Name OES_EGL_image_external Name Strings GL_OES_EGL_image_external Contributors Acorn Pooley David Garcia Bruce Merry Aske Simon Christensen Mark Callow Tom Olson Jon Leech Maurice Ribble Contacts Acorn Pooley, NVIDIA Corporation (apooley 'at' nvidia.com) Notice Copyright (c) 2009-2013 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html Specification Update Policy Khronos-approved extension specifications are updated in response to issues and bugs prioritized by the Khronos OpenGL ES Working Group. For extensions which have been promoted to a core Specification, fixes will first appear in the latest version of that core Specification, and will eventually be backported to the extension document. This policy is described in more detail at https://www.khronos.org/registry/OpenGL/docs/update_policy.php Status Ratified by Khronos Promoters, 10 December 2010 Approved by the OpenGL ES Working Group, 15 September 2010 Version April 6, 2018 (version 25) Number OpenGL ES Extension #87 Dependencies Requires OpenGL ES 1.1 or OpenGL ES 2.0. Requires EGL 1.2 Requires either the EGL_KHR_image_base or the EGL_KHR_image extension This extension is written based on the wording of the OpenGL ES 2.0 specification, the OpenGL ES Shading Language version 1.0, and the EGL_KHR_image_base extension. On an OpenGL ES 2.0 implementation, ignore sections which are added only to the OpenGL ES 1.1 specification. This extension is also written based on the wording of the OpenGL ES 1.1 specification. On an OpenGL ES 1.X implementation, ignore sections which are added only to the OpenGL ES 2.0 or OpenGL ES Shading Language specification. Also ignore all mention of MAX_VERTEX_TEXTURE_IMAGE_UNITS, and MAX_COMBINED_TEXTURE_IMAGE_UNITS. This extension borrows concepts and function names from the GL_OES_EGL_image extension. This extension is compatible with, but does not require, the GL_OES_EGL_image extension. Overview This extension provides a mechanism for creating EGLImage texture targets from EGLImages. This extension defines a new texture target, TEXTURE_EXTERNAL_OES. This texture target can only be specified using an EGLImage. There is no support for most of the functions that manipulate other texture targets (e.g. you cannot use gl*Tex*Image*() functions with TEXTURE_EXTERNAL_OES). Also, TEXTURE_EXTERNAL_OES targets never have more than a single LOD level. Because of these restrictions, it is possible to bind EGLImages which have internal formats not otherwise supported by OpenGL ES. For example some implementations may allow EGLImages with planar or interleaved YUV data to be GLES texture target siblings. It is up to the implementation exactly what formats are accepted. Glossary Please see the EGL_OES_image_base specification for a list of terms used by this specification. New Types /* * GLeglImageOES is an opaque handle to an EGLImage * Note: GLeglImageOES is also defined in GL_OES_EGL_image */ typedef void* GLeglImageOES; /* (OpenGL ES 2.x only) * New sampler type allowed by the OpenGL ES Shading Language when * #extension GL_OES_EGL_image_external * is used. */ samplerExternalOES New Procedures and Functions /* Note: EGLImageTargetTexture2DOES is also defined in GL_OES_EGL_image */ void EGLImageTargetTexture2DOES(enum target, eglImageOES image) New Tokens Accepted as a target in the parameter of BindTexture and EGLImageTargetTexture2DOES: TEXTURE_EXTERNAL_OES 0x8D65 (OpenGL ES 2.x only) Returned in the parameter of GetActiveUniform: SAMPLER_EXTERNAL_OES 0x8D66 Accepted as the parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetFixedv: TEXTURE_BINDING_EXTERNAL_OES 0x8D67 Accepted as in GetTexParameter*() queries: REQUIRED_TEXTURE_IMAGE_UNITS_OES 0x8D68 Additions to Chapter 3 of the OpenGL 1.1 or OpenGL 2.0 Specification - For OpenGL ES 2.0 add a new section: "3.7.14 External Textures," which follows section "3.7.13 Texture Objects." For OpenGL ES 1.1 add a new section after section "3.7.11 Texture Objects." "3.7.14 External Textures External textures cannot be used with TexImage2D, TexSubImage2D, CompressedTexImage2D, CompressedTexSubImage2D, CopyTexImage2D, or CopyTexSubImage2D, and an INVALID_ENUM error will be generated if this is attempted. Their default min filter is LINEAR. It is an INVALID_ENUM error to set the min filter value to anything other than LINEAR or NEAREST. The default s and t wrap modes are CLAMP_TO_EDGE and it is an INVALID_ENUM error to set the wrap mode to any other value. (For OpenGL ES 1.x only: The texture parameter GENERATE_MIPMAP is always FALSE, and setting it to any other value generates an INVALID_ENUM error. (For OpenGL ES 2.x only: Calling GenerateMipmaps with set to TEXTURE_EXTERNAL_OES results in an INVALID_ENUM.) The command void EGLImageTargetTexture2DOES(enum target, eglImageOES image); with set to TEXTURE_EXTERNAL_OES defines the currently bound external texture object to be a target