write_image

Write color value to location in the 1D or 2D image object.

void write_imagef ( image2d_t image,
  int2 coord,
  float4 color)
void write_imagei ( image2d_t image,
  int2 coord,
  int4 color)
void write_imageui ( image2d_t image,
  int2 coord,
  unsigned int4 color)

Description

Write color value to location specified by coordinate (x, y) in the 1D or 2D image object specified by image. Appropriate data format conversion to the specified image format is done before writing the color value. x and y are considered to be unnormalized coordinates and must be in the range 0... image width - 1, and 0... image height - 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, or 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, or CL_UNSIGNED_INT32.

The read_imagef calls that take integer coordinates must use a sampler with filter mode set to CLK_FILTER_NEAREST, normalized coordinates set to CLK_NORMALIZED_COORDS_FALSE and addressing mode set to CLK_ADDRESS_CLAMP_TO_EDGE, CLK_ADDRESS_CLAMP or CLK_ADDRESS_NONE; otherwise the values returned are undefined.

The behavior of write_imagef, write_imagei and write_imageui 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.

Notes

The following table describes the mapping of the number of channels of an image element to the appropriate components in the float4, int4 or unsigned int4 vector data type for the color values returned by read_image{f|i|ui} or supplied to write_image{f|i|ui}. The unmapped components will be set to 0.0 for red, green and blue channels and will be set to 1.0 for the alpha channel.

Channel Order float4, int4 or unsigned int4 components of channel data
CL_R (r, 0.0, 0.0, 1.0)
CL_A (0.0, 0.0, 0.0, a)
CL_RG (r, g, 0.0, 1.0)
CL_RA (r, 0.0, 0.0, a)
CL_RGB (r, g, b, 1.0)
CL_RGBA, CL_BGRA, CL_ARGB (r, g, b, a)
CL_INTENSITY (I, I, I, I)
CL_LUMINANCE (L, L, L, 1.0)

Specification

OpenCL Specification

Also see

Image Functions

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