Package org.lwjgl.vulkan

Class QCOMFilterCubicClamp

java.lang.Object
org.lwjgl.vulkan.QCOMFilterCubicClamp
public final class QCOMFilterCubicClamp extends Object
This extension extends cubic filtering by adding the ability to enable an anti-ringing clamp. Cubic filtering samples from a 4x4 region of texels and computes a cubic weighted average of the region. In some cases, the resulting value is outside the range of any of the texels in the 4x4 region. This is sometimes referred to as “filter overshoot” or “filter ringing” and can occur when there is a sharp discontinuity in the 4x4 region being filtered. For some use cases this “ringing” can produces unacceptable artifacts.

The solution to the ringing problem is to clamp the post-cubic-filtered value to be within the max and min of texel values in the 4x4 region. While such “range clamping” can be performed in shader code, the additional texture fetches and clamping ALU operations can be costly.

Certain Adreno GPUs are able to perform the range clamp in the texture unit during cubic filtering at significant performance/power savings versus a shader-based clamping approach. This extension exposes such hardware functionality.

This extension extends VkSamplerReductionMode, adding SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_RANGECLAMP_QCOM which enables the range clamp operation.

Name String
VK_QCOM_filter_cubic_clamp
Extension Type
Device extension
Registered Extension Number
522
Revision
1
Extension and Version Dependencies
VK_EXT_filter_cubic and Version 1.2 or VK_EXT_sampler_filter_minmax
Contact
Other Extension Metadata
Last Modified Date
2023-08-02
Contributors
  • Jeff Leger, Qualcomm Technologies, Inc.

  • Field Details

    • VK_QCOM_FILTER_CUBIC_CLAMP_SPEC_VERSION

      public static final int VK_QCOM_FILTER_CUBIC_CLAMP_SPEC_VERSION
      The extension specification version.
      See Also:

    • VK_QCOM_FILTER_CUBIC_CLAMP_EXTENSION_NAME

      public static final String VK_QCOM_FILTER_CUBIC_CLAMP_EXTENSION_NAME
      The extension name.
      See Also:

    • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CUBIC_CLAMP_FEATURES_QCOM

      public static final int VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CUBIC_CLAMP_FEATURES_QCOM
      Extends VkStructureType.
      See Also:

    • VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_RANGECLAMP_QCOM

      public static final int VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_RANGECLAMP_QCOM
      Extends VkSamplerReductionMode.
      See Also: