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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
// LinearInterpolation.cpp
// Implements methods for linear interpolation over 1D, 2D and 3D arrays
#include "Globals.h"
#include "LinearInterpolation.h"
/*
// Perform an automatic test upon program start (use breakpoints to debug):
extern void Debug3DNoise(float * a_Noise, int a_SizeX, int a_SizeY, int a_SizeZ, const AString & a_FileNameBase);
class Test
{
public:
Test(void)
{
// DoTest1();
DoTest2();
}
void DoTest1(void)
{
float In[8] = {0, 1, 2, 3, 1, 2, 2, 2};
float Out[3 * 3 * 3];
LinearInterpolate1DArray(In, 4, Out, 9);
LinearInterpolate2DArray(In, 2, 2, Out, 3, 3);
LinearInterpolate3DArray(In, 2, 2, 2, Out, 3, 3, 3);
LOGD("Out[0]: %f", Out[0]);
}
void DoTest2(void)
{
float In[3 * 3 * 3];
for (size_t i = 0; i < ARRAYCOUNT(In); i++)
{
In[i] = (float)(i % 5);
}
float Out[15 * 16 * 17];
LinearInterpolate3DArray(In, 3, 3, 3, Out, 15, 16, 17);
Debug3DNoise(Out, 15, 16, 17, "LERP test");
}
} gTest;
//*/
// Puts linearly interpolated values from one array into another array. 1D version
void LinearInterpolate1DArray(
float * a_Src,
int a_SrcSizeX,
float * a_Dst,
int a_DstSizeX
)
{
a_Dst[0] = a_Src[0];
int DstSizeXm1 = a_DstSizeX - 1;
int SrcSizeXm1 = a_SrcSizeX - 1;
float fDstSizeXm1 = static_cast<float>(DstSizeXm1);
float fSrcSizeXm1 = static_cast<float>(SrcSizeXm1);
for (int x = 1; x < DstSizeXm1; x++)
{
int SrcIdx = x * SrcSizeXm1 / DstSizeXm1;
float ValLo = a_Src[SrcIdx];
float ValHi = a_Src[SrcIdx + 1];
float Ratio = static_cast<float>(x) * fSrcSizeXm1 / fDstSizeXm1 - SrcIdx;
a_Dst[x] = ValLo + (ValHi - ValLo) * Ratio;
}
a_Dst[a_DstSizeX - 1] = a_Src[a_SrcSizeX - 1];
}
// Puts linearly interpolated values from one array into another array. 2D version
void LinearInterpolate2DArray(
float * a_Src,
int a_SrcSizeX, int a_SrcSizeY,
float * a_Dst,
int a_DstSizeX, int a_DstSizeY
)
{
ASSERT(a_DstSizeX > 0);
ASSERT(a_DstSizeX < MAX_INTERPOL_SIZEX);
ASSERT(a_DstSizeY > 0);
ASSERT(a_DstSizeY < MAX_INTERPOL_SIZEY);
// Calculate interpolation ratios and src indices along each axis:
float RatioX[MAX_INTERPOL_SIZEX];
float RatioY[MAX_INTERPOL_SIZEY];
int SrcIdxX[MAX_INTERPOL_SIZEX];
int SrcIdxY[MAX_INTERPOL_SIZEY];
for (int x = 1; x < a_DstSizeX; x++)
{
SrcIdxX[x] = x * (a_SrcSizeX - 1) / (a_DstSizeX - 1);
RatioX[x] = (static_cast<float>(x * (a_SrcSizeX - 1)) / (a_DstSizeX - 1)) - SrcIdxX[x];
}
for (int y = 1; y < a_DstSizeY; y++)
{
SrcIdxY[y] = y * (a_SrcSizeY - 1) / (a_DstSizeY - 1);
RatioY[y] = (static_cast<float>(y * (a_SrcSizeY - 1)) / (a_DstSizeY - 1)) - SrcIdxY[y];
}
// Special values at the ends. Notice especially the last indices being (size - 2) with ratio set to 1, to avoid index overflow:
SrcIdxX[0] = 0;
RatioX[0] = 0;
SrcIdxY[0] = 0;
RatioY[0] = 0;
SrcIdxX[a_DstSizeX - 1] = a_SrcSizeX - 2;
RatioX[a_DstSizeX - 1] = 1;
SrcIdxY[a_DstSizeY - 1] = a_SrcSizeY - 2;
RatioY[a_DstSizeY - 1] = 1;
// Output all the dst array values using the indices and ratios:
int idx = 0;
for (int y = 0; y < a_DstSizeY; y++)
{
int idxLoY = a_SrcSizeX * SrcIdxY[y];
int idxHiY = a_SrcSizeX * (SrcIdxY[y] + 1);
float ry = RatioY[y];
for (int x = 0; x < a_DstSizeX; x++)
{
// The four src corners of the current "cell":
float LoXLoY = a_Src[SrcIdxX[x] + idxLoY];
float HiXLoY = a_Src[SrcIdxX[x] + 1 + idxLoY];
float LoXHiY = a_Src[SrcIdxX[x] + idxHiY];
float HiXHiY = a_Src[SrcIdxX[x] + 1 + idxHiY];
