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, *texcoord_const, *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->texcoord_const == NULL) {
 108       state->texcoord_const = create_uniform(state->shader,
 109                                    "gl_MultiTexCoord0",
 110                                    state->options->texcoord_state_tokens);
 111    }
 112    return nir_load_var(&state->b, state->texcoord_const);
 113 }
 114
 115 static void
 116 lower_color(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 117 {
 118    nir_builder *b = &state->b;
 119    nir_ssa_def *texcoord;
 120    nir_tex_instr *tex;
 121    nir_ssa_def *def;
 122
 123    assert(intr->dest.is_ssa);
 124
 125    b->cursor = nir_before_instr(&intr->instr);
 126
 127    texcoord = get_texcoord(state);
 128
 129    const struct glsl_type *sampler2D =
 130       glsl_sampler_type(GLSL_SAMPLER_DIM_2D, false, false, GLSL_TYPE_FLOAT);
 131
 132    if (!state->tex) {
 133       state->tex =
 134          nir_variable_create(b->shader, nir_var_uniform, sampler2D, "drawpix");
 135       state->tex->data.binding = state->options->drawpix_sampler;
 136       state->tex->data.explicit_binding = true;
 137       state->tex->data.how_declared = nir_var_hidden;
 138    }
 139
 140    nir_deref_instr *tex_deref = nir_build_deref_var(b, state->tex);
 141
 142    /* replace load_var(gl_Color) w/ texture sample:
 143     *   TEX def, texcoord, drawpix_sampler, 2D
 144     */
 145    tex = nir_tex_instr_create(state->shader, 3);
 146    tex->op = nir_texop_tex;
 147    tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 148    tex->coord_components = 2;
 149    tex->dest_type = nir_type_float;
 150    tex->src[0].src_type = nir_tex_src_texture_deref;
 151    tex->src[0].src = nir_src_for_ssa(&tex_deref->dest.ssa);
 152    tex->src[1].src_type = nir_tex_src_sampler_deref;
 153    tex->src[1].src = nir_src_for_ssa(&tex_deref->dest.ssa);
 154    tex->src[2].src_type = nir_tex_src_coord;
 155    tex->src[2].src =
 156       nir_src_for_ssa(nir_channels(b, texcoord,
 157                                    (1 << tex->coord_components) - 1));
 158
 159    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 160    nir_builder_instr_insert(b, &tex->instr);
 161    def = &tex->dest.ssa;
 162
 163    /* Apply the scale and bias. */
 164    if (state->options->scale_and_bias) {
 165       /* MAD def, def, scale, bias; */
 166       def = nir_ffma(b, def, get_scale(state), get_bias(state));
 167    }
 168
 169    if (state->options->pixel_maps) {
 170       if (!state->pixelmap) {
 171          state->pixelmap = nir_variable_create(b->shader, nir_var_uniform,
 172                                                sampler2D, "pixelmap");
 173          state->pixelmap->data.binding = state->options->pixelmap_sampler;
 174          state->pixelmap->data.explicit_binding = true;
 175          state->pixelmap->data.how_declared = nir_var_hidden;
 176       }
 177
 178       nir_deref_instr *pixelmap_deref =
 179          nir_build_deref_var(b, state->pixelmap);
 180
 181       /* do four pixel map look-ups with two TEX instructions: */
 182       nir_ssa_def *def_xy, *def_zw;
 183
 184       /* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
 185       tex = nir_tex_instr_create(state->shader, 3);
 186       tex->op = nir_texop_tex;
 187       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 188       tex->coord_components = 2;
 189       tex->sampler_index = state->options->pixelmap_sampler;
 190       tex->texture_index = state->options->pixelmap_sampler;
 191       tex->dest_type = nir_type_float;
 192       tex->src[0].src_type = nir_tex_src_texture_deref;
 193       tex->src[0].src = nir_src_for_ssa(&pixelmap_deref->dest.ssa);
 194       tex->src[1].src_type = nir_tex_src_sampler_deref;
 195       tex->src[1].src = nir_src_for_ssa(&pixelmap_deref->dest.ssa);
 196       tex->src[2].src_type = nir_tex_src_coord;
 197       tex->src[2].src = nir_src_for_ssa(nir_channels(b, def, 0x3));
 198
 199       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 200       nir_builder_instr_insert(b, &tex->instr);
 201       def_xy = &tex->dest.ssa;
 202
 203       /* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