sibling of . The width, height, format, type, internalformat, border, and image data are all determined based on the specified eglImageOES . Any sibling previously associated with this external texture object is deleted. A EGLImageTargetTexture2DOES() call with set to TEXTURE_EXTERNAL_OES will not modify the pixel data values in the EGLImage. must be the handle of a valid EGLImage resource, cast into the type eglImageOES. Assuming no errors are generated in EGLImageTargetTexture2DOES, the newly specified texture object will be an EGLImage target of the specified eglImageOES. If the GL is unable to specify a texture object using the supplied eglImageOES (if, for example, refers to a multisampled eglImageOES), the error INVALID_OPERATION is generated. If is not TEXTURE_EXTERNAL_OES, the error INVALID_ENUM is generated. (Note: if GL_OES_EGL_image is supported then may also be TEXTURE_2D). Sampling an external texture which is not associated with any EGLImage sibling will return a sample value of (0,0,0,1). Each TEXTURE_EXTERNAL_OES texture object may require up to 3 texture image units for each texture unit to which it is bound. The number of texture image units required by a bound texture object can be queried using GetTexParameteriv() with set to the texture target in question, set to REQUIRED_TEXTURE_IMAGE_UNITS_OES, and ActiveTexture set to the texture unit to which the texture object is bound. When is set to TEXTURE_EXTERNAL_OES this value will be between 1 and 3 (inclusive). For other valid texture targets this value will always be 1. Note that, when a TEXTURE_EXTERNAL_OES texture object is bound, the number of texture image units required by a single texture unit may be 1, 2, or 3, while for other texture objects each texture unit requires exactly 1 texture image unit. (For OpenGL ES 1.x only) DrawArrays and DrawElements will fail and generate an INVALID_OPERATION error if the number of texture image units required is greater than the number available. The number of required texture image units is equal to the sum of the requirements for each enabled texture unit. For each texture unit the requirement is the value returned by GetTexParameteriv() when is set to REQUIRED_TEXTURE_IMAGE_UNITS_OES, is set to the target which is enabled, and ActiveTexture has been set to the texture unit in question. (For OpenGL ES 2.x only) DrawArrays and DrawElements will fail and generate an INVALID_OPERATION error if the number of texture image units required is greater than the number available. The number of required texture image units for each stage (fragment or vertex) is equal to the sum of the requirements for each sampler referenced by the stage. A sampler is considered referenced if its location (returned by GetUniformLocation) is not -1. For each referenced sampler the requirement is the value returned by GetTexParameteriv() when is set to REQUIRED_TEXTURE_IMAGE_UNITS_OES, is set to the target corresponding to the sampler type, and ActiveTexture has been set to the texture unit corresponding to the value of the sampler uniform. The condition can be detected by calling Validate. (For OpenGL ES 2.x only) A shader that uses external texture samplers may require some number of hidden uniform variables to implement the conversion from YUV to RGB, and this may reduce the amount of space available for uniforms defined by the shader program. This may cause a shader program which was working to stop working when a different external texture is used (i.e. when Uniform1i or BindTexture is called). If there are not enough uniforms available then calls to DrawArrays or DrawElements will fail and generate an INVALID_OPERATION error. This condition can be detected by calling ValidateProgram. Sampling an external texture which has been modified since it was bound will return samples which may correspond to image values either before, during, or after the modification. Binding (or re-binding if already bound) an external texture by calling BindTexture after all modifications are complete guarantees that sampling done in future draw calls will return values corresponding to the values in the buffer at or after the time that BindTexture is called. (Note that calling BindTexture after calling commands that modify the EGLImage may not be sufficient to ensure that the modifications are complete; additional synchronization (for example eglWaitAPI, eglWaitNative, glFinish, vgFinish, or eglWaitSyncKHR, etc) may be required following the call initiating modifications, to ensure they have taken effect on the texture, before the call to BindTexture is made.) Sampling an external texture will return an RGBA vector in the same colorspace as the source image. If the source image is stored in YUV (or some other basis) then the YUV values will be transformed to RGB values. (But these RGB values will be in the same colorspace as the original