Reimplement noise functions

code/qcommon/q_math.c

@@ -948,58 +948,242 @@ float LerpAngle (float from, float to, float frac) {
 
 	return a;
 }
-static int p[514];
+float bias(float a, float b)
-static float g3[514][3];
-static float g2[514][2];
-static float g1[514];
-
-static void init(void)
 {
-	//This is an ugly func I wont bother variable naming.
+	return pow(a, log(b) / log(0.5));
-	int i;
-	for (i = 0; i < 256; i++)
-	{
-		p[i] = i;
-		g1[i] = (rand() % 512 - 256) * 0.00390625;
-	}
-	int v21, v22;
-	for (int j = i - 1; j; p[v22 % 256] = v21)
-	{
-		v21 = p[j];
-		v22 = rand();
-		p[j--] = p[v22 % 256];
-	}
-
-	for (size_t k = 0; k < 258; k++)
-	{
-		g1[k + 256] = g1[k];
-	}
-
 }
+
+float gain(float a, float b)
+{
+	float p = log(1. - b) / log(0.5);
+
+	if (a < .001)
+		return 0.;
+	else if (a > .999)
+		return 1.;
+	if (a < 0.5)
+		return pow(2 * a, p) / 2;
+	else
+		return 1. - pow(2 * (1. - a), p) / 2;
+}
+
+float noise(float vec[], int len)
+{
+	switch (len) {
+	case 0:
+		return 0.;
+	case 1:
+		return noise1(vec[0]);
+	case 2:
+		return noise2(vec);
+	default:
+		return noise3(vec);
+	}
+}
+
+float turbulence(float *v, float freq)
+{
+	float t, vec[3];
+
+	for (t = 0. ; freq >= 1. ; freq /= 2) {
+		vec[0] = freq * v[0];
+		vec[1] = freq * v[1];
+		vec[2] = freq * v[2];
+		t += fabs(noise3(vec)) / freq;
+	}
+	return t;
+}
+
+/* noise functions over 1, 2, and 3 dimensions */
+
+#define B 0x100
+#define BM 0xff
+
+#define N 0x1000
+#define NP 12   /* 2^N */
+#define NM 0xfff
+
+static int p[B + B + 2];
+static float g3[B + B + 2][3];
+static float g2[B + B + 2][2];
+static float g1[B + B + 2];
 static int start = 1;
 
+static void init(void);
+
+#define s_curve(t) ( t * t * (3. - 2. * t) )
+
+#define lerp(t, a, b) ( a + t * (b - a) )
+
+#define setup(i,b0,b1,r0,r1)\
+	t = vec[i] + N;\
+	b0 = ((int)t) & BM;\
+	b1 = (b0+1) & BM;\
+	r0 = t - (int)t;\
+	r1 = r0 - 1.;
+
 float noise1(float arg)
 {
-	float rx0;
+	int bx0, bx1;
-	float rx1;
+	float rx0, rx1, sx, t, u, v, vec[1];
-	float u;
-	float sx;
-	float t;
-	int bx0;
 
