#!/usr/bin/env python3
# Gera os dois efeitos sonoros que trocam game/goal/get_ball.wav e game/goal/close.wav do Escape Space (os
# originais sao de "manuts" no Freesound, sem fonte original localizavel; ver o LICENSE.txt do jogo). Os sons
# daqui sao nossos, sintetizados do zero (seno e ruido com semente fixa), 44100 Hz, 16 bits, mono, e ficam
# em CC0 (dominio publico). A saida e deterministica; o build-escape-space.sh usa os .wav gerados.
#
#   python3 -I gen-goal-sounds.py
import math, random, struct, wave, os

RATE = 44100

def write(name, samples):
    peak = max(abs(s) for s in samples) or 1.0
    path = os.path.join(os.path.dirname(os.path.abspath(__file__)), name)
    with wave.open(path, 'wb') as w:
        w.setnchannels(1); w.setsampwidth(2); w.setframerate(RATE)
        w.writeframes(b''.join(struct.pack('<h', int(max(-1.0, min(1.0, s / peak * 0.8)) * 32767)) for s in samples))

def env(i, n, attack=0.005, power=3.0):
    t = i / RATE
    a = min(1.0, t / attack)
    return a * (1.0 - i / n) ** power

# get_ball: dois toques de sino que sobem (La5 e Mi6), com um harmonico suave.
def get_ball():
    n = int(RATE * 0.55)
    out = [0.0] * n
    for start, f in ((0.0, 880.0), (0.11, 1318.5)):
        s0 = int(start * RATE)
        m = n - s0
        for i in range(m):
            t = i / RATE
            v = math.sin(2 * math.pi * f * t) + 0.35 * math.sin(2 * math.pi * 2 * f * t) + 0.12 * math.sin(2 * math.pi * 3 * f * t)
            out[s0 + i] += v * env(i, m, 0.003, 2.5)
    return out

# close: o portao fecha, uma queda de tom com um "clunk" curto de ruido filtrado no fim.
def close():
    n = int(RATE * 0.7)
    rnd = random.Random(20261029)
    out = [0.0] * n
    phase = 0.0
    for i in range(n):
        t = i / RATE
        f = 520.0 * math.exp(-3.2 * t) + 90.0
        phase += 2 * math.pi * f / RATE
        out[i] += math.sin(phase) * env(i, n, 0.004, 1.6) * 0.8
    s0 = int(0.28 * RATE)
    lp = 0.0
    for i in range(n - s0):
        lp += 0.12 * (rnd.uniform(-1, 1) - lp)
        out[s0 + i] += lp * 2.2 * env(i, n - s0, 0.001, 5.0) + math.sin(2 * math.pi * 70 * i / RATE) * env(i, n - s0, 0.001, 4.0) * 0.9
    return out

write('goal-get_ball.wav', get_ball())
write('goal-close.wav', close())