image. Colorspace here includes the linear or non-linear encoding of the samples. For example, if the original image is in the sRGB color space then the RGB value returned by the sampler will also be sRGB, and if the original image is stored in ITU-R Rec. 601 YV12 then the RGB value returned by the sampler will be an RGB value in the ITU-R Rec. 601 colorspace.) The parameters of the transformation from one basis (e.g. YUV) to RGB (color conversion matrix, sampling offsets, etc) are taken from the EGLImage which is associated with the external texture. The implementation may choose to do this transformation when the external texture is sampled, when the external texture is bound, or any other time so long as the effect is the same. It is undefined whether texture filtering occurs before or after the transformation to RGB. If the EGLImage associated with the external texture contains alpha values then the value of the alpha component returned is taken from the image; otherwise the alpha component is 1.0. Changes to section "2.10.4 Shader Variables" of the OpenGL ES 2.0 specification (ignore for OpenGL ES 1.x) - In the subsection "Uniform Variables" paragraph 13, last sentence, add "SAMPLER_EXTERNAL_OES" to the list of types that can be returned. Changes to section "2.10.5 Shader Execution" of the OpenGL ES 2.0 specification (ignore for OpenGL ES 1.x) - In the subsection "Validation", add to the bullet points in the second paragraph: "- the number of texture image units required is greater than the number available (see REQUIRED_TEXTURE_IMAGE_UNITS_OES, MAX_COMBINED_TEXTURE_IMAGE_UNITS, MAX_VERTEX_TEXTURE_IMAGE_UNITS, and MAX_TEXTURE_IMAGE_UNITS). - the number of uniforms required to implement the shader program is greater than the number available." Changes to section "3.7.5 Texture Parameters" of the OpenGL ES 1.1 specification - Add to the end of the section a new paragraph: "When is TEXTURE_EXTERNAL_OES only NEAREST and LINEAR are accepted as TEXTURE_MIN_FILTER, only CLAMP_TO_EDGE is accepted as TEXTURE_WRAP_S and TEXTURE_WRAP_T, and only FALSE is accepted as GENERATE_MIPMAP. Attempting to set other values for TEXTURE_MIN_FILTER, TEXTURE_WRAP_S, TEXTURE_WRAP_T, or GENERATE_MIPMAP will result in an INVALID_ENUM error. Changes to section "3.7.4 Texture Parameters" of the OpenGL ES 2.0 Specification - Add to the end of the section a new paragraph: "When is TEXTURE_EXTERNAL_OES only NEAREST and LINEAR are accepted as TEXTURE_MIN_FILTER and only CLAMP_TO_EDGE is accepted as TEXTURE_WRAP_S and TEXTURE_WRAP_T. Attempting to set other values for TEXTURE_MIN_FILTER, TEXTURE_WRAP_S, or TEXTURE_WRAP_T will result in an INVALID_ENUM error. Changes to section "3.7.10 Texture State" of the OpenGL ES 1.1 Specification and section "3.7.12 Texture State" of the OpenGL ES 2.0 Specification - Add an additional sentence at the end of the section: "In the initial state of a TEXTURE_EXTERNAL_OES texture object, the value assigned to TEXTURE_MIN_FILTER and TEXTURE_MAG_FILTER is LINEAR, and the s and t wrap modes are both set to CLAMP_TO_EDGE." Changes to section "3.7.11 Mipmap Generation" of the OpenGL ES 2.0 Specification (ignore for OpenGL ES 1.x) - Add two additional paragraphs to the end of the section: "When is set to TEXTURE_EXTERNAL_OES, GenerateMipmap always fails and generates an INVALID_ENUM error." Changes to section "3.7.11 Texture Objects" of the OpenGL ES 1.1 specification (ignore for OpenGL ES 2.x) - Modify this section as follows: (changed lines marked with *, and added lines are marked with +) * "In addition to the default textures TEXTURE_2D and * TEXTURE_EXTERNAL_OES, named two-dimensional and external texture objects can be created and operated upon. The name space for texture objects is the unsigned integers, with zero reserved by the GL. A texture object is created by binding an unused name to * TEXTURE_2D or TEXTURE_EXTERNAL_OES. The binding is effected by calling void BindTexture( enum target, uint texture ); * with target set to the desired texture target and texture set to the unused name. The resulting texture object is a new state vector, comprising all the state values listed in section 3.7.10, set to the + same initial values. If the new texture object is bound to TEXTURE_2D + or TEXTURE_EXTERNAL_OES it is and remains a two-dimensional or + external texture respectively until it is deleted. BindTexture may also be used to bind an existing texture object to * TEXTURE_2D or TEXTURE_EXTERNAL_OES. If the bind is successful no change is made to the state of the bound texture object, and any previous binding to target is broken. While a texture object is bound, GL operations on the target to which it is bound affect the bound object, and queries of the target to which it is bound return state from the bound object. If texture mapping is enabled, the state of the bound texture object directs the