Perlin noise: Difference between revisions

=={{header|Vlang}==

{{trans|go}}

<lang vlang>import math

// vlang doesn't have globals

const (

p = [151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,

140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148,

247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32,

57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175,

74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122,

60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,

65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169,

200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64,

52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212,

207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213,

119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,

129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104,

218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,

81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,

184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,

222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180,

151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,

140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148,

247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32,

57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175,

74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122,

60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54,

65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169,

200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64,

52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212,

207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213,

119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,

129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104,

218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,

81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,

184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,

222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180 ]

)

fn main() {

println(noise(3.14, 42, 7))

}

fn noise(x1 f64, y1 f64, z1 f64) f64 {

bx := int(math.floor(x1)) & 255

by := int(math.floor(y1)) & 255

bz := int(math.floor(z1)) & 255

x := x1 - math.floor(x1)

y := y1 - math.floor(y1)

z := z1 - math.floor(z1)

u := fade(x)

v := fade(y)

w := fade(z)

ba := p[bx] + by

baa := p[ba] + bz

bab := p[ba+1] + bz

bb := p[bx+1] + by

bba := p[bb] + bz

bbb := p[bb+1] + bz

return lerp(w, lerp(v, lerp(u, grad(p[baa], x, y, z),

grad(p[bba], x-1, y, z)),

lerp(u, grad(p[bab], x, y-1, z),

grad(p[bbb], x-1, y-1, z))),

lerp(v, lerp(u, grad(p[baa+1], x, y, z-1),

grad(p[bba+1], x-1, y, z-1)),

lerp(u, grad(p[bab+1], x, y-1, z-1),

grad(p[bbb+1], x-1, y-1, z-1))))

}

fn fade(t f64) f64 { return t * t * t * (t*(t*6-15) + 10) }

fn lerp(t f64, a f64, b f64) f64 { return a + t*(b-a) }

fn grad(hash int, x f64, y f64, z f64) f64 {

// Vlang doesn't have a ternary. Ternaries can be translated directly

// with if statements, but chains of if statements are often better

// expressed with match statements.

match hash & 15 {

0 {

return x + y

}

1 {

return y - x

}

2 {

return x - y

}

3 {

return -x - y

}

4 {

return x + z

}

5 {

return z - x

}

6{

return x - z

}

7{

return -x - z

}

8 {

return y + z

}

9 {

return z - y

}

10 {

return y - z

}

12 {

return x + y

}

13 {

return z - y

}

14 {

return y - x

}

else {

// case 11, 16:

return -y - z

}

}

}</lang>

{{out}}

<pre>

0.13691995878400012

</pre>