i965: Fix fragment shader struct inputs.

Apparently we have literally no support for FS varying struct inputs.
This is somewhat surprising, given that we've had tests for that very
feature that have been passing for a long time.

Normally, varying packing splits up structures for us, so we don't see
them in the backend.  However, with SSO, varying packing isn't around
to save us, and we get actual structs that we have to handle.

This patch changes fs_visitor::emit_general_interpolation() to work
recursively, properly handling nested structs/arrays/and so on.
(It's easier to read with diff -b, as indentation changes.)

When using the vec4 VS backend, this fixes rendering in an upcoming
game from Feral Interactive.  (The scalar VS backend requires additional
bug fixes in the next patch.)

v2: Use pointers instead of pass-by-mutable-reference (Jason, Matt)

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Jason Ekstrand <[email protected]>
Reviewed-by: Matt Turner <[email protected]>
(cherry picked from commit 3e9003e9cf55265ab1fb6522dc5cbb2f455ea1f9)

3 files changed, 84 insertions, 82 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 4e9c96c3925..12bf0c855a6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1039,33 +1039,19 @@ fs_visitor::emit_linterp(const fs_reg &attr, const fs_reg &interp,
 }
 
 void
-fs_visitor::emit_general_interpolation(fs_reg attr, const char *name,
+fs_visitor::emit_general_interpolation(fs_reg *attr, const char *name,
                                        const glsl_type *type,
                                        glsl_interp_qualifier interpolation_mode,
-                                       int location, bool mod_centroid,
+                                       int *location, bool mod_centroid,
                                        bool mod_sample)
 {
-   attr.type = brw_type_for_base_type(type->get_scalar_type());
-
    assert(stage == MESA_SHADER_FRAGMENT);
    brw_wm_prog_data *prog_data = (brw_wm_prog_data*) this->prog_data;
    brw_wm_prog_key *key = (brw_wm_prog_key*) this->key;
 
-   unsigned int array_elements;
-
-   if (type->is_array()) {
-      array_elements = type->length;
-      if (array_elements == 0) {
-         fail("dereferenced array '%s' has length 0\n", name);
-      }
-      type = type->fields.array;
-   } else {
-      array_elements = 1;
-   }
-
    if (interpolation_mode == INTERP_QUALIFIER_NONE) {
       bool is_gl_Color =
-         location == VARYING_SLOT_COL0 || location == VARYING_SLOT_COL1;
+         *location == VARYING_SLOT_COL0 || *location == VARYING_SLOT_COL1;
       if (key->flat_shade && is_gl_Color) {
          interpolation_mode = INTERP_QUALIFIER_FLAT;
       } else {
@@ -1073,71 +1059,86 @@ fs_visitor::emit_general_interpolation(fs_reg attr, const char *name,
       }
    }
 
-   for (unsigned int i = 0; i < array_elements; i++) {
-      for (unsigned int j = 0; j < type->matrix_columns; j++) {
-	 if (prog_data->urb_setup[location] == -1) {
-	    /* If there's no incoming setup data for this slot, don't
-	     * emit interpolation for it.
-	     */
-	    attr = offset(attr, bld, type->vector_elements);
-	    location++;
-	    continue;
-	 }
+   if (type->is_array() || type->is_matrix()) {
+      const glsl_type *elem_type = glsl_get_array_element(type);
+      const unsigned length = glsl_get_length(type);
 
-	 if (interpolation_mode == INTERP_QUALIFIER_FLAT) {
-	    /* Constant interpolation (flat shading) case. The SF has
-	     * handed us defined values in only the constant offset
-	     * field of the setup reg.
-	     */
-	    for (unsigned int k = 0; k < type->vector_elements; k++) {
-	       struct brw_reg interp = interp_reg(location, k);
-	       interp = suboffset(interp, 3);
-               interp.type = attr.type;
-               bld.emit(FS_OPCODE_CINTERP, attr, fs_reg(interp));
-	       attr = offset(attr, bld, 1);
-	    }
-	 } else {
-	    /* Smooth/noperspective interpolation case. */
-	    for (unsigned int k = 0; k < type->vector_elements; k++) {
-               struct brw_reg interp = interp_reg(location, k);
-               if (devinfo->needs_unlit_centroid_workaround && mod_centroid) {
-                  /* Get the pixel/sample mask into f0 so that we know
-                   * which pixels are lit.  Then, for each channel that is
-                   * unlit, replace the centroid data with non-centroid
-                   * data.
-                   */
-                  bld.emit(FS_OPCODE_MOV_DISPATCH_TO_FLAGS);
-
-                  fs_inst *inst;
-                  inst = emit_linterp(attr, fs_reg(interp), interpolation_mode,
-                                      false, false);
-                  inst->predicate = BRW_PREDICATE_NORMAL;
-                  inst->predicate_inverse = true;
-                  if (devinfo->has_pln)
-                     inst->no_dd_clear = true;
-
-                  inst = emit_linterp(attr, fs_reg(interp), interpolation_mode,
-                                      mod_centroid && !key->persample_shading,
-                                      mod_sample || key->persample_shading);
-                  inst->predicate = BRW_PREDICATE_NORMAL;
-                  inst->predicate_inverse = false;
-                  if (devinfo->has_pln)
-                     inst->no_dd_check = true;
+      for (unsigned i = 0; i < length; i++) {
+         emit_general_interpolation(attr, name, elem_type, interpolation_mode,
+                                    location, mod_centroid, mod_sample);
+      }
+   } else if (type->is_record()) {
+      for (unsigned i = 0; i < type->length; i++) {
+         const glsl_type *field_type = type->fields.structure[i].type;
+         emit_general_interpolation(attr, name, field_type, interpolation_mode,
+                                    location, mod_centroid, mod_sample);
+      }
+   } else {
+      assert(type->is_scalar() || type->is_vector());
 
