nir: Add nir_load_interpolated_input lowering code.

Now nir_lower_io can optionally produce load_interpolated_input
and load_barycentric_* intrinsics for fragment shader inputs.

flat inputs continue using regular load_input.

v2: Use a nir_shader_compiler_options flag rather than ad-hoc boolean
    passing (in response to review feedback from Chris Forbes).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
This commit is contained in:
Kenneth Graunke
2016-07-12 01:46:53 -07:00
parent 2496462479
commit 707ca00fce
2 changed files with 100 additions and 5 deletions

View File

@@ -1699,6 +1699,14 @@ typedef struct nir_shader_compiler_options {
bool vertex_id_zero_based;
bool lower_cs_local_index_from_id;
/**
* Should nir_lower_io() create load_interpolated_input intrinsics?
*
* If not, it generates regular load_input intrinsics and interpolation
* information must be inferred from the list of input nir_variables.
*/
bool use_interpolated_input_intrinsics;
} nir_shader_compiler_options;
typedef struct nir_shader_info {

View File

@@ -171,14 +171,34 @@ static nir_intrinsic_instr *
lower_load(nir_intrinsic_instr *intrin, struct lower_io_state *state,
nir_ssa_def *vertex_index, nir_ssa_def *offset)
{
const nir_shader *nir = state->builder.shader;
nir_variable *var = intrin->variables[0]->var;
nir_variable_mode mode = var->data.mode;
nir_ssa_def *barycentric = NULL;
nir_intrinsic_op op;
switch (mode) {
case nir_var_shader_in:
if (nir->stage == MESA_SHADER_FRAGMENT &&
nir->options->use_interpolated_input_intrinsics &&
var->data.interpolation != INTERP_MODE_FLAT) {
assert(vertex_index == NULL);
nir_intrinsic_op bary_op;
if (var->data.sample)
bary_op = nir_intrinsic_load_barycentric_sample;
else if (var->data.centroid)
bary_op = nir_intrinsic_load_barycentric_centroid;
else
bary_op = nir_intrinsic_load_barycentric_pixel;
barycentric = nir_load_barycentric(&state->builder, bary_op,
var->data.interpolation);
op = nir_intrinsic_load_interpolated_input;
} else {
op = vertex_index ? nir_intrinsic_load_per_vertex_input :
nir_intrinsic_load_input;
}
break;
case nir_var_shader_out:
op = vertex_index ? nir_intrinsic_load_per_vertex_output :
@@ -204,10 +224,15 @@ lower_load(nir_intrinsic_instr *intrin, struct lower_io_state *state,
if (load->intrinsic == nir_intrinsic_load_uniform)
nir_intrinsic_set_range(load, state->type_size(var->type));
if (vertex_index)
if (vertex_index) {
load->src[0] = nir_src_for_ssa(vertex_index);
load->src[vertex_index ? 1 : 0] = nir_src_for_ssa(offset);
load->src[1] = nir_src_for_ssa(offset);
} else if (barycentric) {
load->src[0] = nir_src_for_ssa(barycentric);
load->src[1] = nir_src_for_ssa(offset);
} else {
load->src[0] = nir_src_for_ssa(offset);
}
return load;
}
@@ -287,11 +312,60 @@ lower_atomic(nir_intrinsic_instr *intrin, struct lower_io_state *state,
return atomic;
}
static nir_intrinsic_instr *
lower_interpolate_at(nir_intrinsic_instr *intrin, struct lower_io_state *state,
nir_ssa_def *offset)
{
nir_variable *var = intrin->variables[0]->var;
assert(var->data.mode == nir_var_shader_in);
nir_intrinsic_op bary_op;
switch (intrin->intrinsic) {
case nir_intrinsic_interp_var_at_centroid:
bary_op = nir_intrinsic_load_barycentric_centroid;
break;
case nir_intrinsic_interp_var_at_sample:
bary_op = nir_intrinsic_load_barycentric_at_sample;
break;
case nir_intrinsic_interp_var_at_offset:
bary_op = nir_intrinsic_load_barycentric_at_offset;
break;
default:
unreachable("Bogus interpolateAt() intrinsic.");
}
nir_intrinsic_instr *bary_setup =
nir_intrinsic_instr_create(state->mem_ctx, bary_op);
nir_ssa_dest_init(&bary_setup->instr, &bary_setup->dest, 2, 32, NULL);
nir_intrinsic_set_interp_mode(bary_setup, var->data.interpolation);
if (intrin->intrinsic != nir_intrinsic_interp_var_at_centroid)
nir_src_copy(&bary_setup->src[0], &intrin->src[0], bary_setup);
nir_builder_instr_insert(&state->builder, &bary_setup->instr);
nir_intrinsic_instr *load =
nir_intrinsic_instr_create(state->mem_ctx,
nir_intrinsic_load_interpolated_input);
load->num_components = intrin->num_components;
nir_intrinsic_set_base(load, var->data.driver_location);
nir_intrinsic_set_component(load, var->data.location_frac);
load->src[0] = nir_src_for_ssa(&bary_setup->dest.ssa);
load->src[1] = nir_src_for_ssa(offset);
return load;
}
static bool
nir_lower_io_block(nir_block *block,
struct lower_io_state *state)
{
nir_builder *b = &state->builder;
const nir_shader_compiler_options *options = b->shader->options;
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
@@ -314,6 +388,12 @@ nir_lower_io_block(nir_block *block,
case nir_intrinsic_var_atomic_comp_swap:
/* We can lower the io for this nir instrinsic */
break;
case nir_intrinsic_interp_var_at_centroid:
case nir_intrinsic_interp_var_at_sample:
case nir_intrinsic_interp_var_at_offset:
/* We can optionally lower these to load_interpolated_input */
if (options->use_interpolated_input_intrinsics)
break;
default:
/* We can't lower the io for this nir instrinsic, so skip it */
continue;
@@ -368,6 +448,13 @@ nir_lower_io_block(nir_block *block,
replacement = lower_atomic(intrin, state, offset);
break;
case nir_intrinsic_interp_var_at_centroid:
case nir_intrinsic_interp_var_at_sample:
case nir_intrinsic_interp_var_at_offset:
assert(vertex_index == NULL);
replacement = lower_interpolate_at(intrin, state, offset);
break;
default:
continue;
}