VB Perlin Noise (32K)
1 Nov 2003
First Posted
vbAccelerator - Contents of code file: cPerlin3D.cls
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
END
Attribute VB_Name = "cPerlin3D"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
'
' vbAccelerator.com
' Perlin Noise
' Pretyy much optimal algorithm for calculation, converted to VB from
'// JAVA REFERENCE IMPLEMENTATION OF IMPROVED NOISE - COPYRIGHT 2002 KEN PERLIN.
' http://mrl.nyu.edu/~perlin/noise/
' See also http://www.noisemachine.com/
'
' Takes approx 30ms for a 100x100 grid with all optimisations on,
' using AMD Athlon 2k.
'
Private p() As Long
Private permutation() As Long
Public Function Noise(ByVal x As Double, ByVal y As Double, ByVal z As Double)
As Double
Dim iX As Long
Dim iY As Long
Dim iZ As Long
Dim u As Double
Dim v As Double
Dim w As Double
Dim a As Long
Dim aa As Long
Dim ab As Long
Dim b As Long
Dim ba As Long
Dim bb As Long
' Find unit cube that contains point:
iX = Int(x) And &HFF&
iY = Int(y) And &HFF&
iZ = Int(z) And &HFF&
' Find relative x,y,z of point in cube:
x = x - Int(x)
y = y - Int(y)
z = z - Int(z)
' Compute fade curves for each of x,y,z
u = fade(x)
v = fade(y)
w = fade(z)
' Hash coordinates of the 8 cube corners:
a = p(iX) + iY
aa = p(a) + iZ
ab = p(a + 1) + iZ
b = p(iX + 1) + iY
ba = p(b) + iZ
bb = p(b + 1) + iZ
' Add the blended results from 8 corners of the cube:
Noise = lerp(w, lerp(v, lerp(u, grad(p(aa), x, y, z), _
grad(p(ba), x - 1, y, z)), _
lerp(u, grad(p(ab), x, y - 1, z), _
grad(p(bb), x - 1, y - 1, z))), _
lerp(v, lerp(u, grad(p(aa + 1), x, y, z - 1), _
grad(p(ba + 1), x - 1, y, z - 1)), _
lerp(u, grad(p(ab + 1), x, y - 1, z - 1), _
grad(p(bb + 1), x - 1, y - 1, z - 1))))
End Function
Private Function fade(ByVal t As Double) As Double
fade = t * t * t * (t * (t * 6# - 15#) + 10#)
End Function
Private Function lerp(ByVal t As Double, ByVal a As Double, ByVal b As Double)
As Double
lerp = a + t * (b - a)
End Function
Private Function grad(ByVal hash As Long, ByVal x As Double, ByVal y As Double,
ByVal z As Double) As Double
Dim h As Long
Dim u As Double
Dim v As Double
Dim g As Double
'// CONVERT LO 4 BITS OF HASH CODE
h = hash And &HF&
'// INTO 12 GRADIENT DIRECTIONS.
If (h < 8) Or (h = 12) Or (h = 13) Then
u = x
Else
u = y
End If
If (h < 4) Or (h = 12) Or (h = 13) Then
v = y
Else
y = z
End If
If ((h And 1) = 0) Then
g = u
Else
g = -u
End If
If ((h And 2) = 0) Then
g = g + v
Else
g = g - v
End If
grad = g
End Function
Private Sub Class_Initialize()
ReDim p(0 To 511) As Long
ReDim permutation(0 To 255) As Long
' What would I do for variable and particularly
' array variable initialisers in VB...
permutation(0) = 151
permutation(1) = 160
permutation(2) = 137
permutation(3) = 91
permutation(4) = 90
permutation(5) = 15
permutation(6) = 131
permutation(7) = 13
permutation(8) = 201
permutation(9) = 95
permutation(10) = 96
permutation(11) = 53
permutation(12) = 194
permutation(13) = 233
permutation(14) = 7
permutation(15) = 225
permutation(16) = 140
permutation(17) = 36
permutation(18) = 103
permutation(19) = 30
permutation(20) = 69
permutation(21) = 142
permutation(22) = 8
permutation(23) = 99
permutation(24) = 37
permutation(25) = 240
permutation(26) = 21
permutation(27) = 10
permutation(28) = 23
permutation(29) = 190
permutation(30) = 6
permutation(31) = 148
permutation(32) = 247
permutation(33) = 120
permutation(34) = 234
permutation(35) = 75
permutation(36) = 0
permutation(37) = 26
permutation(38) = 197
permutation(39) = 62
permutation(40) = 94
permutation(41) = 252
permutation(42) = 219
permutation(43) = 203
permutation(44) = 117
permutation(45) = 35
permutation(46) = 11
permutation(47) = 32
permutation(48) = 57
permutation(49) = 177
permutation(50) = 33
permutation(51) = 88
permutation(52) = 237
permutation(53) = 149
permutation(54) = 56
permutation(55) = 87
permutation(56) = 174
permutation(57) = 20
permutation(58) = 125
permutation(59) = 136
permutation(60) = 171
permutation(61) = 168
permutation(62) = 68
permutation(63) = 175
permutation(64) = 74
permutation(65) = 165
permutation(66) = 71
permutation(67) = 134
permutation(68) = 139
permutation(69) = 48
permutation(70) = 27
permutation(71) = 166
permutation(72) = 77
