in gym/envs/box2d/car_racing.py [0:0]
def _create_track(self):
CHECKPOINTS = 12
# Create checkpoints
checkpoints = []
for c in range(CHECKPOINTS):
noise = self.np_random.uniform(0, 2 * math.pi * 1 / CHECKPOINTS)
alpha = 2 * math.pi * c / CHECKPOINTS + noise
rad = self.np_random.uniform(TRACK_RAD / 3, TRACK_RAD)
if c == 0:
alpha = 0
rad = 1.5 * TRACK_RAD
if c == CHECKPOINTS - 1:
alpha = 2 * math.pi * c / CHECKPOINTS
self.start_alpha = 2 * math.pi * (-0.5) / CHECKPOINTS
rad = 1.5 * TRACK_RAD
checkpoints.append((alpha, rad * math.cos(alpha), rad * math.sin(alpha)))
self.road = []
# Go from one checkpoint to another to create track
x, y, beta = 1.5 * TRACK_RAD, 0, 0
dest_i = 0
laps = 0
track = []
no_freeze = 2500
visited_other_side = False
while True:
alpha = math.atan2(y, x)
if visited_other_side and alpha > 0:
laps += 1
visited_other_side = False
if alpha < 0:
visited_other_side = True
alpha += 2 * math.pi
while True: # Find destination from checkpoints
failed = True
while True:
dest_alpha, dest_x, dest_y = checkpoints[dest_i % len(checkpoints)]
if alpha <= dest_alpha:
failed = False
break
dest_i += 1
if dest_i % len(checkpoints) == 0:
break
if not failed:
break
alpha -= 2 * math.pi
continue
r1x = math.cos(beta)
r1y = math.sin(beta)
p1x = -r1y
p1y = r1x
dest_dx = dest_x - x # vector towards destination
dest_dy = dest_y - y
# destination vector projected on rad:
proj = r1x * dest_dx + r1y * dest_dy
while beta - alpha > 1.5 * math.pi:
beta -= 2 * math.pi
while beta - alpha < -1.5 * math.pi:
beta += 2 * math.pi
prev_beta = beta
proj *= SCALE
if proj > 0.3:
beta -= min(TRACK_TURN_RATE, abs(0.001 * proj))
if proj < -0.3:
beta += min(TRACK_TURN_RATE, abs(0.001 * proj))
x += p1x * TRACK_DETAIL_STEP
y += p1y * TRACK_DETAIL_STEP
track.append((alpha, prev_beta * 0.5 + beta * 0.5, x, y))
if laps > 4:
break
no_freeze -= 1
if no_freeze == 0:
break
# Find closed loop range i1..i2, first loop should be ignored, second is OK
i1, i2 = -1, -1
i = len(track)
while True:
i -= 1
if i == 0:
return False # Failed
pass_through_start = (
track[i][0] > self.start_alpha and track[i - 1][0] <= self.start_alpha
)
if pass_through_start and i2 == -1:
i2 = i
elif pass_through_start and i1 == -1:
i1 = i
break
if self.verbose:
print("Track generation: %i..%i -> %i-tiles track" % (i1, i2, i2 - i1))
assert i1 != -1
assert i2 != -1
track = track[i1 : i2 - 1]
first_beta = track[0][1]
first_perp_x = math.cos(first_beta)
first_perp_y = math.sin(first_beta)
# Length of perpendicular jump to put together head and tail
well_glued_together = np.sqrt(
np.square(first_perp_x * (track[0][2] - track[-1][2]))
+ np.square(first_perp_y * (track[0][3] - track[-1][3]))
)
if well_glued_together > TRACK_DETAIL_STEP:
return False
# Red-white border on hard turns
border = [False] * len(track)
for i in range(len(track)):
good = True
oneside = 0
for neg in range(BORDER_MIN_COUNT):
beta1 = track[i - neg - 0][1]
beta2 = track[i - neg - 1][1]
good &= abs(beta1 - beta2) > TRACK_TURN_RATE * 0.2
oneside += np.sign(beta1 - beta2)
good &= abs(oneside) == BORDER_MIN_COUNT
border[i] = good
for i in range(len(track)):
for neg in range(BORDER_MIN_COUNT):
border[i - neg] |= border[i]
# Create tiles
for i in range(len(track)):
alpha1, beta1, x1, y1 = track[i]
alpha2, beta2, x2, y2 = track[i - 1]
road1_l = (
x1 - TRACK_WIDTH * math.cos(beta1),
y1 - TRACK_WIDTH * math.sin(beta1),
)
road1_r = (
x1 + TRACK_WIDTH * math.cos(beta1),
y1 + TRACK_WIDTH * math.sin(beta1),
)
road2_l = (
x2 - TRACK_WIDTH * math.cos(beta2),
y2 - TRACK_WIDTH * math.sin(beta2),
)
road2_r = (
x2 + TRACK_WIDTH * math.cos(beta2),
y2 + TRACK_WIDTH * math.sin(beta2),
)
vertices = [road1_l, road1_r, road2_r, road2_l]
self.fd_tile.shape.vertices = vertices
t = self.world.CreateStaticBody(fixtures=self.fd_tile)
t.userData = t
c = 0.01 * (i % 3) * 255
t.color = self.road_color + c
t.road_visited = False
t.road_friction = 1.0
t.idx = i
t.fixtures[0].sensor = True
self.road_poly.append(([road1_l, road1_r, road2_r, road2_l], t.color))
self.road.append(t)
if border[i]:
side = np.sign(beta2 - beta1)
b1_l = (
x1 + side * TRACK_WIDTH * math.cos(beta1),
y1 + side * TRACK_WIDTH * math.sin(beta1),
)
b1_r = (
x1 + side * (TRACK_WIDTH + BORDER) * math.cos(beta1),
y1 + side * (TRACK_WIDTH + BORDER) * math.sin(beta1),
)
b2_l = (
x2 + side * TRACK_WIDTH * math.cos(beta2),
y2 + side * TRACK_WIDTH * math.sin(beta2),
)
b2_r = (
x2 + side * (TRACK_WIDTH + BORDER) * math.cos(beta2),
y2 + side * (TRACK_WIDTH + BORDER) * math.sin(beta2),
)
self.road_poly.append(
(
[b1_l, b1_r, b2_r, b2_l],
(255, 255, 255) if i % 2 == 0 else (255, 0, 0),
)
)
self.track = track
return True