[[VK_NV_sample_mask_override_coverage]]
== VK_NV_sample_mask_override_coverage
*Name String*::
    VK_NV_sample_mask_override_coverage
*Extension Type*::
    Device extension
*Registered Extension Number*::
    95
*Status*::
    Complete
*Last Modified Data*::
    2016-12-08
*Revision*::
    1
*IP Status*::
    No known IP claims.
*Dependencies*::
    - This extension is written against version 1.0 of the Vulkan API.
    - This extension requires Vulkan 1.0.
    - This extension requires the
      https://www.khronos.org/registry/spir-v/extensions/NV/SPV_NV_sample_mask_override_coverage.html[+SPV_NV_sample_mask_override_coverage+]
      SPIR-V extension.
    - This extension requires the
      https://www.opengl.org/registry/specs/NV/sample_mask_override_coverage.txt[+GL_NV_sample_mask_override_coverage+]
      extension for GLSL source languages.
*Contributors*::
    - Daniel Koch, NVIDIA
    - Jeff Bolz, NVIDIA
*Contact*::
    - Piers Daniell (pdaniell 'at' nvidia.com)
*Overview*::
+
--
This extension adds support for the following SPIR-V extension in Vulkan:

  * SPV_NV_sample_mask_override_coverage

The extension provides access to the code:OverrideCoverageNV decoration
under the code:SampleMaskOverrideCoverageNV capability.
Adding this decoration to a variable with the code:SampleMask builtin
decoration allows the shader to modify the coverage mask and affect which
samples are used to process the fragment.

When using GLSL source-based shader languages, the code:override_coverage
layout qualifier from GL_NV_sample_mask_override_coverage maps to the
code:OverrideCoverageNV decoration.
To use the code:override_coverage layout qualifier in GLSL the
GL_NV_sample_mask_override_coverage extension must be enabled.
Behavior is described in the GL_NV_sample_mask_override_coverage extension
spec.
--

=== New Object Types
None.

=== New Enum Constants
None.

=== New Enums
None.

=== New Structures
None.

=== New Functions
None.

=== New Built-In Variables
None.

=== New Variable Decoration
  * <<interfaces-builtin-variables-samplemask,OverrideCoverageNV in
    SampleMask>>

=== New SPIR-V Capabilities
  * <<spirvenv-capabilities-table-samplemaskoverridecoverage,SampleMaskOverrideCoverageNV>>

=== Issues
None.

=== Version History
  * Revision 1, 2016-12-08 (Piers Daniell)
    - Internal revisions