texturing operation. * In the initial state, TEXTURE_2D and TEXTURE_EXTERNAL_OES have * two-dimensional and external texture state vectors respectively * associated with them. In order that access to these initial textures * not be lost, they are treated as texture objects all of whose names * are 0. The initial two-dimensional and external texture are therefore * operated upon, queried, and applied as TEXTURE_2D or * TEXTURE_EXTERNAL_OES respectively while 0 is bound to the * corresponding targets. Texture objects are deleted by calling void DeleteTextures( sizei n, uint *textures ); textures contains n names of texture objects to be deleted. After a texture object is deleted, it has no contents, and its name is again unused. If a texture that is currently bound to the target TEXTURE_2D * or TEXTURE_EXTERNAL_OES is deleted, it is as though BindTexture had been executed with the same target and texture zero. Unused names in textures are silently ignored, as is the value zero. The command void GenTextures( sizei n, uint *textures ); returns n previously unused texture object names in textures. These names are marked as used, for the purposes of GenTextures only, but they acquire texture state only when they are first bound, just as if they were unused. The texture object name space, including the initial texture object, is shared among all texture units. A texture object may be bound to more than one texture unit simultaneously. After a texture object is bound, any GL operations on that target object affect any other texture units to which the same texture object is bound. Texture binding is affected by the setting of the state ACTIVE_TEXTURE. If a texture object is deleted, it is as if all texture units which are bound to that texture object are rebound to texture object zero. Changes to section "3.7.13 Texture Objects" of the OpenGL ES 2.0 specification (ignore for OpenGL ES 1.x) - Modify this section as follows: (changed lines marked with *, and added lines are marked with +) * "In addition to the default textures TEXTURE_2D, TEXTURE_CUBE_MAP, * and TEXTURE_EXTERNAL_OES, named two-dimensional, cube map, and external texture objects can be created and operated upon. The name space for texture objects is the unsigned integers, with zero reserved by the GL. A texture object is created by binding an unused name to * TEXTURE_2D, TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL_OES. The binding is effected by calling void BindTexture( enum target, uint texture ); with target set to the desired texture target and texture set to the unused name. The resulting texture object is a new state vector, comprising all the state values listed in section 3.7.12, set to the same initial values. If the new texture object is bound to TEXTURE_2D, * TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL_OES it is and remains a * two-dimensional, cube map, or external texture respectively until it is deleted. BindTexture may also be used to bind an existing texture object to * either TEXTURE_2D, TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL_OES. The error INVALID_OPERATION is generated if an attempt is made to bind a texture * object of different target than the specified target. If the bind is successful no change is made to the state of the bound texture object, and any previous binding to target is broken. While a texture object is bound, GL operations on the target to which it is bound affect the bound object, and queries of the target to which it is bound return state from the bound object. If texture mapping is enabled, the state of the bound texture object directs the texturing operation. * In the initial state, TEXTURE_2D, TEXTURE_CUBE_MAP, and * TEXTURE_EXTERNAL_OES have two-dimensional, cube map, and external texture state vectors respectively associated with them. In order that access to these initial textures not be lost, they are treated as texture objects all of whose names are 0. The initial two-dimensional, * cube map, and external texture are therefore operated upon, queried, * and applied as TEXTURE_2D, TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL_OES respectively while 0 is bound to the corresponding targets. Texture objects are deleted by calling void DeleteTextures( sizei n, uint *textures ); textures contains n names of texture objects to be deleted. After a texture object is deleted, it has no contents or dimensionality, and its name is again unused. If a texture that is currently bound to one * of the targets TEXTURE_2D, TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL_OES is deleted, it is as though BindTexture had been executed with the same target and texture zero. Unused names in textures are silently ignored, as is the value zero. The command void GenTextures( sizei n, uint *textures ); returns n previously unused texture object names in textures. These names are