I converted some code to use tiled resources and noticed a few issues that I was wondering if anyone else knows anything about.
First of all, the tiled resource is working and visually everything is correct-- but..
1. It takes a long time to create the tiled resource. The call to CreateTexture2D to create the tiles(D3D11_RESOURCE_MISC_TILED) often doesn't return for a few seconds. There aren't any warnings or messages from the debug layer either, so this seems very strange. My resource is a texture2d array with 453 entries, each 2d slice is 2048x2048. I tried reducing the size to 256x256 instead and it still takes at least 2 seconds to complete the function call.
2. I set the lowest mip layer(128x128) in each slice to a unique mapping, and all of the rest of the tiles to a single default tile, I'd expect performance to be fairly good since this means that aside from the lowest mip, there is only 65k of texture memory being accessed, but it destroys my FPS-- going from 80 to 20. Visually it is correct, the tiles show as expected--
This is on a tier1 device and apparently mip maps under the tile size(128x128 in my case) do not work with texture arrays. So in the shader I check the distance and only use the tiled resource when near the camera, this helps but performance is still rubbish.
GPU is an AMD 285x
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