def getMissingHgtFiles(self):
"""
Returns the list of missing .hgt files
"""
latIntervals = self.latIntervals
lonIntervals = self.lonIntervals
missingFiles = []
for latInterval in latIntervals:
# latitude of the lower-left corner of the .hgt tile
_lat = math.floor(latInterval[0])
for lonInterval in lonIntervals:
# longitude of the lower-left corner of the .hgt tile
_lon = math.floor(lonInterval[0])
hgtFileName = os.path.join(self.terrainDir, Terrain.getHgtFileName(_lat, _lon))
# check if the .hgt file exists
if not os.path.isfile(hgtFileName):
missingFiles.append(hgtFileName)
return missingFiles
def buildTerrain(self, verts, indices, heightOffset):
"""
The method fills verts and indices lists with values
verts is a list of vertices
indices is a list of tuples; each tuple is composed of 3 indices of verts that define a triangle
Returns the minimal height
"""
latIntervals = self.latIntervals
lonIntervals = self.lonIntervals
size = self.terrainSize
makeQuads = (self.terrainPrimitiveType == "quad")
minHeight = 32767
vertsCounter = 0
# we have an extra row for the first latitude interval
firstLatInterval = 1
# initialize the array of vertCounter values
lonIntervalVertsCounterValues = []
for lonInterval in lonIntervals:
lonIntervalVertsCounterValues.append(None)
for latInterval in latIntervals:
# latitude of the lower-left corner of the .hgt tile
_lat = math.floor(latInterval[0])
# vertical indices that limit the active .hgt tile area
y1 = math.floor( size * (latInterval[0] - _lat) )
y2 = math.ceil( size * (latInterval[1] - _lat) ) + firstLatInterval - 1
# we have an extra column for the first longitude interval
firstLonInterval = 1
for lonIntervalIndex,lonInterval in enumerate(lonIntervals):
# longitude of the lower-left corner of the .hgt tile
_lon = math.floor(lonInterval[0])
# horizontal indices that limit the active .hgt tile area
x1 = math.floor( size * (lonInterval[0] - _lon) ) + 1 - firstLonInterval
x2 = math.ceil( size * (lonInterval[1] - _lon) )
xSize = x2-x1
filepath = os.path.join(self.terrainDir, Terrain.getHgtFileName(_lat, _lon))
with gzip.open(filepath, "rb") as f:
for y in range(y2, y1-1, -1):
# set the file object position at y, x1
f.seek( 2*((size-y)*(size+1) + x1) )
for x in range(x1, x2+1):
lat = _lat + y/size
lon = _lon + x/size
xy = self.projection.fromGeographic(lat, lon)
# read two bytes and convert them
buf = f.read(2)
# ">h" is a signed two byte integer
z = struct.unpack('>h', buf)[0]
if z==self.voidValue:
z = self.voidSubstitution
if heightOffset is None and z<minHeight:
minHeight = z
# add a new vertex to the verts array
verts.append([xy[0], xy[1], z])
if not firstLatInterval and y==y2:
topNeighborIndex = lonIntervalVertsCounterValues[lonIntervalIndex] + x - x1
if x!=x1:
if makeQuads:
indices.append((vertsCounter, topNeighborIndex, topNeighborIndex-1, vertsCounter-1))
else: # self.primitiveType == "triangle"
indices.append((vertsCounter-1, topNeighborIndex, topNeighborIndex-1))
indices.append((vertsCounter, topNeighborIndex, vertsCounter-1))
elif not firstLonInterval:
leftNeighborIndex = prevLonIntervalVertsCounter - (y2-y1)*(prevXsize+1)
leftTopNeighborIndex = topNeighborIndex-prevYsize*(x2-x1+1)-1
if makeQuads:
indices.append((vertsCounter, topNeighborIndex, leftTopNeighborIndex, leftNeighborIndex))
else: # self.primitiveType == "triangle"
indices.append((leftNeighborIndex, topNeighborIndex, leftTopNeighborIndex))
indices.append((vertsCounter, topNeighborIndex, leftNeighborIndex))
elif not firstLonInterval and x==x1:
if y!=y2:
leftNeighborIndex = prevLonIntervalVertsCounter - (y-y1)*(prevXsize+1)
topNeighborIndex = vertsCounter-xSize-1
leftTopNeighborIndex = leftNeighborIndex-prevXsize-1
if makeQuads:
indices.append((vertsCounter, topNeighborIndex, leftTopNeighborIndex, leftNeighborIndex))
else: # self.primitiveType == "triangle"
indices.append((leftNeighborIndex, topNeighborIndex, leftTopNeighborIndex))
indices.append((vertsCounter, topNeighborIndex, leftNeighborIndex))
elif x>x1 and y<y2:
topNeighborIndex = vertsCounter-xSize-1
leftTopNeighborIndex = vertsCounter-xSize-2
if makeQuads:
indices.append((vertsCounter, topNeighborIndex, leftTopNeighborIndex, vertsCounter-1))
else: # self.primitiveType == "triangle"
indices.append((vertsCounter-1, topNeighborIndex, leftTopNeighborIndex))
indices.append((vertsCounter, topNeighborIndex, vertsCounter-1))
vertsCounter += 1
if firstLonInterval:
# we don't have an extra column anymore
firstLonInterval = 0
# remembering vertsCounter value
prevLonIntervalVertsCounter = vertsCounter - 1
lonIntervalVertsCounterValues[lonIntervalIndex] = prevLonIntervalVertsCounter - xSize
# remembering xSize
prevXsize = xSize
if firstLatInterval:
firstLatInterval = 0
# remembering ySize
prevYsize = y2-y
return minHeight if heightOffset is None else heightOffset
