Merge pull request #436 from nvpbrown/pbrown-NV_primitive_shading_rate
Add NV_primitive_shading_rate extension.
diff --git a/extensions/NV/NV_primitive_shading_rate.txt b/extensions/NV/NV_primitive_shading_rate.txt
new file mode 100644
index 0000000..dc0bb42
--- /dev/null
+++ b/extensions/NV/NV_primitive_shading_rate.txt
@@ -0,0 +1,267 @@
+Name
+
+ NV_primitive_shading_rate
+
+Name Strings
+
+ GL_NV_primitive_shading_rate
+
+Contact
+
+ Pat Brown, NVIDIA Corporation (pbrown 'at' nvidia.com)
+
+Contributors
+
+ Jeff Bolz, NVIDIA
+
+Status
+
+ Shipping
+
+Version
+
+ Last Modified: October 30, 2020
+ Revision: 1
+
+Number
+
+ OpenGL Extension #554
+ OpenGL ES Extension #332
+
+Dependencies
+
+ This extension is written against the OpenGL 4.6 Specification
+ (Compatibility Profile), dated February 2, 2019.
+
+ OpenGL 4.5 or OpenGL ES 3.2 is required.
+
+ NV_shading_rate_image is required.
+
+ This extension requires support from the OpenGL Shading Language (GLSL)
+ extension "NV_primitive_shading_rate", which can be found at the Khronos
+ Group Github site here:
+
+ https://github.com/KhronosGroup/GLSL
+
+ This extension interacts with NV_mesh_shader.
+
+Overview
+
+ This extension builds on top of the NV_shading_rate_image extension to
+ provide OpenGL API support for using a per-primitive shading rate value to
+ control the computation of the rate used to process each fragment.
+
+ In the NV_shading_rate_image extension, the shading rate for each fragment
+ produced by a primitive is determined by looking up a texel in the bound
+ shading rate image and using that value as an index into a shading rate
+ palette. That extension provides a separate shading rate image lookup
+ enable and palette for each viewport. When a primitive is rasterized, the
+ implementation uses the enable and palette associated with the primitive's
+ viewport to determine the shading rate.
+
+ This extension decouples the shading rate image enables and palettes from
+ viewports. The number of enables/palettes now comes from the
+ implementation-dependent constant SHADING_RATE_IMAGE_PALETTE_COUNT_NV. When
+ SHADING_RATE_IMAGE_PER_PRIMITIVE_NV (added here) is enabled, the value of
+ the new gl_ShadingRateNV built-in output is used to select an enable and
+ palette to determine the shading rate. Otherwise, the viewport number for
+ the primitive is used, as in NV_shading_rate_image.
+
+
+New Procedures and Functions
+
+ None.
+
+
+New Tokens
+
+ Accepted by the <cap> parameter of Enable, Disable, and IsEnabled and by the
+ <pname> parameter of GetBooleanv, GetIntegerv, GetInteger64v, GetFloatv,
+ GetDoublev:
+
+ SHADING_RATE_IMAGE_PER_PRIMITIVE_NV 0x95B1
+
+ Accepted by the <pname> parameter of GetBooleanv, GetDoublev,
+ GetIntegerv, and GetFloatv:
+
+ SHADING_RATE_IMAGE_PALETTE_COUNT_NV 0x95B2
+
+
+Modifications to the OpenGL 4.6 Specification (Compatibility Profile)
+
+ Modify Section 14.3.1, Multisampling, as modified by the
+ NV_shading_rate_image extension.
+
+ (modify the introduction of the shading rate image functionality to decouple
+ shading rate image enables and viewports)
+
+ When using a shading rate image (Section 14.4.1), rasterization may produce
+ fragments covering multiple pixels, where each pixel is treated as a sample.
+ If any of the SHADING_RATE_IMAGE_NV enables is enabled, primitives will be
+ processed with multisample rasterization rules, regardless of the
+ MULTISAMPLE enable or the value of SAMPLE_BUFFERS. ...
+
+
+ Modify Section 14.4.1, Shading Rate Image, as added by the
+ NV_shading_rate_image extension.
+
+ (rework the introduction of the shading rate image functionality to decouple
+ shading rate image enables and viewports)
+
+ Applications can specify the use of a shading rate that varies by (x,y)
+ location using a _shading rate image_. For each primitive, the shading rate
+ image is enabled or disabled by selecting a single enable in an array of
+ enables whose size is given by the implementation-dependent constant
+ SHADING_RATE_IMAGE_PALETTE_COUNT_NV. Use of a shading rate image is enabled
+ or disabled globally by using Enable or Disable with target
+ SHADING_RATE_IMAGE_NV. A single shading rate image enable can be modified
+ by calling Enablei or Disablei with the constant SHADING_RATE_IMAGE_NV and
+ the index of the selected enable. The shading rate image may only be used
+ with a framebuffer object. When rendering to the default framebuffer, the
+ shading rate image enables are ignored and operations in this section are
+ disabled. In the initial state, all shading rate image enables are
+ disabled.
