Name ANGLE_external_objects_flags Name Strings GL_ANGLE_memory_object_flags Contributors Shahbaz Youssefi, Google Contact Shahbaz Youssefi, Google (syoussefi 'at' google.com) Status Draft Version Last Modified Date: Nov 10, 2021 Revision: 2 Number TBD Dependencies Written against the OpenGL 4.5 and OpenGL ES 3.2 specifications GL_ANGLE_memory_object_flags requires GL_EXT_memory_object. Overview Building upon the OpenGL memory object framework defined in EXT_external_objects, this extension introduces new Texture entry points for specifying create and usage flags parameters. These parameters match an external Texture's corresponding Vulkan create and usage flags. This allows applications to drop usage flags that are detrimental to performance, or add create flags as necessary. Additionally, these entry points take the pointer to the chain of extension structures appended to VkImageCreateInfo, so that the OpenGL implementation can recreate the image identically. New Procedures and Functions The following commands are added: void TexStorageMemFlags2DANGLE(enum target, sizei levels, enum internalFormat, sizei width, sizei height, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TexStorageMemFlags2DMultisampleANGLE(enum target, sizei samples, enum internalFormat, sizei width, sizei height, boolean fixedSampleLocations, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TexStorageMemFlags3DANGLE(enum target, sizei levels, enum internalFormat, sizei width, sizei height, sizei depth, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TexStorageMemFlags3DMultisampleANGLE(enum target, sizei samples, enum internalFormat, sizei width, sizei height, sizei depth, boolean fixedSampleLocations, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); [[ The following are added if direct state access is supported ]] void TextureStorageMemFlags2DANGLE(uint texture, sizei levels, enum internalFormat, sizei width, sizei height, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TextureStorageMemFlags2DMultisampleANGLE(uint texture, sizei samples, enum internalFormat, sizei width, sizei height, boolean fixedSampleLocations, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TextureStorageMemFlags3DANGLE(uint texture, sizei levels, enum internalFormat, sizei width, sizei height, sizei depth, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TextureStorageMemFlags3DMultisampleANGLE(uint texture, sizei samples, enum internalFormat, sizei width, sizei height, sizei depth, boolean fixedSampleLocations, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); [[ The following are available in OpenGL only ]] void TexStorageMemFlags1DANGLE(enum target, sizei levels, enum internalFormat, sizei width, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); [[ The following are availble in OpenGL only, and only when direct state access is available ]] void TextureStorageMemFlags1DANGLE(uint texture, sizei levels, enum internalFormat, sizei width, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); New Tokens The following tokens are added: Accepted by the parameter of TexStorageMemFlags*ANGLE() and TextureStorageMemFlags*ANGLE(). CREATE_SPARSE_BINDING_BIT_ANGLE 0x00000001 CREATE_SPARSE_RESIDENCY_BIT_ANGLE 0x00000002 CREATE_SPARSE_ALIASED_BIT_ANGLE 0x00000004 CREATE_MUTABLE_FORMAT_BIT_ANGLE 0x00000008 CREATE_CUBE_COMPATIBLE_BIT_ANGLE 0x00000010 CREATE_ALIAS_BIT_ANGLE 0x00000400 CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_ANGLE 0x00000040 CREATE_2D_ARRAY_COMPATIBLE_BIT_ANGLE 0x00000020 CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_ANGLE 0x00000080 CREATE_EXTENDED_USAGE_BIT_ANGLE 0x00000100 CREATE_PROTECTED_BIT_ANGLE 0x00000800 CREATE_DISJOINT_BIT_ANGLE 0x00000200 CREATE_CORNER_SAMPLED_BIT_ANGLE 0x00002000 CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_ANGLE 0x00001000 CREATE_SUBSAMPLED_BIT_ANGLE 0x00004000 Accepted by the parameter of TexStorageMemFlags*ANGLE() and TextureStorageMemFlags*ANGLE(). USAGE_TRANSFER_SRC_BIT_ANGLE 0x00000001 USAGE_TRANSFER_DST_BIT_ANGLE 0x00000002 USAGE_SAMPLED_BIT_ANGLE 0x00000004 USAGE_STORAGE_BIT_ANGLE 0x00000008 USAGE_COLOR_ATTACHMENT_BIT_ANGLE 0x00000010 USAGE_DEPTH_STENCIL_ATTACHMENT_BIT_ANGLE 0x00000020 USAGE_TRANSIENT_ATTACHMENT_BIT_ANGLE 0x00000040 USAGE_INPUT_ATTACHMENT_BIT_ANGLE 0x00000080 USAGE_SHADING_RATE_IMAGE_BIT_ANGLE 0x00000100 USAGE_FRAGMENT_DENSITY_MAP_BIT_ANGLE 0x00000200 Additions to Chapter 8 of the OpenGL 4.5 Specification (Textures and Samplers) For each list of TexStorage* commands in the 1D, 2D, 3D, 2DMultisample, and 3DMultisample families, add the following variants: void TexStorageMemFlags*ANGLE(, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); void TextureStorageMemFlags*ANGLE(, uint memory, uint64 offset, bitfield createFlags, bitfield usageFlags, const void *imageCreateInfoPNext); For each of the TexStorageMemFlags*ANGLE commands, move the description from the corresponding TexStorageMem*EXT from EXT_external_objects under that command and add the following language: "The