src/viewport_sprite_sorter_sse4.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file viewport_sprite_sorter_sse.cpp Sprite sorter that uses SSE4.1. */
  11
  12 #ifdef WITH_SSE
  13
  14 #include "stdafx.h"
  15 #include "smmintrin.h"
  16 #include "viewport_sprite_sorter.h"
  17
  18 #ifdef _SQ64
  19         assert_compile((sizeof(ParentSpriteToDraw) % 16) == 0);
  20         #define LOAD_128 _mm_load_si128
  21 #else
  22         #define LOAD_128 _mm_loadu_si128
  23 #endif
  24
  25 struct CompareParentSpritesSSE41 {
  26         const __m128i mask_ptest;
  27
  28         CompareParentSpritesSSE41 (void) :
  29                 mask_ptest (_mm_setr_epi8 (-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  0,  0,  0,  0))
  30         {
  31         }
  32
  33         bool operator() (const ParentSpriteToDraw *ps1,
  34                                 const ParentSpriteToDraw *ps2) const;
  35 };
  36
  37 inline bool CompareParentSpritesSSE41::operator()
  38         (const ParentSpriteToDraw *ps1, const ParentSpriteToDraw *ps2) const
  39 {
  40         /*
  41          * Original code:
  42          * if (ps->xmax >= ps2->xmin && ps->xmin <= ps2->xmax && // overlap in X?
  43          *     ps->ymax >= ps2->ymin && ps->ymin <= ps2->ymax && // overlap in Y?
  44          *     ps->zmax >= ps2->zmin && ps->zmin <= ps2->zmax) { // overlap in Z?
  45          *
  46          * Above conditions are equivalent to:
  47          * 1/    !( (ps->xmax >= ps2->xmin) && (ps->ymax >= ps2->ymin) && (ps->zmax >= ps2->zmin)   &&    (ps->xmin <= ps2->xmax) && (ps->ymin <= ps2->ymax) && (ps->zmin <= ps2->zmax) )
  48          * 2/    !( (ps->xmax >= ps2->xmin) && (ps->ymax >= ps2->ymin) && (ps->zmax >= ps2->zmin)   &&    (ps2->xmax >= ps->xmin) && (ps2->ymax >= ps->ymin) && (ps2->zmax >= ps->zmin) )
  49          * 3/  !( ( (ps->xmax >= ps2->xmin) && (ps->ymax >= ps2->ymin) && (ps->zmax >= ps2->zmin) ) &&  ( (ps2->xmax >= ps->xmin) && (ps2->ymax >= ps->ymin) && (ps2->zmax >= ps->zmin) ) )
  50          * 4/ !( !( (ps->xmax <  ps2->xmin) || (ps->ymax <  ps2->ymin) || (ps->zmax <  ps2->zmin) ) && !( (ps2->xmax <  ps->xmin) || (ps2->ymax <  ps->ymin) || (ps2->zmax <  ps->zmin) ) )
  51          * 5/ PTEST <---------------------------------- rslt1 ---------------------------------->         <------------------------------ rslt2 -------------------------------------->
  52          */
  53         __m128i ps1_max = LOAD_128((const __m128i*) &ps1->xmax);
  54         __m128i ps2_min = LOAD_128((const __m128i*) &ps2->xmin);
  55         __m128i rslt1 = _mm_cmplt_epi32 (ps1_max, ps2_min);
  56         if (!_mm_testz_si128 (this->mask_ptest, rslt1)) return true;
  57
  58         __m128i ps1_min = LOAD_128((const __m128i*) &ps1->xmin);
  59         __m128i ps2_max = LOAD_128((const __m128i*) &ps2->xmax);
  60         __m128i rslt2 = _mm_cmplt_epi32 (ps2_max, ps1_min);
  61         if (!_mm_testz_si128 (this->mask_ptest, rslt2)) return false;
  62
  63         /* Use X+Y+Z as the sorting order, so sprites closer to the bottom of
  64          * the screen and with higher Z elevation, are drawn in front. Here
  65          * X,Y,Z are the coordinates of the "center of mass" of the sprite,
  66          * i.e. X=(left+right)/2, etc. However, since we only care about
  67          * order, don't actually divide / 2. */
  68         return  ps1->xmin + ps1->xmax + ps1->ymin + ps1->ymax + ps1->zmin + ps1->zmax <=
  69                 ps2->xmin + ps2->xmax + ps2->ymin + ps2->ymax + ps2->zmin + ps2->zmax;
  70 }
  71
  72 /** Sort parent sprites pointer array using SSE4.1 optimizations. */
  73 void ViewportSortParentSpritesSSE41 (ParentSpriteToDraw **psd,
  74         const ParentSpriteToDraw *const *psdvend)
  75 {
  76         CompareParentSpritesSSE41 comparator;
  77         SortParentSprites (comparator, psd, psdvend);
  78 }
  79
  80 #endif /* WITH_SSE */