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 *
get_texcoord(lower_drawpixels_state * state)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 *
create_uniform(nir_shader * shader,const char * name,const int state_tokens[5])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 *
get_scale(lower_drawpixels_state * state)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 *
get_bias(lower_drawpixels_state * state)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 *
get_texcoord_const(lower_drawpixels_state * state)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
lower_color(lower_drawpixels_state * state,nir_intrinsic_instr * intr)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
lower_texcoord(lower_drawpixels_state * state,nir_intrinsic_instr * intr)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
lower_drawpixels_block(lower_drawpixels_state * state,nir_block * block)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
lower_drawpixels_impl(lower_drawpixels_state * state,nir_function_impl * impl)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
nir_lower_drawpixels(nir_shader * shader,const nir_lower_drawpixels_options * options)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->info.stage == MESA_SHADER_FRAGMENT);
256
257 nir_foreach_function(function, shader) {
258 if (function->impl)
259 lower_drawpixels_impl(&state, function->impl);
260 }
261 }
262