fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-05-05 09:38:07 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

agx: Handle discard intrinsics

Browse source 
Lower to `sample_mask = 0`. Actually that implements a demote... doing
discard correctly probably requires rewriting the shader control flow to
insert a return where necessary...

Also, possibly we should be lowering this in NIR to play nice with
gl_SampleMask writes but that's a problem for when we understand the
hardware better.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14219>
This commit is contained in:
Alyssa Rosenzweig 2021-12-15 21:01:19 -05:00 • committed by Marge Bot
parent f248f6623c
commit 9645fa9107
1 changed files with 31 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

31
src/asahi/compiler/agx_compile.c
View file

@ -278,6 +278,15 @@ agx_emit_fragment_out(agx_builder *b, nir_intrinsic_instr *instr)
agx_writeout(b, 0x000C);
}
if (b->shader->nir->info.fs.uses_discard) {
/* If the shader uses discard, the sample mask must be written by the
* shader on all exeuction paths. If we've reached the end of the shader,
* we are therefore still active and need to write a full sample mask.
* TODO: interactions with MSAA and gl_SampleMask writes
*/
agx_sample_mask(b, agx_immediate(1));
}
b->shader->did_writeout = true;
return agx_st_tile(b, agx_src_index(&instr->src[0]),
b->shader->key->fs.tib_formats[rt]);
@ -391,6 +400,25 @@ agx_blend_const(agx_builder *b, agx_index dst, unsigned comp)
return agx_mov_to(b, dst, val);
}
/*
* Demoting a helper invocation is logically equivalent to zeroing the sample
* mask. Metal implement discard as such.
*
* XXX: Actually, Metal's "discard" is a demote, and what is implemented here
* is a demote. There might be a better way to implement this to get correct
* helper invocation semantics. For now, I'm kicking the can down the road.
*/
static agx_instr *
agx_emit_discard(agx_builder *b, nir_intrinsic_instr *instr)
{
agx_writeout(b, 0xC200);
agx_writeout(b, 0x0001);
b->shader->did_writeout = true;
b->shader->out->writes_sample_mask = true;
return agx_sample_mask(b, agx_immediate(0));
}
static agx_instr *
agx_emit_intrinsic(agx_builder *b, nir_intrinsic_instr *instr)
{
@ -437,6 +465,9 @@ agx_emit_intrinsic(agx_builder *b, nir_intrinsic_instr *instr)
case nir_intrinsic_load_frag_coord:
return agx_emit_load_frag_coord(b, instr);
case nir_intrinsic_discard:
return agx_emit_discard(b, instr);
case nir_intrinsic_load_back_face_agx:
return agx_get_sr_to(b, dst, AGX_SR_BACKFACING);