1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
#include "RowAtlasAlloc.h"
#include <vector>
#include "System/bitops.h"
// texture spacing in the atlas (in pixels)
static const int ATLAS_PADDING = 1;
CRowAtlasAlloc::CRowAtlasAlloc()
: nextRowPos(0)
{
atlasSize.x = 256;
atlasSize.y = 256;
}
inline int CRowAtlasAlloc::CompareTex(SAtlasEntry* tex1, SAtlasEntry* tex2)
{
// sort by large to small
if (tex1->size.y == tex2->size.y) {
return (tex1->size.x > tex2->size.x);
}
return (tex1->size.y > tex2->size.y);
}
void CRowAtlasAlloc::EstimateNeededSize()
{
int spaceNeeded = 0;
int spaceFree = atlasSize.x * (atlasSize.y - nextRowPos);
for (auto it: entries) {
spaceNeeded += it.second.size.x * it.second.size.y;
}
for(auto& row: imageRows) {
spaceFree += row.height * (atlasSize.x - row.width);
}
while (spaceFree < spaceNeeded * 1.2f) {
if (atlasSize.x>=maxsize.x && atlasSize.y>=maxsize.y) {
break;
}
// Resize texture
if ((atlasSize.x << 1) <= maxsize.x) {
spaceFree += atlasSize.x * atlasSize.y;
atlasSize.x = std::min(maxsize.x, atlasSize.x << 1);
}
if ((atlasSize.y << 1) <= maxsize.y) {
spaceFree += atlasSize.x * atlasSize.y;
atlasSize.y = std::min(maxsize.y, atlasSize.y << 1);
}
}
}
CRowAtlasAlloc::Row* CRowAtlasAlloc::AddRow(int glyphWidth, int glyphHeight)
{
const int wantedRowHeight = glyphHeight;
while (atlasSize.y < (nextRowPos + wantedRowHeight)) {
if (atlasSize.x>=maxsize.x && atlasSize.y>=maxsize.y) {
//throw texture_size_exception();
return nullptr;
}
// Resize texture
atlasSize.x = std::min(maxsize.x, atlasSize.x << 1);
atlasSize.y = std::min(maxsize.y, atlasSize.y << 1);
}
Row newrow(nextRowPos, wantedRowHeight);
nextRowPos += wantedRowHeight;
imageRows.push_back(newrow);
return &imageRows.back();
}
bool CRowAtlasAlloc::Allocate()
{
bool success = true;
if (npot) {
// revert the used height clamping at the bottom of this function
// else for the case when Allocate() is called multiple times, the width would grew faster than height
// also AddRow() only works with PowerOfTwo values.
atlasSize.y = next_power_of_2(atlasSize.y);
}
// it gives much better results when we resize the available space before starting allocation
// esp. allocation is more horizontal and so we can clip more free space at bottom
EstimateNeededSize();
// sort new entries by height from large to small
std::vector<SAtlasEntry*> memtextures;
for (auto it = entries.begin(); it != entries.end(); ++it) {
memtextures.push_back(&it->second);
}
sort(memtextures.begin(), memtextures.end(), CRowAtlasAlloc::CompareTex);
// find space for them
for (auto& curtex: memtextures) {
Row* row = FindRow(curtex->size.x + ATLAS_PADDING, curtex->size.y + ATLAS_PADDING);
if (!row) {
success = false;
continue;
}
curtex->texCoords.x1 = row->width;
curtex->texCoords.y1 = row->position;
curtex->texCoords.x2 = row->width + curtex->size.x;
curtex->texCoords.y2 = row->position + curtex->size.y;
row->width += curtex->size.x + ATLAS_PADDING;
}
if (npot) {
atlasSize.y = nextRowPos;
} else {
atlasSize.y = next_power_of_2(nextRowPos);
}
return success;
}
CRowAtlasAlloc::Row* CRowAtlasAlloc::FindRow(int glyphWidth, int glyphHeight)
{
int best_width = atlasSize.x;
float best_ratio = 10000.0f;
Row* best_row = nullptr;
// first try to find a row with similar height
for(auto& row: imageRows) {
// Check if there is enough space in this row
if (glyphWidth > (atlasSize.x - row.width))
continue;
if (glyphHeight > row.height)
continue;
const float ratio = float(row.height) / glyphHeight;
if ((ratio < best_ratio) || ((ratio == best_ratio) && (row.width < best_width))) {
best_width = row.width;
best_ratio = ratio;
best_row = &row;
}
}
if (best_row != nullptr)
return best_row;
// no row found create a new one
return AddRow(glyphWidth, glyphHeight);
}
|