// Linear interpolation along the X axis:
float InterpXLoY = LoXLoY + (HiXLoY - LoXLoY) * RatioX[x];
float InterpXHiY = LoXHiY + (HiXHiY - LoXHiY) * RatioX[x];
// Linear interpolation along the Y axis:
a_Dst[idx] = InterpXLoY + (InterpXHiY - InterpXLoY) * ry;
idx += 1;
}
}
}
void LinearInterpolate3DArray(
float * a_Src,
int a_SrcSizeX, int a_SrcSizeY, int a_SrcSizeZ,
float * a_Dst,
int a_DstSizeX, int a_DstSizeY, int a_DstSizeZ
)
{
ASSERT(a_DstSizeX > 0);
ASSERT(a_DstSizeX < MAX_INTERPOL_SIZEX);
ASSERT(a_DstSizeY > 0);
ASSERT(a_DstSizeY < MAX_INTERPOL_SIZEY);
ASSERT(a_DstSizeZ > 0);
ASSERT(a_DstSizeZ < MAX_INTERPOL_SIZEZ);
// Calculate interpolation ratios and src indices along each axis:
float RatioX[MAX_INTERPOL_SIZEX];
float RatioY[MAX_INTERPOL_SIZEY];
float RatioZ[MAX_INTERPOL_SIZEZ];
int SrcIdxX[MAX_INTERPOL_SIZEX];
int SrcIdxY[MAX_INTERPOL_SIZEY];
int SrcIdxZ[MAX_INTERPOL_SIZEZ];
for (int x = 1; x < a_DstSizeX; x++)
{
SrcIdxX[x] = x * (a_SrcSizeX - 1) / (a_DstSizeX - 1);
RatioX[x] = (static_cast<float>(x * (a_SrcSizeX - 1)) / (a_DstSizeX - 1)) - SrcIdxX[x];
}
for (int y = 1; y < a_DstSizeY; y++)
{
SrcIdxY[y] = y * (a_SrcSizeY - 1) / (a_DstSizeY - 1);
RatioY[y] = (static_cast<float>(y * (a_SrcSizeY - 1)) / (a_DstSizeY - 1)) - SrcIdxY[y];
}
for (int z = 1; z < a_DstSizeZ; z++)
{
SrcIdxZ[z] = z * (a_SrcSizeZ - 1) / (a_DstSizeZ - 1);
RatioZ[z] = (static_cast<float>(z * (a_SrcSizeZ - 1)) / (a_DstSizeZ - 1)) - SrcIdxZ[z];
}
// Special values at the ends. Notice especially the last indices being (size - 2) with ratio set to 1, to avoid index overflow:
SrcIdxX[0] = 0;
RatioX[0] = 0;
SrcIdxY[0] = 0;
RatioY[0] = 0;
SrcIdxZ[0] = 0;
RatioZ[0] = 0;
SrcIdxX[a_DstSizeX - 1] = a_SrcSizeX - 2;
RatioX[a_DstSizeX - 1] = 1;
SrcIdxY[a_DstSizeY - 1] = a_SrcSizeY - 2;
RatioY[a_DstSizeY - 1] = 1;
SrcIdxZ[a_DstSizeZ - 1] = a_SrcSizeZ - 2;
RatioZ[a_DstSizeZ - 1] = 1;
// Output all the dst array values using the indices and ratios:
int idx = 0;
for (int z = 0; z < a_DstSizeZ; z++)
{
int idxLoZ = a_SrcSizeX * a_SrcSizeY * SrcIdxZ[z];
int idxHiZ = a_SrcSizeX * a_SrcSizeY * (SrcIdxZ[z] + 1);
float rz = RatioZ[z];
for (int y = 0; y < a_DstSizeY; y++)
{
int idxLoY = a_SrcSizeX * SrcIdxY[y];
int idxHiY = a_SrcSizeX * (SrcIdxY[y] + 1);
float ry = RatioY[y];
for (int x = 0; x < a_DstSizeX; x++)
{
// The eight src corners of the current "cell":
float LoXLoYLoZ = a_Src[SrcIdxX[x] + idxLoY + idxLoZ];
float HiXLoYLoZ = a_Src[SrcIdxX[x] + 1 + idxLoY + idxLoZ];
float LoXHiYLoZ = a_Src[SrcIdxX[x] + idxHiY + idxLoZ];
float HiXHiYLoZ = a_Src[SrcIdxX[x] + 1 + idxHiY + idxLoZ];
float LoXLoYHiZ = a_Src[SrcIdxX[x] + idxLoY + idxHiZ];
float HiXLoYHiZ = a_Src[SrcIdxX[x] + 1 + idxLoY + idxHiZ];
float LoXHiYHiZ = a_Src[SrcIdxX[x] + idxHiY + idxHiZ];
float HiXHiYHiZ = a_Src[SrcIdxX[x] + 1 + idxHiY + idxHiZ];
// Linear interpolation along the Z axis:
float LoXLoYInZ = LoXLoYLoZ + (LoXLoYHiZ - LoXLoYLoZ) * rz;
float HiXLoYInZ = HiXLoYLoZ + (HiXLoYHiZ - HiXLoYLoZ) * rz;
float LoXHiYInZ = LoXHiYLoZ + (LoXHiYHiZ - LoXHiYLoZ) * rz;
float HiXHiYInZ = HiXHiYLoZ + (HiXHiYHiZ - HiXHiYLoZ) * rz;
// Linear interpolation along the Y axis:
float LoXInYInZ = LoXLoYInZ + (LoXHiYInZ - LoXLoYInZ) * ry;
float HiXInYInZ = HiXLoYInZ + (HiXHiYInZ - HiXLoYInZ) * ry;
// Linear interpolation along the X axis:
a_Dst[idx] = LoXInYInZ + (HiXInYInZ - LoXInYInZ) * RatioX[x];
idx += 1;
} // for x
} // for y
} // for z
}
|
