OpenTTD Source: src/viewport_sprite_sorter_sse4.cpp Source File

OpenTTD Source 14.0-beta3

viewport_sprite_sorter_sse4.cpp
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1 /*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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/>.
6 */
7
10 #ifdef WITH_SSE
11
12 #include "stdafx.h"
13 #include "cpu.h"
14 #include "smmintrin.h"
15 #include "viewport_sprite_sorter.h"
16 #include <forward_list>
17 #include <stack>
18
19 #include "safeguards.h"
20
21 #ifdef POINTER_IS_64BIT
22 static_assert((sizeof(ParentSpriteToDraw) % 16) == 0);
23 # define LOAD_128 _mm_load_si128
24 #else
25 # define LOAD_128 _mm_loadu_si128
26 #endif
27
28 GNU_TARGET("sse4.1")
29 void ViewportSortParentSpritesSSE41(ParentSpriteToSortVector *psdv)
30 {
31 if (psdv->size() < 2) return;
32
33 const __m128i mask_ptest = _mm_setr_epi8(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0);
34
35 /* We rely on sprites being, for the most part, already ordered.
36 * So we don't need to move many of them and can keep track of their
37 * order efficiently by using stack. We always move sprites to the front
38 * of the current position, i.e. to the top of the stack.
39 * Also use special constants to indicate sorting state without
40 * adding extra fields to ParentSpriteToDraw structure.
41 */
42 const uint32_t ORDER_COMPARED = UINT32_MAX; // Sprite was compared but we still need to compare the ones preceding it
43 const uint32_t ORDER_RETURNED = UINT32_MAX - 1; // Mark sorted sprite in case there are other occurrences of it in the stack
44 std::stack<ParentSpriteToDraw *> sprite_order;
45 uint32_t next_order = 0;
46
47 std::forward_list<std::pair<int64_t, ParentSpriteToDraw *>> sprite_list; // We store sprites in a list sorted by xmin+ymin
48
49 /* Initialize sprite list and order. */
50 for (auto p = psdv->rbegin(); p != psdv->rend(); p++) {
51 sprite_list.push_front(std::make_pair((*p)->xmin + (*p)->ymin, *p));
52 sprite_order.push(*p);
53 (*p)->order = next_order++;
54 }
55
56 sprite_list.sort();
57
58 std::vector<ParentSpriteToDraw *> preceding; // Temporarily stores sprites that precede current and their position in the list
59 auto preceding_prev = sprite_list.begin(); // Store iterator in case we need to delete a single preciding sprite
60 auto out = psdv->begin(); // Iterator to output sorted sprites
61
62 while (!sprite_order.empty()) {
63
64 auto s = sprite_order.top();
65 sprite_order.pop();
66
67 /* Sprite is already sorted, ignore it. */
68 if (s->order == ORDER_RETURNED) continue;
69
70 /* Sprite was already compared, just need to output it. */
71 if (s->order == ORDER_COMPARED) {
72 *(out++) = s;
73 s->order = ORDER_RETURNED;
74 continue;
75 }
76
77 preceding.clear();
78
79 /* We only need sprites with xmin <= s->xmax && ymin <= s->ymax && zmin <= s->zmax
80 * So by iterating sprites with xmin + ymin <= s->xmax + s->ymax
81 * we get all we need and some more that we filter out later.
82 * We don't include zmin into the sum as there are usually more neighbors on x and y than z
83 * so including it will actually increase the amount of false positives.
84 * Also min coordinates can be > max so using max(xmin, xmax) + max(ymin, ymax)
85 * to ensure that we iterate the current sprite as we need to remove it from the list.
86 */
87 auto ssum = std::max(s->xmax, s->xmin) + std::max(s->ymax, s->ymin);
88 auto prev = sprite_list.before_begin();
89 auto x = sprite_list.begin();
90 while (x != sprite_list.end() && ((*x).first <= ssum)) {
91 auto p = (*x).second;
92 if (p == s) {
93 /* We found the current sprite, remove it and move on. */
94 x = sprite_list.erase_after(prev);
95 continue;
96 }
97
98 auto p_prev = prev;
99 prev = x++;
100
101 /* Check that p->xmin <= s->xmax && p->ymin <= s->ymax && p->zmin <= s->zmax */
102 __m128i s_max = LOAD_128((__m128i*) &s->xmax);
103 __m128i p_min = LOAD_128((__m128i*) &p->xmin);
104 __m128i r1 = _mm_cmplt_epi32(s_max, p_min);
105 if (!_mm_testz_si128(mask_ptest, r1))
106 continue;
107
108 /* Check if sprites overlap, i.e.
109 * s->xmin <= p->xmax && s->ymin <= p->ymax && s->zmin <= p->zmax
110 */
111 __m128i s_min = LOAD_128((__m128i*) &s->xmin);
112 __m128i p_max = LOAD_128((__m128i*) &p->xmax);
113 __m128i r2 = _mm_cmplt_epi32(p_max, s_min);
114 if (_mm_testz_si128(mask_ptest, r2)) {
115 /* Use X+Y+Z as the sorting order, so sprites closer to the bottom of
116 * the screen and with higher Z elevation, are drawn in front.
117 * Here X,Y,Z are the coordinates of the "center of mass" of the sprite,
118 * i.e. X=(left+right)/2, etc.
119 * However, since we only care about order, don't actually divide / 2
120 */
121 if (s->xmin + s->xmax + s->ymin + s->ymax + s->zmin + s->zmax <=
122 p->xmin + p->xmax + p->ymin + p->ymax + p->zmin + p->zmax) {
123 continue;
124 }
125 }
126
127 preceding.push_back(p);
128 preceding_prev = p_prev;
129 }
130
131 if (preceding.empty()) {
132 /* No preceding sprites, add current one to the output */
133 *(out++) = s;
134 s->order = ORDER_RETURNED;
135 continue;
136 }
137
138 /* Optimization for the case when we only have 1 sprite to move. */
139 if (preceding.size() == 1) {
140 auto p = preceding[0];
141 /* We can only output the preceding sprite if there can't be any other sprites preceding it. */
142 if (p->xmax <= s->xmax && p->ymax <= s->ymax && p->zmax <= s->zmax) {
143 p->order = ORDER_RETURNED;
144 s->order = ORDER_RETURNED;
145 sprite_list.erase_after(preceding_prev);
146 *(out++) = p;
147 *(out++) = s;
148 continue;
149 }
150 }
151
152 /* Sort all preceding sprites by order and assign new orders in reverse (as original sorter did). */
153 std::sort(preceding.begin(), preceding.end(), [](const ParentSpriteToDraw *a, const ParentSpriteToDraw *b) {
154 return a->order > b->order;
155 });
156
157 s->order = ORDER_COMPARED;
158 sprite_order.push(s); // Still need to output so push it back for now
159
160 for (auto p: preceding) {
161 p->order = next_order++;
162 sprite_order.push(p);
163 }
164 }
165 }
166
167
172 bool ViewportSortParentSpritesSSE41Checker()
173 {
174 return HasCPUIDFlag(1, 2, 19);
175 }
176
177 #endif /* WITH_SSE */
safeguards.h
stdafx.h
cpu.h
ParentSpriteToDraw
Parent sprite that should be drawn.
Definition: viewport_sprite_sorter.h:17
viewport_sprite_sorter.h
HasCPUIDFlag
bool HasCPUIDFlag(uint type, uint index, uint bit)
Check whether the current CPU has the given flag.
Definition: cpu.cpp:84