VK_KHR_line_rasterization

Other Extension Metadata

Last Modified Date

2023-06-08

IP Status

No known IP claims.

Contributors

• Jeff Bolz, NVIDIA
• Allen Jensen, NVIDIA
• Faith Ekstrand, Intel

Description

This extension adds some line rasterization features that are commonly used in CAD applications and supported in other APIs like OpenGL. Bresenham-style line rasterization is supported, smooth rectangular lines (coverage to alpha) are supported, and stippled lines are supported for all three line rasterization modes.

New Commands

• vkCmdSetLineStippleKHR

New Structures

• Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
  • VkPhysicalDeviceLineRasterizationFeaturesKHR
• Extending VkPhysicalDeviceProperties2:
  • VkPhysicalDeviceLineRasterizationPropertiesKHR
• Extending VkPipelineRasterizationStateCreateInfo:
  • VkPipelineRasterizationLineStateCreateInfoKHR

New Enums

• VkLineRasterizationModeKHR

New Enum Constants

• VK_KHR_LINE_RASTERIZATION_EXTENSION_NAME
• VK_KHR_LINE_RASTERIZATION_SPEC_VERSION
• Extending VkDynamicState:
  • VK_DYNAMIC_STATE_LINE_STIPPLE_KHR
• Extending VkLineRasterizationMode:
  • VK_LINE_RASTERIZATION_MODE_BRESENHAM_KHR
  • VK_LINE_RASTERIZATION_MODE_DEFAULT_KHR
  • VK_LINE_RASTERIZATION_MODE_RECTANGULAR_KHR
  • VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_KHR
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_FEATURES_KHR
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_PROPERTIES_KHR
  • VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_LINE_STATE_CREATE_INFO_KHR

Promotion to Vulkan 1.4

Functionality in this extension is included in core Vulkan 1.4 with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

When Version 1.4 is supported, the bresenhamLines feature must be supported.

Issues

1) Do we need to support Bresenham-style and smooth lines with more than one rasterization sample? i.e. the equivalent of glDisable(GL_MULTISAMPLE) in OpenGL when the framebuffer has more than one sample?

RESOLVED: Yes. For simplicity, Bresenham line rasterization carries forward a few restrictions from OpenGL, such as not supporting per-sample shading, alpha to coverage, or alpha to one.

Version History

• Revision 1, 2019-05-09 (Jeff Bolz)
  • Initial draft