WRITE_IMAGE3D(3clc)

✨ WRITE_IMAGE (3D) ✨

okay bestie, welcome to write_image from the OpenCL manual 💖 — the 3D-flavored one. This is the whole page for write_image (3D), section 3clc, and we're gonna go through every single crumb of it together. no skimming, no skipping, periodt.

---

💅 NAME 💅

write_image — write a color value to a location in a 3D image object. 🎀

and here's the whole squad of function signatures, looking all cute in a code block:

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, uint4 color);

void write_imageh(image3d_t image, int4 coord, half4 color);

four flavors, one job. slay. 🌈

---

🦋 DESCRIPTION 🦋

okay so first thing, and this is important: writing to a 3D image memory object is only supported when the cl_khr_3d_image_writes(3clc) extension is implemented. that's the vibe check. and also — reads and writes to the same 3D image memory object are not allowed in a kernel. not allowed, bestie. no cap. 💀

so if your application wants to use this extension to write to 3D image memory objects, you're gonna need to include this directive in the OpenCL program source:

#pragma OPENCL EXTENSION cl_khr_3d_image_writes(3clc) : enable

these functions write a color value to the location specified by the coordinate (x, y, z) in the 3D image object specified by image. appropriate data format conversion to the specified image format happens before the color value gets written — so it's already looking right when it lands. ✨

now, coord.x, coord.y and coord.z are considered to be unnormalized coordinates and must be in the range:

• 0 ... image width - 1 for coord.x
• 0 ... image height - 1 for coord.y
• 0 ... image depth - 1 for coord.z

🫶

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 the actual data format in which the channels are stored. it's giving glow-up, honestly. 💖

write_imagei can only be used with image objects created with image_channel_data_type set to one of these 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 these values: CL_UNSIGNED_INT8, CL_UNSIGNED_INT16, or CL_UNSIGNED_INT32. 🔥

⚠️ and now the scary part, listen up: 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. undefined!! we do not go there. 🙈

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. 🌸

⚠️ and same energy: the behavior of 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, 0 ... image depth - 1) respectively, is undefined. 💀

and one last lil' thing: an application that wants to use half and halfn types will need to include this directive:

#pragma OPENCL EXTENSION cl_khr_fp16 : enable

---

👑 SPECIFICATION 👑

OpenCL Specification[1]

that's the main character right there. ⭐

---

🌟 SEE ALSO 🌟

• imageFunctions(3clc)
• cl_khr_3d_image_writes(3clc) scalarDataTypes(3clc)

go read those next, iykyk 🧚

---

🎀 AUTHORS 🎀

The Khronos Group

kings. icons. legends. 💜

---

💖 COPYRIGHT 💖

Copyright © 2007-2011 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.

like... generous much? we love a permissive license. 🫶

---

📝 NOTES 📝

1. OpenCL Specification — page 12, section 9.4 - Writing to 3D image memory objects 📖

---

and that's the whole page, bestie, every crumb accounted for. mwah 💋

this gorgeous little number came to you from The Khronos Group, dated 01/14/2021, and it's officially WRITE_IMAGE (3D)(3clc) from the OpenCL Manual. ok bye, go write some images (the 3D kind, with the extension enabled) 🦋✨