-	if (start)
+	vec[0] = arg;
-	{
+	if (start) {
 		start = 0;
 		init();
 	}
 
-	rx0 = arg + 4096.0;
+	setup(0, bx0,bx1, rx0,rx1);
-	bx0 = (int)rx0;
+
-	rx1 = rx0 - bx0;
+	sx = s_curve(rx0);
-	sx = rx1 - 1.0;
+
-	t = rx1 * rx1 * (3.0 - (rx1 + rx1));
+	u = rx0 * g1[ p[ bx0 ] ];
-	u = rx1 * g1[p[bx0]];
+	v = rx1 * g1[ p[ bx1 ] ];
-	return u + t * (sx * g1[p[bx0 + 1]] - u);
+
+	return lerp(sx, u, v);
+}
+
+float noise2(vec3_t vec)
+{
+	int bx0, bx1, by0, by1, b00, b10, b01, b11;
+	float rx0, rx1, ry0, ry1, *q, sx, sy, a, b, t, u, v;
+	register int i, j;
+
+	if (start) {
+		start = 0;
+		init();
+	}
+
+	setup(0, bx0,bx1, rx0,rx1);
+	setup(1, by0,by1, ry0,ry1);
+
+	i = p[ bx0 ];
+	j = p[ bx1 ];
+
+	b00 = p[ i + by0 ];
+	b10 = p[ j + by0 ];
+	b01 = p[ i + by1 ];
+	b11 = p[ j + by1 ];
+
+	sx = s_curve(rx0);
+	sy = s_curve(ry0);
+
+#define at2(rx,ry) ( rx * q[0] + ry * q[1] )
+
+	q = g2[ b00 ] ; u = at2(rx0,ry0);
+	q = g2[ b10 ] ; v = at2(rx1,ry0);
+	a = lerp(sx, u, v);
+
+	q = g2[ b01 ] ; u = at2(rx0,ry1);
+	q = g2[ b11 ] ; v = at2(rx1,ry1);
+	b = lerp(sx, u, v);
+
+	return lerp(sy, a, b);
+}
+
+float noise3(vec3_t vec)
+{
+	int bx0, bx1, by0, by1, bz0, bz1, b00, b10, b01, b11;
+	float rx0, rx1, ry0, ry1, rz0, rz1, *q, sy, sz, a, b, c, d, t, u, v;
+	register int i, j;
+
+	if (start) {
+		start = 0;
+		init();
+	}
+
+	setup(0, bx0,bx1, rx0,rx1);
+	setup(1, by0,by1, ry0,ry1);
+	setup(2, bz0,bz1, rz0,rz1);
+
+	i = p[ bx0 ];
+	j = p[ bx1 ];
+
+	b00 = p[ i + by0 ];
+	b10 = p[ j + by0 ];
+	b01 = p[ i + by1 ];
+	b11 = p[ j + by1 ];
+
+	t  = s_curve(rx0);
+	sy = s_curve(ry0);
+	sz = s_curve(rz0);
+
+#define at3(rx,ry,rz) ( rx * q[0] + ry * q[1] + rz * q[2] )
+
+	q = g3[ b00 + bz0 ] ; u = at3(rx0,ry0,rz0);
+	q = g3[ b10 + bz0 ] ; v = at3(rx1,ry0,rz0);
+	a = lerp(t, u, v);
+
+	q = g3[ b01 + bz0 ] ; u = at3(rx0,ry1,rz0);
+	q = g3[ b11 + bz0 ] ; v = at3(rx1,ry1,rz0);
+	b = lerp(t, u, v);
+
+	c = lerp(sy, a, b);
+
+	q = g3[ b00 + bz1 ] ; u = at3(rx0,ry0,rz1);
+	q = g3[ b10 + bz1 ] ; v = at3(rx1,ry0,rz1);
+	a = lerp(t, u, v);
+
+	q = g3[ b01 + bz1 ] ; u = at3(rx0,ry1,rz1);
+	q = g3[ b11 + bz1 ] ; v = at3(rx1,ry1,rz1);
+	b = lerp(t, u, v);
+
+	d = lerp(sy, a, b);
+
+	return lerp(sz, c, d);
+}
+
+static void normalize2(vec2_t v)
+{
+	float s;
+
+	s = sqrt(v[0] * v[0] + v[1] * v[1]);
+	v[0] = v[0] / s;
+	v[1] = v[1] / s;
+}
+
+static void normalize3(vec3_t v)
+{
+	float s;
+
+	s = sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
+	v[0] = v[0] / s;
+	v[1] = v[1] / s;
+	v[2] = v[2] / s;
+}
+
+static void init(void)
+{
+	int i, j, k;
+
+	for (i = 0 ; i < B ; i++) {
+		p[i] = i;
+
+		g1[i] = (float)((rand() % (B + B)) - B) / B;
+
+		for (j = 0 ; j < 2 ; j++)
+			g2[i][j] = (float)((rand() % (B + B)) - B) / B;
+		normalize2(g2[i]);
+
+		for (j = 0 ; j < 3 ; j++)
+			g3[i][j] = (float)((rand() % (B + B)) - B) / B;
+		normalize3(g3[i]);
+	}
+
+	while (--i) {
+		k = p[i];
+		p[i] = p[j = rand() % B];
+		p[j] = k;
+	}
+
+	for (i = 0 ; i < B + 2 ; i++) {
+		p[B + i] = p[i];
+		g1[B + i] = g1[i];
+		for (j = 0 ; j < 2 ; j++)
+			g2[B + i][j] = g2[i][j];
+		for (j = 0 ; j < 3 ; j++)
+			g3[B + i][j] = g3[i][j];
+	}
 }
 
 /*

code/qcommon/q_shared.h

@@ -838,8 +838,11 @@ void vectoangles( const vec3_t value1, vec3_t angles );
 void VectorToAngles( const vec3_t vec, vec3_t angles );
 void AnglesToAxis(const vec3_t angles, vec3_t axis[3]);
 void YawToAxis(float yaw, float axis[2]);
-static  void init( void );
+
-float	noise1(float arg);
+float noise(float vec[], int len);
+float noise1(float arg);
+float noise2(vec3_t arg);
+float noise3(vec3_t arg);
 
 void	R_ConcatRotations( float in1[ 3 ][ 3 ], float in2[ 3 ][ 3 ], float out[ 3 ][ 3 ] );
 void	R_ConcatTransforms( float in1[ 3 ][ 4 ], float in2[ 3 ][ 4 ], float out[ 3 ][ 4 ] );