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GLGETFRAMEBUFFERATTA(3G)                         OpenGL 3.3                         GLGETFRAMEBUFFERATTA(3G)



NAME
       glGetFramebufferAttachmentParameteriv - retrieve information about attachments of a bound framebuffer
       object

C SPECIFICATION
       void glGetFramebufferAttachmentParameter(GLenum target, GLenum attachment, GLenum pname,
                                                GLint *params);

PARAMETERS
       target
           Specifies the target of the query operation.

       attachment
           Specifies the attachment within target

       pname
           Specifies the parameter of attachment to query.

       params
           Specifies the address of a variable receive the value of pname for attachment.

DESCRIPTION
       glGetFramebufferAttachmentParameter returns information about attachments of a bound framebuffer
       object.  target specifies the framebuffer binding point and must be GL_DRAW_FRAMEBUFFER,
       GL_READ_FRAMEBUFFER or GL_FRAMEBUFFER.  GL_FRAMEBUFFER is equivalent to GL_DRAW_FRAMEBUFFER.

       If the default framebuffer is bound to target then attachment must be one of GL_FRONT_LEFT,
       GL_FRONT_RIGHT, GL_BACK_LEFT, or GL_BACK_RIGHT, identifying a color buffer, GL_DEPTH, identifying the
       depth buffer, or GL_STENCIL, identifying the stencil buffer.

       If a framebuffer object is bound, then attachment must be one of GL_COLOR_ATTACHMENTi,
       GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT, or GL_DEPTH_STENCIL_ATTACHMENT.  i in
       GL_COLOR_ATTACHMENTi must be in the range zero to the value of GL_MAX_COLOR_ATTACHMENTS - 1.

       If attachment is GL_DEPTH_STENCIL_ATTACHMENT and different objects are bound to the depth and stencil
       attachment points of target the query will fail. If the same object is bound to both attachment
       points, information about that object will be returned.

       Upon successful return from glGetFramebufferAttachmentParameteriv, if pname is
       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, then params will contain one of GL_NONE,
       GL_FRAMEBUFFER_DEFAULT, GL_TEXTURE, or GL_RENDERBUFFER, identifying the type of object which contains
       the attached image. Other values accepted for pname depend on the type of object, as described below.

       If the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_NONE, no framebuffer is bound to target.
       In this case querying pname GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME will return zero, and all other
       queries will generate an error.

       If the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is not GL_NONE, these queries apply to all
       other framebuffer types:

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE, GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE,
           GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE, GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE,
           GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE, or GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE, then params will
           contain the number of bits in the corresponding red, green, blue, alpha, depth, or stencil
           component of the specified attachment. Zero is returned if the requested component is not present
           in attachment.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE, params will contain the format of
           components of the specified attachment, one of GL_FLOAT, GL_INT, GL_UNSIGNED_INT,
           GL_SIGNED_NORMALIZED, or GL_UNSIGNED_NORMALIZED for floating-point, signed integer, unsigned
           integer, signed normalized fixed-point, or unsigned normalized fixed-point components
           respectively. Only color buffers may have integer components.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING, param will contain the encoding of
           components of the specified attachment, one of GL_LINEAR or GL_SRGB for linear or sRGB-encoded
           components, respectively. Only color buffer components may be sRGB-encoded; such components are
           treated as described in sections 4.1.7 and 4.1.8. For the default framebuffer, color encoding is
           determined by the implementation. For framebuffer objects, components are sRGB-encoded if the
           internal format of a color attachment is one of the color-renderable SRGB formats.

       If the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_RENDERBUFFER, then:

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, params will contain the name of the
           renderbuffer object which contains the attached image.

       If the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_TEXTURE, then:

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, then params will contain the name of the
           texture object which contains the attached image.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL, then params will contain the mipmap level of
           the texture object which contains the attached image.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE and the texture object named
           GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME is a cube map texture, then params will contain the cube
           map face of the cubemap texture object which contains the attached image. Otherwise params will
           contain the value zero.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER and the texture object named
           GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME is a layer of a three-dimensional texture or a one-or
           two-dimensional array texture, then params will contain the number of the texture layer which
           contains the attached image. Otherwise params will contain the value zero.

       •   If pname is GL_FRAMEBUFFER_ATTACHMENT_LAYERED, then params will contain GL_TRUE if an entire
           level of a three-dimesional texture, cube map texture, or one-or two-dimensional array texture is
           attached. Otherwise, params will contain GL_FALSE.

       Any combinations of framebuffer type and pname not described above will generate an error.

ERRORS
       GL_INVALID_ENUM is generated if target is not one of the accepted tokens.


       GL_INVALID_ENUM is generated if pname is not valid for the value of
       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE.


       GL_INVALID_OPERATION is generated if attachment is not the accepted values for target.


       GL_INVALID_OPERATION is generated if attachment is GL_DEPTH_STENCIL_ATTACHMENT and different objects
       are bound to the depth and stencil attachment points of target.


       GL_INVALID_OPERATION is generated if the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_NONE
       and pname is not GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME.

SEE ALSO
       glGenFramebuffers(), glBindFramebuffer()


COPYRIGHT
       Copyright (C) 2010 Khronos Group. This material may be distributed subject to the terms and
       conditions set forth in the Open Publication License, v 1.0, 8 June 1999.
       http://opencontent.org/openpub/.



OpenGL 3.3                                       03/08/2011                         GLGETFRAMEBUFFERATTA(3G)