NAME¶
cl_image_format - The image format descriptor structure is defined as:
typedef struct _cl_image_format { cl_channel_order image_channel_order;
cl_channel_type image_channel_data_type; } cl_image_format; |
MEMBERS¶
image_channel_order
Specifies the number of channels and the channel layout i.e. the memory layout
in which channels are stored in the image. Valid values are described in the
table below.
Format |
Description |
CL_R, CL_Rx, or CL_A |
|
CL_INTENSITY |
This format can only be used if channel data type = CL_UNORM_INT8,
CL_UNORM_INT16, CL_SNORM_INT8, CL_SNORM_INT16, CL_HALF_FLOAT, or
CL_FLOAT. |
CL_LUMINANCE |
This format can only be used if channel data type = CL_UNORM_INT8,
CL_UNORM_INT16, CL_SNORM_INT8, CL_SNORM_INT16, CL_HALF_FLOAT, or
CL_FLOAT. |
CL_RG, CL_RGx, or CL_RA |
|
CL_RGB or CL_RGBx |
This format can only be used if channel data type = CL_UNORM_SHORT_565,
CL_UNORM_SHORT_555 or CL_UNORM_INT101010. |
CL_RGBA |
|
CL_ARGB, CL_BGRA. |
This format can only be used if channel data type = CL_UNORM_INT8,
CL_SNORM_INT8, CL_SIGNED_INT8 or CL_UNSIGNED_INT8. |
image_channel_data_type
Describes the size of the channel data type. The number of bits per element
determined by the
image_channel_data_type and
image_channel_order must be a power of two. The list of supported
values is described in the table below.
Image Channel Data Type |
Description |
CL_SNORM_INT8 |
Each channel component is a normalized signed 8-bit integer value. |
CL_SNORM_INT16 |
Each channel component is a normalized signed 16-bit integer value. |
CL_UNORM_INT8 |
Each channel component is a normalized unsigned 8-bit integer
value. |
CL_UNORM_INT16 |
Each channel component is a normalized unsigned 16-bit integer
value. |
CL_UNORM_SHORT_565 |
Represents a normalized 5-6-5 3-channel RGB image. The channel order
must be CL_RGB or CL_RGBx. |
CL_UNORM_SHORT_555 |
Represents a normalized x-5-5-5 4-channel xRGB image. The channel order
must be CL_RGB or CL_RGBx. |
CL_UNORM_INT_101010 |
Represents a normalized x-10-10-10 4-channel xRGB image. The channel
order must be CL_RGB or CL_RGBx. |
CL_SIGNED_INT8 |
Each channel component is an unnormalized signed 8-bit integer
value. |
CL_SIGNED_INT16 |
Each channel component is an unnormalized signed 16-bit integer
value. |
CL_SIGNED_INT32 |
Each channel component is an unnormalized signed 32-bit integer
value. |
CL_UNSIGNED_INT8 |
Each channel component is an unnormalized unsigned 8-bit integer
value. |
CL_UNSIGNED_INT16 |
Each channel component is an unnormalized unsigned 16-bit integer
value. |
CL_UNSIGNED_INT32 |
Each channel component is an unnormalized unsigned 32-bit integer
value. |
CL_HALF_FLOAT |
Each channel component is a 16-bit half-float value. |
CL_FLOAT |
Each channel component is a single precision floating-point value. |
DESCRIPTION¶
For example, to specify a normalized unsigned 8-bit / channel RGBA image:
image_channel_order = CL_RGBA
image_channel_data_type = CL_UNORM_INT8
image_channel_data_type values of
CL_UNORM_SHORT_565,
CL_UNORM_SHORT_555 and
CL_UNORM_INT_101010 are special cases of
packed image formats where the channels of each element are packed into a
single unsigned short or unsigned int. For these special packed image formats,
the channels are normally packed with the first channel in the most
significant bits of the bitfield, and successive channels occupying
progressively less significant locations. For
CL_UNORM_SHORT_565, R is
in bits 15:11, G is in bits 10:5 and B is in bits 4:0. For
CL_UNORM_SHORT_555, bit 15 is undefined, R is in bits 14:10, G in bits
9:5 and B in bits 4:0. For
CL_UNORM_INT_101010, bits 31:30 are
undefined, R is in bits 29:20, G in bits 19:10 and B in bits 9:0.
OpenCL implementations must maintain the minimum precision specified by the
number of bits in image_channel_data_type. If the image format specified by
image_channel_order, and image_channel_data_type cannot be supported by the
OpenCL implementation, then the call to
clCreateImage(3clc) will return
a NULL memory object.
SPECIFICATION¶
OpenCL Specification[1]
SEE ALSO¶
imageDescriptor(3clc),
EXTENSION(3clc),
clGetSupportedImageFormats(3clc),
clCreateImage(3clc)
AUTHORS¶
The Khronos Group
COPYRIGHT¶
Copyright © 2007-2010 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction,
including without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to permit
persons to whom the Materials are furnished to do so, subject to the condition
that this copyright notice and permission notice shall be included in all
copies or substantial portions of the Materials.
NOTES¶
- 1.
- OpenCL Specification
page 92, section 5.3.1.1 - Image Format Descriptor