marked as used, for the purposes of GenTextures only, but they acquire texture state only when they are first bound, just as if they were unused. The texture object name space, including the initial texture object, is shared among all texture units. A texture object may be bound to more than one texture unit simultaneously. After a texture object is bound, any GL operations on that target object affect any other texture units to which the same texture object is bound. Texture binding is affected by the setting of the state ACTIVE_TEXTURE. If a texture object is deleted, it is as if all texture units which are bound to that texture object are rebound to texture object zero. Changes to section "3.7.13 Texture Application" of the OpenGL ES 1.1 specification (ignore for OpenGL ES 2.x) - Replace the first sentence of the first paragraph with: "Texturing is enabled or disabled using the generic Enable and Disable commands, with the symbolic constant TEXTURE_2D or TEXTURE_EXTERNAL_OES to enable or disable texturing with the TEXTURE_2D or TEXTURE_EXTERNAL_OES texture target, respectively. If TEXTURE_EXTERNAL_OES is enabled it takes precedence over TEXTURE_2D, TEXTURE_CUBE_MAP_OES, TEXTURE_RECTANGLE_ARB, and TEXTURE_RECTANGLE_NV." Changes to section "3.8.2 Shader Execution" of the OpenGL ES 2.0 specification (ignore for OpenGL ES 1.x) - Add to the end of the last paragraph of the subsection "Texture Access" "The REQUIRED_TEXTURE_IMAGE_UNITS_OES parameter can change based on the number of external textures which are currently bound (see section 3.7.14)." Changes to section "6.1.3 Enumerated Queries" of the OpenGL ES 1.1 specification - Change: "...TEXTURE_2D..." to "...TEXTURE_2D or TEXTURE_EXTERNAL..." in the last paragraph. Changes to section "6.1.3 Enumerated Queries" of the OpenGL ES 2.0 specification - Change: "...TEXTURE_2D or TEXTURE_CUBE_MAP..." to "...TEXTURE_2D, TEXTURE_CUBE_MAP, or TEXTURE_EXTERNAL..." in the second paragraph. Changes to section "6.2 State Tables" of the OpenGL ES 1.1 specification - Add to "Table 6.13 Textures (state per texture unit and binding point)" +-------------------+-------+-------------+-------+------------------+ | TEXTURE_BINDING_- | 8*xZ+ | GetIntegerv | 0 | Texture object | | EXTERNAL_OES | | | | bound to | | | | | | TEXTURE_- | | | | | | EXTERNAL_OES | +-------------------+-------+-------------+-------+------------------+ | TEXTURE_- | 2*xB | IsEnabled | False | True if external | | EXTERNAL_OES | | | | texturing is | | | | | | enabled | +-------------------+-------+-------------+---+----------------------+ - Add to "Table 6.14 Textures (state per texture object)" +--------------------+-------+-----------------+---+----------------+ | REQUIRED_TEXTURE_- | n*xZ3 | GetTexParameter | 1 | Number of | | IMAGE_UNITS_OES | | | | texture image | | | | | | units required | | | | | | by texture | +--------------------+-------+-----------------+---+----------------+ Changes to section "6.2 State Tables" of the OpenGL ES 2.0 specification - Add to "Table 6.7 Textures (state per texture unit and binding point)" +-------------------+-------+-------------+-------+------------------+ | TEXTURE_BINDING_- | 8*xZ+ | GetIntegerv | 0 | Texture object | | EXTERNAL_OES | | | | bound to | | | | | | TEXTURE_- | | | | | | EXTERNAL_OES | +-------------------+-------+-------------+-------+------------------+ - Add to "Table 6.8 Textures (state per texture object)" +--------------------+-------+-----------------+---+----------------+ | REQUIRED_TEXTURE_- | n*xZ3 | GetTexParameter | 1 | Number of | | IMAGE_UNITS_OES | | | | texture image | | | | | | units required | | | | | | by texture | +--------------------+-------+-----------------+---+----------------+ Changes to section 3.7 of the OpenGL ES Shading Language specification - Add to the list of keywords: "samplerExternalOES" Changes to section 4.1 of the OpenGL ES Shading Language specification - Add to the list of basic types: "samplerExternalOES a handle for accessing an external texture" Changes to section 4.5.3 of the OpenGL ES Shading Language specification - Add to the list of "vertex language has the following predeclared globally scoped default precision statements:" "precision lowp samplerExternalOES;" - Add to the list of "fragment language has the following predeclared globally scoped default precision statements:" "precision lowp samplerExternalOES;" Changes to section 8.7 of the OpenGL ES Shading Language specification - Add to the table the following sampler functions: "vec4 texture2D( samplerExternalOES sampler, vec2 coord) vec4 texture2DProj( samplerExternalOES sampler, vec3 coord) vec4 texture2DProj( samplerExternalOES sampler, vec4 coord)" Changes to section 9 of the OpenGL ES Shading Language specification - Add to token list: "SAMPLEREXTERNAL" - Add following "type_specifier_no_prec:" "SAMPLEREXTERNAL" Changes to section "A.7 