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GLTEXIMAGE2D(3G)			  OpenGL Manual 			 GLTEXIMAGE2D(3G)

NAME
       glTexImage2D - specify a two-dimensional texture image

C SPECIFICATION
       void glTexImage2D(GLenum target, GLint level, GLint internalFormat, GLsizei width,
			 GLsizei height, GLint border, GLenum format, GLenum type,
			 const GLvoid * data);

PARAMETERS
       target
	   Specifies the target texture. Must be GL_TEXTURE_2D, GL_PROXY_TEXTURE_2D,
	   GL_TEXTURE_1D_ARRAY, GL_PROXY_TEXTURE_1D_ARRAY, GL_TEXTURE_RECTANGLE,
	   GL_PROXY_TEXTURE_RECTANGLE, GL_TEXTURE_CUBE_MAP_POSITIVE_X,
	   GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
	   GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z,
	   GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or GL_PROXY_TEXTURE_CUBE_MAP.

       level
	   Specifies the level-of-detail number. Level 0 is the base image level. Level n is the
	   nth mipmap reduction image. If target is GL_TEXTURE_RECTANGLE or
	   GL_PROXY_TEXTURE_RECTANGLE, level must be 0.

       internalFormat
	   Specifies the number of color components in the texture. Must be one of base internal
	   formats given in Table 1, one of the sized internal formats given in Table 2, or one
	   of the compressed internal formats given in Table 3, below.

       width
	   Specifies the width of the texture image. All implementations support texture images
	   that are at least 1024 texels wide.

       height
	   Specifies the height of the texture image, or the number of layers in a texture array,
	   in the case of the GL_TEXTURE_1D_ARRAY and GL_PROXY_TEXTURE_1D_ARRAY targets. All
	   implementations support 2D texture images that are at least 1024 texels high, and
	   texture arrays that are at least 256 layers deep.

       border
	   This value must be 0.

       format
	   Specifies the format of the pixel data. The following symbolic values are accepted:
	   GL_RED, GL_RG, GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.

       type
	   Specifies the data type of the pixel data. The following symbolic values are accepted:
	   GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT,
	   GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
	   GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
	   GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8,
	   GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, and
	   GL_UNSIGNED_INT_2_10_10_10_REV.

       data
	   Specifies a pointer to the image data in memory.

DESCRIPTION
       Texturing allows elements of an image array to be read by shaders.

       To define texture images, call glTexImage2D. The arguments describe the parameters of the
       texture image, such as height, width, width of the border, level-of-detail number (see
       glTexParameter()), and number of color components provided. The last three arguments
       describe how the image is represented in memory.

       If target is GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_1D_ARRAY, GL_PROXY_TEXTURE_CUBE_MAP, or
       GL_PROXY_TEXTURE_RECTANGLE, no data is read from data, but all of the texture image state
       is recalculated, checked for consistency, and checked against the implementation's
       capabilities. If the implementation cannot handle a texture of the requested texture size,
       it sets all of the image state to 0, but does not generate an error (see glGetError()). To
       query for an entire mipmap array, use an image array level greater than or equal to 1.

       If target is GL_TEXTURE_2D, GL_TEXTURE_RECTANGLE or one of the GL_TEXTURE_CUBE_MAP
       targets, data is read from data as a sequence of signed or unsigned bytes, shorts, or
       longs, or single-precision floating-point values, depending on type. These values are
       grouped into sets of one, two, three, or four values, depending on format, to form
       elements. Each data byte is treated as eight 1-bit elements, with bit ordering determined
       by GL_UNPACK_LSB_FIRST (see glPixelStore()).

       If target is GL_TEXTURE_1D_ARRAY, data is interpreted as an array of one-dimensional
       images.

       If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see
       glBindBuffer()) while a texture image is specified, data is treated as a byte offset into
       the buffer object's data store.

       The first element corresponds to the lower left corner of the texture image. Subsequent
       elements progress left-to-right through the remaining texels in the lowest row of the
       texture image, and then in successively higher rows of the texture image. The final
       element corresponds to the upper right corner of the texture image.

       format determines the composition of each element in data. It can assume one of these
       symbolic values:

       GL_RED
	   Each element is a single red component. The GL converts it to floating point and
	   assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha.
	   Each component is then multiplied by the signed scale factor GL_c_SCALE, added to the
	   signed bias GL_c_BIAS, and clamped to the range [0,1].

