lp_bld_sample.c revision c4d2a14d6e98dae29a9a04da122521e25eaf7986
1/**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28/**
29 * @file
30 * Texture sampling -- common code.
31 *
32 * @author Jose Fonseca <jfonseca@vmware.com>
33 */
34
35#include "pipe/p_defines.h"
36#include "pipe/p_state.h"
37#include "util/u_format.h"
38#include "util/u_math.h"
39#include "lp_bld_arit.h"
40#include "lp_bld_const.h"
41#include "lp_bld_debug.h"
42#include "lp_bld_printf.h"
43#include "lp_bld_flow.h"
44#include "lp_bld_sample.h"
45#include "lp_bld_swizzle.h"
46#include "lp_bld_type.h"
47#include "lp_bld_logic.h"
48#include "lp_bld_pack.h"
49
50
51/*
52 * Bri-linear factor. Should be greater than one.
53 */
54#define BRILINEAR_FACTOR 2
55
56/**
57 * Does the given texture wrap mode allow sampling the texture border color?
58 * XXX maybe move this into gallium util code.
59 */
60boolean
61lp_sampler_wrap_mode_uses_border_color(unsigned mode,
62                                       unsigned min_img_filter,
63                                       unsigned mag_img_filter)
64{
65   switch (mode) {
66   case PIPE_TEX_WRAP_REPEAT:
67   case PIPE_TEX_WRAP_CLAMP_TO_EDGE:
68   case PIPE_TEX_WRAP_MIRROR_REPEAT:
69   case PIPE_TEX_WRAP_MIRROR_CLAMP_TO_EDGE:
70      return FALSE;
71   case PIPE_TEX_WRAP_CLAMP:
72   case PIPE_TEX_WRAP_MIRROR_CLAMP:
73      if (min_img_filter == PIPE_TEX_FILTER_NEAREST &&
74          mag_img_filter == PIPE_TEX_FILTER_NEAREST) {
75         return FALSE;
76      } else {
77         return TRUE;
78      }
79   case PIPE_TEX_WRAP_CLAMP_TO_BORDER:
80   case PIPE_TEX_WRAP_MIRROR_CLAMP_TO_BORDER:
81      return TRUE;
82   default:
83      assert(0 && "unexpected wrap mode");
84      return FALSE;
85   }
86}
87
88
89/**
90 * Initialize lp_sampler_static_state object with the gallium sampler
91 * and texture state.
92 * The former is considered to be static and the later dynamic.
93 */
94void
95lp_sampler_static_state(struct lp_sampler_static_state *state,
96                        const struct pipe_sampler_view *view,
97                        const struct pipe_sampler_state *sampler)
98{
99   const struct pipe_resource *texture = view->texture;
100
101   memset(state, 0, sizeof *state);
102
103   if(!texture)
104      return;
105
106   if(!sampler)
107      return;
108
109   /*
110    * We don't copy sampler state over unless it is actually enabled, to avoid
111    * spurious recompiles, as the sampler static state is part of the shader
112    * key.
113    *
114    * Ideally the state tracker or cso_cache module would make all state
115    * canonical, but until that happens it's better to be safe than sorry here.
116    *
117    * XXX: Actually there's much more than can be done here, especially
118    * regarding 1D/2D/3D/CUBE textures, wrap modes, etc.
119    */
120
121   state->format            = view->format;
122   state->swizzle_r         = view->swizzle_r;
123   state->swizzle_g         = view->swizzle_g;
124   state->swizzle_b         = view->swizzle_b;
125   state->swizzle_a         = view->swizzle_a;
126
127   state->target            = texture->target;
128   state->pot_width         = util_is_power_of_two(texture->width0);
129   state->pot_height        = util_is_power_of_two(texture->height0);
130   state->pot_depth         = util_is_power_of_two(texture->depth0);
131
132   state->wrap_s            = sampler->wrap_s;
133   state->wrap_t            = sampler->wrap_t;
134   state->wrap_r            = sampler->wrap_r;
135   state->min_img_filter    = sampler->min_img_filter;
136   state->mag_img_filter    = sampler->mag_img_filter;
137
138   if (view->u.tex.last_level && sampler->max_lod > 0.0f) {
139      state->min_mip_filter = sampler->min_mip_filter;
140   } else {
141      state->min_mip_filter = PIPE_TEX_MIPFILTER_NONE;
142   }
143
144   if (state->min_mip_filter != PIPE_TEX_MIPFILTER_NONE) {
145      if (sampler->lod_bias != 0.0f) {
146         state->lod_bias_non_zero = 1;
147      }
148
149      /* If min_lod == max_lod we can greatly simplify mipmap selection.
150       * This is a case that occurs during automatic mipmap generation.
151       */
152      if (sampler->min_lod == sampler->max_lod) {
153         state->min_max_lod_equal = 1;
154      } else {
155         if (sampler->min_lod > 0.0f) {
156            state->apply_min_lod = 1;
157         }
158
159         if (sampler->max_lod < (float)view->u.tex.last_level) {
160            state->apply_max_lod = 1;
161         }
162      }
163   }
164
165   state->compare_mode      = sampler->compare_mode;
166   if (sampler->compare_mode != PIPE_TEX_COMPARE_NONE) {
167      state->compare_func   = sampler->compare_func;
168   }
169
170   state->normalized_coords = sampler->normalized_coords;
171
172   /*
173    * FIXME: Handle the remainder of pipe_sampler_view.
174    */
175}
176
177
178/**
179 * Generate code to compute coordinate gradient (rho).
180 * \param derivs  partial derivatives of (s, t, r, q) with respect to X and Y
181 *
182 * The resulting rho is scalar per quad.