+
+ The method used to select a single shading rate image enable used to process
+ each primitive is controlled by calling Enable or Disable with the target
+ SHADING_RATE_IMAGE_PER_PRIMITIVE_NV. When enabled, a shading rate enable
+ used for a primitive is selected using an index taken from the value of the
+ built-in output gl_ShadingRateNV for the primitive's provoking vertex. If
+ the value of gl_ShadingRateNV is negative or greater than or equal to the
+ number of shading rate enables, the shading rate used for a primitive is
+ undefined. When SHADING_RATE_IMAGE_PER_PRIMITIVE_NV is disabled, a shading
+ rate enable is selected using the index of the viewport used for processing
+ the primitive. In the initial state, SHADING_RATE_IMAGE_PER_PRIMITIVE_NV is
+ disabled.
+
+
+ (rework the introduction of the shading rate image functionality to decouple
+ shading rate image palettes and viewports)
+
+ A shading rate index is mapped to a _base shading rate_ using a lookup table
+ called the shading rate image palette. There is a separate palette
+ associated with each shading rate image enable. As with the shading rate
+ image enables, a single palette is selected for a primitive according to the
+ enable SHADING_RATE_IMAGE_PER_PRIMITIVE_NV. The number of palettes and the
+ number of entries in each palette are given by the implementation-dependent
+ constants SHADING_RATE_IMAGE_PALETTE_COUNT_NV and
+ SHADING_RATE_IMAGE_PALETTE_SIZE_NV, respectively. The base shading rate for
+ an (x,y) coordinate with a shading rate index of <i> will be given by entry
+ <i> of the selected palette. If the shading rate index is greater than or
+ equal to the palette size, the results of the palette lookup are undefined.
+
+
+ (rework the introduction of ShadingRateImagePaletteNV to decouple shading
+ rate image palettes and viewports)
+
+ Shading rate image palettes are updated using the command
+
+ void ShadingRateImagePaletteNV(uint viewport, uint first, sizei count,
+ const enum *rates);
+
+ <viewport> specifies the number of the palette that should be updated.
+ [[ Note: The formal parameter name <viewport> is a remnant of the
+ original NV_shading_rate_image extension, where palettes were tightly
+ coupled with viewports. ]] <rates> is an array ...
+
+
+ (modify the discussion of ShadingRateImagePaletteNV errors to decouple
+ shading rate image palettes and viewports)
+
+ INVALID_VALUE is generated if <viewport> is greater than or equal to
+ SHADING_RATE_IMAGE_PALETTE_COUNT_NV.
+
+ INVALID_VALUE is generated if <first> plus <count> is greater than
+ SHADING_RATE_IMAGE_PALETTE_SIZE_NV.
+
+
+ (modify the discussion of GetShadingRateImagePaletteNV to decouple shading
+ rate image palettes and viewports)
+
+ Individual entries in the shading rate palette can be queried using the
+ command:
+
+ void GetShadingRateImagePaletteNV(uint viewport, uint entry,
+ enum *rate);
+
+ where <viewport> specifies the number of the palette to query and...
+ <entry> specifies the palette entry number. [[ Note: The formal
+ parameter name <viewport> is a remnant of the original
+ NV_shading_rate_image extension, where palettes were tightly coupled
+ with viewports. ]] A single enum from Table X.1 is returned in <rate>.
+
+ Errors
+
+ INVALID_VALUE is generated if <viewport> is greater than or equal to
+ SHADING_RATE_IMAGE_PALETTE_COUNT_NV.
+
+ INVALID_VALUE is generated if <first> plus <count> is greater than
+ SHADING_RATE_IMAGE_PALETTE_SIZE_NV.
+
+
+ Modify Section 14.9.3, Multisample Fragment Operations, as edited by
+ NV_shading_rate_image.
+
+ (modify the discussion of the shading rate image multisample functionality
+ to decouple shading rate image enables and viewports)
+
+ ... This step is skipped if MULTISAMPLE is disabled or if the value of
+ SAMPLE_BUFFERS is not one, unless one or more of the SHADING_RATE_IMAGE_NV
+ enables are enabled.
+
+
+Dependencies on NV_mesh_shader
+
+ When NV_mesh_shader is supported, the "NV_primitive_shading_rate" GLSL
+ extension allows multi-view mesh shaders to write separate per-primitive
+ shading rates for each view using the built-in gl_ShadingRatePerViewNV[].
+ When gl_ShadingRatePerViewNV[] is used with
+ SHADING_RATE_IMAGE_PER_PRIMITIVE_NV enabled, a separate shading rate image
+ enable and palette will be used for each view.
+
+
+Additions to the AGL/GLX/WGL Specifications
+
+ None
+
+Errors
+
+ See the "Errors" sections for individual commands above.
+
+New State
+
+ Get Value Get Command Type Initial Value Description Sec. Attribute
+ --------- --------------- ---- ------------- ----------- ---- ---------
+ SHADING_RATE_IMAGE_ IsEnabled B FALSE Use per-primitive shading 14.4.1 enable
+ PER_PRIMITIVE_NV rate to select shading
+ rate images/palettes
+
+New Implementation Dependent State
+
+ Minimum
+ Get Value Type Get Command Value Description Sec.