permutation(73) = 146
permutation(74) = 158
permutation(75) = 231
permutation(76) = 83
permutation(77) = 111
permutation(78) = 229
permutation(79) = 122
permutation(80) = 60
permutation(81) = 211
permutation(82) = 133
permutation(83) = 230
permutation(84) = 220
permutation(85) = 105
permutation(86) = 92
permutation(87) = 41
permutation(88) = 55
permutation(89) = 46
permutation(90) = 245
permutation(91) = 40
permutation(92) = 244
permutation(93) = 102
permutation(94) = 143
permutation(95) = 54
permutation(96) = 65
permutation(97) = 25
permutation(98) = 63
permutation(99) = 161
permutation(100) = 1
permutation(101) = 216
permutation(102) = 80
permutation(103) = 73
permutation(104) = 209
permutation(105) = 76
permutation(106) = 132
permutation(107) = 187
permutation(108) = 208
permutation(109) = 89
permutation(110) = 18
permutation(111) = 169
permutation(112) = 200
permutation(113) = 196
permutation(114) = 135
permutation(115) = 130
permutation(116) = 116
permutation(117) = 188
permutation(118) = 159
permutation(119) = 86
permutation(120) = 164
permutation(121) = 100
permutation(122) = 109
permutation(123) = 198
permutation(124) = 173
permutation(125) = 186
permutation(126) = 3
permutation(127) = 64
permutation(128) = 52
permutation(129) = 217
permutation(130) = 226
permutation(131) = 250
permutation(132) = 124
permutation(133) = 123
permutation(134) = 5
permutation(135) = 202
permutation(136) = 38
permutation(137) = 147
permutation(138) = 118
permutation(139) = 126
permutation(140) = 255
permutation(141) = 82
permutation(142) = 85
permutation(143) = 212
permutation(144) = 207
permutation(145) = 206
permutation(146) = 59
permutation(147) = 227
permutation(148) = 47
permutation(149) = 16
permutation(150) = 58
permutation(151) = 17
permutation(152) = 182
permutation(153) = 189
permutation(154) = 28
permutation(155) = 42
permutation(156) = 223
permutation(157) = 183
permutation(158) = 170
permutation(159) = 213
permutation(160) = 119
permutation(161) = 248
permutation(162) = 152
permutation(163) = 2
permutation(164) = 44
permutation(165) = 154
permutation(166) = 163
permutation(167) = 70
permutation(168) = 221
permutation(169) = 153
permutation(170) = 101
permutation(171) = 155
permutation(172) = 167
permutation(173) = 43
permutation(174) = 172
permutation(175) = 9
permutation(176) = 129
permutation(177) = 22
permutation(178) = 39
permutation(179) = 253
permutation(180) = 19
permutation(181) = 98
permutation(182) = 108
permutation(183) = 110
permutation(184) = 79
permutation(185) = 113
permutation(186) = 224
permutation(187) = 232
permutation(188) = 178
permutation(189) = 185
permutation(190) = 112
permutation(191) = 104
permutation(192) = 218
permutation(193) = 246
permutation(194) = 97
permutation(195) = 228
permutation(196) = 251
permutation(197) = 34
permutation(198) = 242
permutation(199) = 193
permutation(200) = 238
permutation(201) = 210
permutation(202) = 144
permutation(203) = 12
permutation(204) = 191
permutation(205) = 179
permutation(206) = 162
permutation(207) = 241
permutation(208) = 81
permutation(209) = 51
permutation(210) = 145
permutation(211) = 235
permutation(212) = 249
permutation(213) = 14
permutation(214) = 239
permutation(215) = 107
permutation(216) = 49
permutation(217) = 192
permutation(218) = 214
permutation(219) = 31
permutation(220) = 181
permutation(221) = 199
permutation(222) = 106
permutation(223) = 157
permutation(224) = 184
permutation(225) = 84
permutation(226) = 204
permutation(227) = 176
permutation(228) = 115
permutation(229) = 121
permutation(230) = 50
permutation(231) = 45
permutation(232) = 127
permutation(233) = 4
permutation(234) = 150
permutation(235) = 254
permutation(236) = 138
permutation(237) = 236
permutation(238) = 205
permutation(239) = 93
permutation(240) = 222
permutation(241) = 114
permutation(242) = 67
permutation(243) = 29
permutation(244) = 24
permutation(245) = 72
permutation(246) = 243
permutation(247) = 141
permutation(248) = 128
permutation(249) = 195
permutation(250) = 78
permutation(251) = 66
permutation(252) = 215
permutation(253) = 61
permutation(254) = 156
permutation(255) = 180
Dim i As Long
For i = 0 To 255
p(i) = permutation(i)
p(256 + i) = p(i)
Next i
End Sub
