2018
The Khronos Group Inc.
eglCreateImage
3G
eglCreateImage
Create a new EGLImage object
C Specification
EGLImage eglCreateImage
(EGLDisplay display
EGLContext context
EGLenum target
EGLClientBuffer buffer
const EGLAttrib *attrib_list
Parameters
display
Specifies the EGL display connection.
context
Specifies the client API context for which the image is
created.
target
Specifies the type of resource used as the image source.
buffer
Specifies the resource to be used as the image source.
attrib_list
Specifies attributes used to select sub-sections of the
resource to be used as the image source.
Description
eglCreateImage is used to create an
EGLImage object from an existing image resource
buffer. display
specifies the EGL display used for this operation.
context specifies the EGL client API
context used for this operation, or
EGL_NO_CONTEXT if a client API context is
not required. target specifies the type
of resource being used as the EGLImage source
(examples include two-dimensional textures in OpenGL ES contexts
and VGImage objects in OpenVG contexts).
buffer is the name (or handle) of a
resource to be used as the EGLImage source, cast
into the type EGLClientBuffer.
attrib_list is a list of attribute-value
pairs which is used to select sub-sections of
buffer for use as the
EGLImage source, such as mipmap levels for OpenGL
ES texture map resources, as well as behavioral options, such as
whether to preserve pixel data during creation. If
attrib_list is
non-NULL, the last attribute specified in
the list must be EGL_NONE.
The resource specified by display,
context, target,
buffer, and
attrib_list must not itself be an
EGLImage sibling, or bound to a pbuffer
EGLSurface resource
(eglBindTexImage,
eglCreatePbufferFromClientBuffer).
Values accepted for target are shown in
table .
Legal values for eglCreateImage target
target
Notes
EGL_GL_TEXTURE_2D
Used for GL 2D texture images
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_X
Used for the +X face of GL cubemap texture images
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X
Used for the -X face of GL cubemap texture images
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y
Used for the +Y face of GL cubemap texture images
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
Used for the -Y face of GL cubemap texture images
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z
Used for the +Z face of GL cubemap texture images
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
Used for the -Z face of GL cubemap texture images
EGL_GL_TEXTURE_3D
Used for OpenGL and OpenGL ES 3D texture images
EGL_GL_RENDERBUFFER
Used for OpenGL and OpenGL ES renderbuffer images
Attribute names accepted in attrib_list
are shown in table , together
with the target for which each attribute
name is valid, and the default value used for each attribute if
it is not included in attrib_list.
Legal attributes for eglCreateImage
attrib_list parameter
target
Notes
Attribute
Description
Valid targets
Default Value
EGL_NONE
Marks the end of the attribute-value list
All
N/A
EGL_GL_TEXTURE_LEVEL
Specifies the mipmap level used as the
EGLImage source. Must be part of
the complete texture object
buffer
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*, or
EGL_GL_TEXTURE_3D
0
EGL_GL_TEXTURE_ZOFFSET
Specifies the depth offset of the image to use
as the EGLImage source. Must be
part of the complete texture object
buffer
EGL_GL_TEXTURE_3D
0
EGL_IMAGE_PRESERVED
Whether to preserve pixel data
All
EGL_FALSE
eglCreateImage returns an
EGLImage object corresponding to the image data
specified by display,
context, target,
buffer and
attrib_list which may be referenced by
client API operations.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_3D,
EGL_GL_RENDERBUFFER,
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_X,
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X,
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y,
EGL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or
EGL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z,
display must be a valid
EGLDisplay, and context must
be a valid OpenGL or OpenGL ES API context on that display.
If target is
EGL_GL_TEXTURE_2D,
buffer must be the name of a nonzero,
GL_TEXTURE_2D target texture object, cast
into the type EGLClientBuffer.
If target is one of the
EGL_GL_TEXTURE_CUBE_MAP_* enumerants,
buffer must be the name of a nonzero,
GL_TEXTURE_CUBE_MAP (or equivalent in GL
extensions) target texture object, cast into the type
EGLClientBuffer.
If target is
EGL_GL_TEXTURE_3D,
buffer must be the name of a nonzero,
GL_TEXTURE_3D (or equivalent in GL
extensions) target texture object, cast into the type
EGLClientBuffer.
attrib_list should specify the mipmap
level (EGL_GL_TEXTURE_LEVEL) and, where
applicable, z-offset
(EGL_GL_TEXTURE_ZOFFSET) which will be used
as the EGLImage source; If not specified, the
default values listed in table
will be used instead. Additional values specified in are
ignored.
