gallium: add # of MRT to blend state

To make it possible for drivers to avoid unnecessary blend state change
for unused MRTs.  Otherwise the driver would have to manage different
blend CSOs for different potential #s of render targets.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4619>

diff --git a/src/gallium/auxiliary/driver_trace/tr_dump_state.c b/src/gallium/auxiliary/driver_trace/tr_dump_state.c
index bd0d7204cfff928286e19add667725aafba97af8..49d2109101a11274670601d81093042c283397b4 100644 (file)
--- a/src/gallium/auxiliary/driver_trace/tr_dump_state.c
+++ b/src/gallium/auxiliary/driver_trace/tr_dump_state.c
@@ -432,7 +432,7 @@ void trace_dump_blend_state(const struct pipe_blend_state *state)
 
    trace_dump_member_begin("rt");
    if (state->independent_blend_enable)
-      valid_entries = PIPE_MAX_COLOR_BUFS;
+      valid_entries = state->max_rt + 1;
    trace_dump_struct_array(rt_blend_state, state->rt, valid_entries);
    trace_dump_member_end();
 

diff --git a/src/gallium/auxiliary/util/u_blitter.c b/src/gallium/auxiliary/util/u_blitter.c
index fd7813aae11e059f359a0a000b7d38b24768ec0a..d5b886ca36f02e0cbed6c2d53d62d0556d6384b9 100644 (file)
--- a/src/gallium/auxiliary/util/u_blitter.c
+++ b/src/gallium/auxiliary/util/u_blitter.c
@@ -1419,6 +1419,7 @@ static void *get_clear_blend_state(struct blitter_context_priv *ctx,
       for (i = 0; i < PIPE_MAX_COLOR_BUFS; i++) {
          if (clear_buffers & (PIPE_CLEAR_COLOR0 << i)) {
             blend.rt[i].colormask = PIPE_MASK_RGBA;
+            blend.max_rt = i;
          }
       }
 

diff --git a/src/gallium/auxiliary/util/u_dump_state.c b/src/gallium/auxiliary/util/u_dump_state.c
index 422dc86754f1bbb80f1cec2964039d281ba947af..f57a5923ad0a1084267378ff515f79aef24d42c0 100644 (file)
--- a/src/gallium/auxiliary/util/u_dump_state.c
+++ b/src/gallium/auxiliary/util/u_dump_state.c
@@ -603,6 +603,7 @@ util_dump_blend_state(FILE *stream, const struct pipe_blend_state *state)
    util_dump_member(stream, bool, state, dither);
    util_dump_member(stream, bool, state, alpha_to_coverage);
    util_dump_member(stream, bool, state, alpha_to_one);
+   util_dump_member(stream, uint, state, max_rt);
 
    util_dump_member(stream, bool, state, logicop_enable);
    if (state->logicop_enable) {
@@ -613,7 +614,7 @@ util_dump_blend_state(FILE *stream, const struct pipe_blend_state *state)
 
       util_dump_member_begin(stream, "rt");
       if (state->independent_blend_enable)
-         valid_entries = PIPE_MAX_COLOR_BUFS;
+         valid_entries = state->max_rt + 1;
       util_dump_struct_array(stream, rt_blend_state, state->rt, valid_entries);
       util_dump_member_end(stream);
    }

diff --git a/src/gallium/docs/source/cso/blend.rst b/src/gallium/docs/source/cso/blend.rst
index 7316e5c71cf66a90204d8e014b832cb1775bbce8..be5a2ef795678c6b275cc9f1b1d44ee7dd05666c 100644 (file)
--- a/src/gallium/docs/source/cso/blend.rst
+++ b/src/gallium/docs/source/cso/blend.rst
@@ -99,6 +99,10 @@ alpha_to_one
    If enabled, the fragment's alpha value will be set to one.  As with
    alpha_to_coverage, this step happens regardless of whether multisample
    is enabled or the destination buffer is multisampled.
+max_rt
+   The index of the max render target (irrespecitive of whether independent
+   blend is enabled), ie. the number of MRTs minus one.  This is provided
+   so that the driver can avoid the overhead of programming unused MRTs.
 
