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GLTEXSUBIMAGE2D(3G)                                                                      GLTEXSUBIMAGE2D(3G)



NAME
       glTexSubImage2D - specify a two-dimensional texture subimage


C SPECIFICATION
       void glTexSubImage2D( GLenum target,
                             GLint level,
                             GLint xoffset,
                             GLint yoffset,
                             GLsizei width,
                             GLsizei height,
                             GLenum format,
                             GLenum type,
                             const GLvoid *pixels )


PARAMETERS
       target   Specifies the target texture.  Must be GL_TEXTURE_2D.

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

       xoffset  Specifies a texel offset in the x direction within the texture array.

       yoffset  Specifies a texel offset in the y direction within the texture array.

       width    Specifies the width of the texture subimage.

       height   Specifies the height of the texture subimage.

       format   Specifies the format of the  pixel  data.   The  following  symbolic  values  are  accepted:
                GL_COLOR_INDEX,  GL_RED,  GL_GREEN,  GL_BLUE,  GL_ALPHA,  GL_RGB,  GL_BGR, GL_RGBA, GL_BGRA,
                GL_LUMINANCE, and GL_LUMINANCE_ALPHA.

       type     Specifies the data type of the pixel data.  The  following  symbolic  values  are  accepted:
                GL_UNSIGNED_BYTE,  GL_BYTE, GL_BITMAP, 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.

       pixels   Specifies a pointer to the image data in memory.

DESCRIPTION
       Texturing maps a portion of a specified texture image onto each graphical primitive for which textur-ing texturing
       ing  is  enabled.   To enable and disable two-dimensional texturing, call glEnable and glDisable with
       argument GL_TEXTURE_2D.

       glTexSubImage2D redefines a contiguous subregion of an existing two-dimensional texture  image.   The
       texels  referenced by pixels replace the portion of the existing texture array with x indices xoffset
       and xoffset+width-1, inclusive, and y indices yoffset and yoffset+height-1, inclusive.   This  region
       may not include any texels outside the range of the texture array as it was originally specified.  It
       is not an error to specify a subtexture with zero width or height, but such a  specification  has  no
       effect.

NOTES
       glTexSubImage2D is available only if the GL version is 1.1 or greater.

       Texturing has no effect in color index mode.

       glPixelStore  and  glPixelTransfer  modes  affect  texture  images  in  exactly  the  way they affect
       glDrawPixels.

       Formats  GL_BGR,  and   GL_BGRA   and   types   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 are available only if the GL version is 1.2 or greater.

       When the GL_ARB_multitexture extension is supported, glTexSubImage2D specifies a two-dimensional  sub
       texture for the current texture unit, specified with glActiveTextureARB.

       When  the  GL_ARB_imaging extension is supported, the RGBA components specified in pixels may be pro-cessed processed
       cessed by the imaging pipeline.  See glTexImage1D for specific details.

ERRORS
       GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D.

       GL_INVALID_OPERATION is  generated  if  the  texture  array  has  not  been  defined  by  a  previous
       glTexImage2D operation.

       GL_INVALID_VALUE is generated if level is less than 0.

       GL_INVALID_VALUE may be generated if level is greater than log2(max), where max is the returned value
       of GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if xoffset < -b, xoffset + width > (w-b), yoffset < -b,  or  yoffset  +
       height  >  (h  - b), where w is the GL_TEXTURE_WIDTH, h is the GL_TEXTURE_HEIGHT, and b is the border
       width of the texture image being modified.  Note that w and h include twice the border width.

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

       GL_INVALID_ENUM is generated if format is not an accepted
        constant.

       GL_INVALID_ENUM is generated if type is not a type constant.

       GL_INVALID_ENUM is generated if type is GL_BITMAP and format is not GL_COLOR_INDEX.

       GL_INVALID_OPERATION is generated if glTexSubImage2D is executed between the execution of glBegin and
       the corresponding execution of glEnd.

       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, or GL_UNSIGNED_SHORT_5_6_5_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,      or
       GL_UNSIGNED_INT_2_10_10_10_REV and format is neither GL_RGBA nor GL_BGRA.

ASSOCIATED GETS
       glGetTexImage
       glIsEnabled with argument GL_TEXTURE_2D

SEE ALSO
       glActiveTextureARB(3G),  glCopyTexImage1D(3G),  glCopyTexImage2D(3G),  glCopyTexSubImage1D(3G),  glCopyTexSubImage2D(3G),
       glCopyTexSubImage3D(3G),  glDrawPixels(3G),  glPixelStore(3G), glPixelTransfer(3G), glTexEnv(3G), glTexGen(3G), glTexImage1D(3G),
       glTexImage2D(3G), glTexImage3D(3G), glTexSubImage1D(3G), glTexSubImage3D(3G), glTexParameter(3G)





                                                                                         GLTEXSUBIMAGE2D(3G)