There must exist some levels x and
y such that the mipmap level requested lies
between x and y
(inclusive), the texture would be mipmap complete were
x substituted for the base level and
y substituted for the max level, and all
levels less than x or greater than
y are unspecified. For cubemaps a single
pair x and y must
apply to all faces. For three-dimensional textures, the
specified z-offset must be smaller than the depth of the
specified mipmap level.
If target is
EGL_GL_RENDERBUFFER,
buffer must be the name of a complete,
nonzero, non-multisampled GL_RENDERBUFFER
(or equivalent in extensions) target object, cast into the type
EGLClientBuffer. Values specified in
attrib_list are ignored.
If the value of attribute
EGL_IMAGE_PRESERVED is
EGL_FALSE (the default), then all pixel
data values associated with buffer will
be undefined after eglCreateImage returns.
If the value of attribute
EGL_IMAGE_PRESERVED is
EGL_TRUE, then all pixel data values
associated with buffer are preserved.
Errors
eglCreateImage returns
EGL_NO_IMAGE on failure. The contents of
buffer will be unaffected.
If display is not the handle of a valid
EGLDisplay object, the error
EGL_BAD_DISPLAY is generated.
If context is neither the handle of a
valid EGLContext object on
display nor
EGL_NO_CONTEXT, the error
EGL_BAD_CONTEXT is generated.
If target is not one of the values in
table , the error
EGL_BAD_PARAMETER is generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*,
EGL_GL_RENDERBUFFER or
EGL_GL_TEXTURE_3D, and
display is not a valid
EGLDisplay, the error
EGL_BAD_DISPLAY is generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*,
EGL_GL_RENDERBUFFER or
EGL_GL_TEXTURE_3D, and
context is not a valid
EGLContext, the error
EGL_BAD_CONTEXT is generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*,
EGL_GL_RENDERBUFFER or
EGL_GL_TEXTURE_3D, and
context is not a valid GL context, or
does not match the display, the error
EGL_BAD_MATCH is generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_* or
EGL_GL_TEXTURE_3D and
buffer is not the name of a texture
object of type target, the error
EGL_BAD_PARAMETER is generated.
If target is
EGL_GL_RENDERBUFFER and
buffer is not the name of a renderbuffer
object, or if buffer is the name of a
multisampled renderbuffer object, the error
EGL_BAD_PARAMETER is generated.
If EGL_GL_TEXTURE_LEVEL is nonzero,
target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_* or
EGL_GL_TEXTURE_3D, and
buffer is not the name of a complete GL
texture object, the error EGL_BAD_PARAMETER
is generated.
If EGL_GL_TEXTURE_LEVEL is 0,
target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_* or
EGL_GL_TEXTURE_3D,
buffer is the name of an incomplete GL
texture object, and any mipmap levels other than mipmap level 0
are specified, the error EGL_BAD_PARAMETER
is generated.
If EGL_GL_TEXTURE_LEVEL is 0,
target is
EGL_GL_TEXTURE_2D or
EGL_GL_TEXTURE_3D,
buffer is not the name of a complete GL
texture object, and mipmap level 0 is not specified, the error
EGL_BAD_PARAMETER is generated.
If EGL_GL_TEXTURE_LEVEL is 0,
target is
EGL_GL_TEXTURE_CUBE_MAP_*,
buffer is not the name of a complete GL
texture object, and one or more faces do not have mipmap level 0
specified, the error EGL_BAD_PARAMETER is
generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*,
EGL_GL_RENDERBUFFER or
EGL_GL_TEXTURE_3D and
buffer refers to the default GL texture
object (0) for the corresponding GL target, the error
EGL_BAD_PARAMETER is generated.
If target is
EGL_GL_TEXTURE_2D,
EGL_GL_TEXTURE_CUBE_MAP_*, or
EGL_GL_TEXTURE_3D, and the value specified
in attrib_list for
EGL_GL_TEXTURE_LEVEL is not a valid mipmap
level for the specified GL texture object
buffer, the error
EGL_BAD_MATCH is generated.
