class Hunk:
"""
Helper class to wrap low-level VBO objects with data caches, change ranges,
and flushing of the changed range to the hunk VBO in graphics card RAM.
"""
def __init__(self, hunkNumber, nVertices, nCoords):
"""
hunkNumber - The index of this hunk, e.g. 0 for the first in a group.
Specifies the range of IDs residing in this hunk.
nVertices - The number of vertices in the primitive drawing pattern.
nCoords - The number of entries per attribute, e.g. 1 for float, 3 for
vec3, 4 for vec4, so the right size storage can be allocated.
"""
self.nVertices = nVertices
self.hunkNumber = hunkNumber
self.nCoords = nCoords
self.VBO = GLBufferObject(
GL_ARRAY_BUFFER_ARB,
# Per-vertex attributes are all multiples (1-4) of Float32.
HUNK_SIZE * self.nVertices * self.nCoords * BYTES_PER_FLOAT,
GL_STATIC_DRAW)
# Low- and high-water marks to optimize for sending a range of data.
self.unchanged()
return
def unchanged(self):
"""
Mark a Hunk as unchanged. (Empty or flushed.)
"""
self.low = self.high = 0
return
def changedRange(self, chgLowID, chgHighID):
"""
Record a range of data changes, for later flushing.
chgLowID and chgHighID are primitive IDs, possibly spanning many hunks.
The high end is the index of the one *after* the end of the range, as
usual in Python.
"""
(lowHunk, lowIndex) = decodePrimID(chgLowID)
(highHunk, highIndex) = decodePrimID(chgHighID)
if self.hunkNumber < lowHunk or self.hunkNumber > highHunk:
return # This hunk is not in the hunk range.
if lowHunk < self.hunkNumber:
self.low = 0
else:
self.low = min(self.low, lowIndex) # Maybe extend the range.
pass
if highHunk > self.hunkNumber:
self.high = HUNK_SIZE
else:
self.high = max(self.high, highIndex) # Maybe extend the range.
pass
return
def flush(self, allData):
"""
Update a changed range of the data that applies to this hunk, sending it
to the Buffer Object in graphics card RAM.
allData - List of data blocks for the whole hunk-list. We'll extract
just the part relevant to the changed part of this particular hunk.
Internally, the data is a list, block-indexed by primitive ID, but
replicated in block sublists by a factor of self.nVertices to match the
vertex buffer size. What reaches the attribute VBO is automatically
flattened into a sequence.
"""
rangeSize = self.high - self.low
assert rangeSize >= 0
if rangeSize == 0:
# Nothing to do.
return
lowID = (self.hunkNumber * HUNK_SIZE) + self.low
highID = (self.hunkNumber * HUNK_SIZE) + self.high
# Send all or part of the Python data to C.
C_data = numpy.array(allData[lowID:highID], dtype=numpy.float32)
if rangeSize == HUNK_SIZE:
# Special case to send the whole Hunk's worth of data.
self.VBO.updateAll(C_data)
else:
# Send a portion of the HunkBuffer, with byte offset within the VBO.
# (Per-vertex attributes are all multiples (1-4) of Float32.)
offset = self.low * self.nVertices * self.nCoords * BYTES_PER_FLOAT
self.VBO.update(offset, C_data)
pass
self.unchanged() # Now we're in sync.
return
pass # End of class HunkBuffer.
class Hunk:
"""
Helper class to wrap low-level VBO objects with data caches, change ranges,
and flushing of the changed range to the hunk VBO in graphics card RAM.
"""
def __init__(self, hunkNumber, nVertices, nCoords):
"""
hunkNumber - The index of this hunk, e.g. 0 for the first in a group.
Specifies the range of IDs residing in this hunk.
nVertices - The number of vertices in the primitive drawing pattern.
nCoords - The number of entries per attribute, e.g. 1 for float, 3 for
vec3, 4 for vec4, so the right size storage can be allocated.
"""
self.nVertices = nVertices
self.hunkNumber = hunkNumber
self.nCoords = nCoords
self.VBO = GLBufferObject(
GL_ARRAY_BUFFER_ARB,
# Per-vertex attributes are all multiples (1-4) of Float32.
HUNK_SIZE * self.nVertices * self.nCoords * BYTES_PER_FLOAT,
GL_STATIC_DRAW)
# Low- and high-water marks to optimize for sending a range of data.
self.unchanged()
return
def unchanged(self):
"""
Mark a Hunk as unchanged. (Empty or flushed.)
"""
self.low = self.high = 0
return
def changedRange(self, chgLowID, chgHighID):
"""
Record a range of data changes, for later flushing.
chgLowID and chgHighID are primitive IDs, possibly spanning many hunks.
The high end is the index of the one *after* the end of the range, as
usual in Python.
"""
(lowHunk, lowIndex) = decodePrimID(chgLowID)
(highHunk, highIndex) = decodePrimID(chgHighID)
if self.hunkNumber < lowHunk or self.hunkNumber > highHunk:
return # This hunk is not in the hunk range.
if lowHunk < self.hunkNumber:
self.low = 0
else:
self.low = min(self.low, lowIndex) # Maybe extend the range.
pass
if highHunk > self.hunkNumber:
self.high = HUNK_SIZE
else:
self.high = max(self.high, highIndex) # Maybe extend the range.
pass
return
def flush(self, allData):
"""
Update a changed range of the data that applies to this hunk, sending it
to the Buffer Object in graphics card RAM.
allData - List of data blocks for the whole hunk-list. We'll extract
just the part relevant to the changed part of this particular hunk.
Internally, the data is a list, block-indexed by primitive ID, but
replicated in block sublists by a factor of self.nVertices to match the
vertex buffer size. What reaches the attribute VBO is automatically
flattened into a sequence.
"""
rangeSize = self.high - self.low
assert rangeSize >= 0
if rangeSize == 0:
# Nothing to do.
return
lowID = (self.hunkNumber * HUNK_SIZE) + self.low
highID = (self.hunkNumber * HUNK_SIZE) + self.high
# Send all or part of the Python data to C.
C_data = numpy.array(allData[lowID:highID], dtype=numpy.float32)
if rangeSize == HUNK_SIZE:
# Special case to send the whole Hunk's worth of data.
self.VBO.updateAll(C_data)
else:
# Send a portion of the HunkBuffer, with byte offset within the VBO.
# (Per-vertex attributes are all multiples (1-4) of Float32.)
offset = self.low * self.nVertices * self.nCoords * BYTES_PER_FLOAT
self.VBO.update(offset, C_data)
pass
self.unchanged() # Now we're in sync.
return
pass # End of class HunkBuffer.
