This extension adds two related features.

Firstly, support for the following SPIR-V extension in Vulkan is added:

• SPV_AMD_texture_gather_bias_lod

Secondly, the extension allows the application to query which formats can be used together with the new function prototypes introduced by the SPIR-V extension.

Examples

struct VkTextureLODGatherFormatPropertiesAMD
{
    VkStructureType sType;
    const void*     pNext;
    VkBool32        supportsTextureGatherLODBiasAMD;
};

// ----------------------------------------------------------------------------------------
// How to detect if an image format can be used with the new function prototypes.
VkPhysicalDeviceImageFormatInfo2   formatInfo;
VkImageFormatProperties2           formatProps;
VkTextureLODGatherFormatPropertiesAMD textureLODGatherSupport;

textureLODGatherSupport.sType = VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD;
textureLODGatherSupport.pNext = nullptr;

formatInfo.sType  = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2;
formatInfo.pNext  = nullptr;
formatInfo.format = ...;
formatInfo.type   = ...;
formatInfo.tiling = ...;
formatInfo.usage  = ...;
formatInfo.flags  = ...;

formatProps.sType = VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2;
formatProps.pNext = &textureLODGatherSupport;

vkGetPhysicalDeviceImageFormatProperties2(physical_device, &formatInfo, &formatProps);

if (textureLODGatherSupport.supportsTextureGatherLODBiasAMD == VK_TRUE)
{
    // physical device supports SPV_AMD_texture_gather_bias_lod for the specified
    // format configuration.
}
else
{
    // physical device does not support SPV_AMD_texture_gather_bias_lod for the
    // specified format configuration.
}

VK_AMD_texture_gather_bias_lod

Name String

VK_AMD_texture_gather_bias_lod

Extension Type

Device extension

Registered Extension Number

42

Revision

1

Extension and Version Dependencies

VK_KHR_get_physical_device_properties2

Contact

• Rex Xu amdrexu

Other Extension Metadata

Last Modified Date

2017-03-21

IP Status

No known IP claims.

Interactions and External Dependencies

• This extension requires SPV_AMD_texture_gather_bias_lod
• This extension provides API support for GL_AMD_texture_gather_bias_lod

Contributors

• Dominik Witczak, AMD
• Daniel Rakos, AMD
• Graham Sellers, AMD
• Matthaeus G. Chajdas, AMD
• Qun Lin, AMD
• Rex Xu, AMD
• Timothy Lottes, AMD