       GL_RG
	   Each element is a red/green double. The GL converts it to floating point and assembles
	   it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is
	   then multiplied by the signed scale factor GL_c_SCALE, added to the signed bias
	   GL_c_BIAS, and clamped to the range [0,1].

       GL_RGB

       GL_BGR
	   Each element is an RGB triple. The GL converts it to floating point and assembles it
	   into an RGBA element by attaching 1 for alpha. Each component is then multiplied by
	   the signed scale factor GL_c_SCALE, added to the signed bias GL_c_BIAS, and clamped to
	   the range [0,1].

       GL_RGBA

       GL_BGRA
	   Each element contains all four components. Each component is multiplied by the signed
	   scale factor GL_c_SCALE, added to the signed bias GL_c_BIAS, and clamped to the range
	   [0,1].

       GL_DEPTH_COMPONENT
	   Each element is a single depth value. The GL converts it to floating point, multiplies
	   by the signed scale factor GL_DEPTH_SCALE, adds the signed bias GL_DEPTH_BIAS, and
	   clamps to the range [0,1].

       GL_DEPTH_STENCIL
	   Each element is a pair of depth and stencil values. The depth component of the pair is
	   interpreted as in GL_DEPTH_COMPONENT. The stencil component is interpreted based on
	   specified the depth + stencil internal format.

       If an application wants to store the texture at a certain resolution or in a certain
       format, it can request the resolution and format with internalFormat. The GL will choose
       an internal representation that closely approximates that requested by internalFormat, but
       it may not match exactly. (The representations specified by GL_RED, GL_RG, GL_RGB, and
       GL_RGBA must match exactly.)

       internalFormat may be one of the base internal formats shown in Table 1, below

       <xi:include></xi:include>

       internalFormat may also be one of the sized internal formats shown in Table 2, below

       <xi:include></xi:include>

       Finally, internalFormat may also be one of the generic or compressed compressed texture
       formats shown in Table 3 below

       <xi:include></xi:include>

       If the internalFormat parameter is one of the generic compressed formats,
       GL_COMPRESSED_RED, GL_COMPRESSED_RG, GL_COMPRESSED_RGB, or GL_COMPRESSED_RGBA, the GL will
       replace the internal format with the symbolic constant for a specific internal format and
       compress the texture before storage. If no corresponding internal format is available, or
       the GL can not compress that image for any reason, the internal format is instead replaced
       with a corresponding base internal format.

       If the internalFormat parameter is GL_SRGB, GL_SRGB8, GL_SRGB_ALPHA, or GL_SRGB8_ALPHA8,
       the texture is treated as if the red, green, or blue components are encoded in the sRGB
       color space. Any alpha component is left unchanged. The conversion from the sRGB encoded
       component c s to a linear component c l is:

       c l = { c s 12.92 if c s <= 0.04045 ( c s + 0.055 1.055 ) 2.4 if c s > 0.04045

       Assume c s is the sRGB component in the range [0,1].

       Use the GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_1D_ARRAY, GL_PROXY_TEXTURE_RECTANGLE, or
       GL_PROXY_TEXTURE_CUBE_MAP target to try out a resolution and format. The implementation
       will update and recompute its best match for the requested storage resolution and format.
       To then query this state, call glGetTexLevelParameter(). If the texture cannot be
       accommodated, texture state is set to 0.

       A one-component texture image uses only the red component of the RGBA color extracted from
       data. A two-component image uses the R and G values. A three-component image uses the R,
       G, and B values. A four-component image uses all of the RGBA components.

       Image-based shadowing can be enabled by comparing texture r coordinates to depth texture
       values to generate a boolean result. See glTexParameter() for details on texture
       comparison.

NOTES
       The glPixelStore() mode affects texture images.

       data may be a null pointer. In this case, texture memory is allocated to accommodate a
       texture of width width and height height. You can then download subtextures to initialize
       this texture memory. The image is undefined if the user tries to apply an uninitialized
       portion of the texture image to a primitive.

       glTexImage2D specifies the two-dimensional texture for the current texture unit, specified
       with glActiveTexture().