Counting of Varyings and Uniforms" of the OpenGL ES Shading Language specification - Change the first sentence of the last paragraph to "Part of the storage may be reserved by an implementation for its own use e.g. for computation of transcendental functions or conversion of external textures." Issues 1. What happens when GenerateMipmaps() is called with set to TEXTURE_EXTERNAL_OES? Possible options: A) Fail (INVALID_ENUM) B) Generate the mipmaps and copy them into the TEXTURE_2D target. Option B could be useful and should not be difficult to implement. What happens when the texture is NPOT and GenerateMipmaps() is called? Ben Bowman and David Garcia have indicated they prefer A. No other strong opinions yet. RESOLVED: A (fail) 2. Should the wrap mode of an external texture be allowed to be anything other than CLAMP_TO_EDGE? RESOLVED: no 3. What about portability problems introduced by allowing implementation- dependent failures? This is the same issue described in Issue 14 of the EGL_OES_image specification. Like the resolution for that issue, this specification should include some minimum requirements, but leave the larger portability problem unresolved at the moment. RESOLVED: This and other (EGL_KHR_image_uses and EGL_KHR_il_image) extensions attempt to minimize this problem by allowing EGL to pick EGLImage attributes which will work in various situations. However it is not possible to guarantee that every usecase will work on every platform. 4. Should EGLImageTargetTexture2DOES result in undefined pixel data, as with calls to eglCreateImageOES? See also issue 4 of GL_OES_EGL_image Comment from Aske: In the description for EGLImageTargetTexture2DOES, it says: "As a result of this operation all pixel data in will become undefined." Why is this? I would imagine one would want to take an existing EGL image containing image data and bind it as an external texture, possibly multiple times, to use it for rendering. I have read through issue 4 of OES_EGL_image, and it seems the concern here is what happens when the image is (potentially) modified from OpenGL ES. Since external images cannot be modified from OpenGL ES, I would guess the same issues do not apply here. Comment from Acorn: Another potential issue is that the memory for the EGLImage may have to be reallocated in order to be compatible with GLES (e.g. GLES may have more strict alignment or other requirements). However, the implementation can fail (or do a copy) if this is the case. If the EGL_KHR_image_uses extension is used to specify that the EGLImage will be used as a GLES external texture then this should not be an issue because EGL will be able to allocate the memory correctly in the first place. RESOLVED: pixel data will not become undefined when EGLImageTargetTexture2DOES() is used with an external texture target. 5. What happens if the texture is bound while the associated EGLImage is being modified. Some implementations may need to color convert the data after it has been generated. A solution to this is to state that the texels become undefined if the external texture is bound while the underlying texels are modified. This way any color conversion can be done (e.g. to a second buffer) when the texture is bound. Options: A) require the texture be unbound while the EGLImage is being modified B) Require the texture to be bound (or re-bound if already bound) between modification and use (i.e. after modification and before used as a texture). C) No requirement. RESOLVED: B 6. How can current generation hardware support planar YUV EGLImage formats? GLES 2.0 hardware can perform color conversion by inserting extra instructions into the shader program. However, planar textures require 2 or 3 surfaces to be read in order to sample a single texture. One solution is to increase the number of texture image units required by a texture object which is associated with such an EGLImage. RESOLVED: allow the implementation to set the number of texture image units required by each texture object. Allow the app to query this with REQUIRED_TEXTURE_IMAGE_UNITS_OES. Have drawing commands fail (INVALID_OPERATION) when the number of texture image units required by all enabled/referenced texture units exceeds the implementation limit (which can be queried with MAX_COMBINED_TEXTURE_IMAGE_UNITS, MAX_VERTEX_TEXTURE_IMAGE_UNITS, and MAX_TEXTURE_IMAGE_UNITS) See also issue 10. 7. Should there be new texture sampling functions for samplerExternalOES or is it OK to use the existing 2D sampler functions. RESOLVED: Use existing 2D sampler functions. 