183 */
184static LLVMValueRef
185lp_build_rho(struct lp_build_sample_context *bld,
186             unsigned unit,
187             const struct lp_derivatives *derivs)
188{
189   struct gallivm_state *gallivm = bld->gallivm;
190   struct lp_build_context *int_size_bld = &bld->int_size_bld;
191   struct lp_build_context *float_size_bld = &bld->float_size_bld;
192   struct lp_build_context *float_bld = &bld->float_bld;
193   struct lp_build_context *coord_bld = &bld->coord_bld;
194   struct lp_build_context *perquadf_bld = &bld->perquadf_bld;
195   const LLVMValueRef *ddx_ddy = derivs->ddx_ddy;
196   const unsigned dims = bld->dims;
197   LLVMBuilderRef builder = bld->gallivm->builder;
198   LLVMTypeRef i32t = LLVMInt32TypeInContext(bld->gallivm->context);
199   LLVMValueRef index0 = LLVMConstInt(i32t, 0, 0);
200   LLVMValueRef index1 = LLVMConstInt(i32t, 1, 0);
201   LLVMValueRef index2 = LLVMConstInt(i32t, 2, 0);
202   LLVMValueRef rho_vec;
203   LLVMValueRef int_size, float_size;
204   LLVMValueRef rho;
205   LLVMValueRef first_level, first_level_vec;
206   LLVMValueRef abs_ddx_ddy[2];
207   unsigned length = coord_bld->type.length;
208   unsigned num_quads = length / 4;
209   unsigned i;
210   LLVMValueRef i32undef = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
211   LLVMValueRef rho_xvec, rho_yvec;
212
213   abs_ddx_ddy[0] = lp_build_abs(coord_bld, ddx_ddy[0]);
214   if (dims > 2) {
215      abs_ddx_ddy[1] = lp_build_abs(coord_bld, ddx_ddy[1]);
216   }
217   else {
218      abs_ddx_ddy[1] = NULL;
219   }
220
221   if (dims == 1) {
222      static const unsigned char swizzle1[] = {
223         0, LP_BLD_SWIZZLE_DONTCARE,
224         LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
225      };
226      static const unsigned char swizzle2[] = {
227         1, LP_BLD_SWIZZLE_DONTCARE,
228         LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
229      };
230      rho_xvec = lp_build_swizzle_aos(coord_bld, abs_ddx_ddy[0], swizzle1);
231      rho_yvec = lp_build_swizzle_aos(coord_bld, abs_ddx_ddy[0], swizzle2);
232   }
233   else if (dims == 2) {
234      static const unsigned char swizzle1[] = {
235         0, 2,
236         LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
237      };
238      static const unsigned char swizzle2[] = {
239         1, 3,
240         LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
241      };
242      rho_xvec = lp_build_swizzle_aos(coord_bld, abs_ddx_ddy[0], swizzle1);
243      rho_yvec = lp_build_swizzle_aos(coord_bld, abs_ddx_ddy[0], swizzle2);
244   }
245   else {
246      LLVMValueRef shuffles1[LP_MAX_VECTOR_LENGTH];
247      LLVMValueRef shuffles2[LP_MAX_VECTOR_LENGTH];
248      assert(dims == 3);
249      for (i = 0; i < num_quads; i++) {
250         shuffles1[4*i + 0] = lp_build_const_int32(gallivm, 4*i);
251         shuffles1[4*i + 1] = lp_build_const_int32(gallivm, 4*i + 2);
252         shuffles1[4*i + 2] = lp_build_const_int32(gallivm, length + 4*i);
253         shuffles1[4*i + 3] = i32undef;
254         shuffles2[4*i + 0] = lp_build_const_int32(gallivm, 4*i + 1);
255         shuffles2[4*i + 1] = lp_build_const_int32(gallivm, 4*i + 3);
256         shuffles2[4*i + 2] = lp_build_const_int32(gallivm, length + 4*i + 1);
257         shuffles2[4*i + 3] = i32undef;
258      }
259      rho_xvec = LLVMBuildShuffleVector(builder, abs_ddx_ddy[0], abs_ddx_ddy[1],
260                                        LLVMConstVector(shuffles1, length), "");
261      rho_yvec = LLVMBuildShuffleVector(builder, abs_ddx_ddy[0], abs_ddx_ddy[1],
262                                        LLVMConstVector(shuffles2, length), "");
263   }
264
265   rho_vec = lp_build_max(coord_bld, rho_xvec, rho_yvec);
266
267   first_level = bld->dynamic_state->first_level(bld->dynamic_state,
268                                                 bld->gallivm, unit);
269   first_level_vec = lp_build_broadcast_scalar(&bld->int_size_bld, first_level);
270   int_size = lp_build_minify(int_size_bld, bld->int_size, first_level_vec);
271   float_size = lp_build_int_to_float(float_size_bld, int_size);
272
273   if (bld->coord_type.length > 4) {
274      /* expand size to each quad */
275      if (dims > 1) {
276         /* could use some broadcast_vector helper for this? */
277         int num_quads = bld->coord_type.length / 4;
278         LLVMValueRef src[LP_MAX_VECTOR_LENGTH/4];
279         for (i = 0; i < num_quads; i++) {
280            src[i] = float_size;
281         }
282         float_size = lp_build_concat(bld->gallivm, src, float_size_bld->type, num_quads);
283      }
284      else {
285         float_size = lp_build_broadcast_scalar(coord_bld, float_size);
286      }
287      rho_vec = lp_build_mul(coord_bld, rho_vec, float_size);
288
289      if (dims <= 1) {
290         rho = rho_vec;
291      }
292      else {
293         if (dims >= 2) {
294            static const unsigned char swizzle1[] = {
295               0, LP_BLD_SWIZZLE_DONTCARE,
296               LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
297            };
298            static const unsigned char swizzle2[] = {
299               1, LP_BLD_SWIZZLE_DONTCARE,
300               LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
301            };
302            LLVMValueRef rho_s, rho_t, rho_r;
303
304            rho_s = lp_build_swizzle_aos(coord_bld, rho_vec, swizzle1);
305            rho_t = lp_build_swizzle_aos(coord_bld, rho_vec, swizzle2);
306
307            rho = lp_build_max(coord_bld, rho_s, rho_t);
308
309            if (dims >= 3) {
310               static const unsigned char swizzle3[] = {
311                  2, LP_BLD_SWIZZLE_DONTCARE,
312                  LP_BLD_SWIZZLE_DONTCARE, LP_BLD_SWIZZLE_DONTCARE
313               };
314               rho_r = lp_build_swizzle_aos(coord_bld, rho_vec, swizzle3);
315               rho = lp_build_max(coord_bld, rho, rho_r);
316            }
317         }
318      }
319      rho = lp_build_pack_aos_scalars(bld->gallivm, coord_bld->type,
320                                      perquadf_bld->type, rho);
321   }
322   else {
323      if (dims <= 1) {
324         rho_vec = LLVMBuildExtractElement(builder, rho_vec, index0, "");
325      }
326      rho_vec = lp_build_mul(float_size_bld, rho_vec, float_size);
327
328      if (dims <= 1) {
329         rho = rho_vec;
330      }
331      else {
332         if (dims >= 2) {
333            LLVMValueRef rho_s, rho_t, rho_r;
334
335            rho_s = LLVMBuildExtractElement(builder, rho_vec, index0, "");
336            rho_t = LLVMBuildExtractElement(builder, rho_vec, index1, "");
337
338            rho = lp_build_max(float_bld, rho_s, rho_t);
339
340            if (dims >= 3) {
341               rho_r = LLVMBuildExtractElement(builder, rho_vec, index2, "");
342               rho = lp_build_max(float_bld, rho, rho_r);
343            }
344         }
345      }
346   }
347
348   return rho;
349}
350
351
352/*
353 * Bri-linear lod computation
354 *
355 * Use a piece-wise linear approximation of log2 such that:
356 * - round to nearest, for values in the neighborhood of -1, 0, 1, 2, etc.
357 * - linear approximation for values in the neighborhood of 0.5, 1.5., etc,
358 *   with the steepness specified in 'factor'
359 * - exact result for 0.5, 1.5, etc.
360 *
361 *
362 *   1.0 -              /----*
363 *                     /
364 *                    /
365 *                   /
366 *   0.5 -          *
367 *                 /
368 *                /
369 *               /
370 *   0.0 - *----/
371 *
372 *         |                 |
373 *        2^0               2^1
374 *
375 * This is a technique also commonly used in hardware:
376 * - http://ixbtlabs.com/articles2/gffx/nv40-rx800-3.html
377 *
378 * TODO: For correctness, this should only be applied when texture is known to
379 * have regular mipmaps, i.e., mipmaps derived from the base level.
380 *
381 * TODO: This could be done in fixed point, where applicable.
