1// Copyright (c) 2019-2020 NVIDIA Corporation 2// 3// SPDX-License-Identifier: CC-BY-4.0 4 5include::{generated}/meta/{refprefix}VK_NV_coverage_reduction_mode.adoc[] 6 7=== Other Extension Metadata 8 9*Last Modified Date*:: 10 2019-01-29 11*Contributors*:: 12 - Kedarnath Thangudu, NVIDIA 13 - Jeff Bolz, NVIDIA 14 15=== Description 16 17When using a framebuffer with mixed samples, a per-fragment coverage 18reduction operation is performed which generates color sample coverage from 19the pixel coverage. 20This extension defines the following modes to control how this reduction is 21performed. 22 23 * Merge: When there are more samples in the pixel coverage than color 24 samples, there is an implementation-dependent association of each pixel 25 coverage sample to a color sample. 26 In the merge mode, the color sample coverage is computed such that only 27 if any associated sample in the pixel coverage is covered, the color 28 sample is covered. 29 This is the default mode. 30 31 * Truncate: When there are more raster samples (N) than color samples(M), 32 there is one to one association of the first M raster samples to the M 33 color samples; other raster samples are ignored. 34 35When the number of raster samples is equal to the color samples, there is a 36one to one mapping between them in either of the above modes. 37 38The new command 39flink:vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV can 40be used to query the various raster, color, depth/stencil sample count and 41reduction mode combinations that are supported by the implementation. 42This extension would allow an implementation to support the behavior of both 43`VK_NV_framebuffer_mixed_samples` and `VK_AMD_mixed_attachment_samples` 44extensions simultaneously. 45 46include::{generated}/interfaces/VK_NV_coverage_reduction_mode.adoc[] 47 48=== Version History 49 50 * Revision 1, 2019-01-29 (Kedarnath Thangudu) 51 ** Internal revisions 52