 
 Per-rendertarget Members

diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
index 736649acd2f474b694b25d6c99e71acda5a79006..c557ecc186983bfc4f69e5dec9e878b0c4f2c721 100644 (file)
--- a/src/gallium/include/pipe/p_state.h
+++ b/src/gallium/include/pipe/p_state.h
@@ -363,6 +363,7 @@ struct pipe_blend_state
    unsigned dither:1;
    unsigned alpha_to_coverage:1;
    unsigned alpha_to_one:1;
+   unsigned max_rt:3;            /* index of max rt, Ie. # of cbufs minus 1 */
    struct pipe_rt_blend_state rt[PIPE_MAX_COLOR_BUFS];
 };
 

diff --git a/src/gallium/state_trackers/nine/nine_pipe.c b/src/gallium/state_trackers/nine/nine_pipe.c
index dd858aef743b7dce577a0d2e0c88c9a3c34376a4..7531845efd6aff158adc2496d7d78718ea93397b 100644 (file)
--- a/src/gallium/state_trackers/nine/nine_pipe.c
+++ b/src/gallium/state_trackers/nine/nine_pipe.c
@@ -186,6 +186,7 @@ nine_convert_blend_state(struct pipe_blend_state *blend_state, const DWORD *rs)
         nine_convert_blend_state_fixup(&blend, rs); /* for BOTH[INV]SRCALPHA */
     }
 
+    blend.max_rt = 0;
     blend.rt[0].colormask = rs[D3DRS_COLORWRITEENABLE];
 
     if (rs[D3DRS_COLORWRITEENABLE1] != rs[D3DRS_COLORWRITEENABLE] ||
@@ -198,6 +199,7 @@ nine_convert_blend_state(struct pipe_blend_state *blend_state, const DWORD *rs)
         blend.rt[1].colormask = rs[D3DRS_COLORWRITEENABLE1];
         blend.rt[2].colormask = rs[D3DRS_COLORWRITEENABLE2];
         blend.rt[3].colormask = rs[D3DRS_COLORWRITEENABLE3];
+        blend.max_rt = 3;
     }
 
     /* blend.force_srgb = !!rs[D3DRS_SRGBWRITEENABLE]; */

diff --git a/src/mesa/state_tracker/st_atom_blend.c b/src/mesa/state_tracker/st_atom_blend.c
index 0d429dac460bcd6836a54890f7f0860b449ee155..10e9b6a38c427e22ab70f7ab0d653ba28da7aca1 100644 (file)
--- a/src/mesa/state_tracker/st_atom_blend.c
+++ b/src/mesa/state_tracker/st_atom_blend.c
@@ -201,6 +201,8 @@ st_update_blend( struct st_context *st )
 
    memset(blend, 0, sizeof(*blend));
 
+   blend->max_rt = MAX2(1, num_cb) - 1;
+
    if (num_cb > 1 &&
        (blend_per_rt(st, num_cb) || colormask_per_rt(ctx, num_cb))) {
       num_state = num_cb;

diff --git a/src/mesa/state_tracker/st_cb_clear.c b/src/mesa/state_tracker/st_cb_clear.c
index 3cf4c79f083a573b0d15822e03c8b86c2693e534..b7d44d2c1b54fc7af66639ac24bfe2be73974853 100644 (file)
--- a/src/mesa/state_tracker/st_cb_clear.c
+++ b/src/mesa/state_tracker/st_cb_clear.c
@@ -280,6 +280,7 @@ clear_with_quad(struct gl_context *ctx, unsigned clear_buffers)
          int i;
 
          blend.independent_blend_enable = num_buffers > 1;
+         blend.max_rt = num_buffers - 1;
 
          for (i = 0; i < num_buffers; i++) {
             if (!(clear_buffers & (PIPE_CLEAR_COLOR0 << i)))