382 */
383static void
384lp_build_brilinear_lod(struct lp_build_context *bld,
385                       LLVMValueRef lod,
386                       double factor,
387                       LLVMValueRef *out_lod_ipart,
388                       LLVMValueRef *out_lod_fpart)
389{
390   LLVMValueRef lod_fpart;
391   double pre_offset = (factor - 0.5)/factor - 0.5;
392   double post_offset = 1 - factor;
393
394   if (0) {
395      lp_build_printf(bld->gallivm, "lod = %f\n", lod);
396   }
397
398   lod = lp_build_add(bld, lod,
399                      lp_build_const_vec(bld->gallivm, bld->type, pre_offset));
400
401   lp_build_ifloor_fract(bld, lod, out_lod_ipart, &lod_fpart);
402
403   lod_fpart = lp_build_mul(bld, lod_fpart,
404                            lp_build_const_vec(bld->gallivm, bld->type, factor));
405
406   lod_fpart = lp_build_add(bld, lod_fpart,
407                            lp_build_const_vec(bld->gallivm, bld->type, post_offset));
408
409   /*
410    * It's not necessary to clamp lod_fpart since:
411    * - the above expression will never produce numbers greater than one.
412    * - the mip filtering branch is only taken if lod_fpart is positive
413    */
414
415   *out_lod_fpart = lod_fpart;
416
417   if (0) {
418      lp_build_printf(bld->gallivm, "lod_ipart = %i\n", *out_lod_ipart);
419      lp_build_printf(bld->gallivm, "lod_fpart = %f\n\n", *out_lod_fpart);
420   }
421}
422
423
424/*
425 * Combined log2 and brilinear lod computation.
426 *
427 * It's in all identical to calling lp_build_fast_log2() and
428 * lp_build_brilinear_lod() above, but by combining we can compute the integer
429 * and fractional part independently.
430 */
431static void
432lp_build_brilinear_rho(struct lp_build_context *bld,
433                       LLVMValueRef rho,
434                       double factor,
435                       LLVMValueRef *out_lod_ipart,
436                       LLVMValueRef *out_lod_fpart)
437{
438   LLVMValueRef lod_ipart;
439   LLVMValueRef lod_fpart;
440
441   const double pre_factor = (2*factor - 0.5)/(M_SQRT2*factor);
442   const double post_offset = 1 - 2*factor;
443
444   assert(bld->type.floating);
445
446   assert(lp_check_value(bld->type, rho));
447
448   /*
449    * The pre factor will make the intersections with the exact powers of two
450    * happen precisely where we want then to be, which means that the integer
451    * part will not need any post adjustments.
452    */
453   rho = lp_build_mul(bld, rho,
454                      lp_build_const_vec(bld->gallivm, bld->type, pre_factor));
455
456   /* ipart = ifloor(log2(rho)) */
457   lod_ipart = lp_build_extract_exponent(bld, rho, 0);
458
459   /* fpart = rho / 2**ipart */
460   lod_fpart = lp_build_extract_mantissa(bld, rho);
461
462   lod_fpart = lp_build_mul(bld, lod_fpart,
463                            lp_build_const_vec(bld->gallivm, bld->type, factor));
464
465   lod_fpart = lp_build_add(bld, lod_fpart,
466                            lp_build_const_vec(bld->gallivm, bld->type, post_offset));
467
468   /*
469    * Like lp_build_brilinear_lod, it's not necessary to clamp lod_fpart since:
470    * - the above expression will never produce numbers greater than one.
471    * - the mip filtering branch is only taken if lod_fpart is positive
472    */
473
474   *out_lod_ipart = lod_ipart;
475   *out_lod_fpart = lod_fpart;
476}
477
478
479/**
480 * Generate code to compute texture level of detail (lambda).
481 * \param derivs  partial derivatives of (s, t, r, q) with respect to X and Y
482 * \param lod_bias  optional float vector with the shader lod bias
483 * \param explicit_lod  optional float vector with the explicit lod
484 * \param width  scalar int texture width
485 * \param height  scalar int texture height
486 * \param depth  scalar int texture depth
487 *
488 * The resulting lod is scalar per quad, so only the first value per quad
489 * passed in from lod_bias, explicit_lod is used.
490 */
491void
492lp_build_lod_selector(struct lp_build_sample_context *bld,
493                      unsigned unit,
494                      const struct lp_derivatives *derivs,
495                      LLVMValueRef lod_bias, /* optional */
496                      LLVMValueRef explicit_lod, /* optional */
497                      unsigned mip_filter,
498                      LLVMValueRef *out_lod_ipart,
499                      LLVMValueRef *out_lod_fpart)
500
501{
502   LLVMBuilderRef builder = bld->gallivm->builder;
503   struct lp_build_context *perquadf_bld = &bld->perquadf_bld;
504   LLVMValueRef lod;
505
506   *out_lod_ipart = bld->perquadi_bld.zero;
507   *out_lod_fpart = perquadf_bld->zero;
508
509   if (bld->static_state->min_max_lod_equal) {
510      /* User is forcing sampling from a particular mipmap level.
511       * This is hit during mipmap generation.
512       */
513      LLVMValueRef min_lod =
514         bld->dynamic_state->min_lod(bld->dynamic_state, bld->gallivm, unit);
515
516      lod = lp_build_broadcast_scalar(perquadf_bld, min_lod);
517   }
518   else {
519      if (explicit_lod) {
520         lod = lp_build_pack_aos_scalars(bld->gallivm, bld->coord_bld.type,
521                                         perquadf_bld->type, explicit_lod);
522      }
523      else {
524         LLVMValueRef rho;
525
526         rho = lp_build_rho(bld, unit, derivs);
527
528         /*
529          * Compute lod = log2(rho)
530          */
531
532         if (!lod_bias &&
533             !bld->static_state->lod_bias_non_zero &&
534             !bld->static_state->apply_max_lod &&
535             !bld->static_state->apply_min_lod) {
536            /*
537             * Special case when there are no post-log2 adjustments, which
538             * saves instructions but keeping the integer and fractional lod
539             * computations separate from the start.
