def riverErosion(self, river):
'''Simulate erosion in heightmap based on river path.
* current location must be equal to or less than previous location
* riverbed is carved out by % of volume/flow
* sides of river are also eroded to slope into riverbed.
'''
# erosion of riverbed itself
maxElevation = 1.0
minElevation = 0.0
for r in river:
rx, ry = r
if self.heightmap[rx, ry] < maxElevation:
maxElevation = self.heightmap[rx, ry]
minElevation = maxElevation * 0.99
maxElevation = random.uniform(minElevation, maxElevation)
self.heightmap[rx, ry] = maxElevation
# erosion around river, create river valley
for r in river:
rx, ry = r
radius = 2
for x in range(rx - radius, rx + radius):
for y in range(ry - radius, ry + radius):
if not self.wrap and utilities.outOfBounds([x, y], self.size): # ignore edges of map
continue
x, y = utilities.overflow(x, self.worldW), utilities.overflow(y, self.worldH)
curve = 1.0
if [x, y] == [0, 0]: # ignore center
continue
if [x, y] in river: # ignore river itself
continue
if self.heightmap[x, y] <= self.heightmap[rx, ry]: # ignore areas lower than river itself
continue
if not utilities.inCircle(radius, rx, ry, x, y): # ignore things outside a circle
continue
adx, ady = math.fabs(rx - x), math.fabs(ry - y)
if adx == 1 or ady == 1:
curve = 0.2
elif adx == 2 or ady == 2:
curve = 0.05
diff = self.heightmap[rx, ry] - self.heightmap[x, y]
newElevation = self.heightmap[x, y] + (diff * curve)
if newElevation <= self.heightmap[rx, ry]:
print('newElevation is <= than river, fix me...')
newElevation = self.heightmap[x, y]
self.heightmap[x, y] = newElevation
return
def findLowerElevation(self, source):
'''Try to find a lower elevation with in a range of an increasing
circle's radius and try to find the best path and return it'''
x, y = source
currentRadius = 1
maxRadius = 40
lowestElevation = self.heightmap[x, y]
destination = []
notFound = True
isWrapped = False
wrapped = []
while notFound and currentRadius <= maxRadius:
for cx in range(-currentRadius, currentRadius + 1):
for cy in range(-currentRadius, currentRadius + 1):
rx, ry = x + cx, y + cy
# are we within bounds?
if not self.wrap and utilities.outOfBounds([rx, ry], self.size):
continue
# are we within a circle?
if not utilities.inCircle(currentRadius, x, y, rx, ry):
continue
rx, ry = utilities.overflow(rx, self.worldW), utilities.overflow(ry, self.worldH)
# if utilities.outOfBounds([x+cx, y+cy], self.size):
# print "Fixed:",x ,y, rx, ry
elevation = self.heightmap[rx, ry]
if elevation < lowestElevation: # have we found a lower elevation?
lowestElevation = elevation
destination = [rx, ry]
notFound = False
if utilities.outOfBounds([x+cx, y+cy], self.size):
wrapped.append(destination)
currentRadius += 1
if destination in wrapped:
