/*
* Copyright © 2015 Broadcom
*
* 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 lowering pass converts the coordinate division for texture projection
* to be done in ALU instructions instead of asking the texture operation to
* do so.
*/
#include "nir.h"
#include "nir_builder.h"
static nir_ssa_def *
channel(nir_builder *b, nir_ssa_def *def, int c)
{
return nir_swizzle(b, def, (unsigned[4]){c, c, c, c}, 1, false);
}
static bool
nir_lower_tex_projector_block(nir_block *block, void *void_state)
{
nir_builder *b = void_state;
nir_foreach_instr_safe(block, instr) {
if (instr->type != nir_instr_type_tex)
continue;
nir_tex_instr *tex = nir_instr_as_tex(instr);
nir_builder_insert_before_instr(b, &tex->instr);
/* Find the projector in the srcs list, if present. */
int proj_index;
for (proj_index = 0; proj_index < tex->num_srcs; proj_index++) {
if (tex->src[proj_index].src_type == nir_tex_src_projector)
break;
}
if (proj_index == tex->num_srcs)
continue;
nir_ssa_def *inv_proj =
nir_frcp(b, nir_ssa_for_src(b, tex->src[proj_index].src, 1));
/* Walk through the sources projecting the arguments. */
for (int i = 0; i < tex->num_srcs; i++) {
switch (tex->src[i].src_type) {
case nir_tex_src_coord:
case nir_tex_src_comparitor:
break;
default:
continue;
}
nir_ssa_def *unprojected =
nir_ssa_for_src(b, tex->src[i].src, nir_tex_instr_src_size(tex, i));
nir_ssa_def *projected = nir_fmul(b, unprojected, inv_proj);
/* Array indices don't get projected, so make an new vector with the
* coordinate's array index untouched.
*/
if (tex->is_array && tex->src[i].src_type == nir_tex_src_coord) {
switch (tex->coord_components) {
case 4:
projected = nir_vec4(b,
channel(b, projected, 0),
channel(b, projected, 1),
channel(b, projected, 2),
channel(b, unprojected, 3));
break;
case 3:
projected = nir_vec3(b,
channel(b, projected, 0),
channel(b, projected, 1),
channel(b, unprojected, 2));
break;
case 2:
projected = nir_vec2(b,
channel(b, projected, 0),
channel(b, unprojected, 1));
break;
default:
unreachable("bad texture coord count for array");
break;
}
}
nir_instr_rewrite_src(&tex->instr,
&tex->src[i].src,
nir_src_for_ssa(projected));
}
/* Now move the later tex sources down the array so that the projector
* disappears.
*/
nir_instr_rewrite_src(&tex->instr, &tex->src[proj_index].src,
NIR_SRC_INIT);
for (int i = proj_index + 1; i < tex->num_srcs; i++) {
tex->src[i-1].src_type = tex->src[i].src_type;
nir_instr_move_src(&tex->instr, &tex->src[i-1].src, &tex->src[i].src);
}
tex->num_srcs--;
}
return true;
}
static void
nir_lower_tex_projector_impl(nir_function_impl *impl)
{
nir_builder b;
nir_builder_init(&b, impl);
nir_foreach_block(impl, nir_lower_tex_projector_block, &b);
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance);
}
void
nir_lower_tex_projector(nir_shader *shader)
{
nir_foreach_overload(shader, overload) {
if (overload->impl)
nir_lower_tex_projector_impl(overload->impl);
}
}