protocols/vk-gen/appendices/VK_KHR_sampler_mirror_clamp_to_edge.txt

// Copyright (c) 2014-2018 Khronos Group. This work is licensed under a
// Creative Commons Attribution 4.0 International License; see
// http://creativecommons.org/licenses/by/4.0/

include::meta/VK_KHR_sampler_mirror_clamp_to_edge.txt[]

*Last Modified Date*::
    2016-02-16
*Contributors*::
  - Tobias Hector, Imagination Technologies

`VK_KHR_sampler_mirror_clamp_to_edge` extends the set of sampler address
modes to include an additional mode
(ename:VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE) that effectively uses a
texture map twice as large as the original image in which the additional
half of the new image is a mirror image of the original image.

This new mode relaxes the need to generate images whose opposite edges match
by using the original image to generate a matching "`mirror image`".
This mode allows the texture to be mirrored only once in the negative s, t,
and r directions.

=== New Enum Constants

  * Extending elink:VkSamplerAddressMode:
  ** ename:VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE

=== Example

Creating a sampler with the new address mode in each dimension


[source,c++]
----------------------------------------
    VkSamplerCreateInfo createInfo =
    {
        VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO // sType
        // Other members set to application-desired values
    };

    createInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
    createInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
    createInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;

    VkSampler sampler;
    VkResult result = vkCreateSampler(
        device,
        &createInfo,
        &sampler);
----------------------------------------

=== Version History

 * Revision 1, 2016-02-16 (Tobias Hector)
   - Initial draft