write_image

Write color value to location in a 2D image object.

void write_imagef ( image2d_t  image ,
  int2  coord ,
  float4  color )
void write_imagef ( image2d_array_t  image ,
  int4  coord ,
  float4  color )
void write_imagei ( image2d_t  image ,
  int2  coord ,
  int4  color )
void write_imagei ( image2d_array_t  image ,
  int4  coord ,
  int4  color )
void write_imageui ( image2d_t  image ,
  int2  coord ,
  uint4  color )
void write_imageui ( image2d_array_t  image ,
  int4  coord ,
  uint4  color )
void write_imageh ( image2d_t  image ,
  int2  coord ,
  half4  color )
void write_imageh ( image2d_array_t  image ,
  int4  coord ,
  half4  color )

Description

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 functions 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, or CL_UNSIGNED_INT32.

An application that wants to use half and halfn types will need to include the #pragma OPENCL EXTENSION cl_khr_fp16 : enable directive.

write_imageh 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 or CL_HALF_FLOAT.

Functions that take image2d_t

For the functions that take an image_2d_t image, write color value to location specified by coord.xy in the 2D image object specified by image. Appropriate data format conversion to the specified image format is done before writing the color value. coord.x and coord.y are considered to be unnormalized coordinates and must be in the range 0 … image width - 1, and 0 … image height - 1.

For functions that take image_2d_t, the behavior of write_imagef, write_imagei, write_imageui, and write_imageh for image objects created with image_channel_data_type values not specified in the description above or with (x, y) coordinate values that are not in the range (0 … image width - 1, 0 … image height - 1), respectively, is undefined.

Functions that take image2d_array_t

For the functions that take an image_2d_array_t image, write color value to location specified by coord.xy in the 2D image identified by coord.z in the 2D image array 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 width - 1, 0 … image height - 1 and 0 … image number of layers - 1.

For functions that take image_2d_array_t, the behavior of write_imagef, write_imagei, write_imageui, and write_imageh for image objects created 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), respectively, is undefined.

Notes

The built-in functions defined in this section can only be used with image memory objects. An image memory object can be accessed by specific function calls that read from and/or write to specific locations in the image.

Image memory objects that are being read by a kernel should be declared with the __read_only qualifier. write_image calls to image memory objects declared with the __read_only qualifier will generate a compilation error. Image memory objects that are being written to by a kernel should be declared with the __write_only qualifier. read_image calls to image memory objects declared with the __write_only qualifier will generate a compilation error. read_image and write_image calls to the same image memory object in a kernel are not supported.

The read_image calls returns a four component floating-point, integer or unsigned integer color value. The color values returned by read_image are identified as x, y, z, w where x refers to the red component, y refers to the green component, z refers to the blue component and w refers to the alpha component.

Specification

OpenCL Specification

Also see

Image Functions

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