Terrain instancing creates 10mb Texture2Ds in memory?

I'm using the Memory Profiler package to analyze and reduce memory usage in my game. I have 64 terrain tiles (8x8 grid) and the profiler lists 64 Texture2D objects, each 10mb. I assume these are for the terrain, but what are they? Jason Booth said they might be terrain normals, which are generated when instancing is enabled on the terrains. Anyone know if that's true? If so, it would be nice if that was documented somewhere.... and if so, is there anything that can be done to optimize that memory load? Or if not...what are they?

thx
Dave

 

They're probably the textures that control the splat map. Your terrain is painted, with grass here, rocks there, sand over there, right? That data about which texture to use for each texel of the terrain has to be stored somewhere. It's stored in a Texture2D, which is used by the shader to select from the actual textures the player sees.

 

The splatmaps (for terrain textures) are listed separately in the profiler (and identified as Splat 1/2/3).

I guess I'm not sure about the control maps for grass and trees, though....but these Texture2Ds are 10mb each, and my control map resolution is 512, so it makes no sense that they'd be 10mb apiece. (The splats are 1024 and about 3mb in the profiler list.)

 

OK, so much for my theory then. Hopefully someone else will have some idea!

 

The Reference count is zero, and if I click on that number, it opens up an empty panel.... so what does that tell you?

 

Hmm, sorry, where would I see that? Here's the main list of textures, i don't see that in the headers, nor do I if I click on any of the blue link entries...

 

I did a memory capture in the Editor, and got the same (I presume) unnamed Texture2Ds (attached screenshot). Then I switched off instancing on all the terrains, and did another capture....and they're all still there. So...hmm....

 

Well, I thought I had figured it out. I have two main scenes, each with an 8x8 grid of terrain tiles, and each of those terrains has the same dimensions etc in both scenes. They're identical in all ways that I can see, including the splatmap resolution and filesize.

But doing the Memory Profiler (package), I found that the TerrainData objects use 157mb of memory in Scene A but 204mb in Scene B. And also, in Scene 8, there were only about a dozen of these mysterious Texture2Ds of 10mb each, and then a bunch more Texture2Ds that were only 5.3mb. But Scene B has 64 of those 10mb Texture 2Ds. So reading the docs, it occurred to me to check the normal textures assigned to the terrain layers. And sure enough, in Scene A, most of those were 1024 but a handful were 2048, while in Scene B, they were all 2048. Huzzah! So I reduced all those to 1024, did another dev build, and....no change on any of these things in memory. Drat.

But if those Texture2Ds are indeed not the terrain normals, then where *are* the terrain normals being listed in the Memory Profiler (package)? At 2048, they certainly should be near the top when I sort by Descending.... Does anyone know? (Or maybe they are included in the TerrainData object blackboxes, but then why no change when I reduced them from 2048 to 1024?)

Welll, that's not easy, as multiple game systems require the terrain, but I can try to figure out a way to make it work enough for a test.