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render3d: gpu_tex_read_all and gpu_tex_write_all flush the frame first - the read-back is a submit of its own and took the image before the draws that fill it (the sky bake's BRDF table was all zeros at one width in three)

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Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Orkun ÇAKILKAYA 2026-09-29 23:18:05 +03:00
parent b5b3edc6ec
commit 92530c5db7
2 changed files with 11 additions and 1 deletions
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6
changes/r3d-readback-flush.md Normal file
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@ -0,0 +1,6 @@
bump: patch
type: fix
**A bake reads what was drawn.** `gpu_tex_read_all` (every bake's `bake_pack`) copied a texture on a
submit of its own without submitting the frame's draws first, so it read whatever the image held before
them: the sky bake's BRDF table came out all zeros for one light width and right for another, depending on
whether something else had flushed. It flushes first now, and so does `gpu_tex_write_all`.

6
packages/ludic.render3d/gpu_vk_readback.ludic
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@ -36,8 +36,11 @@ function gvk_tex_read_layer(render3d_st: mut Render3dState, tex: int, layer: int
return ok return ok
} }
# every layer's level 0 into `out` (gpu_tex_byte_size bytes), layer after layer # every layer's level 0 into `out` (gpu_tex_byte_size bytes), layer after layer. The frame so far goes
# first: the copy is a submit of its own, and read before the draws that fill the texture were submitted
# it took whatever the image held - a bake of the sky's BRDF table came out all zeros at one width in three
function gpu_tex_read_all(render3d_st: mut Render3dState, tex: int, out: pointer) -> bool { function gpu_tex_read_all(render3d_st: mut Render3dState, tex: int, out: pointer) -> bool {
gvk_flush(render3d_st)
let layers = render3d_st.gvk_tex_layers[tex] let layers = render3d_st.gvk_tex_layers[tex]
let per = gpu_tex_byte_size(render3d_st, tex) / max(layers, 1) let per = gpu_tex_byte_size(render3d_st, tex) / max(layers, 1)
for l in 0 .. layers { if not gvk_tex_read_layer(render3d_st, tex, l, mem_off(out, l * per)) { return false } } for l in 0 .. layers { if not gvk_tex_read_layer(render3d_st, tex, l, mem_off(out, l * per)) { return false } }
@ -47,6 +50,7 @@ function gpu_tex_read_all(render3d_st: mut Render3dState, tex: int, out: pointer
# level 0 of every layer written from bytes read back by gpu_tex_read_all; the texture's storage must # level 0 of every layer written from bytes read back by gpu_tex_read_all; the texture's storage must
# already be what it was (same format, size and layers). Mips, where it has them, are the caller's # already be what it was (same format, size and layers). Mips, where it has them, are the caller's
function gpu_tex_write_all(render3d_st: mut Render3dState, tex: int, data: pointer) -> bool { function gpu_tex_write_all(render3d_st: mut Render3dState, tex: int, data: pointer) -> bool {
gvk_flush(render3d_st) # after whatever the frame so far drew into it
let ifmt = render3d_st.gvk_tex_glfmt[tex] let ifmt = render3d_st.gvk_tex_glfmt[tex]
let c = gvk_channels(ifmt) let c = gvk_channels(ifmt)
let b = gvk_channel_bytes(ifmt) let b = gvk_channel_bytes(ifmt)