Extract more lib functions

[xonotic/xonotic-data.pk3dir.git] / qcsrc / lib / noise.qc

diff --git a/qcsrc/lib/noise.qc b/qcsrc/lib/noise.qc
new file mode 100644 (file)
index 0000000..5bd6ad6
--- /dev/null
+++ b/qcsrc/lib/noise.qc
@@ -0,0 +1,37 @@
+// noises "usually" start in the range -1..1
+entityclass(Noise);
+class(Noise) .float noise_baccum;
+class(Noise) .float noise_paccum;
+class(Noise) .float noise_paccum2;
+class(Noise) .float noise_paccum3;
+class(Noise) .float noise_bstate;
+
+float Noise_Brown(entity e, float dt)
+{
+       e.noise_baccum += random() * sqrt(dt); // same stddev for all dt
+       return e.noise_baccum;
+}
+float Noise_Pink(entity e, float dt)
+{
+       float f;
+       f = dt * 60;
+       // http://home.earthlink.net/~ltrammell/tech/pinkalg.htm
+       if(random() > pow(0.3190, f))
+               e.noise_paccum = 0.34848 * (2 * random() - 1);
+       if(random() > pow(0.7756, f))
+               e.noise_paccum2 = 0.28768 * (2 * random() - 1);
+       if(random() > pow(0.9613, f))
+               e.noise_paccum3 = 0.43488 * (2 * random() - 1);
+       return e.noise_paccum + e.noise_paccum2 + e.noise_paccum3;
+}
+float Noise_White(entity e, float dt)
+{
+       return random() * 2 - 1;
+}
+/** +1 or -1 */
+float Noise_Burst(entity e, float dt, float p)
+{
+       if(random() > pow(p, dt))
+               e.noise_bstate = !e.noise_bstate;
+       return 2 * e.noise_bstate - 1;
+}