If target is
EGL_GL_TEXTURE_3D, and the value specified
in attrib_list for
EGL_GL_TEXTURE_ZOFFSET exceeds the depth of
the specified mipmap level-of-detail in
buffer, the error
EGL_BAD_PARAMETER is generated.
If an attribute specified in attrib_list
is not one of the attributes shown in table , the error
EGL_BAD_PARAMETER is generated.
If an attribute specified in attrib_list
is not a valid attribute for target, as
shown in table , the error
EGL_BAD_MATCH is generated.
If the resource specified by display,
context, target,
buffer and
attrib_list has an off-screen buffer
bound to it (e.g., by a previous call to
eglBindTexImage), the error
EGL_BAD_ACCESS is generated.
If the resource specified by display,
context, target,
buffer and
attrib_list is bound to an off-screen
buffer (e.g., by a previous call to
eglCreatePbufferFromClientBuffer), the
error EGL_BAD_ACCESS is generated.
If the resource specified by display,
context, target,
buffer and
attrib_list is itself an
EGLImage sibling, the error
EGL_BAD_ACCESS is generated.
If insufficient memory is available to complete the specified
operation, the error EGL_BAD_ALLOC is
generated.
If the value specified in attrib_list for
EGL_IMAGE_PRESERVED is
EGL_TRUE, and an EGLImage
handle cannot be created from the specified resource such that
the pixel data values in buffer are
preserved, the error EGL_BAD_ACCESS is
generated.
Note that the success or failure of
eglCreateImage should not affect the
ability to use buffer in its original API
context (or context share group) (although the pixel data values
will be undefined if the command succeeds and the value of
EGL_IMAGE_PRESERVED is not
EGL_TRUE).
Lifetime and Usage of EGLImages
Once an EGLImage is created from an
EGLImage source, the memory associated with the
EGLImage source will remain allocated (and all
EGLImage siblings in all client API contexts will
be useable) as long as either of the following conditions is
true:
Any EGLImage siblings exist in any client
API context
The EGLImage object exists inside EGL
The semantics for specifying, deleting and using
EGLImage siblings are client API-specific, and are
described in the appropriate API specifications.
If an application specifies an EGLImage sibling as
the destination for rendering and/or pixel download operations
(e.g., as an OpenGL or OpenGL ES framebuffer object,
glTexSubImage2D, etc.), the modified image
results will be observed by all EGLImage siblings
in all client API contexts. If multiple client API contexts
access EGLImage sibling resources simultaneously,
with one or more context modifying the image data, rendering
results in all contexts accessing EGLImage siblings
are undefined.
Respecification and/or deletion of any EGLImage
sibling (i.e., both EGLImage source and
EGLImage target resources) inside a client API
context (by issuing a subsequent call to commands such as
glTexImage* or
glDeleteTextures, with the
EGLImage sibling resource as the target of the
operation) affects only that client API context and other
contexts within its share group. For an OpenGL or OpenGL ES
context, respecification always results in
orphaning of the EGLImage,
and may also include allocation of additional memory for the
respecified resource and/or copying of the EGLImage
pixel data.
Note: Behavior of other types of client APIs generally follows
the OpenGL and OpenGL ES behavior described here, although this
is not mandated yet.
Operations inside EGL or any client API context which may affect
the lifetime of an EGLImage (or the memory
allocated for the EGLImage), such as respecifying
and/or deleting an EGLImage sibling inside a client
API context, must be atomic.
Applications may create client API resources from an
EGLImage using client API extensions outside the
scope of this document (such as
GL_OES_EGL_image, which creates OpenGL ES
texture and renderbuffer objects). If the EGLImage
used to create the client resource was created with the
EGL_IMAGE_PRESERVED attribute set to
EGL_TRUE, then the pixel data values
associated with the image will be preserved after creating the
client resource; otherwise, the pixel data values will be
undefined. If the EGLImage was created with the
EGL_IMAGE_PRESERVED attribute set to
EGL_TRUE, and EGL is unable to create the
client resource without modifying the pixel values, then
creation will fail and the pixel data values will be preserved.
Notes
eglCreateImage is available only if the EGL
version is 1.5 or greater.
See Also
eglBindTexImage,
eglCreatePbufferFromClientBuffer,
eglDestroyImage,
glDeleteTextures,
glTexImage*,
glTexSubImage2D