intel/blorp: Add indirect clear color support to mcs_partial_resolve

This is a bit complicated because we have to get the indirect clear
color in there somehow.  In order to not do any more work in the shader
than needed, we set it up as it's own vertex binding which points
directly at the clear color address specified by the client.

Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

src/intel/blorp/blorp_clear.c

@@ -833,9 +833,18 @@ blorp_ccs_resolve(struct blorp_batch *batch,
    batch->blorp->exec(batch, &params);
 }
 
+static nir_ssa_def *
+blorp_nir_bit(nir_builder *b, nir_ssa_def *src, unsigned bit)
+{
+   return nir_iand(b, nir_ushr(b, src, nir_imm_int(b, bit)),
+                      nir_imm_int(b, 1));
+}
+
 struct blorp_mcs_partial_resolve_key
 {
    enum blorp_shader_type shader_type;
+   bool indirect_clear_color;
+   bool int_format;
    uint32_t num_samples;
 };
 
@@ -845,6 +854,8 @@ blorp_params_get_mcs_partial_resolve_kernel(struct blorp_context *blorp,
 {
    const struct blorp_mcs_partial_resolve_key blorp_key = {
       .shader_type = BLORP_SHADER_TYPE_MCS_PARTIAL_RESOLVE,
+      .indirect_clear_color = params->dst.clear_color_addr.buffer != NULL,
+      .int_format = isl_format_has_int_channel(params->dst.view.format),
       .num_samples = params->num_samples,
    };
 
@@ -879,7 +890,18 @@ blorp_params_get_mcs_partial_resolve_kernel(struct blorp_context *blorp,
    discard->src[0] = nir_src_for_ssa(nir_inot(&b, is_clear));
    nir_builder_instr_insert(&b, &discard->instr);
 
-   nir_copy_var(&b, frag_color, v_color);
+   nir_ssa_def *clear_color = nir_load_var(&b, v_color);
+   if (blorp_key.indirect_clear_color && blorp->isl_dev->info->gen <= 8) {
+      /* Gen7-8 clear colors are stored as single 0/1 bits */
+      clear_color = nir_vec4(&b, blorp_nir_bit(&b, clear_color, 31),
+                                 blorp_nir_bit(&b, clear_color, 30),
+                                 blorp_nir_bit(&b, clear_color, 29),
+                                 blorp_nir_bit(&b, clear_color, 28));
+
+      if (!blorp_key.int_format)
+         clear_color = nir_i2f32(&b, clear_color);
+   }
+   nir_store_var(&b, frag_color, clear_color, 0xf);
 
    struct brw_wm_prog_key wm_key;
    brw_blorp_init_wm_prog_key(&wm_key);
@@ -925,6 +947,7 @@ blorp_mcs_partial_resolve(struct blorp_batch *batch,
 
    params.num_samples = params.dst.surf.samples;
    params.num_layers = num_layers;
+   params.dst_clear_color_as_input = surf->clear_color_addr.buffer != NULL;
 
    memcpy(&params.wm_inputs.clear_color,
           surf->clear_color.f32, sizeof(float) * 4);

src/intel/blorp/blorp_genX_exec.h

@@ -297,7 +297,7 @@ static void
 blorp_emit_vertex_buffers(struct blorp_batch *batch,
                           const struct blorp_params *params)
 {
-   struct GENX(VERTEX_BUFFER_STATE) vb[2];
+   struct GENX(VERTEX_BUFFER_STATE) vb[3];
    memset(vb, 0, sizeof(vb));
 
    struct blorp_address addr;
@@ -308,12 +308,20 @@ blorp_emit_vertex_buffers(struct blorp_batch *batch,
    blorp_emit_input_varying_data(batch, params, &addr, &size);
    blorp_fill_vertex_buffer_state(batch, vb, 1, addr, size, 0);
 
-   const unsigned num_dwords = 1 + GENX(VERTEX_BUFFER_STATE_length) * 2;
+   uint32_t num_vbs = 2;
+   if (params->dst_clear_color_as_input) {
+      blorp_fill_vertex_buffer_state(batch, vb, num_vbs++,
+                                     params->dst.clear_color_addr,
+                                     batch->blorp->isl_dev->ss.clear_value_size,
+                                     0);
+   }
+
+   const unsigned num_dwords = 1 + num_vbs * GENX(VERTEX_BUFFER_STATE_length);
    uint32_t *dw = blorp_emitn(batch, GENX(3DSTATE_VERTEX_BUFFERS), num_dwords);
    if (!dw)
       return;
 
-   for (unsigned i = 0; i < 2; i++) {
+   for (unsigned i = 0; i < num_vbs; i++) {
       GENX(VERTEX_BUFFER_STATE_pack)(batch, dw, &vb[i]);
       dw += GENX(VERTEX_BUFFER_STATE_length);
    }
@@ -440,6 +448,33 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
    };
    slot++;
 
+   if (params->dst_clear_color_as_input) {
+      /* If the caller wants the destination indirect clear color, redirect
+       * to vertex buffer 2 where we stored it earlier.  The only users of
+       * an indirect clear color source have that as their only vertex
+       * attribute.
+       */
+      assert(num_varyings == 1);
+      ve[slot] = (struct GENX(VERTEX_ELEMENT_STATE)) {
+         .VertexBufferIndex = 2,
+         .Valid = true,
+         .SourceElementOffset = 0,
+         .Component0Control = VFCOMP_STORE_SRC,
+#if GEN_GEN >= 9
+         .SourceElementFormat = (enum GENX(SURFACE_FORMAT)) ISL_FORMAT_R32G32B32A32_FLOAT,
+         .Component1Control = VFCOMP_STORE_SRC,
+         .Component2Control = VFCOMP_STORE_SRC,
+         .Component3Control = VFCOMP_STORE_SRC,
+#else
+         /* Clear colors on gen7-8 are for bits out of one dword */
+         .SourceElementFormat = (enum GENX(SURFACE_FORMAT)) ISL_FORMAT_R32_FLOAT,
+         .Component1Control = VFCOMP_STORE_0,
+         .Component2Control = VFCOMP_STORE_0,
+         .Component3Control = VFCOMP_STORE_0,
+#endif
+      };
+      slot++;
+   } else {
       for (unsigned i = 0; i < num_varyings; ++i) {
          ve[slot] = (struct GENX(VERTEX_ELEMENT_STATE)) {
             .VertexBufferIndex = 1,
@@ -456,6 +491,7 @@ blorp_emit_vertex_elements(struct blorp_batch *batch,
          };
          slot++;
       }
+   }
 
    const unsigned num_dwords =
       1 + GENX(VERTEX_ELEMENT_STATE_length) * num_elements;

src/intel/blorp/blorp_priv.h

@@ -196,6 +196,7 @@ struct blorp_params
    bool color_write_disable[4];
    struct brw_blorp_wm_inputs wm_inputs;
    struct blorp_vs_inputs vs_inputs;
+   bool dst_clear_color_as_input;
    unsigned num_samples;
    unsigned num_draw_buffers;
    unsigned num_layers;