ERRORS
       GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D, GL_TEXTURE_1D_ARRAY,
       GL_TEXTURE_RECTANGLE, GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_1D_ARRAY,
       GL_PROXY_TEXTURE_RECTANGLE, GL_PROXY_TEXTURE_CUBE_MAP, GL_TEXTURE_CUBE_MAP_POSITIVE_X,
       GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,
       GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or
       GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

       GL_INVALID_ENUM is generated if target is one of the six cube map 2D image targets and the
       width and height parameters are not equal.

       GL_INVALID_ENUM is generated if type is not a type constant.

       GL_INVALID_VALUE is generated if width is less than 0 or greater than GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if target is not GL_TEXTURE_1D_ARRAY or
       GL_PROXY_TEXTURE_1D_ARRAY and height is less than 0 or greater than GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if target is GL_TEXTURE_1D_ARRAY or
       GL_PROXY_TEXTURE_1D_ARRAY and height is less than 0 or greater than
       GL_MAX_ARRAY_TEXTURE_LAYERS.

       GL_INVALID_VALUE is generated if level is less than 0.

       GL_INVALID_VALUE may be generated if level is greater than log 2  max, where max is the
       returned value of GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if internalFormat is not one of the accepted resolution and
       format symbolic constants.

       GL_INVALID_VALUE is generated if width or height is less than 0 or greater than
       GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if non-power-of-two textures are not supported and the width
       or height cannot be represented as 2 k + 2  border for some integer value of k.

       GL_INVALID_VALUE is generated if border is not 0.

       GL_INVALID_OPERATION is generated if type is one of GL_UNSIGNED_BYTE_3_3_2,
       GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV, or
       GL_UNSIGNED_INT_10F_11F_11F_REV, and format is not GL_RGB.

       GL_INVALID_OPERATION is generated if type is one of GL_UNSIGNED_SHORT_4_4_4_4,
       GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
       GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2,
       GL_UNSIGNED_INT_2_10_10_10_REV, or GL_UNSIGNED_INT_5_9_9_9_REV, and format is neither
       GL_RGBA nor GL_BGRA.

       GL_INVALID_OPERATION is generated if target is not GL_TEXTURE_2D, GL_PROXY_TEXTURE_2D,
       GL_TEXTURE_RECTANGLE, or GL_PROXY_TEXTURE_RECTANGLE, and internalFormat is
       GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, or GL_DEPTH_COMPONENT32F.

       GL_INVALID_OPERATION is generated if format is GL_DEPTH_COMPONENT and internalFormat is
       not GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, or
       GL_DEPTH_COMPONENT32F.

       GL_INVALID_OPERATION is generated if internalFormat is GL_DEPTH_COMPONENT,
       GL_DEPTH_COMPONENT16, GL_DEPTH_COMPONENT24, or GL_DEPTH_COMPONENT32F, and format is not
       GL_DEPTH_COMPONENT.

       GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
       GL_PIXEL_UNPACK_BUFFER target and the buffer object's data store is currently mapped.

       GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
       GL_PIXEL_UNPACK_BUFFER target and the data would be unpacked from the buffer object such
       that the memory reads required would exceed the data store size.

       GL_INVALID_OPERATION is generated if a non-zero buffer object name is bound to the
       GL_PIXEL_UNPACK_BUFFER target and data is not evenly divisible into the number of bytes
       needed to store in memory a datum indicated by type.

       GL_INVALID_VALUE is generated if target is GL_TEXTURE_RECTANGLE or
       GL_PROXY_TEXTURE_RECTANGLE and level is not 0.

ASSOCIATED GETS
       glGetTexImage()

       glGet() with argument GL_PIXEL_UNPACK_BUFFER_BINDING

SEE ALSO
       glActiveTexture(), glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(),
       glCopyTexSubImage2D(), glCopyTexSubImage3D(), glPixelStore(), glTexImage1D(),
       glTexImage3D(), glTexSubImage1D(), glTexSubImage2D(), glTexSubImage3D(), glTexParameter()

COPYRIGHT
       Copyright (C) 1991-2006 Silicon Graphics, Inc. Copyright (C) 2011 Khronos Group. This
       document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS
       opengl.org

opengl.org				    06/10/2014				 GLTEXIMAGE2D(3G)
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