ASTC: decode and re-compress to BC1/BC3 on the GPU; texture cache budget

- accelerate_astc=Gpu with astc_recompression=Bc1/Bc3 now decodes ASTC
  with the GPU decoder into a temporary RGBA8 image (dedicated memory,
  freed once the GPU is past it) and compresses it with a new compute
  shader (bc_encoder.comp: bounding-box endpoints along the colours'
  covariance, inset 1/16, nearest palette entry; BC3 alpha ramp; BC1
  punch-through), then copies the blocks into the image. No CPU decode,
  so streamed textures are ready the frame they are first used instead
  of showing placeholders for seconds; the decode pass no longer waits
  for the GPU on this path.
- The CPU path (CpuAsynchronous) fills a new image with zero blocks
  before its first decode instead of showing stale VRAM, and the
  transcode pool is a quarter of the hardware threads.
- Switch 2 titles: collector thresholds near the device budget, re-read
  every 60 frames from VK_EXT_memory_budget (another game shrank it from
  7.0 to 5.4 GB).
- EDEN_NX2_HIDE_WINDOW=0 now leaves the window visible.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/video_core/texture_cache/image_base.h b/src/video_core/texture_cache/image_base.h
index d0af53631d..47bab9617a 100644
--- a/src/video_core/texture_cache/image_base.h
+++ b/src/video_core/texture_cache/image_base.h
@@ -49,6 +49,7 @@ enum class ImageFlagBits : u32 {
     /// The host image keeps only mip levels >= host_level_offset (its decoded copy would not fit
     /// in VRAM); uploads skip the rest, downloads are never done.
     TrimmedLevels = 1 << 19,
+    ZeroFilled = 1 << 20, ///< Cleared to zero blocks before its first asynchronous decode.
 };
 DECLARE_ENUM_FLAG_OPERATORS(ImageFlagBits)