540             */
541
542            if (mip_filter == PIPE_TEX_MIPFILTER_NONE ||
543                mip_filter == PIPE_TEX_MIPFILTER_NEAREST) {
544               *out_lod_ipart = lp_build_ilog2(perquadf_bld, rho);
545               *out_lod_fpart = perquadf_bld->zero;
546               return;
547            }
548            if (mip_filter == PIPE_TEX_MIPFILTER_LINEAR &&
549                !(gallivm_debug & GALLIVM_DEBUG_NO_BRILINEAR)) {
550               lp_build_brilinear_rho(perquadf_bld, rho, BRILINEAR_FACTOR,
551                                      out_lod_ipart, out_lod_fpart);
552               return;
553            }
554         }
555
556         if (0) {
557            lod = lp_build_log2(perquadf_bld, rho);
558         }
559         else {
560            lod = lp_build_fast_log2(perquadf_bld, rho);
561         }
562
563         /* add shader lod bias */
564         if (lod_bias) {
565            lod_bias = lp_build_pack_aos_scalars(bld->gallivm, bld->coord_bld.type,
566                  perquadf_bld->type, lod_bias);
567            lod = LLVMBuildFAdd(builder, lod, lod_bias, "shader_lod_bias");
568         }
569      }
570
571      /* add sampler lod bias */
572      if (bld->static_state->lod_bias_non_zero) {
573         LLVMValueRef sampler_lod_bias =
574            bld->dynamic_state->lod_bias(bld->dynamic_state, bld->gallivm, unit);
575         sampler_lod_bias = lp_build_broadcast_scalar(perquadf_bld,
576                                                      sampler_lod_bias);
577         lod = LLVMBuildFAdd(builder, lod, sampler_lod_bias, "sampler_lod_bias");
578      }
579
580      /* clamp lod */
581      if (bld->static_state->apply_max_lod) {
582         LLVMValueRef max_lod =
583            bld->dynamic_state->max_lod(bld->dynamic_state, bld->gallivm, unit);
584         max_lod = lp_build_broadcast_scalar(perquadf_bld, max_lod);
585
586         lod = lp_build_min(perquadf_bld, lod, max_lod);
587      }
588      if (bld->static_state->apply_min_lod) {
589         LLVMValueRef min_lod =
590            bld->dynamic_state->min_lod(bld->dynamic_state, bld->gallivm, unit);
591         min_lod = lp_build_broadcast_scalar(perquadf_bld, min_lod);
592
593         lod = lp_build_max(perquadf_bld, lod, min_lod);
594      }
595   }
596
597   if (mip_filter == PIPE_TEX_MIPFILTER_LINEAR) {
598      if (!(gallivm_debug & GALLIVM_DEBUG_NO_BRILINEAR)) {
599         lp_build_brilinear_lod(perquadf_bld, lod, BRILINEAR_FACTOR,
600                                out_lod_ipart, out_lod_fpart);
601      }
602      else {
603         lp_build_ifloor_fract(perquadf_bld, lod, out_lod_ipart, out_lod_fpart);
604      }
605
606      lp_build_name(*out_lod_fpart, "lod_fpart");
607   }
608   else {
609      *out_lod_ipart = lp_build_iround(perquadf_bld, lod);
610   }
611
612   lp_build_name(*out_lod_ipart, "lod_ipart");
613
614   return;
615}
616
617
618/**
619 * For PIPE_TEX_MIPFILTER_NEAREST, convert float LOD to integer
620 * mipmap level index.
621 * Note: this is all scalar per quad code.
622 * \param lod_ipart  int texture level of detail
623 * \param level_out  returns integer
624 */
625void
626lp_build_nearest_mip_level(struct lp_build_sample_context *bld,
627                           unsigned unit,
628                           LLVMValueRef lod_ipart,
629                           LLVMValueRef *level_out)
630{
631   struct lp_build_context *perquadi_bld = &bld->perquadi_bld;
632   LLVMValueRef first_level, last_level, level;
633
634   first_level = bld->dynamic_state->first_level(bld->dynamic_state,
635                                                 bld->gallivm, unit);
636   last_level = bld->dynamic_state->last_level(bld->dynamic_state,
637                                               bld->gallivm, unit);
638   first_level = lp_build_broadcast_scalar(perquadi_bld, first_level);
639   last_level = lp_build_broadcast_scalar(perquadi_bld, last_level);
640
641   level = lp_build_add(perquadi_bld, lod_ipart, first_level);
642
643   /* clamp level to legal range of levels */
644   *level_out = lp_build_clamp(perquadi_bld, level, first_level, last_level);
645}
646
647
648/**
649 * For PIPE_TEX_MIPFILTER_LINEAR, convert per-quad int LOD(s) to two (per-quad)
650 * (adjacent) mipmap level indexes, and fix up float lod part accordingly.
651 * Later, we'll sample from those two mipmap levels and interpolate between them.
652 */
653void
654lp_build_linear_mip_levels(struct lp_build_sample_context *bld,
655                           unsigned unit,
656                           LLVMValueRef lod_ipart,
657                           LLVMValueRef *lod_fpart_inout,
658                           LLVMValueRef *level0_out,
659                           LLVMValueRef *level1_out)
660{
661   LLVMBuilderRef builder = bld->gallivm->builder;
662   struct lp_build_context *perquadi_bld = &bld->perquadi_bld;
663   struct lp_build_context *perquadf_bld = &bld->perquadf_bld;
664   LLVMValueRef first_level, last_level;
665   LLVMValueRef clamp_min;
666   LLVMValueRef clamp_max;
667
668   first_level = bld->dynamic_state->first_level(bld->dynamic_state,
669                                                 bld->gallivm, unit);
670   last_level = bld->dynamic_state->last_level(bld->dynamic_state,
671                                               bld->gallivm, unit);
672   first_level = lp_build_broadcast_scalar(perquadi_bld, first_level);
673   last_level = lp_build_broadcast_scalar(perquadi_bld, last_level);
674
675   *level0_out = lp_build_add(perquadi_bld, lod_ipart, first_level);
676   *level1_out = lp_build_add(perquadi_bld, *level0_out, perquadi_bld->one);
677
678   /*
679    * Clamp both *level0_out and *level1_out to [first_level, last_level], with
680    * the minimum number of comparisons, and zeroing lod_fpart in the extreme
681    * ends in the process.
682    */
683
684   /*
685    * This code (vector select in particular) only works with llvm 3.1
686    * (if there's more than one quad, with x86 backend). Might consider
687    * converting to our lp_bld_logic helpers.
688    */
689#if HAVE_LLVM < 0x0301
690   assert(perquadi_bld->type.length == 1);
691#endif
692
693   /* *level0_out < first_level */
694   clamp_min = LLVMBuildICmp(builder, LLVMIntSLT,
695                             *level0_out, first_level,
696                             "clamp_lod_to_first");
697
698   *level0_out = LLVMBuildSelect(builder, clamp_min,
699                                 first_level, *level0_out, "");
700
701   *level1_out = LLVMBuildSelect(builder, clamp_min,
702                                 first_level, *level1_out, "");
703
704   *lod_fpart_inout = LLVMBuildSelect(builder, clamp_min,
705                                      perquadf_bld->zero, *lod_fpart_inout, "");
706
707   /* *level0_out >= last_level */
708   clamp_max = LLVMBuildICmp(builder, LLVMIntSGE,
709                             *level0_out, last_level,
710                             "clamp_lod_to_last");
711
712   *level0_out = LLVMBuildSelect(builder, clamp_max,
713                                 last_level, *level0_out, "");
714
715   *level1_out = LLVMBuildSelect(builder, clamp_max,
716                                 last_level, *level1_out, "");
717
718   *lod_fpart_inout = LLVMBuildSelect(builder, clamp_max,
719                                      perquadf_bld->zero, *lod_fpart_inout, "");
720
721   lp_build_name(*level0_out, "sampler%u_miplevel0", unit);
722   lp_build_name(*level1_out, "sampler%u_miplevel1", unit);
723   lp_build_name(*lod_fpart_inout, "sampler%u_mipweight", unit);
724}
725
726
727/**
728 * Return pointer to a single mipmap level.
