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
|
#include "texturePacker.h"
#include "collections.hpp"
#include <GL/glew.h>
#include <algorithm>
#include <cstdio>
#include <glm/common.hpp>
#include <numeric>
#include <ostream>
#include <set>
TexturePacker::TexturePacker(std::span<const Image> in) :
inputImages {std::move(in)}, sortedIndexes {vectorOfN(inputImages.size(), size_t {})}
{
std::sort(sortedIndexes.rbegin(), sortedIndexes.rend(), [this](const auto a, const auto b) {
return area(inputImages[a]) < area(inputImages[b]);
});
}
TexturePacker::Result
TexturePacker::pack() const
{
return pack(minSize());
}
TexturePacker::Result
TexturePacker::pack(Size size) const
{
using Spaces = std::set<Space>;
Spaces spaces {{{}, size}};
Positions result(inputImages.size());
for (const auto & idx : sortedIndexes) {
const auto & image = inputImages[idx];
if (const auto spaceItr = std::find_if(spaces.begin(), spaces.end(),
[image](const Space & s) {
return image.x <= s.size.x && image.y <= s.size.y;
});
spaceItr != spaces.end()) {
auto space = *spaceItr;
result[idx] = space.position;
spaces.erase(spaceItr);
if (space.size.x > image.x) {
spaces.emplace(Position {space.position.x + image.x, space.position.y},
Size {space.size.x - image.x, image.y});
}
if (space.size.y > image.y) {
spaces.emplace(Position {space.position.x, space.position.y + image.y},
Size {space.size.x, space.size.y - image.y});
}
}
else {
if (size.x < size.y) {
return pack({size.x * 2, size.y});
}
else {
return pack({size.x, size.y * 2});
}
}
}
if (GLEW_ARB_texture_non_power_of_two) {
// Crop the size back to minimum size
size = std::transform_reduce(
result.begin(), result.end(), inputImages.begin(), Size {},
[](auto && max, auto && limit) {
return glm::max(max, limit);
},
[](auto && pos, auto && size) {
return pos + size;
});
}
return {result, size};
}
TexturePacker::Size
TexturePacker::minSize() const
{
return std::accumulate(inputImages.begin(), inputImages.end(), Size {1}, [](Size size, const Image & i) {
while (size.x < i.x) {
size.x *= 2;
}
while (size.y < i.y) {
size.y *= 2;
}
return size;
});
}
decltype(TexturePacker::Size::x)
TexturePacker::area(const Size & size)
{
return size.x * size.y;
}
|
