75 lines
2.4 KiB
Plaintext
75 lines
2.4 KiB
Plaintext
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include::meta/VK_EXT_conservative_rasterization.txt[]
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*Last Modified Data*::
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2017-08-28
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*Contributors*::
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- Daniel Koch, NVIDIA
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- Daniel Rakos, AMD
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- Jeff Bolz, NVIDIA
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- Slawomir Grajewski, Intel
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- Stu Smith, Imagination Technologies
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This extension adds a new rasterization mode called conservative
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rasterization.
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There are two modes of conservative rasterization; overestimation and
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underestimation.
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When overestimation is enabled, if any part of the primitive, including its
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edges, covers any part of the rectangular pixel area, including its sides,
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then a fragment is generated with all coverage samples turned on.
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This extension allows for some variation in implementations by accounting
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for differences in overestimation, where the generating primitive size is
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increased at each of its edges by some sub-pixel amount to further increase
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conservative pixel coverage.
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Implementations can allow the application to specify an extra overestimation
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beyond the base overestimation the implementation already does.
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It also allows implementations to either cull degenerate primitives or
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rasterize them.
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When underestimation is enabled, fragments are only generated if the
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rectangular pixel area is fully covered by the generating primitive.
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If supported by the implementation, when a pixel rectangle is fully covered
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the fragment shader input variable builtin called FullyCoveredEXT is set to
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true.
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The shader variable works in either overestimation or underestimation mode.
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Implementations can process degenerate triangles and lines by either
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discarding them or generating conservative fragments for them.
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Degenerate triangles are those that end up with zero area after the
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rasterizer quantizes them to the fixed-point pixel grid.
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Degenerate lines are those with zero length after quantization.
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=== New Object Types
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None.
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=== New Enum Constants
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* Extending elink:VkStructureType:
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT
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** ename:VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT
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=== New Enums
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* elink:VkPipelineRasterizationConservativeStateCreateFlagsEXT
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* elink:VkConservativeRasterizationModeEXT
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=== New Structures
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* slink:VkPhysicalDeviceConservativeRasterizationPropertiesEXT
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* slink:VkPipelineRasterizationConservativeStateCreateInfoEXT
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=== New Functions
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None.
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=== Issues
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None.
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=== Version History
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* Revision 1, 2017-08-28 (Piers Daniell)
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- Internal revisions
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