729 * \param data_array  array of pointers to mipmap levels
730 * \param level  integer mipmap level
731 */
732LLVMValueRef
733lp_build_get_mipmap_level(struct lp_build_sample_context *bld,
734                          LLVMValueRef level)
735{
736   LLVMBuilderRef builder = bld->gallivm->builder;
737   LLVMValueRef indexes[2], data_ptr;
738
739   indexes[0] = lp_build_const_int32(bld->gallivm, 0);
740   indexes[1] = level;
741   data_ptr = LLVMBuildGEP(builder, bld->data_array, indexes, 2, "");
742   data_ptr = LLVMBuildLoad(builder, data_ptr, "");
743   return data_ptr;
744}
745
746
747/**
748 * Codegen equivalent for u_minify().
749 * Return max(1, base_size >> level);
750 */
751LLVMValueRef
752lp_build_minify(struct lp_build_context *bld,
753                LLVMValueRef base_size,
754                LLVMValueRef level)
755{
756   LLVMBuilderRef builder = bld->gallivm->builder;
757   assert(lp_check_value(bld->type, base_size));
758   assert(lp_check_value(bld->type, level));
759
760   if (level == bld->zero) {
761      /* if we're using mipmap level zero, no minification is needed */
762      return base_size;
763   }
764   else {
765      LLVMValueRef size =
766         LLVMBuildLShr(builder, base_size, level, "minify");
767      assert(bld->type.sign);
768      size = lp_build_max(bld, size, bld->one);
769      return size;
770   }
771}
772
773
774/**
775 * Dereference stride_array[mipmap_level] array to get a stride.
776 * Return stride as a vector.
777 */
778static LLVMValueRef
779lp_build_get_level_stride_vec(struct lp_build_sample_context *bld,
780                              LLVMValueRef stride_array, LLVMValueRef level)
781{
782   LLVMBuilderRef builder = bld->gallivm->builder;
783   LLVMValueRef indexes[2], stride;
784   indexes[0] = lp_build_const_int32(bld->gallivm, 0);
785   indexes[1] = level;
786   stride = LLVMBuildGEP(builder, stride_array, indexes, 2, "");
787   stride = LLVMBuildLoad(builder, stride, "");
788   stride = lp_build_broadcast_scalar(&bld->int_coord_bld, stride);
789   return stride;
790}
791
792
793/**
794 * When sampling a mipmap, we need to compute the width, height, depth
795 * of the source levels from the level indexes.  This helper function
796 * does that.
797 */
798void
799lp_build_mipmap_level_sizes(struct lp_build_sample_context *bld,
800                            LLVMValueRef ilevel,
801                            LLVMValueRef *out_size,
802                            LLVMValueRef *row_stride_vec,
803                            LLVMValueRef *img_stride_vec)
804{
805   const unsigned dims = bld->dims;
806   LLVMValueRef ilevel_vec;
807
808   ilevel_vec = lp_build_broadcast_scalar(&bld->int_size_bld, ilevel);
809
810   /*
811    * Compute width, height, depth at mipmap level 'ilevel'
812    */
813   *out_size = lp_build_minify(&bld->int_size_bld, bld->int_size, ilevel_vec);
814
815   if (dims >= 2) {
816      *row_stride_vec = lp_build_get_level_stride_vec(bld,
817                                                      bld->row_stride_array,
818                                                      ilevel);
819      if (dims == 3 || bld->static_state->target == PIPE_TEXTURE_CUBE) {
820         *img_stride_vec = lp_build_get_level_stride_vec(bld,
821                                                         bld->img_stride_array,
822                                                         ilevel);
823      }
824   }
825}
826
827
828/**
829 * Extract and broadcast texture size.
830 *
831 * @param size_type   type of the texture size vector (either
832 *                    bld->int_size_type or bld->float_size_type)
833 * @param coord_type  type of the texture size vector (either
834 *                    bld->int_coord_type or bld->coord_type)
835 * @param size        vector with the texture size (width, height, depth)
836 */
837void
838lp_build_extract_image_sizes(struct lp_build_sample_context *bld,
839                             struct lp_type size_type,
840                             struct lp_type coord_type,
841                             LLVMValueRef size,
842                             LLVMValueRef *out_width,
843                             LLVMValueRef *out_height,
844                             LLVMValueRef *out_depth)
845{
846   const unsigned dims = bld->dims;
847   LLVMTypeRef i32t = LLVMInt32TypeInContext(bld->gallivm->context);
848
849   *out_width = lp_build_extract_broadcast(bld->gallivm,
850                                           size_type,
851                                           coord_type,
852                                           size,
853                                           LLVMConstInt(i32t, 0, 0));
854   if (dims >= 2) {
855      *out_height = lp_build_extract_broadcast(bld->gallivm,
856                                               size_type,
857                                               coord_type,
858                                               size,
859                                               LLVMConstInt(i32t, 1, 0));
860      if (dims == 3) {
861         *out_depth = lp_build_extract_broadcast(bld->gallivm,
862                                                 size_type,
863                                                 coord_type,
864                                                 size,
865                                                 LLVMConstInt(i32t, 2, 0));
866      }
867   }
868}
869
870
871/**
872 * Unnormalize coords.
873 *
874 * @param flt_size  vector with the integer texture size (width, height, depth)
875 */
876void
877lp_build_unnormalized_coords(struct lp_build_sample_context *bld,
878                             LLVMValueRef flt_size,
879                             LLVMValueRef *s,
880                             LLVMValueRef *t,
881                             LLVMValueRef *r)
882{
883   const unsigned dims = bld->dims;
884   LLVMValueRef width;
885   LLVMValueRef height;
886   LLVMValueRef depth;
887
888   lp_build_extract_image_sizes(bld,
889                                bld->float_size_type,
890                                bld->coord_type,
891                                flt_size,
892                                &width,
893                                &height,
894                                &depth);
895
896   /* s = s * width, t = t * height */
897   *s = lp_build_mul(&bld->coord_bld, *s, width);
898   if (dims >= 2) {
899      *t = lp_build_mul(&bld->coord_bld, *t, height);
900      if (dims >= 3) {
901         *r = lp_build_mul(&bld->coord_bld, *r, depth);
902      }
903   }
904}
905
906
907/** Helper used by lp_build_cube_lookup() */
908static LLVMValueRef
909lp_build_cube_imapos(struct lp_build_context *coord_bld, LLVMValueRef coord)
910{
911   /* ima = +0.5 / abs(coord); */
912   LLVMValueRef posHalf = lp_build_const_vec(coord_bld->gallivm, coord_bld->type, 0.5);
913   LLVMValueRef absCoord = lp_build_abs(coord_bld, coord);
914   LLVMValueRef ima = lp_build_div(coord_bld, posHalf, absCoord);
915   return ima;
916}
917
918/** Helper used by lp_build_cube_lookup() */
919static LLVMValueRef
920lp_build_cube_imaneg(struct lp_build_context *coord_bld, LLVMValueRef coord)
921{
922   /* ima = -0.5 / abs(coord); */
923   LLVMValueRef negHalf = lp_build_const_vec(coord_bld->gallivm, coord_bld->type, -0.5);
924   LLVMValueRef absCoord = lp_build_abs(coord_bld, coord);
925   LLVMValueRef ima = lp_build_div(coord_bld, negHalf, absCoord);
926   return ima;
927}
928
929/**
930 * Helper used by lp_build_cube_lookup()
931 * FIXME: the sign here can also be 0.
932 * Arithmetically this could definitely make a difference. Either
933 * fix the comment or use other (simpler) sign function, not sure
934 * which one it should be.
