public
class
ETC1
extends Object
java.lang.Object | |
↳ | android.opengl.ETC1 |
Methods for encoding and decoding ETC1 textures.
The standard for the ETC1 texture format can be found at http://www.khronos.org/registry/gles/extensions/OES/OES_compressed_ETC1_RGB8_texture.txt
The PKM file format is of a 16-byte header that describes the image bounds followed by the encoded ETC1 texture data.
See also:
Constants | |
---|---|
int |
DECODED_BLOCK_SIZE
Size in bytes of a decoded block. |
int |
ENCODED_BLOCK_SIZE
Size in bytes of an encoded block. |
int |
ETC1_RGB8_OES
Accepted by the internalformat parameter of glCompressedTexImage2D. |
int |
ETC_PKM_HEADER_SIZE
Size of a PKM file header, in bytes. |
Public constructors | |
---|---|
ETC1()
|
Public methods | |
---|---|
static
void
|
decodeBlock(Buffer in, Buffer out)
Decode a block of pixels. |
static
void
|
decodeImage(Buffer in, Buffer out, int width, int height, int pixelSize, int stride)
Decode an entire image. |
static
void
|
encodeBlock(Buffer in, int validPixelMask, Buffer out)
Encode a block of pixels. |
static
void
|
encodeImage(Buffer in, int width, int height, int pixelSize, int stride, Buffer out)
Encode an entire image. |
static
void
|
formatHeader(Buffer header, int width, int height)
Format a PKM header |
static
int
|
getEncodedDataSize(int width, int height)
Return the size of the encoded image data (does not include size of PKM header). |
static
int
|
getHeight(Buffer header)
Read the image height from a PKM header |
static
int
|
getWidth(Buffer header)
Read the image width from a PKM header |
static
boolean
|
isValid(Buffer header)
Check if a PKM header is correctly formatted. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
int DECODED_BLOCK_SIZE
Size in bytes of a decoded block.
Constant Value: 48 (0x00000030)
int ENCODED_BLOCK_SIZE
Size in bytes of an encoded block.
Constant Value: 8 (0x00000008)
int ETC1_RGB8_OES
Accepted by the internalformat parameter of glCompressedTexImage2D.
Constant Value: 36196 (0x00008d64)
int ETC_PKM_HEADER_SIZE
Size of a PKM file header, in bytes.
Constant Value: 16 (0x00000010)
void decodeBlock (Buffer in, Buffer out)
Decode a block of pixels.
Parameters | |
---|---|
in |
Buffer :
a native order direct buffer of size ENCODED_BLOCK_SIZE that contains the
ETC1 compressed version of the data. |
out |
Buffer :
a native order direct buffer of size DECODED_BLOCK_SIZE that will receive
the decoded data. The data represents a
4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R
value of pixel (x, y).
|
void decodeImage (Buffer in, Buffer out, int width, int height, int pixelSize, int stride)
Decode an entire image.
Parameters | |
---|---|
in |
Buffer :
native order direct buffer of the encoded data. |
out |
Buffer :
native order direct buffer of the image data. Will be written such that
pixel (x,y) is at pIn + pixelSize * x + stride * y. Must be
large enough to store entire image. |
width |
int
|
height |
int
|
pixelSize |
int :
must be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image,
3 is a GL_BYTE RGB image.
|
stride |
int
|
void encodeBlock (Buffer in, int validPixelMask, Buffer out)
Encode a block of pixels.
Parameters | |
---|---|
in |
Buffer :
a native order direct buffer of size DECODED_BLOCK_SIZE that represent a
4 x 4 square of 3-byte pixels in form R, G, B. Byte (3 * (x + 4 * y) is the R
value of pixel (x, y). |
validPixelMask |
int :
is a 16-bit mask where bit (1 << (x + y * 4)) indicates whether
the corresponding (x,y) pixel is valid. Invalid pixel color values are ignored when compressing. |
out |
Buffer :
a native order direct buffer of size ENCODED_BLOCK_SIZE that receives the
ETC1 compressed version of the data.
|
void encodeImage (Buffer in, int width, int height, int pixelSize, int stride, Buffer out)
Encode an entire image.
Parameters | |
---|---|
in |
Buffer :
a native order direct buffer of the image data. Formatted such that
pixel (x,y) is at pIn + pixelSize * x + stride * y; |
width |
int
|
height |
int
|
pixelSize |
int :
must be 2 or 3. 2 is an GL_UNSIGNED_SHORT_5_6_5 image,
3 is a GL_BYTE RGB image.
|
stride |
int
|
out |
Buffer :
a native order direct buffer of the encoded data.
Must be large enough to store entire encoded image. |
void formatHeader (Buffer header, int width, int height)
Format a PKM header
Parameters | |
---|---|
header |
Buffer :
native order direct buffer of the header. |
width |
int :
the width of the image in pixels. |
height |
int :
the height of the image in pixels.
|
int getEncodedDataSize (int width, int height)
Return the size of the encoded image data (does not include size of PKM header).
Parameters | |
---|---|
width |
int
|
height |
int
|
Returns | |
---|---|
int |
int getHeight (Buffer header)
Read the image height from a PKM header
Parameters | |
---|---|
header |
Buffer :
native order direct buffer of the header.
|
Returns | |
---|---|
int |
int getWidth (Buffer header)
Read the image width from a PKM header
Parameters | |
---|---|
header |
Buffer :
native order direct buffer of the header.
|
Returns | |
---|---|
int |
boolean isValid (Buffer header)
Check if a PKM header is correctly formatted.
Parameters | |
---|---|
header |
Buffer :
native order direct buffer of the header.
|
Returns | |
---|---|
boolean |