# Draws and synthesises the art kit the beginner's course uses, into docs/learn/art.
#
# A tutorial cannot say "find a picture of a spaceship":  the pictures have to be there, named the
# same on every machine, or half the readers stop at lesson nine.  Everything here is drawn from
# shapes rather than painted, so it is ours, it is tiny, and it can be regenerated.  The engine
# already gives every reader a video, two models, a font, and a click (the Singe folder it unpacks
# on the first run), so this kit is only the things a 2D game needs:  a ship, a rock, a shot, a
# star, one walk cycle, and two noises.
#
# Usage:  python3 util/learnKit.py
import math
import os
import struct
import wave

from PIL import Image, ImageDraw


REPO = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
OUT  = os.path.join(REPO, "docs", "learn", "art")
RATE = 22050


def blank(width, height):
	return Image.new("RGBA", (width, height), (0, 0, 0, 0))


def save(image, name):
	path = os.path.join(OUT, name)
	image.save(path)
	print("%s  %dx%d" % (name, image.width, image.height))


# A ship pointing up:  a hull, a nose, and two fins, so it reads at 32 pixels.
def ship():
	image = blank(32, 24)
	draw  = ImageDraw.Draw(image)

	draw.polygon([(16, 0), (23, 17), (9, 17)], fill=(120, 200, 255, 255))
	draw.polygon([(16, 3), (20, 16), (12, 16)], fill=(230, 245, 255, 255))
	draw.polygon([(9, 12), (2, 22), (9, 20)], fill=(70, 130, 200, 255))
	draw.polygon([(23, 12), (30, 22), (23, 20)], fill=(70, 130, 200, 255))
	draw.rectangle([13, 17, 18, 21], fill=(255, 170, 60, 255))
	draw.rectangle([14, 19, 17, 23], fill=(255, 230, 120, 255))
	return image


# A rock:  an uneven lump with a couple of craters, so a rotation would not be missed.
def rock():
	image = blank(24, 24)
	draw  = ImageDraw.Draw(image)
	points = [(12, 1), (19, 4), (23, 11), (20, 19), (13, 23), (5, 21), (1, 13), (3, 5)]

	draw.polygon(points, fill=(150, 140, 130, 255))
	draw.polygon([(12, 3), (17, 6), (19, 11), (16, 17), (11, 20), (6, 18), (4, 12), (6, 6)],
	             fill=(185, 175, 165, 255))
	draw.ellipse([8, 7, 12, 11], fill=(140, 130, 120, 255))
	draw.ellipse([14, 13, 17, 16], fill=(140, 130, 120, 255))
	return image


def shot():
	image = blank(4, 10)
	draw  = ImageDraw.Draw(image)

	draw.rectangle([0, 2, 3, 9], fill=(255, 210, 90, 255))
	draw.rectangle([1, 0, 2, 9], fill=(255, 255, 220, 255))
	return image


def star():
	image = blank(8, 8)
	draw  = ImageDraw.Draw(image)

	draw.line([4, 0, 4, 7], fill=(255, 240, 160, 255))
	draw.line([0, 4, 7, 4], fill=(255, 240, 160, 255))
	draw.point([(3, 3), (5, 3), (3, 5), (5, 5)], fill=(255, 210, 90, 255))
	return image


# Four frames of a walk, side by side in one picture:  the sheet the frames lesson steps through.
# The legs swing, the arms swing the other way, and frames two and four differ so the cycle reads.
def walk():
	image = blank(24 * 4, 32)
	draw  = ImageDraw.Draw(image)
	swing = [(-5, 5), (0, 0), (5, -5), (0, 0)]

	for frame in range(4):
		x    = frame * 24 + 12
		lead = swing[frame][0]
		back = swing[frame][1]
		bob  = 1 if frame % 2 == 0 else 0

		draw.ellipse([x - 4, 3 + bob, x + 4, 11 + bob], fill=(245, 205, 160, 255))
		draw.rectangle([x - 4, 12 + bob, x + 4, 22 + bob], fill=(80, 130, 200, 255))
		draw.line([x - 4, 13 + bob, x - 4 - abs(back), 19 + bob], fill=(245, 205, 160, 255), width=2)
		draw.line([x + 4, 13 + bob, x + 4 + abs(lead), 19 + bob], fill=(245, 205, 160, 255), width=2)
		draw.line([x - 1, 22 + bob, x - 1 + back, 30], fill=(60, 60, 90, 255), width=3)
		draw.line([x + 1, 22 + bob, x + 1 + lead, 30], fill=(40, 40, 70, 255), width=3)
	return image


# A noise, written straight out as a 16 bit mono WAV:  no library, and small enough to read.
def tone(name, seconds, shape):
	frames = int(RATE * seconds)
	data   = bytearray()

	for i in range(frames):
		t     = i / RATE
		value = shape(t, t / seconds)
		value = max(-1.0, min(1.0, value))
		data += struct.pack("<h", int(value * 32000))
	path = os.path.join(OUT, name)
	with wave.open(path, "wb") as out:
		out.setnchannels(1)
		out.setsampwidth(2)
		out.setframerate(RATE)
		out.writeframes(bytes(data))
	print("%s  %.2f seconds" % (name, seconds))


# A shot:  a tone sliding down fast, which is the oldest arcade sound there is.
def shootShape(t, done):
	pitch = 900.0 - 600.0 * done
	return math.sin(2.0 * math.pi * pitch * t) * (1.0 - done) ** 2


# A bang:  noise shaped by a falling envelope, with a low thump under it.
def boomShape(t, done):
	seed  = int(t * RATE)
	noise = (((seed * 1103515245 + 12345) >> 16) % 2000 - 1000) / 1000.0
	return (noise * 0.8 + math.sin(2.0 * math.pi * 70.0 * t) * 0.5) * (1.0 - done) ** 3


def main():
	os.makedirs(OUT, exist_ok=True)
	save(ship(), "ship.png")
	save(rock(), "rock.png")
	save(shot(), "shot.png")
	save(star(), "star.png")
	save(walk(), "walk.png")
	tone("shoot.wav", 0.18, shootShape)
	tone("boom.wav", 0.45, boomShape)


if __name__ == "__main__":
	main()