935 * \param sign  scalar +1 or -1
936 * \param coord  float vector
937 * \param ima  float vector
938 */
939static LLVMValueRef
940lp_build_cube_coord(struct lp_build_context *coord_bld,
941                    LLVMValueRef sign, int negate_coord,
942                    LLVMValueRef coord, LLVMValueRef ima)
943{
944   /* return negate(coord) * ima * sign + 0.5; */
945   LLVMValueRef half = lp_build_const_vec(coord_bld->gallivm, coord_bld->type, 0.5);
946   LLVMValueRef res;
947
948   assert(negate_coord == +1 || negate_coord == -1);
949
950   if (negate_coord == -1) {
951      coord = lp_build_negate(coord_bld, coord);
952   }
953
954   res = lp_build_mul(coord_bld, coord, ima);
955   if (sign) {
956      sign = lp_build_broadcast_scalar(coord_bld, sign);
957      res = lp_build_mul(coord_bld, res, sign);
958   }
959   res = lp_build_add(coord_bld, res, half);
960
961   return res;
962}
963
964
965/** Helper used by lp_build_cube_lookup()
966 * Return (major_coord >= 0) ? pos_face : neg_face;
967 */
968static LLVMValueRef
969lp_build_cube_face(struct lp_build_sample_context *bld,
970                   LLVMValueRef major_coord,
971                   unsigned pos_face, unsigned neg_face)
972{
973   struct gallivm_state *gallivm = bld->gallivm;
974   LLVMBuilderRef builder = gallivm->builder;
975   LLVMValueRef cmp = LLVMBuildFCmp(builder, LLVMRealUGE,
976                                    major_coord,
977                                    bld->float_bld.zero, "");
978   LLVMValueRef pos = lp_build_const_int32(gallivm, pos_face);
979   LLVMValueRef neg = lp_build_const_int32(gallivm, neg_face);
980   LLVMValueRef res = LLVMBuildSelect(builder, cmp, pos, neg, "");
981   return res;
982}
983
984
985
986/**
987 * Generate code to do cube face selection and compute per-face texcoords.
988 */
989void
990lp_build_cube_lookup(struct lp_build_sample_context *bld,
991                     LLVMValueRef s,
992                     LLVMValueRef t,
993                     LLVMValueRef r,
994                     LLVMValueRef *face,
995                     LLVMValueRef *face_s,
996                     LLVMValueRef *face_t)
997{
998   struct lp_build_context *coord_bld = &bld->coord_bld;
999   LLVMBuilderRef builder = bld->gallivm->builder;
1000   struct gallivm_state *gallivm = bld->gallivm;
1001   LLVMValueRef rx, ry, rz;
1002   LLVMValueRef tmp[4], rxyz, arxyz;
1003
1004   /*
1005    * Use the average of the four pixel's texcoords to choose the face.
1006    * Slight simplification just calculate the sum, skip scaling.
1007    */
1008   tmp[0] = s;
1009   tmp[1] = t;
1010   tmp[2] = r;
1011   rxyz = lp_build_hadd_partial4(&bld->coord_bld, tmp, 3);
1012   arxyz = lp_build_abs(&bld->coord_bld, rxyz);
1013
1014   if (coord_bld->type.length > 4) {
1015      struct lp_build_context *cint_bld = &bld->int_coord_bld;
1016      struct lp_type intctype = cint_bld->type;
1017      LLVMValueRef signrxs, signrys, signrzs, signrxyz, sign;
1018      LLVMValueRef arxs, arys, arzs;
1019      LLVMValueRef arx_ge_ary, maxarxsarys, arz_ge_arx_ary;
1020      LLVMValueRef snewx, tnewx, snewy, tnewy, snewz, tnewz;
1021      LLVMValueRef ryneg, rzneg;
1022      LLVMValueRef ma, ima;
1023      LLVMValueRef posHalf = lp_build_const_vec(gallivm, coord_bld->type, 0.5);
1024      LLVMValueRef signmask = lp_build_const_int_vec(gallivm, intctype,
1025                                                     1 << (intctype.width - 1));
1026      LLVMValueRef signshift = lp_build_const_int_vec(gallivm, intctype,
1027                                                      intctype.width -1);
1028      LLVMValueRef facex = lp_build_const_int_vec(gallivm, intctype, PIPE_TEX_FACE_POS_X);
1029      LLVMValueRef facey = lp_build_const_int_vec(gallivm, intctype, PIPE_TEX_FACE_POS_Y);
1030      LLVMValueRef facez = lp_build_const_int_vec(gallivm, intctype, PIPE_TEX_FACE_POS_Z);
1031
1032      assert(PIPE_TEX_FACE_NEG_X == PIPE_TEX_FACE_POS_X + 1);
1033      assert(PIPE_TEX_FACE_NEG_Y == PIPE_TEX_FACE_POS_Y + 1);
1034      assert(PIPE_TEX_FACE_NEG_Z == PIPE_TEX_FACE_POS_Z + 1);
1035
1036      rx = LLVMBuildBitCast(builder, s, lp_build_vec_type(gallivm, intctype), "");
1037      ry = LLVMBuildBitCast(builder, t, lp_build_vec_type(gallivm, intctype), "");
1038      rz = LLVMBuildBitCast(builder, r, lp_build_vec_type(gallivm, intctype), "");
1039      ryneg = LLVMBuildXor(builder, ry, signmask, "");
1040      rzneg = LLVMBuildXor(builder, rz, signmask, "");
1041
1042      /* the sign bit comes from the averaged vector (per quad),
1043       * as does the decision which face to use */
1044      signrxyz = LLVMBuildBitCast(builder, rxyz, lp_build_vec_type(gallivm, intctype), "");
1045      signrxyz = LLVMBuildAnd(builder, signrxyz, signmask, "");
1046
1047      arxs = lp_build_swizzle_scalar_aos(coord_bld, arxyz, 0);
1048      arys = lp_build_swizzle_scalar_aos(coord_bld, arxyz, 1);
1049      arzs = lp_build_swizzle_scalar_aos(coord_bld, arxyz, 2);
1050
1051      /*
1052       * select x if x >= y else select y
1053       * select previous result if y >= max(x,y) else select z
1054       */
1055      arx_ge_ary = lp_build_cmp(coord_bld, PIPE_FUNC_GEQUAL, arxs, arys);
1056      maxarxsarys = lp_build_max(coord_bld, arxs, arys);
1057      arz_ge_arx_ary = lp_build_cmp(coord_bld, PIPE_FUNC_GEQUAL, maxarxsarys, arzs);
1058
1059      /*
1060       * compute all possible new s/t coords
1061       * snewx = signrx * -rz;
1062       * tnewx = -ry;
1063       * snewy = rx;
1064       * tnewy = signry * rz;
1065       * snewz = signrz * rx;
1066       * tnewz = -ry;
1067       */
1068      signrxs = lp_build_swizzle_scalar_aos(cint_bld, signrxyz, 0);
1069      snewx = LLVMBuildXor(builder, signrxs, rzneg, "");
1070      tnewx = ryneg;
1071
1072      signrys = lp_build_swizzle_scalar_aos(cint_bld, signrxyz, 1);
1073      snewy = rx;
1074      tnewy = LLVMBuildXor(builder, signrys, rz, "");
1075
1076      signrzs = lp_build_swizzle_scalar_aos(cint_bld, signrxyz, 2);
1077      snewz = LLVMBuildXor(builder, signrzs, rx, "");
1078      tnewz = ryneg;
1079
1080      /* XXX on x86 unclear if we should cast the values back to float
1081       * or not - on some cpus (nehalem) pblendvb has twice the throughput
1082       * of blendvps though on others there just might be domain
1083       * transition penalties when using it (this depends on what llvm
1084       * will chose for the bit ops above so there appears no "right way",
1085       * but given the boatload of selects let's just use the int type).
