*/
/*
- * 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.
+ * This lowering pass supports (as configured via nir_lower_tex_options)
+ * various texture related conversions:
+ * + texture projector lowering: converts the coordinate division for
+ * texture projection to be done in ALU instructions instead of
+ * asking the texture operation to do so.
+ * + lowering RECT: converts the un-normalized RECT texture coordinates
+ * to normalized coordinates with txs plus ALU instructions
*/
#include "nir.h"
tex->num_srcs--;
}
+static nir_ssa_def *
+get_texture_size(nir_builder *b, nir_tex_instr *tex)
+{
+ b->cursor = nir_before_instr(&tex->instr);
+
+ /* RECT textures should not be array: */
+ assert(!tex->is_array);
+
+ nir_tex_instr *txs;
+
+ txs = nir_tex_instr_create(b->shader, 1);
+ txs->op = nir_texop_txs;
+ txs->sampler_dim = GLSL_SAMPLER_DIM_RECT;
+ txs->sampler_index = tex->sampler_index;
+
+ /* only single src, the lod: */
+ txs->src[0].src = nir_src_for_ssa(nir_imm_int(b, 0));
+ txs->src[0].src_type = nir_tex_src_lod;
+
+ nir_ssa_dest_init(&txs->instr, &txs->dest, 2, NULL);
+ nir_builder_instr_insert(b, &txs->instr);
+
+ return nir_i2f(b, &txs->dest.ssa);
+}
+
+static void
+lower_rect(nir_builder *b, nir_tex_instr *tex)
+{
+ nir_ssa_def *txs = get_texture_size(b, tex);
+ nir_ssa_def *scale = nir_frcp(b, txs);
+
+ /* Walk through the sources normalizing the requested arguments. */
+ for (unsigned i = 0; i < tex->num_srcs; i++) {
+ if (tex->src[i].src_type != nir_tex_src_coord)
+ continue;
+
+ nir_ssa_def *coords =
+ nir_ssa_for_src(b, tex->src[i].src, tex->coord_components);
+ nir_instr_rewrite_src(&tex->instr,
+ &tex->src[i].src,
+ nir_src_for_ssa(nir_fmul(b, coords, scale)));
+ }
+
+ tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
+}
+
static bool
nir_lower_tex_block(nir_block *block, void *void_state)
{
if (lower_txp)
project_src(b, tex);
+ if ((tex->sampler_dim == GLSL_SAMPLER_DIM_RECT) &&
+ state->options->lower_rect)
+ lower_rect(b, tex);
}
return true;