in gym/gym/envs/box2d/car_racing.py [0:0]
def _create_track(self):
CHECKPOINTS = 12
# Create checkpoints
checkpoints = []
for c in range(CHECKPOINTS):
alpha = 2*math.pi*c/CHECKPOINTS + self.np_random.uniform(0, 2*math.pi*1/CHECKPOINTS)
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)) )
#print "\n".join(str(h) for h in checkpoints)
#self.road_poly = [ ( # uncomment this to see checkpoints
# [ (tx,ty) for a,tx,ty in checkpoints ],
# (0.7,0.7,0.9) ) ]
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 1:
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
proj = r1x*dest_dx + r1y*dest_dy # destination vector projected on rad
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
#print "\n".join([str(t) for t in enumerate(track)])
# 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
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))
t = self.world.CreateStaticBody( fixtures = fixtureDef(
shape=polygonShape(vertices=[road1_l, road1_r, road2_r, road2_l])
))
t.userData = t
c = 0.01*(i%3)
t.color = [ROAD_COLOR[0] + c, ROAD_COLOR[1] + c, ROAD_COLOR[2] + c]
t.road_visited = False
t.road_friction = 1.0
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], (1,1,1) if i%2==0 else (1,0,0) ))
self.track = track
return True