imageDescriptor(3) The image descriptor structure describes the type and dimensions of the image or image array and is defined as:

typedef struct _cl_image_desc { cl_mem_object_type image_type; size_t image_width; size_t image_height; size_t image_depth; size_t image_array_size; size_t image_row_pitch; size_t image_slice_pitch; cl_uint num_mip_levels; cl_uint num_samples; cl_mem buffer; } cl_image_desc;

MEMBERS

image_type

Describes the image type and must be either CL_MEM_OBJECT_IMAGE1D, CL_MEM_OBJECT_IMAGE1D_BUFFER, CL_MEM_OBJECT_IMAGE1D_ARRAY, CL_MEM_OBJECT_IMAGE2D, CL_MEM_OBJECT_IMAGE2D_ARRAY, or CL_MEM_OBJECT_IMAGE3D.

image_width

The width of the image in pixels. For a 2D image and image array, the image width must be ≤ CL_DEVICE_IMAGE2D_MAX_WIDTH. For a 3D image, the image width must be ≤ CL_DEVICE_IMAGE3D_MAX_WIDTH. For a 1D image buffer, the image width must be ≤ CL_DEVICE_IMAGE_MAX_BUFFER_SIZE. For a 1D image and 1D image array, the image width must be ≤ CL_DEVICE_IMAGE2D_MAX_WIDTH.

image_height

The height of the image in pixels. This is only used if the image is a 2D, 3D or 2D image array. For a 2D image or image array, the image height must be ≤ CL_DEVICE_IMAGE2D_MAX_HEIGHT. For a 3D image, the image height must be ≤ CL_DEVICE_IMAGE3D_MAX_HEIGHT.

image_depth

The depth of the image in pixels. This is only used if the image is a 3D image and must be a value ≥ 1 and ≤ CL_DEVICE_IMAGE3D_MAX_DEPTH.

image_array_size

The number of images in the image array. This is only used if the image is a 1D or 2D image array. The values for image_array_size, if specified, must be a value ≥ 1 and ≤ CL_DEVICE_IMAGE_MAX_ARRAY_SIZE.

Note that reading and writing 2D image arrays from a kernel with image_array_size = 1 may be lower performance than 2D images.

image_row_pitch

The scan-line pitch in bytes. This must be 0 if host_ptr is NULL and can be either 0 or ≥ image_width * size of element in bytes if host_ptr is not NULL. If host_ptr is not NULL and image_row_pitch = 0, image_row_pitch is calculated as image_width * size of element in bytes. If image_row_pitch is not 0, it must be a multiple of the image element size in bytes.

image_slice_pitch

The size in bytes of each 2D slice in the 3D image or the size in bytes of each image in a 1D or 2D image array. This must be 0 if host_ptr is NULL. If host_ptr is not NULL, image_slice_pitch can be either 0 or ≥ image_row_pitch * image_height for a 2D image array or 3D image and can be either 0 or ≥ image_row_pitch for a 1D image array. If host_ptr is not NULL and image_slice_pitch = 0, image_slice_pitch is calculated as image_row_pitch * image_height for a 2D image array or 3D image and image_row_pitch for a 1D image array. If image_slice_pitch is not 0, it must be a multiple of the image_row_pitch.

num_mip_level, num_samples

, Must be 0.

buffer

Refers to a valid buffer memory object if image_type is CL_MEM_OBJECT_IMAGE1D_BUFFER. Otherwise it must be NULL. For a 1D image buffer object, the image pixels are taken from the buffer object's data store. When the contents of a buffer object's data store are modified, those changes are reflected in the contents of the 1D image buffer object and vice-versa at corresponding sychronization points. The image_width * size of element in bytes must be ≤ size of buffer object data store.

NOTE

Concurrent reading from, writing to and copying between both a buffer object and 1D image buffer object associated with the buffer object is undefined. Only reading from both a buffer object and 1D image buffer object associated with the buffer object is defined.

SPECIFICATION

m[blue]OpenCL Specificationm[][1]

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 95, section 5.3.1.2 - Image Descriptor