8. If an EGLImage associated with an external texture does not contain an alpha channel, should the alpha be 1 or undefined. From an app point of view, 1 probably makes more sense. However, if the texture is in a RGBA format and there is garbage in the A channel, it may be difficult for implementations to return 1. An implementation may have to recompile the shader to force the alpha channel to 1. RESOLVED: alpha is defined to be 1 in this case. 9. How should the color conversion be described. Options: A) State that the color values are transformed to a linear colorspace and represented as RGB values in that space. This may be difficult for implementations since it may require nonlinear transformations (e.g. gamma decoding). It is also problematic because usually many more bits are required to represent a value in a linear colorspace than in a gamma encoded colorspace. B) State that the color is transformed to RGB but in the same colorspace as the source image (i.e. no gamma encode or decode). RESOLVED: Option B. 10. How does the implementation indicate which texture samplers and/or texture units are not available when one or more external textures are bound. See discussion on GLES email list around Feb 23 with subject "RE: [OpenGL-ES] IL/ES interaction: YUV texture extension proposal" Proposals: A) The MAX_COMBINED_TEXTURE_IMAGE_UNITS, MAX_VERTEX_TEXTURE_IMAGE_UNITS, and MAX_TEXTURE_IMAGE_UNITS parameters change to reflect the current state. B) New queries AVAILABLE_COMBINED_TEXTURE_IMAGE_UNITS, AVAILABLE_VERTEX_TEXTURE_IMAGE_UNITS, and AVAILABLE_TEXTURE_IMAGE_UNITS indicate current state, while MAX_COMBINED_TEXTURE_IMAGE_UNITS, MAX_VERTEX_TEXTURE_IMAGE_UNITS, and MAX_TEXTURE_IMAGE_UNITS remain constant and indicate the state when no external textures are bound. C) Query for number of required texture image units per texture object. Draw calls fail with INVALID_OPERATION if the current requirements for texture image units exceeds the number available. RESOLVED: C 11. What happens when glUniform1i() sets a sampler to a value that is larger than the number of available texture units? NOTE: This issue no longer affects this extension. See issue 10 for different issue related to texture *image* units. This is really a GLES2 spec issue. See khronos bug 3702 https://cvs.khronos.org/bugzilla/show_bug.cgi?id=3702 http://www.khronos.org/members/login/list_archives/arb-glsl/ 0705/msg00010.html http://www.khronos.org/members/login/list_archives/opengl_es/ 0902/msg00148.html RESOLVED: The issue is not resolved, but it no longer applies directly to this extension. Further discussion should be in bug 3702. 12. What happens at draw time when the current state requires more texture units than the implementation can support? RESOLVED: The precedent, from (desktop) OpenGL, is to fail in glValidate, and to fail in any draw call with an INVALID_OPERATION error. Behavior described in this extension will match that precedent. 13. How can this be conformance tested? In the native code, add a function which takes as a parameter an array of pixels. The function returns an EGLImage which contains the pixels in some unspecified format. A test can call this function, call glEGLImageTargetTexture2DOES() to associate it with an external texture, and render using this texture, and read back the framebuffer to confirm that the result is the expected result. Note1: since the format is unknown and unknowable, possibly only the high bit of each component (RGB) should be tested. It may be sufficient to pass a single pixel (or single bit for each of R, G, an B) and then create the EGLImage with every pixel in the image set to that same value. Note2: It might be a good idea to have an extra parameter, int index, which allows the function to be implemented several different ways. The test could be run several times, with index set to 0, 1, 2, ... until the function returns EGL_NO_IMAGE. This way the function could generate EGLImages with various formats. For example when index is 0 it could call OMX IL to generate a YUV planar EGLImage, when index is 1 it could call OMX AL to generate a YUV interleaved EGLImage, and when index is 2 it could call into VG to generate an RGB EGLImage. The meaning of each index would be up to the implementation. A simple implementation might return an EGLImage when index=0 and return EGL_NO_IMAGE otherwise. Additional suggestion from Jon Leech: The suggested conformance test in issue 13 is intentionally so vague on precision (1 bit/component) that the conversion language seems even less meaningful. The RGB bits that come out of texture sampling would need have almost no relationship to what went in. ISTM the supplier of the EGLImage knows the precision of it, and that information could be provided to the test to put on tighter constraints. RESOLVED: As described above. 