+ --------- ----- --------------- ------- ------------------------ ------
+ SHADING_RATE_IMAGE_ Z+ GetIntegerv 16 Number of shading rate image 14.4.1
+ PALETTE_COUNT_NV enables/palettes supported
+
+Issues
+
+ (1) How should we name this extension?
+
+ RESOLVED: We are calling this extension "NV_primitive_shading_rate"
+ because it adds a new per-primitive shading rate to the variable-rate
+ shading functionality added by NV_shading_rate_image.
+
+ (2) Do we need to add queries like LAYER_PROVOKING_VERTEX and
+ VIEWPORT_INDEX_PROVOKING_VERTEX to determine the vertex used to obtain
+ the per-primitive shading rate for each primitive?
+
+ RESOLVED: No -- we will always use the provoking vertex. In the event
+ that this extension is standardized in the future with behavior that
+ diverges between implementations, such a query could be added as part of
+ that effort.
+
+Revision History
+
+ Revision 1 (pbrown)
+ - Internal revisions.
diff --git a/extensions/esext.php b/extensions/esext.php
index 3d80fe4..4d6946d 100644
--- a/extensions/esext.php
+++ b/extensions/esext.php
@@ -689,4 +689,6 @@
</li>
<li value=331><a href="extensions/QCOM/QCOM_texture_foveated2.txt">GL_QCOM_texture_foveated2</a>
</li>
+<li value=332><a href="extensions/NV/NV_primitive_shading_rate.txt">GL_NV_primitive_shading_rate</a>
+</li>
</ol>
diff --git a/extensions/glext.php b/extensions/glext.php
index 89618c1..1e2c0f1 100644
--- a/extensions/glext.php
+++ b/extensions/glext.php
@@ -1045,4 +1045,6 @@
</li>
<li value=553><a href="extensions/EXT/GLX_EXT_no_config_context.txt">GLX_EXT_no_config_context</a>
</li>
+<li value=554><a href="extensions/NV/NV_primitive_shading_rate.txt">GL_NV_primitive_shading_rate</a>
+</li>
</ol>
diff --git a/extensions/registry.py b/extensions/registry.py
index 86d395e..441e312 100644
--- a/extensions/registry.py
+++ b/extensions/registry.py
@@ -3660,6 +3660,13 @@
'supporters' : { 'NVIDIA' },
'url' : 'extensions/NV/NV_primitive_restart.txt',
},
+ 'GL_NV_primitive_shading_rate' : {
+ 'number' : 554,
+ 'esnumber' : 332,
+ 'flags' : { 'public' },
+ 'supporters' : { 'NVIDIA' },
+ 'url' : 'extensions/NV/NV_primitive_shading_rate.txt',
+ },
'GL_NV_query_resource' : {
'number' : 511,
'flags' : { 'public' },
diff --git a/xml/gl.xml b/xml/gl.xml
index 56513b5..3bf68cb 100644
--- a/xml/gl.xml
+++ b/xml/gl.xml
@@ -11586,7 +11586,8 @@
<enum value="0x95AE" name="GL_SHADING_RATE_SAMPLE_ORDER_DEFAULT_NV"/>
<enum value="0x95AF" name="GL_SHADING_RATE_SAMPLE_ORDER_PIXEL_MAJOR_NV"/>
<enum value="0x95B0" name="GL_SHADING_RATE_SAMPLE_ORDER_SAMPLE_MAJOR_NV"/>
- <unused start="0x95B1" end="0x95B2" vendor="NV"/>
+ <enum value="0x95B1" name="GL_SHADING_RATE_IMAGE_PER_PRIMITIVE_NV" group="EnableCap,GetPName"/>
+ <enum value="0x95B2" name="GL_SHADING_RATE_IMAGE_PALETTE_COUNT_NV" group="GetPName"/>
<enum value="0x95B3" name="GL_SEMAPHORE_TYPE_NV" group="SemaphoreParameterName"/>
<enum value="0x95B4" name="GL_SEMAPHORE_TYPE_BINARY_NV" group="SemaphoreParameterName"/>
<enum value="0x95B5" name="GL_SEMAPHORE_TYPE_TIMELINE_NV" group="SemaphoreParameterName"/>
@@ -49201,6 +49202,12 @@
<command name="glPrimitiveRestartIndexNV"/>
</require>
</extension>
+ <extension name="GL_NV_primitive_shading_rate" supported="gl|glcore|gles2">
+ <require>
+ <enum name="GL_SHADING_RATE_IMAGE_PER_PRIMITIVE_NV"/>
+ <enum name="GL_SHADING_RATE_IMAGE_PALETTE_COUNT_NV"/>
+ </require>
+ </extension>
<extension name="GL_NV_query_resource" supported="gl">
<require>
<enum name="GL_QUERY_RESOURCE_TYPE_VIDMEM_ALLOC_NV"/>