-               } else {
-                  emit_linterp(attr, fs_reg(interp), interpolation_mode,
-                               mod_centroid && !key->persample_shading,
-                               mod_sample || key->persample_shading);
-               }
-               if (devinfo->gen < 6 && interpolation_mode == INTERP_QUALIFIER_SMOOTH) {
-                  bld.MUL(attr, attr, this->pixel_w);
-               }
-	       attr = offset(attr, bld, 1);
-	    }
+      if (prog_data->urb_setup[*location] == -1) {
+         /* If there's no incoming setup data for this slot, don't
+          * emit interpolation for it.
+          */
+         *attr = offset(*attr, bld, type->vector_elements);
+         (*location)++;
+         return;
+      }
 
-	 }
-	 location++;
+      attr->type = brw_type_for_base_type(type->get_scalar_type());
+
+      if (interpolation_mode == INTERP_QUALIFIER_FLAT) {
+         /* Constant interpolation (flat shading) case. The SF has
+          * handed us defined values in only the constant offset
+          * field of the setup reg.
+          */
+         for (unsigned int i = 0; i < type->vector_elements; i++) {
+            struct brw_reg interp = interp_reg(*location, i);
+            interp = suboffset(interp, 3);
+            interp.type = attr->type;
+            bld.emit(FS_OPCODE_CINTERP, *attr, fs_reg(interp));
+            *attr = offset(*attr, bld, 1);
+         }
+      } else {
+         /* Smooth/noperspective interpolation case. */
+         for (unsigned int i = 0; i < type->vector_elements; i++) {
+            struct brw_reg interp = interp_reg(*location, i);
+            if (devinfo->needs_unlit_centroid_workaround && mod_centroid) {
+               /* Get the pixel/sample mask into f0 so that we know
+                * which pixels are lit.  Then, for each channel that is
+                * unlit, replace the centroid data with non-centroid
+                * data.
+                */
+               bld.emit(FS_OPCODE_MOV_DISPATCH_TO_FLAGS);
+
+               fs_inst *inst;
+               inst = emit_linterp(*attr, fs_reg(interp), interpolation_mode,
+                                   false, false);
+               inst->predicate = BRW_PREDICATE_NORMAL;
+               inst->predicate_inverse = true;
+               if (devinfo->has_pln)
+                  inst->no_dd_clear = true;
+
+               inst = emit_linterp(*attr, fs_reg(interp), interpolation_mode,
+                                   mod_centroid && !key->persample_shading,
+                                   mod_sample || key->persample_shading);
+               inst->predicate = BRW_PREDICATE_NORMAL;
+               inst->predicate_inverse = false;
+               if (devinfo->has_pln)
+                  inst->no_dd_check = true;
+
+            } else {
+               emit_linterp(*attr, fs_reg(interp), interpolation_mode,
+                            mod_centroid && !key->persample_shading,
+                            mod_sample || key->persample_shading);
+            }
+            if (devinfo->gen < 6 && interpolation_mode == INTERP_QUALIFIER_SMOOTH) {
+               bld.MUL(*attr, *attr, this->pixel_w);
+            }
+            *attr = offset(*attr, bld, 1);
+         }
       }
+      (*location)++;
    }
 }
 
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 975183e990d..0297ec0d74c 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -197,10 +197,10 @@ public:
    fs_reg *emit_frontfacing_interpolation();
    fs_reg *emit_samplepos_setup();
    fs_reg *emit_sampleid_setup();
-   void emit_general_interpolation(fs_reg attr, const char *name,
+   void emit_general_interpolation(fs_reg *attr, const char *name,
                                    const glsl_type *type,
                                    glsl_interp_qualifier interpolation_mode,
-                                   int location, bool mod_centroid,
+                                   int *location, bool mod_centroid,
                                    bool mod_sample);
    fs_reg *emit_vs_system_value(int location);
    void emit_interpolation_setup_gen4();
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index c726c72ebbe..c97fb931230 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -105,9 +105,10 @@ fs_visitor::nir_setup_inputs(nir_shader *shader)
             emit_percomp(bld, fs_inst(BRW_OPCODE_MOV, bld.dispatch_width(),
                                       input, reg), 0xF);
          } else {
-            emit_general_interpolation(input, var->name, var->type,
+            int location = var->data.location;
+            emit_general_interpolation(&input, var->name, var->type,
                                        (glsl_interp_qualifier) var->data.interpolation,
-                                       var->data.location, var->data.centroid,
+                                       &location, var->data.centroid,
                                        var->data.sample);
          }
          break;