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      1 /*
      2  * Copyright  2016 Red Hat
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the "Software"),
      6  * to deal in the Software without restriction, including without limitation
      7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8  * and/or sell copies of the Software, and to permit persons to whom the
      9  * Software is furnished to do so, subject to the following conditions:
     10  *
     11  * The above copyright notice and this permission notice (including the next
     12  * paragraph) shall be included in all copies or substantial portions of the
     13  * Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     21  * SOFTWARE.
     22  */
     23 
     24 /* Lowers the additional tex_src_plane src, generated by nir_lower_tex
     25  * for planar YUV textures, into separate samplers, matching the logic
     26  * that mesa/st uses to insert additional sampler view/state (since both
     27  * sides need to agree).
     28  *
     29  * This should run after nir_lower_samplers.
     30  */
     31 
     32 #include "compiler/nir/nir.h"
     33 #include "st_nir.h"
     34 
     35 typedef struct {
     36    unsigned lower_2plane;
     37    unsigned lower_3plane;
     38 
     39    /* Maps a primary sampler (used for Y) to the U or UV sampler.  In
     40     * case of 3-plane YUV format, the V plane is next sampler after U.
     41     */
     42    unsigned char sampler_map[PIPE_MAX_SAMPLERS][2];
     43 } lower_tex_src_state;
     44 
     45 static void
     46 assign_extra_samplers(lower_tex_src_state *state, unsigned free_slots)
     47 {
     48    unsigned mask = state->lower_2plane | state->lower_3plane;
     49 
     50    while (mask) {
     51       unsigned extra, y_samp = u_bit_scan(&mask);
     52 
     53       extra = u_bit_scan(&free_slots);
     54       state->sampler_map[y_samp][0] = extra;
     55 
     56       if (state->lower_3plane & (1 << y_samp)) {
     57          extra = u_bit_scan(&free_slots);
     58          state->sampler_map[y_samp][1] = extra;
     59       }
     60    }
     61 }
     62 
     63 static void
     64 lower_tex_src_plane_block(lower_tex_src_state *state, nir_block *block)
     65 {
     66    nir_foreach_instr(instr, block) {
     67       if (instr->type != nir_instr_type_tex)
     68          continue;
     69 
     70       nir_tex_instr *tex = nir_instr_as_tex(instr);
     71       int plane_index = nir_tex_instr_src_index(tex, nir_tex_src_plane);
     72 
     73       if (plane_index < 0)
     74          continue;
     75 
     76       nir_const_value *plane = nir_src_as_const_value(tex->src[plane_index].src);
     77       assume(plane);
     78 
     79       if (plane->i32[0] > 0) {
     80          unsigned y_samp = tex->texture_index;
     81 
     82          assume(tex->texture_index == tex->sampler_index);
     83          assume(((state->lower_3plane & (1 << y_samp)) && plane->i32[0] < 3) ||
     84                (plane->i32[0] < 2));
     85 
     86          tex->texture_index = tex->sampler_index =
     87                state->sampler_map[y_samp][plane->i32[0] - 1];
     88       }
     89 
     90       nir_tex_instr_remove_src(tex, plane_index);
     91    }
     92 }
     93 
     94 static void
     95 lower_tex_src_plane_impl(lower_tex_src_state *state, nir_function_impl *impl)
     96 {
     97    nir_foreach_block(block, impl) {
     98       lower_tex_src_plane_block(state, block);
     99    }
    100 
    101    nir_metadata_preserve(impl, nir_metadata_block_index |
    102                                nir_metadata_dominance);
    103 }
    104 
    105 void
    106 st_nir_lower_tex_src_plane(struct nir_shader *shader, unsigned free_slots,
    107                            unsigned lower_2plane, unsigned lower_3plane)
    108 {
    109    lower_tex_src_state state = {0};
    110 
    111    state.lower_2plane = lower_2plane;
    112    state.lower_3plane = lower_3plane;
    113 
    114    assign_extra_samplers(&state, free_slots);
    115 
    116    nir_foreach_function(function, shader) {
    117       if (function->impl)
    118          lower_tex_src_plane_impl(&state, function->impl);
    119    }
    120 }
    121