14. Can the number of uniforms required by a shader change when switching from one external texture to another, and therefore cause the shader to fail? For example, imagine a program does this: glLinkProgram(prog); // successful link sampler = glGetUniformLocation(prog, "myExtSampler"); glUniform1i(sampler, 1); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_EXTERNAL, myTex1_rgb); glDrawArrays(); // draw successfully glBindTexture(GL_TEXTURE_EXTERNAL, myTex2_yuv); glDrawArrays(); // Can this fail??? Is it acceptable for an implementation to fail the second glDrawArrays() call because myTex2_yuv is a yuv image and requires more uniforms to implement a color conversion matrix than myTex1_rgb which is an rgb image and does not require any conversion matrix? Note that this situation will only occur on implementation which will recompile the shader based on the color conversion required. Options: A) No, the implementation is not allowed to fail. When the program is linked the implementation must verify that there are enough uniforms to implement the program for any flavor of external texture. If the implementation does not provide enough uniforms for the program to work with any external texture that the implementation supports, then the implementation must fail at link time. B) Yes, the implementation may fail in glDrawArrays or glDrawElements if the number of uniforms required by the program exceeds those available. This means that a call to glUniform1i() or glBindTexture() can cause a shader program that used to work to stop working. (Note that this is possible anyway since the new external texture may use more texture image units than the old external texture (independent of the number of uniforms). But that can be detected by the application by querying REQUIRED_TEXTURE_IMAGE_UNITS_OES) RESOLVED: choice B. 15. How should filtering of non-RGB formats be specified. Options: A) filtering occurs before transformation to RGB. B) filtering occurs after transformation to RGB. C) undefined (up to the implementation) RESOLVED: C Dependencies on EGL_OES_image_base and EGL 1.1 If either EGL 1.1 or the EGL_OES_image extension is not supported, all discussion of EGLImages should be ignored, and any calls to EGLImageTargetTexture2DOES should generate the error INVALID_OPERATION. Dependencies on GL_OES_EGL_image If GL_OES_EGL_image is supported then change the text in both extensions to allow either TEXTURE_2D or TEXTURE_EXTERNAL_OES to be passed as the parameter to EGLImageTargetTexture2DOES(). When is TEXTURE_2D, behavior of EGLImageTargetTexture2DOES() is as described in the GL_OES_EGL_image spec. When is TEXTURE_EXTERNAL_OES, behavior of EGLImageTargetTexture2DOES() is as described in this spec. Revision History #25 - (April 6, 2018) H1Gdev Fix typo. #24 - (April 23, 2015) Jon Leech) - Fix typo EGLImageTargetTexImage2DOES -> EGLImageTargetTexture2DOES (Bug 8114). Improve description of supported queries for new tokens (Bug 8118). #23 - (July 19, 2012) Acorn Pooley - fix extension name from OES_EGL_image_external to GL_OES_EGL_image_external #22 - (Dec 17, 2010) Acorn Pooley status to ratified. #21 - (Sept. 29, 2010) Maurice Ribble Update token numbers and updated status to approved. #20 - (April 2, 2009) Acorn Pooley Rename GL_OES_egl_image_external to GL_OES_EGL_image_external to be consistant with GL_OES_EGL_image. #19 - (March 31, 2009) Acorn Pooley Minor fixes #18 - (March 30, 2009) Acorn Pooley Fix inconsistancy #17 - (March 25, 2009) Acorn Pooley Resolved issue 4 (and some others) #16 - (March 16, 2009) Acorn Pooley Augment issue 13 #15 - (March 13, 2009) Acorn Pooley fix dependancy section resolve issue 14 and fix text #14 - (March 9, 2009) Acorn Pooley Fix colorspace comments. Issue 9 is resolved. #13 - (March 6, 2009) Acorn Pooley Mark issue 6, 10, and 11 resolved. Add issue 15. #12 - (March 4, 2009) Acorn Pooley Fix wording of uniform stuff. #11 - (March 4, 2009) Acorn Pooley Add issues 13, 14. Add comments about extra uniforms required by external texture samplers. Allow external textures to work with default object 0. Correct colorspace language. #10 - (March 3, 2009) Acorn Pooley Remove stale reference to MAX_TEXTURE_IMAGE_UNITS. Add fix to OpenGL ES 2.0 section 2.10.5 (from bruce). Add contributors. Clarify "texture unit" vs "texture image unit". Fix typos. #9 - (February 26, 2009) Acorn Pooley Clarify sync further. Add issue 12. Change "too many texture units" behavior. #8 - (February 26, 2009) Acorn Pooley Clarify sync requirements (i.e. that EGLImage does not do sync) #7 - (February 25, 2009) Acorn Pooley Relax binding requirement - see issue 5 #6 - (February 25, 2009) Acorn Pooley Add TEXTURE_BINDING_EXTERNAL_OES. Add texture state notes. Modify colorspace conversion to be a linear function. #5 - (February 24, 2009) Acorn Pooley Disable GenerateMipmaps. Add issues 10 & 11. #4 - (February 23, 2009) Acorn Pooley Modify the "Texture Parameters" section in ES 1 and 2 specs #3 - (February 20, 2009) Acorn Pooley Clarify the reduction in number of texture units. #2 - (February 20, 2009) Acorn Pooley Fix some errors. replace textureExternal* sampler functions with existing sampler2D* functions. Add issue 7,8,9. Fix spelling. #1 - (February 9, 2009) Original draft