src/compiler/nir/nir_lower_drawpixels.c

   1 /*
   2  * Copyright © 2015 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 #include "nir.h"
  25 #include "nir_builder.h"
  26
  27 /* Lower glDrawPixels().
  28  *
  29  * This is based on the logic in st_get_drawpix_shader() in TGSI compiler.
  30  *
  31  * Run before nir_lower_io.
  32  */
  33
  34 typedef struct {
  35    const nir_lower_drawpixels_options *options;
  36    nir_shader   *shader;
  37    nir_builder   b;
  38    nir_variable *texcoord, *scale, *bias, *tex, *pixelmap;
  39 } lower_drawpixels_state;
  40
  41 static nir_ssa_def *
  42 get_texcoord(lower_drawpixels_state *state)
  43 {
  44    if (state->texcoord == NULL) {
  45       nir_variable *texcoord = NULL;
  46
  47       /* find gl_TexCoord, if it exists: */
  48       nir_foreach_variable(var, &state->shader->inputs) {
  49          if (var->data.location == VARYING_SLOT_TEX0) {
  50             texcoord = var;
  51             break;
  52          }
  53       }
  54
  55       /* otherwise create it: */
  56       if (texcoord == NULL) {
  57          texcoord = nir_variable_create(state->shader,
  58                                         nir_var_shader_in,
  59                                         glsl_vec4_type(),
  60                                         "gl_TexCoord");
  61          texcoord->data.location = VARYING_SLOT_TEX0;
  62       }
  63
  64       state->texcoord = texcoord;
  65    }
  66    return nir_load_var(&state->b, state->texcoord);
  67 }
  68
  69 static nir_variable *
  70 create_uniform(nir_shader *shader, const char *name,
  71                const gl_state_index16 state_tokens[STATE_LENGTH])
  72 {
  73    nir_variable *var = nir_variable_create(shader,
  74                                            nir_var_uniform,
  75                                            glsl_vec4_type(),
  76                                            name);
  77    var->num_state_slots = 1;
  78    var->state_slots = ralloc_array(var, nir_state_slot, 1);
  79    memcpy(var->state_slots[0].tokens, state_tokens,
  80           sizeof(var->state_slots[0].tokens));
  81    return var;
  82 }
  83
  84 static nir_ssa_def *
  85 get_scale(lower_drawpixels_state *state)
  86 {
  87    if (state->scale == NULL) {
  88       state->scale = create_uniform(state->shader, "gl_PTscale",
  89                                     state->options->scale_state_tokens);
  90    }
  91    return nir_load_var(&state->b, state->scale);
  92 }
  93
  94 static nir_ssa_def *
  95 get_bias(lower_drawpixels_state *state)
  96 {
  97    if (state->bias == NULL) {
  98       state->bias = create_uniform(state->shader, "gl_PTbias",
  99                                    state->options->bias_state_tokens);
 100    }
 101    return nir_load_var(&state->b, state->bias);
 102 }
 103
 104 static nir_ssa_def *
 105 get_texcoord_const(lower_drawpixels_state *state)
 106 {
 107    if (state->bias == NULL) {
 108       state->bias = create_uniform(state->shader, "gl_MultiTexCoord0",
 109                                    state->options->texcoord_state_tokens);
 110    }
 111    return nir_load_var(&state->b, state->bias);
 112 }
 113
 114 static void
 115 lower_color(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 116 {
 117    nir_builder *b = &state->b;
 118    nir_ssa_def *texcoord;
 119    nir_tex_instr *tex;
 120    nir_ssa_def *def;
 121
 122    assert(intr->dest.is_ssa);
 123
 124    b->cursor = nir_before_instr(&intr->instr);
 125
 126    texcoord = get_texcoord(state);
 127
 128    const struct glsl_type *sampler2D =
 129       glsl_sampler_type(GLSL_SAMPLER_DIM_2D, false, false, GLSL_TYPE_FLOAT);
 130
 131    if (!state->tex) {
 132       state->tex =
 133          nir_variable_create(b->shader, nir_var_uniform, sampler2D, "drawpix");
 134       state->tex->data.binding = state->options->drawpix_sampler;
 135       state->tex->data.explicit_binding = true;
 136       state->tex->data.how_declared = nir_var_hidden;
 137    }
 138
 139    nir_deref_instr *tex_deref = nir_build_deref_var(b, state->tex);
 140
 141    /* replace load_var(gl_Color) w/ texture sample:
 142     *   TEX def, texcoord, drawpix_sampler, 2D
 143     */
 144    tex = nir_tex_instr_create(state->shader, 3);
 145    tex->op = nir_texop_tex;
 146    tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 147    tex->coord_components = 2;
 148    tex->dest_type = nir_type_float;
 149    tex->src[0].src_type = nir_tex_src_texture_deref;
 150    tex->src[0].src = nir_src_for_ssa(&tex_deref->dest.ssa);
 151    tex->src[1].src_type = nir_tex_src_sampler_deref;
 152    tex->src[1].src = nir_src_for_ssa(&tex_deref->dest.ssa);
 153    tex->src[2].src_type = nir_tex_src_coord;
 154    tex->src[2].src =
 155       nir_src_for_ssa(nir_channels(b, texcoord,
 156                                    (1 << tex->coord_components) - 1));
 157
 158    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 159    nir_builder_instr_insert(b, &tex->instr);
 160    def = &tex->dest.ssa;
 161
 162    /* Apply the scale and bias. */
 163    if (state->options->scale_and_bias) {
