Contact
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Jeff Bolz jeffbolznv
Other Extension Metadata
- Last Modified Date
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2017-01-13
- IP Status
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No known IP claims.
- Interactions and External Dependencies
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This extension provides API support for
GL_NVX_multiview_per_view_attributes -
This extension interacts with
VK_NV_viewport_array2.
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- Contributors
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Jeff Bolz, NVIDIA
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Daniel Koch, NVIDIA
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Description
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
pre-rasterization shader
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
pre-rasterization shader
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. gl_PositionPerViewNV)
must also write the non-per-view output (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 Enum Constants
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VK_NVX_MULTIVIEW_PER_VIEW_ATTRIBUTES_EXTENSION_NAME -
VK_NVX_MULTIVIEW_PER_VIEW_ATTRIBUTES_SPEC_VERSION -
Extending VkStructureType:
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VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX
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Extending VkSubpassDescriptionFlagBits:
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VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX -
VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX
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Examples
#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;
}Document Notes
For more information, see the Vulkan Specification
This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.