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
34typedef 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
41static nir_ssa_def *
42get_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
69static nir_variable *
70create_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
84static nir_ssa_def *
85get_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
94static nir_ssa_def *
95get_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
104static nir_ssa_def *
105get_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
114static void
115lower_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
227static void
228lower_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
236static bool
237lower_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
262static void
263lower_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
274void
275nir_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}
290