1086       *
1087       * Unfortunately we also need the sign bit of the summed coords.
1088       */
1089      *face_s = lp_build_select(cint_bld, arx_ge_ary, snewx, snewy);
1090      *face_t = lp_build_select(cint_bld, arx_ge_ary, tnewx, tnewy);
1091      ma = lp_build_select(coord_bld, arx_ge_ary, s, t);
1092      *face = lp_build_select(cint_bld, arx_ge_ary, facex, facey);
1093      sign = lp_build_select(cint_bld, arx_ge_ary, signrxs, signrys);
1094
1095      *face_s = lp_build_select(cint_bld, arz_ge_arx_ary, *face_s, snewz);
1096      *face_t = lp_build_select(cint_bld, arz_ge_arx_ary, *face_t, tnewz);
1097      ma = lp_build_select(coord_bld, arz_ge_arx_ary, ma, r);
1098      *face = lp_build_select(cint_bld, arz_ge_arx_ary, *face, facez);
1099      sign = lp_build_select(cint_bld, arz_ge_arx_ary, sign, signrzs);
1100
1101      *face_s = LLVMBuildBitCast(builder, *face_s,
1102                               lp_build_vec_type(gallivm, coord_bld->type), "");
1103      *face_t = LLVMBuildBitCast(builder, *face_t,
1104                               lp_build_vec_type(gallivm, coord_bld->type), "");
1105
1106      /* add +1 for neg face */
1107      /* XXX with AVX probably want to use another select here -
1108       * as long as we ensure vblendvps gets used we can actually
1109       * skip the comparison and just use sign as a "mask" directly.
1110       */
1111      sign = LLVMBuildLShr(builder, sign, signshift, "");
1112      *face = LLVMBuildOr(builder, *face, sign, "face");
1113
1114      ima = lp_build_cube_imapos(coord_bld, ma);
1115
1116      *face_s = lp_build_mul(coord_bld, *face_s, ima);
1117      *face_s = lp_build_add(coord_bld, *face_s, posHalf);
1118      *face_t = lp_build_mul(coord_bld, *face_t, ima);
1119      *face_t = lp_build_add(coord_bld, *face_t, posHalf);
1120   }
1121
1122   else {
1123      struct lp_build_if_state if_ctx;
1124      LLVMValueRef face_s_var;
1125      LLVMValueRef face_t_var;
1126      LLVMValueRef face_var;
1127      LLVMValueRef arx_ge_ary_arz, ary_ge_arx_arz;
1128      LLVMValueRef shuffles[4];
1129      LLVMValueRef arxy_ge_aryx, arxy_ge_arzz, arxy_ge_arxy_arzz;
1130      LLVMValueRef arxyxy, aryxzz, arxyxy_ge_aryxzz;
1131      struct lp_build_context *float_bld = &bld->float_bld;
1132
1133      assert(bld->coord_bld.type.length == 4);
1134
1135      shuffles[0] = lp_build_const_int32(gallivm, 0);
1136      shuffles[1] = lp_build_const_int32(gallivm, 1);
1137      shuffles[2] = lp_build_const_int32(gallivm, 0);
1138      shuffles[3] = lp_build_const_int32(gallivm, 1);
1139      arxyxy = LLVMBuildShuffleVector(builder, arxyz, arxyz, LLVMConstVector(shuffles, 4), "");
1140      shuffles[0] = lp_build_const_int32(gallivm, 1);
1141      shuffles[1] = lp_build_const_int32(gallivm, 0);
1142      shuffles[2] = lp_build_const_int32(gallivm, 2);
1143      shuffles[3] = lp_build_const_int32(gallivm, 2);
1144      aryxzz = LLVMBuildShuffleVector(builder, arxyz, arxyz, LLVMConstVector(shuffles, 4), "");
1145      arxyxy_ge_aryxzz = lp_build_cmp(&bld->coord_bld, PIPE_FUNC_GEQUAL, arxyxy, aryxzz);
1146
1147      shuffles[0] = lp_build_const_int32(gallivm, 0);
1148      shuffles[1] = lp_build_const_int32(gallivm, 1);
1149      arxy_ge_aryx = LLVMBuildShuffleVector(builder, arxyxy_ge_aryxzz, arxyxy_ge_aryxzz,
1150                                            LLVMConstVector(shuffles, 2), "");
1151      shuffles[0] = lp_build_const_int32(gallivm, 2);
1152      shuffles[1] = lp_build_const_int32(gallivm, 3);
1153      arxy_ge_arzz = LLVMBuildShuffleVector(builder, arxyxy_ge_aryxzz, arxyxy_ge_aryxzz,
1154                                            LLVMConstVector(shuffles, 2), "");
1155      arxy_ge_arxy_arzz = LLVMBuildAnd(builder, arxy_ge_aryx, arxy_ge_arzz, "");
1156
1157      arx_ge_ary_arz = LLVMBuildExtractElement(builder, arxy_ge_arxy_arzz,
1158                                               lp_build_const_int32(gallivm, 0), "");
1159      arx_ge_ary_arz = LLVMBuildICmp(builder, LLVMIntNE, arx_ge_ary_arz,
1160                                               lp_build_const_int32(gallivm, 0), "");
1161      ary_ge_arx_arz = LLVMBuildExtractElement(builder, arxy_ge_arxy_arzz,
1162                                               lp_build_const_int32(gallivm, 1), "");
1163      ary_ge_arx_arz = LLVMBuildICmp(builder, LLVMIntNE, ary_ge_arx_arz,
1164                                               lp_build_const_int32(gallivm, 0), "");
1165      face_s_var = lp_build_alloca(gallivm, bld->coord_bld.vec_type, "face_s_var");
1166      face_t_var = lp_build_alloca(gallivm, bld->coord_bld.vec_type, "face_t_var");
1167      face_var = lp_build_alloca(gallivm, bld->int_bld.vec_type, "face_var");
1168
1169      lp_build_if(&if_ctx, gallivm, arx_ge_ary_arz);
1170      {
1171         /* +/- X face */
1172         LLVMValueRef sign, ima;
1173         rx = LLVMBuildExtractElement(builder, rxyz,
1174                                      lp_build_const_int32(gallivm, 0), "");
1175         /* +/- X face */
1176         sign = lp_build_sgn(float_bld, rx);
1177         ima = lp_build_cube_imaneg(coord_bld, s);
1178         *face_s = lp_build_cube_coord(coord_bld, sign, +1, r, ima);
1179         *face_t = lp_build_cube_coord(coord_bld, NULL, +1, t, ima);
1180         *face = lp_build_cube_face(bld, rx,
1181                                    PIPE_TEX_FACE_POS_X,
1182                                    PIPE_TEX_FACE_NEG_X);
1183         LLVMBuildStore(builder, *face_s, face_s_var);
1184         LLVMBuildStore(builder, *face_t, face_t_var);
1185         LLVMBuildStore(builder, *face, face_var);
1186      }
1187      lp_build_else(&if_ctx);
1188      {
1189         struct lp_build_if_state if_ctx2;
1190
1191         lp_build_if(&if_ctx2, gallivm, ary_ge_arx_arz);
1192         {
1193            LLVMValueRef sign, ima;
1194            /* +/- Y face */
1195            ry = LLVMBuildExtractElement(builder, rxyz,
1196                                         lp_build_const_int32(gallivm, 1), "");
1197            sign = lp_build_sgn(float_bld, ry);
1198            ima = lp_build_cube_imaneg(coord_bld, t);
