The BC3 encoder's colour half is a four-colour BC1 block (c0 above c1, or every index 0 when they are equal), so a BC1 image of an opaque texture decodes to exactly the texels the BC3 one did. The encoder writes that half alone with its specialization constant BC1 set; its push constants are as before, so the BC3 pipeline is unchanged.
Every ASTC texture the CPU provides is made BC3, and its first upload checks its blocks while it copies them into staging: when all decode with alpha 255 (tex_astc.c astc_blocks_opaque, from the block header for all but the endpoint modes with alpha, which are decoded), the entry gets a BC1 image in place of the BC3 one before the decode. Later uploads into a BC1 image check again and go back to BC3 for content with alpha. A large texture's copy and check run on the ASTC decode workers, so its first upload copies faster than before. A check of its own where the texture is made cost 1.7 s of the render thread over a seven-minute teleport tour.
On that tour (Kakariko Village, the Graveyard, Death Mountain Trail, Kokiri Forest, Hyrule Field, RX 7900 XT), against BC3 alone in the same batch: the ASTC textures in Hyrule Field at the end 2,568 instead of 3,104 MiB, video memory at its peak 11,814 instead of 12,374 MiB, process commit at its peak 25,539 instead of 26,139 MiB; the first 7,200 frames in 93.7 instead of 101.3 s and the run's slowest 1 % at 24.1 instead of 21.1 fps. --probe-astc checks the header test against a decode of every generated block, the loop, its copy and the worker pool against it, and each BC1 block against the colour half of its BC3 block. NX2NAVI_ASTC_BC1=0 (astc_bc1 = 0) keeps every ASTC texture BC3; the sampling probe NX2NAVI_ASTC_BC_PROBE it replaces is gone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
When the decoder's scratch buffer could not be allocated, the upload logged it and still counted the texture as
uploaded. The image of a new texture then held nothing, and nothing uploaded it again until the game next wrote its
storage, which for most textures is never.
vk_astc_record now tells that failure (-1) from the ones that cannot change, and the upload leaves such a texture as
not uploaded: the lookups try it again every 30 frames until a decode succeeds. A WriteTexels whose decode has no
memory is still only logged.
The memory probe forces one failed scratch request and checks that the texture is left alone during its wait, is
uploaded by the first lookup after it and then holds its blocks.
Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>
The draw path called getenv("NX2NAVI_SKIP_PROG") for each of ~2,000 draws a frame, and getenv walks the whole environment block: in a replay-thread profile it was a sixth of the samples. That switch, the polygon offset log and the ASTC alpha probe now read the environment once. The replay's cost per draw went from 3.7-5.0 us to 1.2-2.8 us in play, and the mean frame rate by minute from 60-131 fps to 103-243 fps (different places in each run, so the figures are approximate).
cfg_get and cfg_value keep each thread's answers per name until the settings version changes (cfg_set, cfg_reset, cfg_load, and cfg_setenv, which the code that sets NX2NAVI_ variables in the process's own environment now uses); NX2NAVI_CFG_MEMO=0 asks every time.
The texture pool creates at most pool_create_budget (NX2NAVI_POOL_CREATE_BUDGET, default 16, was a fixed 64) new texture entries per refresh. The refresh holds the texture lock throughout, and streaming new textures in made 20-40 ms frames; at 16 the lock was held 5 ms per slow frame instead of 24 in a dense area, and the frames over 25 ms in a heavy minute fell from 111-188 to 89, with no pop-in seen.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Performance: draws reuse the bindings that did not change and record only the dynamic states that differ from what
the command buffer holds; small uploads come from a staging arena; finished submissions are held briefly and handed to
the queue in batches; the recorder thread can keep a CPU core of its own; ASTC block-linear textures are deswizzled on
the GPU; dynamic resolution steps the upscaler mode to hold a frame-time target. Each has a setting in nx2navi.ini
(bind_reuse, dyn_delta, stg_arena, submit_batch, recorder_core, recorder_prio, astc_gpu_deswizzle, dyn_res) and the
staging cache now frees what it holds at shutdown.
Capture: NX2NAVI_DUMP=key saves the frame after each press of Insert, with mesh draws listed by task, mesh and fragment
shader, depth test and face culling, and mesh_prims.txt giving each mesh draw's primitive, clipping and fragment counts.
All of it is off unless NX2NAVI_DUMP is set.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
--probe-astc now runs cut-out mip chains through the BC3 encoder at all 14 footprints, linear and sRGB, plus two
chains large enough to take several scratch chunks: transparent and opaque patches of void-extent blocks, whose edges
cut through BC3's 4x4 blocks where the footprint's side is 5, 6 or 10, mixed with ASTC blocks whose alpha jumps from
transparent to opaque between neighbouring texels, down to 1x1. Alpha 0 and 255 must come out exact and every alpha
test at 1/4, 1/2 and 3/4 must keep its side outside the block's alpha step. The encoder passes on an RTX 5090, before
and after this change (418540 BC3 blocks across a transparent-to-opaque edge); an encoder that lets an opaque 255 drop
to 254 in an edge block passes the old bounds and fails the new check.
The encoder reads texel bytes as integers instead of through unpackUnorm4x8, so its alpha endpoints are the block's
exact least and greatest alpha on any GPU.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
