Common.h File Reference

Go to the source code of this file.

Macros
#define	MurmurHash3_32   MurmurHash3_x86_32
	MurmurHash3 for x86 architectures.
#define	B   0x100
	Perlin's B, a power of 2 usually equal to 256.
#define	BM   0xff
	A bit mask, one less than B.
#define	N   0x1000
	Perlin's N.
#define	lerp(t, a, b)   (a + t*(b - a))
	Linear interpolation.
#define	s_curve(t)   (t * t * (3.0f - 2.0f*t))
	Cubic spline.
#define	s_curve2(t)   (t * t * t * (10.0f + 3.0f * t * (2.0f*t - 5.0f)))
	Quintic spline.
#define	setup(i, b0, b1, r0, r1)
	Perlin's setup macro.
#define	at2(rx, ry)   (rx*q[0] + ry*q[1])
	Perlin's dot product macro.

Functions
unsigned int	h2 (unsigned int x, unsigned int y)

Macro Definition Documentation

#define setup	(		i,
			b0,
			b1,
			r0,
			r1
	)

Value:

t = vec[i] + N;\
        b0 = ((int)t) & BM;\
        b1 = (b0+1) & BM;\
        r0 = t - (int)t;\
        r1 = r0 - 1.0f;

Function Documentation

unsigned int h2	(	unsigned int	x,
		unsigned int	y
	)

A 2D hash function. Hash two dimensions into a single unsigned int using MurmurHash.

Parameters

x	X coordinate of value to be hashed.
y	Y coordinate of value to be hashed.

Returns

Hash of (x, y).