Lua

Defold

Extension

Version

Buffer API documentation

Version: beta

FUNCTION
buffer.create()	creates a new buffer
buffer.get_stream()	gets a stream from a buffer
buffer.copy_stream()	copies data from one stream to another
buffer.copy_buffer()	copies one buffer to another
buffer.get_bytes()	gets data from a stream
buffer.set_metadata()	set a metadata entry on a buffer
buffer.get_metadata()	retrieve a metadata entry from a buffer

CONSTANT
buffer.VALUE_TYPE_UINT8	uint8
buffer.VALUE_TYPE_UINT16	uint16
buffer.VALUE_TYPE_UINT32	uint32
buffer.VALUE_TYPE_UINT64	uint64
buffer.VALUE_TYPE_INT8	int8
buffer.VALUE_TYPE_INT16	int16
buffer.VALUE_TYPE_INT32	int32
buffer.VALUE_TYPE_INT64	int64
buffer.VALUE_TYPE_FLOAT32	float32

Functions

buffer.create()

buffer.create(element_count,declaration)

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

RETURNS

buffer buffer the new buffer

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_stream()

buffer.get_stream(buffer,stream_name)

Get a specified stream from a buffer.

PARAMETERS

`buffer`	`buffer`	the buffer to get the stream from
`stream_name`	`hash, string`	the stream name

RETURNS

stream bufferstream the data stream

buffer.copy_stream()

buffer.copy_stream(dst,dstoffset,src,srcoffset,count)

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.copy_buffer()

buffer.copy_buffer(dst,dstoffset,src,srcoffset,count)

Copy all data streams from one buffer to another, element wise. 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.get_bytes()

buffer.get_bytes(buffer,stream_name)

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

RETURNS

data string the buffer data as a Lua string

buffer.set_metadata()

buffer.set_metadata(buf,metadata_name,values,value_type)

Creates or updates a metadata array entry on a buffer. The value type and count given when updating the entry should match those used when first creating it.

PARAMETERS

`buf`	`buffer`	the buffer to set the metadata on
`metadata_name`	`hash, string`	name of the metadata entry
`values`	`table`	actual metadata, an array of numeric values
`value_type`	`constant`	type of values when stored

EXAMPLES

How to set a metadata entry on a buffer

-- create a new metadata entry with three floats
buffer.set_metadata(buf, hash("somefloats"), {1.5, 3.2, 7.9}, buffer.VALUE_TYPE_FLOAT32)
-- ...
-- update to a new set of values
buffer.set_metadata(buf, hash("somefloats"), {-2.5, 10.0, 32.2}, buffer.VALUE_TYPE_FLOAT32)

buffer.get_metadata()

buffer.get_metadata(buf,metadata_name)

Get a named metadata entry from a buffer along with its type.

PARAMETERS

`buf`	`buffer`	the buffer to get the metadata from
`metadata_name`	`hash, string`	name of the metadata entry

RETURNS

`values`	table	table of metadata values or nil if the entry does not exist
`value_type`	constant	numeric type of values or nil

EXAMPLES

How to get a metadata entry from a buffer

-- retrieve a metadata entry named "somefloats" and its nomeric type
local values, type = buffer.get_metadata(buf, hash("somefloats"))
if metadata then print(#metadata.." values in 'somefloats'") end

Buffer API documentation

Functions

Constants