cpp_common/image.cpp at master · ianmage/cpp_common · GitHub

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
154
155
156
157
158
159
160
#include "image.h"
#include <algorithm>
#define STB_IMAGE_IMPLEMENTATION
#include <stb/stb_image.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include <stb/stb_image_write.h>


Image::Image()
	: width_(0), height_(0), channels_(0)
	, pData_(nullptr)
{

}


Image::~Image()
{
	if (pData_)
	{
		STBI_FREE(pData_);
	}
}


bool Image::load(std::string const & filePath)
{
	int w, h, chnl;
	int const reqComp = 0;
	pData_ = stbi_load(filePath.c_str(), &w, &h, &chnl, reqComp);

	if (nullptr == pData_)
	{
		return false;
	}
	width_ = static_cast<decltype(width_)>(w);
	height_ = static_cast<decltype(height_)>(h);
	channels_ = static_cast<decltype(channels_)>(chnl);

	sizeInByte_ = width_ * height_ * channels_;


	return true;
}


float Image::sample(float fU, float fV, size_t nth) const
{
	//u = std::min(1.f, std::max(0.f, u));
	//v = std::min(1.f, std::max(0.f, v));
	fU *= width_ - 1;
	fV *= height_ - 1;
	int iU = static_cast<int>(fU);
	int iV = static_cast<int>(fV);
	int iU1 = std::min(iU + 1, int(width_ - 1));
	int iV1 = std::min(iV + 1, int(height_ - 1));

	auto c0 = at(iU, iV);
	auto c1 = at(iU1, iV);
	auto c2 = at(iU, iV1);
	auto c3 = at(iU1, iV1);

	float dU = fU - iU;
	float dV = fV - iV;
	float pm3 = dU * dV;
	float pm2 = dU * (1.f - dV);
	float pm1 = dV * (1.f - dU);
	float pm0 = (1.f - dU) * (1.f - dV);

	float ret = pm0 * c0 + pm1 * c1 + pm2 * c2 + pm3 * c3;
	return ret;
}


bool Image::save(std::string const & filePath, TEX_FMT texFmt)
{
	if (!pData_)
		return false;

	if (eTexFmt_BMP == texFmt)
		stbi_write_bmp(filePath.c_str(), width_, height_, channels_, pData_);
	else if (eTexFmt_TGA == texFmt)
		stbi_write_tga(filePath.c_str(), width_, height_, channels_, pData_);
	else if (eTexFmt_PNG == texFmt)
		stbi_write_png(filePath.c_str(), width_, height_, channels_, pData_, width_*4);

	return true;
}


bool Image::create(int w, int h, int chnl)
{
	if (pData_)
	{
		STBI_FREE(pData_);
	}

	width_ = static_cast<decltype(width_)>(w);
	height_ = static_cast<decltype(height_)>(h);
	channels_ = static_cast<decltype(channels_)>(chnl);

	sizeInByte_ = width_ * height_ * channels_;

	pData_ = (decltype(pData_))STBI_MALLOC(sizeInByte_);

	return true;
}


void Image::bltFrom(Image const & src, int x, int y)
{
	if (x < 0)
	{
		x = 0;
	}
	if (y < 0)
	{
		y = 0;
	}

	int const srcLine = src.channels_ * src.width_;
	int const dstLine = channels_ * width_;

	for (int i = 0; i < src.height_; ++i)
	{
		byte *pSrcI = src.pData_ + srcLine * i;
		byte *pDstI = pData_ + dstLine * (i + y);
		if (i + y >= height_)
			break;
		for (int j = 0; j < src.width_; ++j)
		{
			byte *pSrcJ = pSrcI + src.channels_ * j;
			byte *pDstJ = pDstI + channels_ * (j + x);
			if (j + x >= width_)
				break;
			for (int k = 0; k < src.channels_; ++k)
			{
				*(pDstJ + k) = *(pSrcJ + k);
			}
		}
	}
}


void Image::transpose()
{
	std::swap(width_, height_);
	if (!pData_)
		return;
	for (int i = 0; i < height_; ++i)
	{
		for (int j = 0; j < width_; ++j)
		{
			for (int k = 0; k < channels_; ++k)
			{
				std::swap(at(i, j, k), at(j, i, k));
			}
		}
	}
}