Home | History | Annotate | Download | only in nir 
      1 /*
      2  * Copyright  2015 Intel Corporation
      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
     20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     21  * IN THE SOFTWARE.
     22  *
     23  * Authors:
     24  *    Jason Ekstrand <jason (at) jlekstrand.net>
     25  */
     26 
     27 #include "nir.h"
     28 #include "nir_builder.h"
     29 
     30 /**
     31  * This file implements a NIR lowering pass to perform the normalization of
     32  * the cubemap coordinates to have the largest magnitude component be -1.0
     33  * or 1.0.  This is based on the old GLSL IR based pass by Eric.
     34  */
     35 
     36 static bool
     37 normalize_cubemap_coords_block(nir_block *block, nir_builder *b)
     38 {
     39    bool progress = false;
     40 
     41    nir_foreach_instr(instr, block) {
     42       if (instr->type != nir_instr_type_tex)
     43          continue;
     44 
     45       nir_tex_instr *tex = nir_instr_as_tex(instr);
     46       if (tex->sampler_dim != GLSL_SAMPLER_DIM_CUBE)
     47          continue;
     48 
     49       b->cursor = nir_before_instr(&tex->instr);
     50 
     51       for (unsigned i = 0; i < tex->num_srcs; i++) {
     52          if (tex->src[i].src_type != nir_tex_src_coord)
     53             continue;
     54 
     55          nir_ssa_def *orig_coord =
     56             nir_ssa_for_src(b, tex->src[i].src, nir_tex_instr_src_size(tex, i));
     57          assert(orig_coord->num_components >= 3);
     58 
     59          nir_ssa_def *abs = nir_fabs(b, orig_coord);
     60          nir_ssa_def *norm = nir_fmax(b, nir_channel(b, abs, 0),
     61                                          nir_fmax(b, nir_channel(b, abs, 1),
     62                                                      nir_channel(b, abs, 2)));
     63 
     64          nir_ssa_def *normalized = nir_fmul(b, orig_coord, nir_frcp(b, norm));
     65 
     66          /* Array indices don't have to be normalized, so make a new vector
     67           * with the coordinate's array index untouched.
     68           */
     69          if (tex->coord_components == 4) {
     70             normalized = nir_vec4(b,
     71                                   nir_channel(b, normalized, 0),
     72                                   nir_channel(b, normalized, 1),
     73                                   nir_channel(b, normalized, 2),
     74                                   nir_channel(b, orig_coord, 3));
     75          }
     76 
     77          nir_instr_rewrite_src(&tex->instr,
     78                                &tex->src[i].src,
     79                                nir_src_for_ssa(normalized));
     80 
     81          progress = true;
     82       }
     83    }
     84 
     85    return progress;
     86 }
     87 
     88 static bool
     89 normalize_cubemap_coords_impl(nir_function_impl *impl)
     90 {
     91    nir_builder b;
     92    nir_builder_init(&b, impl);
     93    bool progress = false;
     94 
     95    nir_foreach_block(block, impl) {
     96       progress |= normalize_cubemap_coords_block(block, &b);
     97    }
     98 
     99    nir_metadata_preserve(impl, nir_metadata_block_index |
    100                                nir_metadata_dominance);
    101 
    102    return progress;
    103 }
    104 
    105 bool
    106 nir_normalize_cubemap_coords(nir_shader *shader)
    107 {
    108    bool progress = false;
    109 
    110    nir_foreach_function(function, shader) {
    111       if (function->impl)
    112          progress = normalize_cubemap_coords_impl(function->impl) || progress;
    113    }
    114 
    115    return progress;
    116 }
    117