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Location: cpp/openttd-patchpack/source/src/viewport_sprite_sorter_sse4.cpp
r23018:159fe34f39c1
4.8 KiB
text/x-c
Codechange: Improve (un)zoom performance
When zooming out with a high res display, there can be about 150k sprites
to be sorted before displaying. With the O(n^2) complexity of the sprite
sorter, this can take several seconds.
This patch works around this by sorting the sprites by the xmin coordinate
first using QSort, which later allows an early bailout out of the inner
loop. This is enough to cut down the full unzoom time on a 4k display to a
fraction of second.
When zooming out with a high res display, there can be about 150k sprites
to be sorted before displaying. With the O(n^2) complexity of the sprite
sorter, this can take several seconds.
This patch works around this by sorting the sprites by the xmin coordinate
first using QSort, which later allows an early bailout out of the inner
loop. This is enough to cut down the full unzoom time on a 4k display to a
fraction of second.
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/*
* This file is part of OpenTTD.
* 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.
* 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.
* 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/>.
*/
/** @file viewport_sprite_sorter_sse.cpp Sprite sorter that uses SSE4.1. */
#ifdef WITH_SSE
#include "stdafx.h"
#include "cpu.h"
#include "smmintrin.h"
#include "viewport_sprite_sorter.h"
#include "core/sort_func.hpp"
#include "safeguards.h"
#ifdef _SQ64
assert_compile((sizeof(ParentSpriteToDraw) % 16) == 0);
#define LOAD_128 _mm_load_si128
#else
#define LOAD_128 _mm_loadu_si128
#endif
static int CDECL CompareParentSprites(ParentSpriteToDraw * const *psd, ParentSpriteToDraw * const *psd2)
{
const ParentSpriteToDraw *ps = *psd;
const ParentSpriteToDraw *ps2 = *psd2;
return ps->xmin - ps2->xmin;
}
/** Sort parent sprites pointer array using SSE4.1 optimizations. */
void ViewportSortParentSpritesSSE41(ParentSpriteToSortVector *psdv)
{
const __m128i mask_ptest = _mm_setr_epi8(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0);
const __m128i mask_ptest2 = _mm_setr_epi8(-1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
ParentSpriteToDraw ** const psdvend = psdv->End();
ParentSpriteToDraw **psd = psdv->Begin();
/* pre-sort by xmin in ascending order */
QSortT(psd, psdvend - psd, CompareParentSprites);
while (psd != psdvend) {
ParentSpriteToDraw * const ps = *psd;
if (ps->comparison_done) {
psd++;
continue;
}
ps->comparison_done = true;
for (ParentSpriteToDraw **psd2 = psd + 1; psd2 != psdvend; psd2++) {
ParentSpriteToDraw * const ps2 = *psd2;
if (ps2->comparison_done) continue;
/*
* Decide which comparator to use, based on whether the bounding boxes overlap
*
* Original code:
* if (ps->xmax >= ps2->xmin && ps->xmin <= ps2->xmax && // overlap in X?
* ps->ymax >= ps2->ymin && ps->ymin <= ps2->ymax && // overlap in Y?
* ps->zmax >= ps2->zmin && ps->zmin <= ps2->zmax) { // overlap in Z?
*
* Above conditions are equivalent to:
* 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) )
* 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) )
* 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) ) )
* 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) ) )
* 5/ PTEST <---------------------------------- rslt1 ----------------------------------> <------------------------------ rslt2 -------------------------------------->
*/
__m128i ps1_max = LOAD_128((__m128i*) &ps->xmax);
__m128i ps2_min = LOAD_128((__m128i*) &ps2->xmin);
__m128i rslt1 = _mm_cmplt_epi32(ps1_max, ps2_min);
if (!_mm_testz_si128(mask_ptest, rslt1)) {
if (!_mm_testz_si128(mask_ptest2, rslt1) /* ps->xmax < ps2->xmin */) {
/* all following sprites have xmin >= ps2->xmin */
break;
} else {
continue;
}
}
__m128i ps1_min = LOAD_128((__m128i*) &ps->xmin);
__m128i ps2_max = LOAD_128((__m128i*) &ps2->xmax);
__m128i rslt2 = _mm_cmplt_epi32(ps2_max, ps1_min);
if (_mm_testz_si128(mask_ptest, rslt2)) {
/* Use X+Y+Z as the sorting order, so sprites closer to the bottom of
* the screen and with higher Z elevation, are drawn in front.
* Here X,Y,Z are the coordinates of the "center of mass" of the sprite,
* i.e. X=(left+right)/2, etc.
* However, since we only care about order, don't actually divide / 2
*/
if (ps->xmin + ps->xmax + ps->ymin + ps->ymax + ps->zmin + ps->zmax <=
ps2->xmin + ps2->xmax + ps2->ymin + ps2->ymax + ps2->zmin + ps2->zmax) {
continue;
}
}
/* Move ps2 in front of ps */
ParentSpriteToDraw * const temp = ps2;
for (ParentSpriteToDraw **psd3 = psd2; psd3 > psd; psd3--) {
*psd3 = *(psd3 - 1);
}
*psd = temp;
}
}
}
/**
* Check whether the current CPU supports SSE 4.1.
* @return True iff the CPU supports SSE 4.1.
*/
bool ViewportSortParentSpritesSSE41Checker()
{
return HasCPUIDFlag(1, 2, 19);
}
#endif /* WITH_SSE */
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