--- /dev/null
+/*
+ * Copyright © 2019 Google, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/*
+ * This lower pass lowers load_interpolated_input for various interpolation
+ * modes (as configured via nir_lower_interpolation_options bitmask) into
+ * load_attribute_deltas plus alu instructions:
+ *
+ * vec3 ad = load_attribute_deltas(varying_slot)
+ * float result = ad.x + ad.y * j + ad.z * i
+ *
+ */
+
+#include "nir.h"
+#include "nir_builder.h"
+
+static bool
+nir_lower_interpolation_block(nir_block *block, nir_builder *b,
+ nir_lower_interpolation_options options)
+{
+ bool progress = false;
+
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+
+ if (intr->intrinsic != nir_intrinsic_load_interpolated_input)
+ continue;
+
+ assert(intr->dest.is_ssa);
+ assert(intr->src[0].is_ssa);
+ assert(intr->src[1].is_ssa);
+
+ nir_intrinsic_instr *bary_intrinsic =
+ nir_instr_as_intrinsic(intr->src[0].ssa->parent_instr);
+
+ /* Leave VARYING_SLOT_POS alone */
+ if (nir_intrinsic_base(intr) == VARYING_SLOT_POS)
+ continue;
+
+ const enum glsl_interp_mode interp_mode =
+ nir_intrinsic_interp_mode(bary_intrinsic);
+
+ /* We need actual interpolation modes by the time we get here */
+ assert(interp_mode != INTERP_MODE_NONE);
+
+ /* Only lower for inputs that need interpolation */
+ if (interp_mode != INTERP_MODE_SMOOTH &&
+ interp_mode != INTERP_MODE_NOPERSPECTIVE)
+ continue;
+
+ nir_intrinsic_op op = bary_intrinsic->intrinsic;
+
+ switch (op) {
+ case nir_intrinsic_load_barycentric_at_sample:
+ if (options & nir_lower_interpolation_at_sample)
+ break;
+ continue;
+ case nir_intrinsic_load_barycentric_at_offset:
+ if (options & nir_lower_interpolation_at_offset)
+ break;
+ continue;
+ case nir_intrinsic_load_barycentric_centroid:
+ if (options & nir_lower_interpolation_centroid)
+ break;
+ continue;
+ case nir_intrinsic_load_barycentric_pixel:
+ if (options & nir_lower_interpolation_pixel)
+ break;
+ continue;
+ case nir_intrinsic_load_barycentric_sample:
+ if (options & nir_lower_interpolation_sample)
+ break;
+ continue;
+ default:
+ continue;
+ }
+
+ b->cursor = nir_before_instr(instr);
+
+ nir_ssa_def *comps[NIR_MAX_VEC_COMPONENTS];
+ for (int i = 0; i < intr->num_components; i++) {
+ nir_intrinsic_instr *load_iid =
+ nir_intrinsic_instr_create(b->shader,
+ nir_intrinsic_load_fs_input_interp_deltas);
+ load_iid->src[0] = nir_src_for_ssa(intr->src[1].ssa);
+ nir_ssa_dest_init(&load_iid->instr, &load_iid->dest,
+ 3, 32, NULL);
+ nir_intrinsic_set_base(load_iid, nir_intrinsic_base(intr));
+ nir_intrinsic_set_component(load_iid,
+ nir_intrinsic_component(intr) + i);
+ nir_builder_instr_insert(b, &load_iid->instr);
+
+ nir_ssa_def *iid = &load_iid->dest.ssa;
+ nir_ssa_def *bary = intr->src[0].ssa;
+ nir_ssa_def *val;
+
+ val = nir_ffma(b, nir_channel(b, bary, 1),
+ nir_channel(b, iid, 1),
+ nir_channel(b, iid, 0));
+ val = nir_ffma(b, nir_channel(b, bary, 0),
+ nir_channel(b, iid, 2),
+ val);
+
+ comps[i] = val;
+ }
+ nir_ssa_def *vec = nir_vec(b, comps, intr->num_components);
+ nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(vec));
+
+ progress = true;
+ }
+
+ return progress;
+}
+
+static bool
+nir_lower_interpolation_impl(nir_function_impl *impl,
+ nir_lower_interpolation_options options)
+{
+ bool progress = false;
+ nir_builder builder;
+ nir_builder_init(&builder, impl);
+
+ nir_foreach_block(block, impl) {
+ progress |= nir_lower_interpolation_block(block, &builder, options);
+ }
+
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+ return progress;
+}
+
+bool
+nir_lower_interpolation(nir_shader *shader, nir_lower_interpolation_options options)
+{
+ bool progress = false;
+
+ nir_foreach_function(function, shader) {
+ if (function->impl)
+ progress |= nir_lower_interpolation_impl(function->impl, options);
+ }
+
+ return progress;
+}
projects / mesa.git / commitdiff