Buffer

Each of the source streams must have a matching stream in the destination buffer. The streams must match in both type and size. The source and destination buffer can be the same.

PARAMETERS

dst -

buffer the destination buffer

dstoffset -

number the offset to start copying data to

src -

buffer the source data buffer

srcoffset -

number the offset to start copying data from

count -

number the number of elements to copy

EXAMPLES

How to copy elements (e.g. vertices) from one buffer to another

-- copy entire buffer
buffer.copy_buffer(dstbuffer, 0, srcbuffer, 0, #srcbuffer)

-- copy last 10 elements to the front of another buffer
buffer.copy_buffer(dstbuffer, 0, srcbuffer, #srcbuffer - 10, 10)

buffer.copy_stream()

copies data from one stream to another

Copy a specified amount of data from one stream to another.

The value type and size must match between source and destination streams. The source and destination streams can be the same.

PARAMETERS

dst -

bufferstream the destination stream

dstoffset -

number the offset to start copying data to (measured in value type)

src -

bufferstream the source data stream

srcoffset -

number the offset to start copying data from (measured in value type)

count -

number the number of values to copy (measured in value type)

EXAMPLES

How to update a texture of a sprite:

-- copy entire stream
local srcstream = buffer.get_stream(srcbuffer, hash("xyz"))
local dststream = buffer.get_stream(dstbuffer, hash("xyz"))
buffer.copy_stream(dststream, 0, srcstream, 0, #srcstream)

buffer.create()

creates a new buffer

Create a new data buffer containing a specified set of streams. A data buffer can contain one or more streams with typed data. This is useful for managing compound data, for instance a vertex buffer could contain separate streams for vertex position, color, normal etc.

PARAMETERS

element_count -

number The number of elements the buffer should hold

declaration -

table A table where each entry (table) describes a stream

hash | string name: The name of the stream
constant type: The data type of the stream
number count: The number of values each element should hold

EXAMPLES

How to create and initialize a buffer

function init(self)
  local size = 128
  self.image = buffer.create( size * size, { {name=hash("rgb"), type=buffer.VALUE_TYPE_UINT8, count=3 } })
  self.imagestream = buffer.get_stream(self.image, hash("rgb"))

  for y=0,self.height-1 do
     for x=0,self.width-1 do
         local index = y * self.width * 3 + x * 3 + 1
         self.imagestream[index + 0] = self.r
         self.imagestream[index + 1] = self.g
         self.imagestream[index + 2] = self.b
     end
  end

buffer.get_bytes()

gets data from a stream

Get a copy of all the bytes from a specified stream as a Lua string.

PARAMETERS

buffer -

buffer the source buffer

stream_name -

hash the name of the stream

RETURN

data -

string the buffer data as a Lua string

buffer.get_stream()

gets a stream from a buffer

Get a specified stream from a buffer.

PARAMETERS

buffer -

buffer the buffer to get the stream from

stream_name -

hash | string the stream name

RETURN

stream -

bufferstream the data stream