Empirical tests show that the polygon offset
behaviour is entirely determined by the content of
the PA_SU_POLY_OFFSET states, and not by the depth buffer
format bound.
PA_SU_POLY_OFFSET seems to directly set the parameters of
the polygon offset formula, and setting 0 for
PA_SU_POLY_OFFSET_DB_FMT_CNTL (ie setting the unorm depth
bias behaviour with a scale of 2^0 = 1.0f) gives the unscaled
behaviour.
Signed-off-by: Axel Davy <axel.d...@ens.fr>
---
src/gallium/drivers/radeonsi/si_pipe.c | 2 +-
src/gallium/drivers/radeonsi/si_state.c | 32 ++++++++++++++++++--------------
2 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/src/gallium/drivers/radeonsi/si_pipe.c
b/src/gallium/drivers/radeonsi/si_pipe.c
index 99c0349..430cca2 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.c
+++ b/src/gallium/drivers/radeonsi/si_pipe.c
@@ -343,6 +343,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum
pipe_cap param)
case PIPE_CAP_TGSI_PACK_HALF_FLOAT:
case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
case PIPE_CAP_ROBUST_BUFFER_ACCESS_BEHAVIOR:
+ case PIPE_CAP_POLYGON_OFFSET_UNITS_UNSCALED:
return 1;
case PIPE_CAP_RESOURCE_FROM_USER_MEMORY:
@@ -400,7 +401,6 @@ static int si_get_param(struct pipe_screen* pscreen, enum
pipe_cap param)
case PIPE_CAP_QUERY_BUFFER_OBJECT:
case PIPE_CAP_CULL_DISTANCE:
case PIPE_CAP_PRIMITIVE_RESTART_FOR_PATCHES:
- case PIPE_CAP_POLYGON_OFFSET_UNITS_UNSCALED:
return 0;
case PIPE_CAP_MAX_SHADER_PATCH_VARYINGS:
diff --git a/src/gallium/drivers/radeonsi/si_state.c
b/src/gallium/drivers/radeonsi/si_state.c
index 06c65be..82b643a 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -812,20 +812,24 @@ static void *si_create_rs_state(struct pipe_context *ctx,
float offset_scale = state->offset_scale * 16.0f;
uint32_t pa_su_poly_offset_db_fmt_cntl = 0;
- switch (i) {
- case 0: /* 16-bit zbuffer */
- offset_units *= 4.0f;
- pa_su_poly_offset_db_fmt_cntl =
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-16);
- break;
- case 1: /* 24-bit zbuffer */
- offset_units *= 2.0f;
- pa_su_poly_offset_db_fmt_cntl =
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-24);
- break;
- case 2: /* 32-bit zbuffer */
- offset_units *= 1.0f;
- pa_su_poly_offset_db_fmt_cntl =
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-23) |
-
S_028B78_POLY_OFFSET_DB_IS_FLOAT_FMT(1);
- break;
+ if (!state->offset_units_unscaled) {
+ switch (i) {
+ case 0: /* 16-bit zbuffer */
+ offset_units *= 4.0f;
+ pa_su_poly_offset_db_fmt_cntl =
+
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-16);
+ break;
+ case 1: /* 24-bit zbuffer */
+ offset_units *= 2.0f;
+ pa_su_poly_offset_db_fmt_cntl =
+
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-24);
+ break;
+ case 2: /* 32-bit zbuffer */
+ offset_units *= 1.0f;
+ pa_su_poly_offset_db_fmt_cntl =
S_028B78_POLY_OFFSET_NEG_NUM_DB_BITS(-23) |
+
S_028B78_POLY_OFFSET_DB_IS_FLOAT_FMT(1);
+ break;
+ }
}
si_pm4_set_reg(pm4, R_028B80_PA_SU_POLY_OFFSET_FRONT_SCALE,
--
2.8.3
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