chunk (which would trigger neighbor updates into unloaded chunks, which would trigger more worldgen).