isWrapped = True
# print "Wrapped lower elevation found:", rx, ry, "!"
return isWrapped, destination
def findQuickPath(self, river):
# Water flows based on cost, seeking the highest elevation difference
# highest positive number is the path of least resistance (lowest point)
# Cost
# *** 1,0 ***
# 0,1 *** 2,1
# *** 1,2 ***
x, y = river
newPath = []
lowestElevation = self.heightmap[x, y]
# lowestDirection = [0, 0]
for dx, dy in DIR_NEIGHBORS:
tempDir = [x + dx, y + dy]
tx, ty = tempDir
if not self.wrap and utilities.outOfBounds(tempDir, self.size):
continue
tx, ty = utilities.overflow(tx, self.worldW), utilities.overflow(ty, self.worldH)
elevation = self.heightmap[tx, ty]
# print river, direction, tempDir, elevation, direction[0], direction[1]
if elevation < lowestElevation:
if utilities.outOfBounds(tempDir, self.size):
#print "Lower OOB:",tempDir, "Corrected:", tx, ty
pass
lowestElevation = elevation
newPath = [tx,ty]
# print newPath, lowestDirection, elevation
# sys.exit()
return newPath
def riverFlow(self, source):
'''simulate fluid dynamics by using starting point and flowing to the
lowest available point'''
currentLocation = source
path = [source]
# start the flow
while True:
x, y = currentLocation
lowerElevation = None
quickSection = None
isWrapped = False
for dx, dy in DIR_NEIGHBORS: # is there a river nearby, flow into it
ax, ay = x + dx, y + dy
if self.wrap:
ax, ay = utilities.overflow(ax, self.worldW), utilities.overflow(ay, self.worldH)
for river in self.riverList:
if [ax, ay] in river:
#print "Found another river at:", x, y, " -> ", ax, ay, " Thus, using that river's path."
merge = False
for rx, ry in river:
if [ax, ay] == [rx, ry]:
merge = True
path.append([rx, ry])
elif merge == True:
path.append([rx, ry])
return path # skip the rest, return path
# found a sea?
#print "Flowing to...",x,y
if self.heightmap[x, y] <= self.seaLevel:
break
# find our immediate lowest elevation and flow there
quickSection = self.findQuickPath(currentLocation)
if quickSection:
path.append(quickSection)
currentLocation = quickSection
continue # stop here and enter back into loop
isWrapped, lowerElevation = self.findLowerElevation(currentLocation)
if lowerElevation and not isWrapped:
lowerPath = None
lowerPath = aStar.pathFinder().find(self.heightmap, currentLocation, lowerElevation)
if lowerPath:
path += lowerPath
currentLocation = path[-1]
else:
break
elif lowerElevation and isWrapped:
#TODO: make this more natural
maxRadius = 40
wrappedX = wrappedY = False
# print 'Found a lower elevation on wrapped path, searching path!'
# print 'We go from',currentLocation,'to',lowerElevation
cx,cy = currentLocation
lx,ly = lowerElevation
nx,ny = lowerElevation
if (x < 0 or y < 0 or x > self.worldW or y > self.worldH):
print("BUG: fix me... we shouldn't be here:", currentLocation, lowerElevation)
break
if not utilities.inCircle(maxRadius, cx, cy, lx, cy):
# are we wrapping on x axis?
#print "We found wrapping along x-axis"
if cx-lx < 0:
lx = 0 # move to left edge
nx = self.worldW-1 # next step is wrapped around
else:
lx = self.worldW-1 # move to right edge
nx = 0 # next step is wrapped around
ly = ny = int( (cy+ly)/2 ) # move halfway
elif not utilities.inCircle(maxRadius, cx, cy, cx, ly):
# are we wrapping on y axis?
# print "We found wrapping along y-axis"
if cy-ly < 0:
ly = 0 # move to top edge
ny = self.worldH-1 # next step is wrapped around
else:
ly = self.worldH-1 # move to bottom edge
ny = 0 # next step is wrapped around
lx = nx = int( (cx+lx)/2 ) # move halfway
else:
# print "BUG: fix me... we are not in circle:", currentLocation, lowerElevation
break
# find our way to the edge
edgePath = None
edgePath = aStar.pathFinder().find(self.heightmap, [cx,cy], [lx,ly])
if not edgePath:
