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-rw-r--r--src/glsl/nir/nir_lower_tex.c137
1 files changed, 137 insertions, 0 deletions
diff --git a/src/glsl/nir/nir_lower_tex.c b/src/glsl/nir/nir_lower_tex.c
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index 00000000000..b5ac1b2647d
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+++ b/src/glsl/nir/nir_lower_tex.c
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+/*
+ * 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 bool
+nir_lower_tex_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);
+ b->cursor = nir_before_instr(&tex->instr);
+
+ /* Find the projector in the srcs list, if present. */
+ unsigned 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 (unsigned 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,
+ nir_channel(b, projected, 0),
+ nir_channel(b, projected, 1),
+ nir_channel(b, projected, 2),
+ nir_channel(b, unprojected, 3));
+ break;
+ case 3:
+ projected = nir_vec3(b,
+ nir_channel(b, projected, 0),
+ nir_channel(b, projected, 1),
+ nir_channel(b, unprojected, 2));
+ break;
+ case 2:
+ projected = nir_vec2(b,
+ nir_channel(b, projected, 0),
+ nir_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 (unsigned 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_impl(nir_function_impl *impl)
+{
+ nir_builder b;
+ nir_builder_init(&b, impl);
+
+ nir_foreach_block(impl, nir_lower_tex_block, &b);
+
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+}
+
+void
+nir_lower_tex(nir_shader *shader)
+{
+ nir_foreach_overload(shader, overload) {
+ if (overload->impl)
+ nir_lower_tex_impl(overload->impl);
+ }
+}