Vulkan-Docs/appendices/VK_NVX_multiview_per_view_attributes.txt
Jon Leech f1a7c4b4f3 Change log for January 13, 2019 Vulkan 1.1.98 spec update:
* Update release number to 98.

Public Issues:

  * Fix missing markup in flink:vkDestroyPipelineLayout valid usage
    statement (pull request 882).
  * Add missing contributors for `<<VK_EXT_buffer_device_address>>` (public
    pull request 891).

Internal Issues:

  * Detect nested bullet points in valid usage blocks and warn about them
    during VUID assignment (internal issue 1382).
  * Update the style guide to document the process for reserving new bits in
    bitmask types (internal issue 1411).
  * Clarify for slink:VkApplicationInfo::pname:apiVersion and in the
    <<fundamentals-validusage-versions, Valid Usage for Newer Core
    Versions>> section when it is valid for an application to use a certain
    version of Vulkan API functionality (for an instance and for a
    device/physical device); and when the validation layers must generate an
    error (internal issue 1412).
  * Add optional <<memory-model-availability-visibility, transitive
    availability/visibility operations to the memory model, including a new
    pname:vulkanMemoryModelAvailabilityVisibilityChains feature for
    slink:VkPhysicalDeviceVulkanMemoryModelFeaturesKHR (internal issue
    1460).
  * Add the code:StorageBuffer storage class to those in the
    <<interfaces-resources-descset, Descriptor Set Interface>> (internal
    issue 1480).
  * Add missing `returnedonly` tags for a number of returned extension
    structures that can be passed in pname:pNext chains (internal issue
    1515).
  * Clean up and rearrange some spec language for
    slink:VkRenderPassCreateInfo and slink:VkAttachmentReference.txt
    (internal issue 1522).
  * Correctly round the code:OpVectorTimesScalar and
    code:OpMatrixTimesScalar SPIR-V operations in the <<Precision of core
    SPIR-V Instructions>> table (internal merge request 2996).
  * Work around cases in flink:vkCmdBeginTransformFeedbackEXT,
    flink:vkCmdEndTransformFeedbackEXT, and
    slink:VkPipelineCoverageModulationStateCreateInfoNV where an array
    parameter is `optional` but the length is not in `vk.xml`. This is an
    interim fix using `noautovalidity` + handcoded VU replacing those that
    should be autogenerated (internal issue 2944 and
    https://github.com/KhronosGroup/Vulkan-ValidationLayers/issues/480).
  * Remove redundant capability validation of the code:float16 and code:int8
    SPIR-V capabilities from the <<spirvenv-capabilities, Capabilities>>
    section, since they are already covered in the preceding table.
  * Update check_spec_links script, including validation for reference page
    open blocks. Fix errors identified by the script.
2019-01-13 05:53:27 -08:00

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include::meta/VK_NVX_multiview_per_view_attributes.txt[]
*Last Modified Date*::
2017-01-13
*IP Status*::
No known IP claims.
*Interactions and External Dependencies*::
- This extension requires the
https://www.khronos.org/registry/spir-v/extensions/NV/SPV_NVX_multiview_per_view_attributes.html[`SPV_NVX_multiview_per_view_attributes`]
SPIR-V extension.
- This extension requires the `GL_NVX_multiview_per_view_attributes`
extension for GLSL source languages.
- This extension interacts with `<<VK_NV_viewport_array2>>`.
*Contributors*::
- Jeff Bolz, NVIDIA
- Daniel Koch, NVIDIA
This extension adds a new way to write shaders to be used with multiview
subpasses, where the attributes for all views are written out by a single
invocation of the vertex processing stages.
Related SPIR-V and GLSL extensions `SPV_NVX_multiview_per_view_attributes`
and `GL_NVX_multiview_per_view_attributes` introduce per-view position and
viewport mask attributes arrays, and this extension defines how those
per-view attribute arrays are interpreted by Vulkan.
Pipelines using per-view attributes may: only execute the vertex processing
stages once for all views rather than once per-view, which reduces redundant
shading work.
A subpass creation flag controls whether the subpass uses this extension.
A subpass must: either exclusively use this extension or not use it at all.
Some Vulkan implementations only support the position attribute varying
between views in the X component.
A subpass can declare via a second creation flag whether all pipelines
compiled for this subpass will obey this restriction.
Shaders that use the new per-view outputs (e.g. code:gl_PositionPerViewNV)
must: also write the non-per-view output (code:gl_Position), and the values
written must: be such that `gl_Position =
gl_PositionPerViewNV[gl_ViewIndex]` for all views in the subpass.
Implementations are free to either use the per-view outputs or the
non-per-view outputs, whichever would be more efficient.
If `<<VK_NV_viewport_array2>>` is not also supported and enabled, the
per-view viewport mask must: not be used.
=== New Object Types
None.
=== New Enum Constants
* Extending elink:VkStructureType
** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX
* Extending elink:VkSubpassDescriptionFlagBits
** ename:VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX
** ename:VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX
=== New Enums
None.
=== New Structures
* slink:VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX
=== New Functions
None.
=== New Built-In Variables
* <<interfaces-builtin-variables-positionperview,code:PositionPerViewNV>>
* <<interfaces-builtin-variables-viewportmaskperview,code:ViewportMaskPerViewNV>>
=== New SPIR-V Capabilities
* <<spirvenv-capabilities-table-perviewattributes,code:PerViewAttributesNV>>
=== Issues
None.
=== Examples
[source,c]
---------------------------------------------------
#version 450 core
#extension GL_KHX_multiview : enable
#extension GL_NVX_multiview_per_view_attributes : enable
layout(location = 0) in vec4 position;
layout(set = 0, binding = 0) uniform Block { mat4 mvpPerView[2]; } buf;
void main()
{
// Output both per-view positions and gl_Position as a function
// of gl_ViewIndex
gl_PositionPerViewNV[0] = buf.mvpPerView[0] * position;
gl_PositionPerViewNV[1] = buf.mvpPerView[1] * position;
gl_Position = buf.mvpPerView[gl_ViewIndex] * position;
}
---------------------------------------------------
=== Version History
* Revision 1, 2017-01-13 (Jeff Bolz)
- Internal revisions