# print "We've reached the end of this river, we cannot get through."
# can't find another other path, make it a lake
self.lakeList.append(currentLocation)
break
path += edgePath # add our newly found path
path.append([nx,ny]) # finally add our overflow to other side
currentLocation = path[-1]
# print "Path found from ", [cx,cy], 'to', [lx,ly], 'via:'
# print edgePath
# print "We then wrap on: ", [nx, ny]
# find our way to lowest position original found
lowerPath = aStar.pathFinder().find(self.heightmap, currentLocation, lowerElevation)
path += lowerPath
currentLocation = path[-1]
# print "We then go to our destination: ", lowerElevation
# print lowerPath
# print " "
# print "Full path begin and end ", path[0], path[-1]
hx,hy = path[0]
hlx,hly = path[-1]
# print "Elevations: ", self.heightmap[hx,hy], self.heightmap[hlx,hly]
# print "Erosion: ", self.erosionMap[hx,hy], self.erosionMap[hlx,hly]
# print " "
#break
else: # can't find any other path, make it a lake
self.lakeList.append(currentLocation)
break # end of river
if utilities.outOfBounds(currentLocation, self.size):
print("Why are we here:",currentLocation)
return path
def riverSources(self):
'''Find places on map where sources of river can be found'''
riverSourceList = []
if self.waterFlow is None:
# Version 1, is 'good enough' but we can do better.
square = 32
# square = int(math.log(self.worldH, 2)**2)
# iterate through map and mark river sources
for x in range(0, self.worldW - 1, square):
for y in range(0, self.worldH - 1, square):
# print 'Ranges: ', x, y, square+x, square+y
# find random location
sources = []
for sx in range(x, x + square):
for sy in range(y, y + square):
if not self.wrap and utilities.outOfBounds([sx, sy], self.size):
continue
# convert to wrap around
sx, sy = utilities.overflow(sx, self.worldW), utilities.overflow(sy, self.worldH)
if self.heightmap[sx, sy] < BIOME_ELEVATION_HILLS or \
self.heightmap[sx, sy] > BIOME_ELEVATION_MOUNTAIN_LOW:
continue
sources.append([sx, sy])
# print len(sources), sources
if sources:
# print "Possible sources: ", len(sources)
source = sources[random.randint(0, len(sources))]
# print "River source: ", source
riverSourceList.append(source)
else:
# Version 2, with rainfall
# Using the wind and rainfall data, create river 'seeds' by
# flowing rainfall along paths until a 'flow' threshold is reached
# and we have a beginning of a river... trickle->stream->river->sea
# step one: Using flow direction, follow the path for each cell
# adding the previous cell's flow to the current cell's flow.
# step two: We loop through the water flow map looking for cells
# above the water flow threshold. These are our river sources and
# we mark them as rivers. While looking, the cells with no
# out-going flow, above water flow threshold and are still
# above sea level are marked as 'sources'.
for x in range(0, self.worldW - 1):
for y in range(0, self.worldH - 1):
rainFall = self.rainMap[x, y]
self.waterFlow[x, y] = rainFall
if self.waterPath[x, y] == 0:
continue # ignore cells without flow direction
cx, cy = x, y # begin with starting location
neighbourSeedFound = False
while not neighbourSeedFound: # follow flow path to where it may lead
# have we found a seed?
if self.heightmap[cx, cy] >= BIOME_ELEVATION_HILLS_LOW and \
self.heightmap[cx, cy] <= BIOME_ELEVATION_MOUNTAIN_LOW and \
self.waterFlow[cx, cy] >= 10.0:
# try not to create seeds around other seeds
for seed in riverSourceList:
sx, sy = seed
if utilities.inCircle(9, cx, cy, sx, sy):
neighbourSeedFound = True
if neighbourSeedFound:
break # we do not want seeds for neighbors
riverSourceList.append([cx, cy]) # river seed
# self.riverMap[cx,cy] = self.waterFlow[cx,cy] #temp: mark it on map to see 'seed'
break
# no path means dead end...
if self.waterPath[cx, cy] == 0:
break # break out of loop
# follow path, add water flow from previous cell
dx, dy = DIR_NEIGHBORS_CENTER[self.waterPath[cx, cy]]
nx, ny = cx + dx, cy + dy # calculate next cell
self.waterFlow[nx, ny] += rainFall
cx, cy = nx, ny # set current cell to next cell
return riverSourceList