implementation should apply the same semantics to the internal storage of the texture based on , and as the corresonding VkImageCreateFlags, VkImageUsageFlags and chained structs to VkImageCreateInfo would have on a Vulkan image respectively. See tables 8.17 and 8.18 for the mapping between the GL and Vulkan flags. It is undefined behavior if the application provides create flags, usage flags or chained structs that are not identical to those used to create the Vulkan image." Table 8.17: Create flags and corresponding Vulkan Image Create Flags | Create Flag | Equivalent Vulkan Create Flag | +----------------------------------------------------+-----------------------------------------------------------+ | CREATE_SPARSE_BINDING_BIT_ANGLE | VK_IMAGE_CREATE_SPARSE_BINDING_BIT | | CREATE_SPARSE_RESIDENCY_BIT_ANGLE | VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT | | CREATE_SPARSE_ALIASED_BIT_ANGLE | VK_IMAGE_CREATE_SPARSE_ALIASED_BIT | | CREATE_MUTABLE_FORMAT_BIT_ANGLE | VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT | | CREATE_CUBE_COMPATIBLE_BIT_ANGLE | VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT | | CREATE_ALIAS_BIT_ANGLE | VK_IMAGE_CREATE_ALIAS_BIT | | CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_ANGLE | VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT | | CREATE_2D_ARRAY_COMPATIBLE_BIT_ANGLE | VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT | | CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_ANGLE | VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT | | CREATE_EXTENDED_USAGE_BIT_ANGLE | VK_IMAGE_CREATE_EXTENDED_USAGE_BIT | | CREATE_PROTECTED_BIT_ANGLE | VK_IMAGE_CREATE_PROTECTED_BIT | | CREATE_DISJOINT_BIT_ANGLE | VK_IMAGE_CREATE_DISJOINT_BIT | | CREATE_CORNER_SAMPLED_BIT_ANGLE | VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV | | CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_ANGLE | VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT | | CREATE_SUBSAMPLED_BIT_ANGLE | VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT | +----------------------------------------------------------------------------------------------------------------+ Table 8.18: Usage flags and corresponding Vulkan Image Usage Flags | Usage Flag | Equivalent Vulkan Usage Flag | +------------------------------------------+---------------------------------------------+ | USAGE_TRANSFER_SRC_BIT_ANGLE | VK_IMAGE_USAGE_TRANSFER_SRC_BIT | | USAGE_TRANSFER_DST_BIT_ANGLE | VK_IMAGE_USAGE_TRANSFER_DST_BIT | | USAGE_SAMPLED_BIT_ANGLE | VK_IMAGE_USAGE_SAMPLED_BIT | | USAGE_STORAGE_BIT_ANGLE | VK_IMAGE_USAGE_STORAGE_BIT | | USAGE_COLOR_ATTACHMENT_BIT_ANGLE | VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | | USAGE_DEPTH_STENCIL_ATTACHMENT_BIT_ANGLE | VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT | | USAGE_TRANSIENT_ATTACHMENT_BIT_ANGLE | VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT | | USAGE_INPUT_ATTACHMENT_BIT_ANGLE | VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT | | USAGE_SHADING_RATE_IMAGE_BIT_ANGLE | VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV | | USAGE_FRAGMENT_DENSITY_MAP_BIT_ANGLE | VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT | +----------------------------------------------------------------------------------------+ Add the following errors for each of the TexStorageMemFlags*ANGLE commands: "An INVALID_VALUE error is generated if has a bit set other than those specified in table 8.17." "An INVALID_VALUE error is generated if has a bit set other than those specified in table 8.18." For each of the TexStorageMem*EXT commands, change the description of TexStorageMem*EXT and TextureStorageMem*EXT as such: "Calling TexStorageMem*EXT is equivalent to calling TexStorageMemFlags*ANGLE with 0 as , all Vulkan-supported usage flags as , even if there are no corresponding GL flags specified in this extension, and NULL as ." Issues 1) Can the GL and Vulkan create and usage flag values diverge? RESOLVED: No. It is expected for the application to provide the flags used to create the Vulkan image verbatim. 2) What if Vulkan adds new create and usage flags? RESOLVED: If the implementation is too old to be aware of those flags, the functions from GL_EXT_memory_object must be used instead. New flags can be added through new extensions that build on this extension. 3) Should the GL implementation apply the same validation as Vulkan based on the create and usage flags? RESOLVED: No. The application has already created an image with these flags in Vulkan, so the GL implementation can assume they are valid. Validating this is expensive and unnecessary in almost all applications. 4) How can extension structs applied to VkImageCreateInfo be communicated to the GL implementation? RESOLVED: The chain of structs itself is directly passed to the implementation. Revision History Revision 2, 2021-11-10 (Shahbaz Youssefi) - Added the imageCreateInfoPNext parameter. Revision 1, 2020-08-03 (Shahbaz Youssefi) - Initial draft based on EXT_external_objects.