glCopyTexImage1DEXT(3G)

NAME
     glCopyTexImage1DEXT - copy pixels into a 1D texture image


C SPECIFICATION
     void glCopyTexImage1DEXT( GLenum target,
                               GLint level,
                               GLenum internalformat,
                               GLint x,
                               GLint y,
                               GLsizei width,
                               GLint border )


PARAMETERS
     target          The target texture.  Must be GL_TEXTURE_1D

     level           The level-of-detail number.  Level 0 is the base image
                     level.  Level n is the nth mipmap reduction image.

     internalformat  The internal storage format of the texture image.  Must
                     be one of the following symbolic constants:  GL_ALPHA,
                     GL_ALPHA4_EXT, GL_ALPHA8_EXT, GL_ALPHA12_EXT,
                     GL_ALPHA16_EXT, GL_LUMINANCE, GL_LUMINANCE4_EXT,
                     GL_LUMINANCE8_EXT, GL_LUMINANCE12_EXT,
                     GL_LUMINANCE16_EXT, GL_LUMINANCE_ALPHA,
                     GL_LUMINANCE4_ALPHA4_EXT, GL_LUMINANCE6_ALPHA2_EXT,
                     GL_LUMINANCE8_ALPHA8_EXT, GL_LUMINANCE12_ALPHA4_EXT,
                     GL_LUMINANCE12_ALPHA12_EXT, GL_LUMINANCE16_ALPHA16_EXT,
                     GL_INTENSITY_EXT, GL_INTENSITY4_EXT, GL_INTENSITY8_EXT,
                     GL_INTENSITY12_EXT, GL_INTENSITY16_EXT, GL_RGB,
                     GL_RGB2_EXT, GL_RGB4_EXT, GL_RGB5_EXT, GL_RGB8_EXT,
                     GL_RGB10_EXT, GL_RGB12_EXT, GL_RGB16_EXT, GL_RGBA,
                     GL_RGBA2_EXT, GL_RGBA4_EXT, GL_RGB5_A1_EXT, GL_RGBA8_EXT,
                     GL_RGB10_A2_EXT, GL_RGBA12_EXT, GL_RGBA16_EXT.  (Note
                     that the values 1, 2, 3, and 4, which are accepted by
                     glTexImage1D, are not accepted by glCopyTexImage1DEXT.)

     x               The x coordinate of the lower-left corner of the pixel
                     rectangle to be transferred to the texture array.

     y               The y coordinate of the lower-left corner of the pixel
                     rectangle to be transferred to the texture array.

     width           The width of the texture image.

     border          The border width of the texture.  Must be 0 or 1.

DESCRIPTION
     glCopyTexImage1DEXT defines a one-dimensional texture image with pixels
     from the current GL_READ_BUFFER (rather than from main memory, as is the
     case for glTexImage1D).
     The screen-aligned pixel rectangle with lower-left corner at (x, y)
     having width width+2*border and height 1 is used to define the texture
     array at the mipmap level specified by level.  The internal format of the
     texture array is selected by internalformat.

     The pixels in the rectangle are processed exactly as if glCopyPixels had
     been called, but the process stops just before final conversion.  At this
     point all pixel component values are clamped to the range [0, 1] and then
     converted to the texture's internal format for storage in the texel
     array.

     Pixel ordering is such that lower x screen coordinates correspond to
     lower i texture coordinates, and lower y screen coordinates correspond to
     lower j texture coordinates.

     If any of the pixels within the specified rectangle of the current
     GL_READ_BUFFER are outside the window associated with the current
     rendering context, then the values obtained for those pixels are
     undefined.

NOTES
     glCopyTexImage1DEXT is part of the EXT_copy_texture extension.  See
     glIntro for more information about using extensions.

ERRORS
     GL_INVALID_ENUM is generated when target is not one of the allowable
     values.

     GL_INVALID_VALUE is generated if level is less than zero or greater than
     log (max), where max is the returned value of GL_MAX_TEXTURE_SIZE.
        2

     GL_INVALID_VALUE is generated if the specified image is too large.

     GL_INVALID_VALUE is generated if width is less than zero, greater than
                                                                    k
     2+GL_MAX_TEXTURE_SIZE, or when width cannot be represented as 2 +2border
     for some integer k.

     GL_INVALID_VALUE is generated if border is not 0 or 1.

     GL_INVALID_VALUE is generated if internalformat is not one of the
     allowable values.

     GL_INVALID_OPERATION is generated if glCopyTexImage1DEXT is executed
     between the execution of glBegin and the corresponding execution of
     glEnd.

ASSOCIATED GETS
     glGetTexImage

MACHINE DEPENDENCIES
     glCopyTexImage1D and glCopyTexImage1DEXT are not supported on
     RealityEngine, RealityEngine2, and VTX systems.

     On InfiniteReality systems, there is a performance benefit when the width
     of the image to be transferred to texture memory is a multiple of 8.

     Texture borders are not supported on InfiniteReality systems.
     Applications should use borderless textures and GL_CLAMP_TO_EDGE_SGIS
     wrap mode.


SEE ALSO
     glTexImage1D, glCopyTexSubImage1DEXT, glCopyPixels.