2 * Copyright © 2015 Red Hat
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:
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
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
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Rob Clark <robclark@freedesktop.org>
28 #include "nir_builder.h"
30 #define MAX_CLIP_PLANES 8
32 /* Generates the lowering code for user-clip-planes, generating CLIPDIST
33 * from UCP[n] + CLIPVERTEX or POSITION. Additionally, an optional pass
34 * for fragment shaders to insert conditional kill's based on the inter-
37 * NOTE: should be run after nir_lower_outputs_to_temporaries() (or at
38 * least in scenarios where you can count on each output written once
44 create_clipdist_var(nir_shader
*shader
, unsigned drvloc
,
45 bool output
, gl_varying_slot slot
)
47 nir_variable
*var
= rzalloc(shader
, nir_variable
);
49 var
->data
.driver_location
= drvloc
;
50 var
->type
= glsl_vec4_type();
51 var
->data
.mode
= output
? nir_var_shader_out
: nir_var_shader_in
;
52 var
->name
= ralloc_asprintf(var
, "clipdist_%d", drvloc
);
54 var
->data
.location
= slot
;
57 exec_list_push_tail(&shader
->outputs
, &var
->node
);
58 shader
->num_outputs
++; /* TODO use type_size() */
61 exec_list_push_tail(&shader
->inputs
, &var
->node
);
62 shader
->num_inputs
++; /* TODO use type_size() */
68 store_clipdist_output(nir_builder
*b
, nir_variable
*out
, nir_ssa_def
**val
)
70 nir_intrinsic_instr
*store
;
72 store
= nir_intrinsic_instr_create(b
->shader
, nir_intrinsic_store_output
);
73 store
->num_components
= 4;
74 store
->const_index
[0] = out
->data
.driver_location
;
75 store
->src
[0].ssa
= nir_vec4(b
, val
[0], val
[1], val
[2], val
[3]);
76 store
->src
[0].is_ssa
= true;
77 store
->src
[1] = nir_src_for_ssa(nir_imm_int(b
, 0));
78 nir_builder_instr_insert(b
, &store
->instr
);
82 load_clipdist_input(nir_builder
*b
, nir_variable
*in
, nir_ssa_def
**val
)
84 nir_intrinsic_instr
*load
;
86 load
= nir_intrinsic_instr_create(b
->shader
, nir_intrinsic_load_input
);
87 load
->num_components
= 4;
88 load
->const_index
[0] = in
->data
.driver_location
;
89 load
->src
[0] = nir_src_for_ssa(nir_imm_int(b
, 0));
90 nir_ssa_dest_init(&load
->instr
, &load
->dest
, 4, NULL
);
91 nir_builder_instr_insert(b
, &load
->instr
);
93 val
[0] = nir_channel(b
, &load
->dest
.ssa
, 0);
94 val
[1] = nir_channel(b
, &load
->dest
.ssa
, 1);
95 val
[2] = nir_channel(b
, &load
->dest
.ssa
, 2);
96 val
[3] = nir_channel(b
, &load
->dest
.ssa
, 3);
99 struct find_output_state
106 find_output_in_block(nir_block
*block
, void *void_state
)
108 struct find_output_state
*state
= void_state
;
109 nir_foreach_instr(block
, instr
) {
111 if (instr
->type
== nir_instr_type_intrinsic
) {
112 nir_intrinsic_instr
*intr
= nir_instr_as_intrinsic(instr
);
113 if ((intr
->intrinsic
== nir_intrinsic_store_output
) &&
114 intr
->const_index
[0] == state
->drvloc
) {
115 assert(state
->def
== NULL
);
116 assert(intr
->src
[0].is_ssa
);
117 assert(nir_src_as_const_value(intr
->src
[1]));
118 state
->def
= intr
->src
[0].ssa
;
121 /* for debug builds, scan entire shader to assert
122 * if output is written multiple times. For release
123 * builds just assume all is well and bail when we
135 /* TODO: maybe this would be a useful helper?
136 * NOTE: assumes each output is written exactly once (and unconditionally)
137 * so if needed nir_lower_outputs_to_temporaries()
140 find_output(nir_shader
*shader
, unsigned drvloc
)
142 struct find_output_state state
= {
146 nir_foreach_overload(shader
, overload
) {
147 if (overload
->impl
) {
148 nir_foreach_block_reverse(overload
->impl
,
149 find_output_in_block
, &state
);
161 lower_clip_vs(nir_function_impl
*impl
, unsigned ucp_enables
,
162 nir_ssa_def
*cv
, nir_variable
**out
)
164 nir_ssa_def
*clipdist
[MAX_CLIP_PLANES
];
167 nir_builder_init(&b
, impl
);
169 /* NIR should ensure that, even in case of loops/if-else, there
170 * should be only a single predecessor block to end_block, which
171 * makes the perfect place to insert the clipdist calculations.
173 * NOTE: in case of early return's, these would have to be lowered
174 * to jumps to end_block predecessor in a previous pass. Not sure
175 * if there is a good way to sanity check this, but for now the
176 * users of this pass don't support sub-routines.
