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GLTEXIMAGE2D(3G)                                 OpenGL 3.3                                 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 the following symbolic
           constants: GL_COMPRESSED_RED, GL_COMPRESSED_RG, GL_COMPRESSED_RGB, GL_COMPRESSED_RGBA,
           GL_COMPRESSED_SRGB, GL_COMPRESSED_SRGB_ALPHA, GL_DEPTH_COMPONENT, GL_DEPTH_COMPONENT16,
           GL_DEPTH_COMPONENT24, GL_DEPTH_COMPONENT32, GL_R3_G3_B2, GL_RED, GL_RG, GL_RGB, GL_RGB4, GL_RGB5,
           GL_RGB8, GL_RGB10, GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1, GL_RGBA8,
           GL_RGB10_A2, GL_RGBA12, GL_RGBA16, GL_SRGB, GL_SRGB8, GL_SRGB_ALPHA, or GL_SRGB8_ALPHA8.

       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.)

       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 ^o 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. This document is licensed under the SGI Free Software
       B License. For details, see http://oss.sgi.com/projects/FreeB/.



OpenGL 3.3                                       03/08/2011                                 GLTEXIMAGE2D(3G)