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,
  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    /* replace load_var(gl_Color) w/ texture sample:
 129     *   TEX def, texcoord, drawpix_sampler, 2D
 130     */
 131    tex = nir_tex_instr_create(state->shader, 1);
 132    tex->op = nir_texop_tex;
 133    tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 134    tex->coord_components = 2;
 135    tex->sampler_index = state->options->drawpix_sampler;
 136    tex->texture_index = state->options->drawpix_sampler;
 137    tex->dest_type = nir_type_float;
 138    tex->src[0].src_type = nir_tex_src_coord;
 139    tex->src[0].src =
 140       nir_src_for_ssa(nir_channels(b, texcoord,
 141                                    (1 << tex->coord_components) - 1));
 142
 143    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 144    nir_builder_instr_insert(b, &tex->instr);
 145    def = &tex->dest.ssa;
 146
 147    /* Apply the scale and bias. */
 148    if (state->options->scale_and_bias) {
 149       /* MAD def, def, scale, bias; */
 150       def = nir_ffma(b, def, get_scale(state), get_bias(state));
 151    }
 152
 153    if (state->options->pixel_maps) {
 154       /* do four pixel map look-ups with two TEX instructions: */
 155       nir_ssa_def *def_xy, *def_zw;
 156
 157       /* TEX def.xy, def.xyyy, pixelmap_sampler, 2D; */
 158       tex = nir_tex_instr_create(state->shader, 1);
 159       tex->op = nir_texop_tex;
 160       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 161       tex->coord_components = 2;
 162       tex->sampler_index = state->options->pixelmap_sampler;
 163       tex->texture_index = state->options->pixelmap_sampler;
 164       tex->dest_type = nir_type_float;
 165       tex->src[0].src_type = nir_tex_src_coord;
 166       tex->src[0].src = nir_src_for_ssa(nir_channels(b, def, 0x3));
 167
 168       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 169       nir_builder_instr_insert(b, &tex->instr);
 170       def_xy = &tex->dest.ssa;
 171
 172       /* TEX def.zw, def.zwww, pixelmap_sampler, 2D; */
 173       tex = nir_tex_instr_create(state->shader, 1);
 174       tex->op = nir_texop_tex;
 175       tex->sampler_dim = GLSL_SAMPLER_DIM_2D;
 176       tex->coord_components = 2;
 177       tex->sampler_index = state->options->pixelmap_sampler;
 178       tex->dest_type = nir_type_float;
 179       tex->src[0].src_type = nir_tex_src_coord;
 180       tex->src[0].src = nir_src_for_ssa(nir_channels(b, def, 0xc));
 181
 182       nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
 183       nir_builder_instr_insert(b, &tex->instr);
 184       def_zw = &tex->dest.ssa;
 185
 186       /* def = vec4(def.xy, def.zw); */
 187       def = nir_vec4(b,
 188                      nir_channel(b, def_xy, 0),
 189                      nir_channel(b, def_xy, 1),
 190                      nir_channel(b, def_zw, 0),
 191                      nir_channel(b, def_zw, 1));
 192    }
 193
 194    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(def));
 195 }
 196
 197 static void
 198 lower_texcoord(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
 199 {
 200    state->b.cursor = nir_before_instr(&intr->instr);
 201
 202    nir_ssa_def *texcoord_const = get_texcoord_const(state);
 203    nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(texcoord_const));
 204 }
 205
 206 static bool
 207 lower_drawpixels_block(lower_drawpixels_state *state, nir_block *block)
 208 {
 209    nir_foreach_instr_safe(instr, block) {
 210       if (instr->type == nir_instr_type_intrinsic) {
 211          nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
 212          if (intr->intrinsic == nir_intrinsic_load_deref) {
 213             nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
 214             nir_variable *var = nir_deref_instr_get_variable(deref);
 215
 216             if (var->data.location == VARYING_SLOT_COL0) {
 217                /* gl_Color should not have array/struct derefs: */
 218                assert(deref->deref_type == nir_deref_type_var);
 219                lower_color(state, intr);
 220             } else if (var->data.location == VARYING_SLOT_TEX0) {
 221                /* gl_TexCoord should not have array/struct derefs: */
 222                assert(deref->deref_type == nir_deref_type_var);
 223                lower_texcoord(state, intr);
 224             }
 225          }
 226       }
 227    }
 228
 229    return true;
 230 }
 231
 232 static void
 233 lower_drawpixels_impl(lower_drawpixels_state *state, nir_function_impl *impl)
 234 {
 235    nir_builder_init(&state->b, impl);
 236
 237    nir_foreach_block(block, impl) {
 238       lower_drawpixels_block(state, block);
 239    }
 240    nir_metadata_preserve(impl, nir_metadata_block_index |
 241                                nir_metadata_dominance);
 242 }
 243
 244 void
 245 nir_lower_drawpixels(nir_shader *shader,
 246                      const nir_lower_drawpixels_options *options)
 247 {
 248    lower_drawpixels_state state = {
 249       .options = options,
 250       .shader = shader,
 251    };
 252
 253    assert(shader->info.stage == MESA_SHADER_FRAGMENT);
 254
 255    nir_foreach_function(function, shader) {
 256       if (function->impl)
 257          lower_drawpixels_impl(&state, function->impl);
 258    }
 259 }