 204       tex = nir_tex_instr_create(state->shader, 1);
 205       tex->op = nir_texop_tex;
 206       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 207       tex->coord_components = 2;
 208       tex->sampler_index = state->options->pixelmap_sampler;
 209       tex->dest_type = nir_type_float;
 210       tex->src[0].src_type = nir_tex_src_coord;
 211       tex->src[0].src = nir_src_for_ssa(nir_channels(b, def, 0xc));
 212
 213       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 214       nir_builder_instr_insert(b, &tex->instr);
 215       def_zw = &tex->dest.ssa;
 216
 217       /* def = vec4(def.xy, def.zw); */
 218       def = nir_vec4(b,
 219                      nir_channel(b, def_xy, 0),
 220                      nir_channel(b, def_xy, 1),
 221                      nir_channel(b, def_zw, 0),
 222                      nir_channel(b, def_zw, 1));
 223    }
 224
 225    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
 226 }
 227
 228 static void
 229 lower_texcoord(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 230 {
 231    state->b.cursor = nir_before_instr(&intr->instr);
 232
 233    nir_ssa_def *texcoord_const = get_texcoord_const(state);
 234    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
 235 }
 236
 237 static bool
 238 lower_drawpixels_block(lower_drawpixels_state *state, nir_block *block)
 239 {
 240    nir_foreach_instr_safe(instr, block) {
 241       if (instr->type == nir_instr_type_intrinsic) {
 242          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
 243
 244          switch (intr->intrinsic) {
 245          case nir_intrinsic_load_deref: {
 246             nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
 247             nir_variable *var = nir_deref_instr_get_variable(deref);
 248
 249             if (var->data.location == VARYING_SLOT_COL0) {
 250                /* gl_Color should not have array/struct derefs: */
 251                assert(deref->deref_type == nir_deref_type_var);
 252                lower_color(state, intr);
 253             } else if (var->data.location == VARYING_SLOT_TEX0) {
 254                /* gl_TexCoord should not have array/struct derefs: */
 255                assert(deref->deref_type == nir_deref_type_var);
 256                lower_texcoord(state, intr);
 257             }
 258             break;
 259          }
 260
 261          case nir_intrinsic_load_color0:
 262             lower_color(state, intr);
 263             break;
 264
 265          case nir_intrinsic_load_interpolated_input:
 266          case nir_intrinsic_load_input: {
 267             /* The intrinsic doesn't carry the variable. We need to find it
 268              * manually.
 269              */
 270             nir_foreach_variable(var, &state->b.shader->inputs) {
 271                if ((var->data.driver_location == nir_intrinsic_base(intr)) &&
 272                    (nir_intrinsic_component(intr) >= var->data.location_frac  &&
 273                     nir_intrinsic_component(intr) <
 274                      (var->data.location_frac + glsl_get_components(var->type))))
 275                   lower_texcoord(state, intr);
 276             }
 277             break;
 278          }
 279          default:
 280             break;
 281          }
 282       }
 283    }
 284
 285    return true;
 286 }
 287
 288 static void
 289 lower_drawpixels_impl(lower_drawpixels_state *state, nir_function_impl *impl)
 290 {
 291    nir_builder_init(&state->b, impl);
 292
 293    nir_foreach_block(block, impl) {
 294       lower_drawpixels_block(state, block);
 295    }
 296    nir_metadata_preserve(impl, nir_metadata_block_index |
 297                                nir_metadata_dominance);
 298 }
 299
 300 void
 301 nir_lower_drawpixels(nir_shader *shader,
 302                      const nir_lower_drawpixels_options *options)
 303 {
 304    lower_drawpixels_state state = {
 305       .options = options,
 306       .shader = shader,
 307    };
 308
 309    assert(shader->info.stage == MESA_SHADER_FRAGMENT);
 310
 311    nir_foreach_function(function, shader) {
 312       if (function->impl)
 313          lower_drawpixels_impl(&state, function->impl);
 314    }
 315 }