178 assert(impl
->end_block
->predecessors
->entries
== 1);
179 b
.cursor
= nir_after_cf_list(&impl
->body
);
181 for (int plane
= 0; plane
< MAX_CLIP_PLANES
; plane
++) {
182 if (ucp_enables
& (1 << plane
)) {
184 nir_load_system_value(&b
, nir_intrinsic_load_user_clip_plane
, plane
);
186 /* calculate clipdist[plane] - dot(ucp, cv): */
187 clipdist
[plane
] = nir_fdot4(&b
, ucp
, cv
);
190 /* 0.0 == don't-clip == disabled: */
191 clipdist
[plane
] = nir_imm_float(&b
, 0.0);
195 if (ucp_enables
& 0x0f)
196 store_clipdist_output(&b
, out
[0], &clipdist
[0]);
197 if (ucp_enables
& 0xf0)
198 store_clipdist_output(&b
, out
[1], &clipdist
[4]);
200 nir_metadata_preserve(impl
, nir_metadata_dominance
);
203 /* ucp_enables is bitmask of enabled ucp's. Actual ucp values are
204 * passed in to shader via user_clip_plane system-values
207 nir_lower_clip_vs(nir_shader
*shader
, unsigned ucp_enables
)
213 nir_variable
*out
[2] = { NULL
};
218 /* find clipvertex/position outputs: */
219 nir_foreach_variable(var
, &shader
->outputs
) {
220 int loc
= var
->data
.driver_location
;
222 /* keep track of last used driver-location.. we'll be
223 * appending CLIP_DIST0/CLIP_DIST1 after last existing
226 maxloc
= MAX2(maxloc
, loc
);
228 switch (var
->data
.location
) {
229 case VARYING_SLOT_POS
:
232 case VARYING_SLOT_CLIP_VERTEX
:
235 case VARYING_SLOT_CLIP_DIST0
:
236 case VARYING_SLOT_CLIP_DIST1
:
237 /* if shader is already writing CLIPDIST, then
238 * there should be no user-clip-planes to deal
245 if (clipvertex
!= -1)
246 cv
= find_output(shader
, clipvertex
);
247 else if (position
!= -1)
248 cv
= find_output(shader
, position
);
252 /* insert CLIPDIST outputs: */
253 if (ucp_enables
& 0x0f)
255 create_clipdist_var(shader
, ++maxloc
, true, VARYING_SLOT_CLIP_DIST0
);
256 if (ucp_enables
& 0xf0)
258 create_clipdist_var(shader
, ++maxloc
, true, VARYING_SLOT_CLIP_DIST1
);
260 nir_foreach_overload(shader
, overload
) {
261 if (!strcmp(overload
->function
->name
, "main"))
262 lower_clip_vs(overload
->impl
, ucp_enables
, cv
, out
);
271 lower_clip_fs(nir_function_impl
*impl
, unsigned ucp_enables
,
274 nir_ssa_def
*clipdist
[MAX_CLIP_PLANES
];
277 nir_builder_init(&b
, impl
);
278 b
.cursor
= nir_before_cf_list(&impl
->body
);
280 if (ucp_enables
& 0x0f)
281 load_clipdist_input(&b
, in
[0], &clipdist
[0]);
282 if (ucp_enables
& 0xf0)
283 load_clipdist_input(&b
, in
[1], &clipdist
[4]);
285 for (int plane
= 0; plane
< MAX_CLIP_PLANES
; plane
++) {
286 if (ucp_enables
& (1 << plane
)) {
287 nir_intrinsic_instr
*discard
;
290 cond
= nir_flt(&b
, clipdist
[plane
], nir_imm_float(&b
, 0.0));
292 discard
= nir_intrinsic_instr_create(b
.shader
,
293 nir_intrinsic_discard_if
);
294 discard
->src
[0] = nir_src_for_ssa(cond
);
295 nir_builder_instr_insert(&b
, &discard
->instr
);
300 /* insert conditional kill based on interpolated CLIPDIST
303 nir_lower_clip_fs(nir_shader
*shader
, unsigned ucp_enables
)
311 nir_foreach_variable(var
, &shader
->inputs
) {
312 int loc
= var
->data
.driver_location
;
314 /* keep track of last used driver-location.. we'll be
315 * appending CLIP_DIST0/CLIP_DIST1 after last existing
318 maxloc
= MAX2(maxloc
, loc
);
321 /* The shader won't normally have CLIPDIST inputs, so we
324 /* insert CLIPDIST outputs: */
325 if (ucp_enables
& 0x0f)
327 create_clipdist_var(shader
, ++maxloc
, false,
328 VARYING_SLOT_CLIP_DIST0
);
329 if (ucp_enables
& 0xf0)
331 create_clipdist_var(shader
, ++maxloc
, false,
332 VARYING_SLOT_CLIP_DIST1
);
334 nir_foreach_overload(shader
, overload
) {
335 if (!strcmp(overload
->function
->name
, "main"))
336 lower_clip_fs(overload
->impl
, ucp_enables
, in
);