 164       /* MAD def, def, scale, bias; */
 165       def = nir_ffma(b, def, get_scale(state), get_bias(state));
 166    }
 167
 168    if (state->options->pixel_maps) {
 169       if (!state->pixelmap) {
 170          state->pixelmap = nir_variable_create(b->shader, nir_var_uniform,
 171                                                sampler2D, "pixelmap");
 172          state->pixelmap->data.binding = state->options->pixelmap_sampler;
 173          state->pixelmap->data.explicit_binding = true;
 174          state->pixelmap->data.how_declared = nir_var_hidden;
 175       }
 176
 177       nir_deref_instr *pixelmap_deref =
 178          nir_build_deref_var(b, state->pixelmap);
 179
 180       /* do four pixel map look-ups with two TEX instructions: */
 181       nir_ssa_def *def_xy, *def_zw;
 182
 183       /* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
 184       tex = nir_tex_instr_create(state->shader, 3);
 185       tex->op = nir_texop_tex;
 186       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 187       tex->coord_components = 2;
 188       tex->sampler_index = state->options->pixelmap_sampler;
 189       tex->texture_index = state->options->pixelmap_sampler;
 190       tex->dest_type = nir_type_float;
 191       tex->src[0].src_type = nir_tex_src_texture_deref;
 192       tex->src[0].src = nir_src_for_ssa(&pixelmap_deref->dest.ssa);
 193       tex->src[1].src_type = nir_tex_src_sampler_deref;
 194       tex->src[1].src = nir_src_for_ssa(&pixelmap_deref->dest.ssa);
 195       tex->src[2].src_type = nir_tex_src_coord;
 196       tex->src[2].src = nir_src_for_ssa(nir_channels(b, def, 0x3));
 197
 198       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 199       nir_builder_instr_insert(b, &tex->instr);
 200       def_xy = &tex->dest.ssa;
 201
 202       /* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
 203       tex = nir_tex_instr_create(state->shader, 1);
 204       tex->op = nir_texop_tex;
 205       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 206       tex->coord_components = 2;
 207       tex->sampler_index = state->options->pixelmap_sampler;
 208       tex->dest_type = nir_type_float;
 209       tex->src[0].src_type = nir_tex_src_coord;
 210       tex->src[0].src = nir_src_for_ssa(nir_channels(b, def, 0xc));
 211
 212       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 213       nir_builder_instr_insert(b, &tex->instr);
 214       def_zw = &tex->dest.ssa;
 215
 216       /* def = vec4(def.xy, def.zw); */
 217       def = nir_vec4(b,
 218                      nir_channel(b, def_xy, 0),
 219                      nir_channel(b, def_xy, 1),
 220                      nir_channel(b, def_zw, 0),
 221                      nir_channel(b, def_zw, 1));
 222    }
 223
 224    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
 225 }
 226
 227 static void
 228 lower_texcoord(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 229 {
 230    state->b.cursor = nir_before_instr(&intr->instr);
 231
 232    nir_ssa_def *texcoord_const = get_texcoord_const(state);
 233    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
 234 }
 235
 236 static bool
 237 lower_drawpixels_block(lower_drawpixels_state *state, nir_block *block)
 238 {
 239    nir_foreach_instr_safe(instr, block) {
 240       if (instr->type == nir_instr_type_intrinsic) {
 241          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
 242          if (intr->intrinsic == nir_intrinsic_load_deref) {
 243             nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
 244             nir_variable *var = nir_deref_instr_get_variable(deref);
 245
 246             if (var->data.location == VARYING_SLOT_COL0) {
 247                /* gl_Color should not have array/struct derefs: */
 248                assert(deref->deref_type == nir_deref_type_var);
 249                lower_color(state, intr);
 250             } else if (var->data.location == VARYING_SLOT_TEX0) {
 251                /* gl_TexCoord should not have array/struct derefs: */
 252                assert(deref->deref_type == nir_deref_type_var);
 253                lower_texcoord(state, intr);
 254             }
 255          }
 256       }
 257    }
 258
 259    return true;
 260 }
 261
 262 static void
 263 lower_drawpixels_impl(lower_drawpixels_state *state, nir_function_impl *impl)
 264 {
 265    nir_builder_init(&state->b, impl);
 266
 267    nir_foreach_block(block, impl) {
 268       lower_drawpixels_block(state, block);
 269    }
 270    nir_metadata_preserve(impl, nir_metadata_block_index |
 271                                nir_metadata_dominance);
 272 }
 273
 274 void
 275 nir_lower_drawpixels(nir_shader *shader,
 276                      const nir_lower_drawpixels_options *options)
 277 {
 278    lower_drawpixels_state state = {
 279       .options = options,
 280       .shader = shader,
 281    };
 282
 283    assert(shader->info.stage == MESA_SHADER_FRAGMENT);
 284
 285    nir_foreach_function(function, shader) {
 286       if (function->impl)
 287          lower_drawpixels_impl(&state, function->impl);
 288    }
 289 }