i965: Generalize wm_key->compute_sample_id to wm_key->multisample_fbo.

I'm going to need a key entry meaning "we have a multisample FBO,
and multisampling is enabled" in an upcoming patch.  This is basically
wm_key->compute_sample_id, except that it also checks that the SAMPLE_ID
system value is read.

The only use of wm_key->compute_sample_id is in emit_sampleid_setup(),
which is only called when handling the SAMPLE_ID system value.  So we
can just eliminate the check and generalize the field.

v2: Also update the Vulkan driver.

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Matt Turner <[email protected]>

3 files changed, 6 insertions, 7 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_compiler.h b/src/mesa/drivers/dri/i965/brw_compiler.h
index 0a14d5dfe63..580730589c3 100644
--- a/src/mesa/drivers/dri/i965/brw_compiler.h
+++ b/src/mesa/drivers/dri/i965/brw_compiler.h
@@ -248,7 +248,7 @@ struct brw_wm_prog_key {
    bool render_to_fbo:1;
    bool clamp_fragment_color:1;
    bool compute_pos_offset:1;
-   bool compute_sample_id:1;
+   bool multisample_fbo:1;
    unsigned line_aa:2;
    bool high_quality_derivatives:1;
    bool force_dual_color_blend:1;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 748b242ad2d..58593ff5ff7 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1337,7 +1337,7 @@ fs_visitor::emit_sampleid_setup()
    const fs_builder abld = bld.annotate("compute sample id");
    fs_reg *reg = new(this->mem_ctx) fs_reg(vgrf(glsl_type::int_type));
 
-   if (!key->compute_sample_id) {
+   if (!key->multisample_fbo) {
       /* As per GL_ARB_sample_shading specification:
        * "When rendering to a non-multisample buffer, or if multisample
        *  rasterization is disabled, gl_SampleID will always be zero."
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 86e8cf4bc76..dbc626c0933 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -260,6 +260,8 @@ brw_wm_debug_recompile(struct brw_context *brw,
                       old_key->render_to_fbo, key->render_to_fbo);
    found |= key_debug(brw, "fragment color clamping",
                       old_key->clamp_fragment_color, key->clamp_fragment_color);
+   found |= key_debug(brw, "multisampled FBO",
+                      old_key->multisample_fbo, key->multisample_fbo);
    found |= key_debug(brw, "line smoothing",
                       old_key->line_aa, key->line_aa);
    found |= key_debug(brw, "renderbuffer height",
@@ -404,7 +406,6 @@ brw_wm_populate_key(struct brw_context *brw, struct brw_wm_prog_key *key)
    GLuint lookup = 0;
    GLuint line_aa;
    bool program_uses_dfdy = fp->program.UsesDFdy;
-   const bool multisample_fbo = _mesa_geometric_samples(ctx->DrawBuffer) > 1;
 
    memset(key, 0, sizeof(*key));
 
@@ -530,10 +531,8 @@ brw_wm_populate_key(struct brw_context *brw, struct brw_wm_prog_key *key)
       _mesa_get_min_invocations_per_fragment(ctx, &fp->program, false) > 1 &&
       fp->program.Base.SystemValuesRead & SYSTEM_BIT_SAMPLE_POS;
 
-   key->compute_sample_id =
-      multisample_fbo &&
-      ctx->Multisample.Enabled &&
-      (fp->program.Base.SystemValuesRead & SYSTEM_BIT_SAMPLE_ID);
+   key->multisample_fbo = ctx->Multisample.Enabled &&
+                          _mesa_geometric_samples(ctx->DrawBuffer) > 1;
 
    /* BRW_NEW_VUE_MAP_GEOM_OUT */
    if (brw->gen < 6 || _mesa_bitcount_64(fp->program.Base.InputsRead &