1199            *face_s = lp_build_cube_coord(coord_bld, NULL, -1, s, ima);
1200            *face_t = lp_build_cube_coord(coord_bld, sign, -1, r, ima);
1201            *face = lp_build_cube_face(bld, ry,
1202                                       PIPE_TEX_FACE_POS_Y,
1203                                       PIPE_TEX_FACE_NEG_Y);
1204            LLVMBuildStore(builder, *face_s, face_s_var);
1205            LLVMBuildStore(builder, *face_t, face_t_var);
1206            LLVMBuildStore(builder, *face, face_var);
1207         }
1208         lp_build_else(&if_ctx2);
1209         {
1210            /* +/- Z face */
1211            LLVMValueRef sign, ima;
1212            rz = LLVMBuildExtractElement(builder, rxyz,
1213                                         lp_build_const_int32(gallivm, 2), "");
1214            sign = lp_build_sgn(float_bld, rz);
1215            ima = lp_build_cube_imaneg(coord_bld, r);
1216            *face_s = lp_build_cube_coord(coord_bld, sign, -1, s, ima);
1217            *face_t = lp_build_cube_coord(coord_bld, NULL, +1, t, ima);
1218            *face = lp_build_cube_face(bld, rz,
1219                                       PIPE_TEX_FACE_POS_Z,
1220                                       PIPE_TEX_FACE_NEG_Z);
1221            LLVMBuildStore(builder, *face_s, face_s_var);
1222            LLVMBuildStore(builder, *face_t, face_t_var);
1223            LLVMBuildStore(builder, *face, face_var);
1224         }
1225         lp_build_endif(&if_ctx2);
1226      }
1227
1228      lp_build_endif(&if_ctx);
1229
1230      *face_s = LLVMBuildLoad(builder, face_s_var, "face_s");
1231      *face_t = LLVMBuildLoad(builder, face_t_var, "face_t");
1232      *face   = LLVMBuildLoad(builder, face_var, "face");
1233      *face   = lp_build_broadcast_scalar(&bld->int_coord_bld, *face);
1234   }
1235}
1236
1237
1238/**
1239 * Compute the partial offset of a pixel block along an arbitrary axis.
1240 *
1241 * @param coord   coordinate in pixels
1242 * @param stride  number of bytes between rows of successive pixel blocks
1243 * @param block_length  number of pixels in a pixels block along the coordinate
1244 *                      axis
1245 * @param out_offset    resulting relative offset of the pixel block in bytes
1246 * @param out_subcoord  resulting sub-block pixel coordinate
1247 */
1248void
1249lp_build_sample_partial_offset(struct lp_build_context *bld,
1250                               unsigned block_length,
1251                               LLVMValueRef coord,
1252                               LLVMValueRef stride,
1253                               LLVMValueRef *out_offset,
1254                               LLVMValueRef *out_subcoord)
1255{
1256   LLVMBuilderRef builder = bld->gallivm->builder;
1257   LLVMValueRef offset;
1258   LLVMValueRef subcoord;
1259
1260   if (block_length == 1) {
1261      subcoord = bld->zero;
1262   }
1263   else {
1264      /*
1265       * Pixel blocks have power of two dimensions. LLVM should convert the
1266       * rem/div to bit arithmetic.
1267       * TODO: Verify this.
1268       * It does indeed BUT it does transform it to scalar (and back) when doing so
1269       * (using roughly extract, shift/and, mov, unpack) (llvm 2.7).
1270       * The generated code looks seriously unfunny and is quite expensive.
1271       */
1272#if 0
1273      LLVMValueRef block_width = lp_build_const_int_vec(bld->type, block_length);
1274      subcoord = LLVMBuildURem(builder, coord, block_width, "");
1275      coord    = LLVMBuildUDiv(builder, coord, block_width, "");
1276#else
1277      unsigned logbase2 = util_logbase2(block_length);
1278      LLVMValueRef block_shift = lp_build_const_int_vec(bld->gallivm, bld->type, logbase2);
1279      LLVMValueRef block_mask = lp_build_const_int_vec(bld->gallivm, bld->type, block_length - 1);
1280      subcoord = LLVMBuildAnd(builder, coord, block_mask, "");
1281      coord = LLVMBuildLShr(builder, coord, block_shift, "");
1282#endif
1283   }
1284
1285   offset = lp_build_mul(bld, coord, stride);
1286
1287   assert(out_offset);
1288   assert(out_subcoord);
1289
1290   *out_offset = offset;
1291   *out_subcoord = subcoord;
1292}
1293
1294
1295/**
1296 * Compute the offset of a pixel block.
1297 *
1298 * x, y, z, y_stride, z_stride are vectors, and they refer to pixels.
1299 *
1300 * Returns the relative offset and i,j sub-block coordinates
1301 */
1302void
1303lp_build_sample_offset(struct lp_build_context *bld,
1304                       const struct util_format_description *format_desc,
1305                       LLVMValueRef x,
1306                       LLVMValueRef y,
1307                       LLVMValueRef z,
1308                       LLVMValueRef y_stride,
1309                       LLVMValueRef z_stride,
1310                       LLVMValueRef *out_offset,
1311                       LLVMValueRef *out_i,
1312                       LLVMValueRef *out_j)
1313{
1314   LLVMValueRef x_stride;
1315   LLVMValueRef offset;
1316
1317   x_stride = lp_build_const_vec(bld->gallivm, bld->type,
1318                                 format_desc->block.bits/8);
1319
1320   lp_build_sample_partial_offset(bld,
1321                                  format_desc->block.width,
1322                                  x, x_stride,
1323                                  &offset, out_i);
1324
1325   if (y && y_stride) {
1326      LLVMValueRef y_offset;
1327      lp_build_sample_partial_offset(bld,
1328                                     format_desc->block.height,
1329                                     y, y_stride,
1330                                     &y_offset, out_j);
1331      offset = lp_build_add(bld, offset, y_offset);
1332   }
1333   else {
1334      *out_j = bld->zero;
1335   }
1336
1337   if (z && z_stride) {
1338      LLVMValueRef z_offset;
1339      LLVMValueRef k;
1340      lp_build_sample_partial_offset(bld,
1341                                     1, /* pixel blocks are always 2D */
1342                                     z, z_stride,
1343                                     &z_offset, &k);
1344      offset = lp_build_add(bld, offset, z_offset);
1345   }
1346
1347   *out_offset = offset;
1348}
1349