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;
  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, const int state_tokens[5])
  71 {
  72    nir_variable *var = nir_variable_create(shader,
  73                                            nir_var_uniform,
  74                                            glsl_vec4_type(),
  75                                            name);
  76    var->num_state_slots = 1;
  77    var->state_slots = ralloc_array(var, nir_state_slot, 1);
  78    memcpy(var->state_slots[0].tokens, state_tokens,
  79           sizeof(var->state_slots[0].tokens));
  80    return var;
  81 }
  82
  83 static nir_ssa_def *
  84 get_scale(lower_drawpixels_state *state)
  85 {
  86    if (state->scale == NULL) {
  87       state->scale = create_uniform(state->shader, "gl_PTscale",
  88                                     state->options->scale_state_tokens);
  89    }
  90    return nir_load_var(&state->b, state->scale);
  91 }
  92
  93 static nir_ssa_def *
  94 get_bias(lower_drawpixels_state *state)
  95 {
  96    if (state->bias == NULL) {
  97       state->bias = create_uniform(state->shader, "gl_PTbias",
  98                                    state->options->bias_state_tokens);
  99    }
 100    return nir_load_var(&state->b, state->bias);
 101 }
 102
 103 static nir_ssa_def *
 104 get_texcoord_const(lower_drawpixels_state *state)
 105 {
 106    if (state->bias == NULL) {
 107       state->bias = create_uniform(state->shader, "gl_MultiTexCoord0",
 108                                    state->options->texcoord_state_tokens);
 109    }
 110    return nir_load_var(&state->b, state->bias);
 111 }
 112
 113 static void
 114 lower_color(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 115 {
 116    nir_builder *b = &state->b;
 117    nir_ssa_def *texcoord;
 118    nir_tex_instr *tex;
 119    nir_ssa_def *def;
 120
 121    assert(intr->dest.is_ssa);
 122
 123    b->cursor = nir_before_instr(&intr->instr);
 124
 125    texcoord = get_texcoord(state);
 126
 127    /* replace load_var(gl_Color) w/ texture sample:
 128     *   TEX def, texcoord, drawpix_sampler, 2D
 129     */
 130    tex = nir_tex_instr_create(state->shader, 1);
 131    tex->op = nir_texop_tex;
 132    tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 133    tex->coord_components = 2;
 134    tex->sampler_index = state->options->drawpix_sampler;
 135    tex->texture_index = state->options->drawpix_sampler;
 136    tex->dest_type = nir_type_float;
 137    tex->src[0].src_type = nir_tex_src_coord;
 138    tex->src[0].src =
 139       nir_src_for_ssa(nir_channels(b, texcoord,
 140                                    (1 << tex->coord_components) - 1));
 141
 142    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 143    nir_builder_instr_insert(b, &tex->instr);
 144    def = &tex->dest.ssa;
 145
 146    /* Apply the scale and bias. */
 147    if (state->options->scale_and_bias) {
 148       /* MAD def, def, scale, bias; */
 149       def = nir_ffma(b, def, get_scale(state), get_bias(state));
 150    }
 151
 152    if (state->options->pixel_maps) {
 153       static const unsigned swiz_xy[4] = {0,1};
 154       static const unsigned swiz_zw[4] = {2,3};
 155
 156       /* do four pixel map look-ups with two TEX instructions: */
 157       nir_ssa_def *def_xy, *def_zw;
 158
 159       /* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
 160       tex = nir_tex_instr_create(state->shader, 1);
 161       tex->op = nir_texop_tex;
 162       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 163       tex->coord_components = 2;
 164       tex->sampler_index = state->options->pixelmap_sampler;
 165       tex->texture_index = state->options->pixelmap_sampler;
 166       tex->dest_type = nir_type_float;
 167       tex->src[0].src_type = nir_tex_src_coord;
 168       tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_xy, 2, true));
 169
 170       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 171       nir_builder_instr_insert(b, &tex->instr);
 172       def_xy = &tex->dest.ssa;
 173
 174       /* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
 175       tex = nir_tex_instr_create(state->shader, 1);
 176       tex->op = nir_texop_tex;
 177       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 178       tex->coord_components = 2;
 179       tex->sampler_index = state->options->pixelmap_sampler;
 180       tex->dest_type = nir_type_float;
 181       tex->src[0].src_type = nir_tex_src_coord;
 182       tex->src[0].src = nir_src_for_ssa(nir_swizzle(b, def, swiz_zw, 2, true));
 183
 184       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 185       nir_builder_instr_insert(b, &tex->instr);
 186       def_zw = &tex->dest.ssa;
 187
 188       /* def = vec4(def.xy, def.zw); */
 189       def = nir_vec4(b,
 190                      nir_channel(b, def_xy, 0),
 191                      nir_channel(b, def_xy, 1),
 192                      nir_channel(b, def_zw, 0),
 193                      nir_channel(b, def_zw, 1));
 194    }
 195
 196    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
 197 }
 198
 199 static void
 200 lower_texcoord(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 201 {
 202    state->b.cursor = nir_before_instr(&intr->instr);
 203
 204    nir_ssa_def *texcoord_const = get_texcoord_const(state);
 205    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
 206 }
 207
 208 static bool
 209 lower_drawpixels_block(lower_drawpixels_state *state, nir_block *block)
 210 {
 211    nir_foreach_instr_safe(instr, block) {
 212       if (instr->type == nir_instr_type_intrinsic) {
 213          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
 214          if (intr->intrinsic == nir_intrinsic_load_var) {
 215             nir_deref_var *dvar = intr->variables[0];
 216             nir_variable *var = dvar->var;
 217
 218             if (var->data.location == VARYING_SLOT_COL0) {
 219                /* gl_Color should not have array/struct derefs: */
 220                assert(dvar->deref.child == NULL);
 221                lower_color(state, intr);
 222             } else if (var->data.location == VARYING_SLOT_TEX0) {
 223                /* gl_TexCoord should not have array/struct derefs: */
 224                assert(dvar->deref.child == NULL);
 225                lower_texcoord(state, intr);
 226             }
 227          }
 228       }
 229    }
 230
 231    return true;
 232 }
 233
 234 static void
 235 lower_drawpixels_impl(lower_drawpixels_state *state, nir_function_impl *impl)
 236 {
 237    nir_builder_init(&state->b, impl);
 238
 239    nir_foreach_block(block, impl) {
 240       lower_drawpixels_block(state, block);
 241    }
 242    nir_metadata_preserve(impl, nir_metadata_block_index |
 243                                nir_metadata_dominance);
 244 }
 245
 246 void
 247 nir_lower_drawpixels(nir_shader *shader,
 248                      const nir_lower_drawpixels_options *options)
 249 {
 250    lower_drawpixels_state state = {
 251       .options = options,
 252       .shader = shader,
 253    };
 254
 255    assert(shader->stage == MESA_SHADER_FRAGMENT);
 256
 257    nir_foreach_function(function, shader) {
 258       if (function->impl)
 259          lower_drawpixels_impl(&state, function->impl);
 260    }
 261 }