public final class NVFramebufferMixedSamples extends java.lang.ObjectThis extension allows multisample rendering with a raster and depth/stencil sample count that is larger than the color sample count. Rasterization and the results of the depth and stencil tests together determine the portion of a pixel that is "
covered". It can be useful to evaluate coverage at a higher frequency than color samples are stored. This coverage is then "
reduced" to a collection of covered color samples, each having an opacity value corresponding to the fraction of the color sample covered. The opacity can optionally be blended into individual color samples.
Rendering with fewer color samples than depth/stencil samples greatly reduces the amount of memory and bandwidth consumed by the color buffer. However, converting the coverage values into opacity introduces artifacts where triangles share edges and may not be suitable for normal triangle mesh rendering.
One expected use case for this functionality is Stencil-then-Cover path rendering (similar to the OpenGL GL_NV_path_rendering extension). The stencil step determines the coverage (in the stencil buffer) for an entire path at the higher sample frequency, and then the cover step draws the path into the lower frequency color buffer using the coverage information to antialias path edges. With this two-step process, internal edges are fully covered when antialiasing is applied and there is no corruption on these edges.
The key features of this extension are:
- It allows render pass and framebuffer objects to be created where the number of samples in the depth/stencil attachment in a subpass is a multiple of the number of samples in the color attachments in the subpass.
- A coverage reduction step is added to Fragment Operations which converts a set of covered raster/depth/stencil samples to a set of color samples that perform blending and color writes. The coverage reduction step also includes an optional coverage modulation step, multiplying color values by a fractional opacity corresponding to the number of associated raster/depth/stencil samples covered.
- Name String
- Extension Type
- Device extension
- Registered Extension Number
- Extension and Version Dependencies
- Requires Vulkan 1.0
- Jeff Bolz jeffbolznv
- Last Modified Date
- Jeff Bolz, NVIDIA
Fields Modifier and Type Field Description
VK_COVERAGE_MODULATION_MODE_RGBA_NVVkCoverageModulationModeNV - Specify the coverage modulation mode
VK_NV_FRAMEBUFFER_MIXED_SAMPLES_EXTENSION_NAMEThe extension name.
VK_NV_FRAMEBUFFER_MIXED_SAMPLES_SPEC_VERSIONThe extension specification version.
The extension specification version.
The extension name.
VK_COVERAGE_MODULATION_MODE_NONE_NV, VK_COVERAGE_MODULATION_MODE_RGB_NV, VK_COVERAGE_MODULATION_MODE_ALPHA_NV, VK_COVERAGE_MODULATION_MODE_RGBA_NVVkCoverageModulationModeNV - Specify the coverage modulation mode
COVERAGE_MODULATION_MODE_NONE_NVspecifies that no components are multiplied by the modulation factor.
COVERAGE_MODULATION_MODE_RGB_NVspecifies that the red, green, and blue components are multiplied by the modulation factor.
COVERAGE_MODULATION_MODE_ALPHA_NVspecifies that the alpha component is multiplied by the modulation factor.
COVERAGE_MODULATION_MODE_RGBA_NVspecifies that all components are multiplied by the modulation factor.