cl_khr_3d_image_writes

Extension to enable writes to 3D image memory objects.

#pragma OPENCL EXTENSION cl_khr_3d_image_writes : enable

Description

OpenCL 1.0 supports 2D image memory objects that can be read or written by kernels. Reads and writes to the same 2D image memory object are not supported in a kernel. OpenCL 1.0 also supports reads to 3D image memory objects in kernels. Writes to a 3D image memory object is not allowed. The cl_khr_3d_image_writes extension implements writes to 3D image memory objects. Reads and writes to the same 3D image memory object are not allowed in a kernel.

An application that wants to use this extension to write to 3D image memory objects will need to include the #pragma OPENCL EXTENSION cl_khr_3d_image_writes : enable directive in the OpenCL program source.

The built-in functions implemented by the cl_khr_3d_image_writes extension are described in the table below.

Function Description


void write_imagef (image3d_t image,
                   int4 coord,
                   float4 color)
   
void write_imagei (image3d_t image,
                   int4 coord,
                   int4 color)
   
void write_imageui (image3d_t image,
                    int4 coord,
                    unsigned int4 color)

Write color value to location specified by coordinate (x, y, z) in the 3D image object specified by image. Appropriate data format conversion to the specified image format is done before writing the color value. coord.x, coord.y, and coord.z are considered to be unnormalized coordinates and must be in the range 0 ... image stream width - 1, 0 ... image stream height - 1 and 0 ... image stream depth - 1.

write_imagef can only be used with image objects created with image_channel_data_type set to one of the pre-defined packed formats or set to CL_SNORM_INT8, CL_UNORM_INT8, CL_SNORM_INT16, CL_UNORM_INT16, CL_HALF_FLOAT or CL_FLOAT. Appropriate data format conversion will be done to convert channel data from a floating-point value to actual data format in which the channels are stored.

write_imagei can only be used with image objects created with image_channel_data_type set to one of the following values:

CL_SIGNED_INT8,
CL_SIGNED_INT16, and
CL_SIGNED_INT32.

write_imageui can only be used with image objects created with image_channel_data_type set to one of the following values:

CL_UNSIGNED_INT8,
CL_UNSIGNED_INT16, and
CL_UNSIGNED_INT32.

The behavior of write_imagef, write_imagei and write_imageui for image objects with image_channel_data_type values not specified in the description above or with (x, y, z) coordinate values that are not in the range (0... image width 1, 0... image height 1, 0... image depth 1) respectively is undefined.

For read-write or write-only 3D images, the minimum list of supported image formats is given by the table below:

image_num_channels  

image_channel_order  

image_channel_data_type  

4 CL_RGBA


CL_UNORM_INT8
CL_UNORM_INT16

CL_SIGNED_INT8
CL_SIGNED_INT16
CL_SIGNED_INT32

CL_UNSIGNED_INT8
CL_UNSIGNED_INT16
CL_UNSIGNED_INT32

CL_HALF_FLOAT
CL_FLOAT

4 CL_BGRA CL_UNORM_INT8

Specification

OpenCL Specification

Also see

EXTENSION, cl_image_format, Image Functions

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