GLint _l_e_v_e_l, GLint _x_o_f_f_s_e_t, GLint _x, GLint _y, GLsizei _w_i_d_t_h )
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The screen-aligned pixel row with left corner at (_x, _y), and with length _w_i_d_t_h replaces the portion of the texture array with x indices _x_o_f_f_s_e_t through $"xoffset" ~+~ "width" ~-~ 1$, inclusive. The destination in the texture array may not include any texels outside the texture array as it was originally specified.
The pixels in the row are processed exactly as if ggllCCooppyyPPiixxeellss 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 for storage in the texel array.
It is not an error to specify a subtexture with zero width, but such a specification has no effect. If any of the pixels within the specified row of the current GGLL__RREEAADD__BBUUFFFFEERR are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined.
No change is made to the _i_n_t_e_r_n_a_l_f_o_r_m_a_t, _w_i_d_t_h, or _b_o_r_d_e_r parameters of the specified texture array or to texel values outside the specified subregion.
Texturing has no effect in color index mode.
ggllPPiixxeellSSttoorree and ggllPPiixxeellTTrraannssffeerr modes affect texture images in exactly the way they affect ggllDDrraawwPPiixxeellss.
When the GGLL__AARRBB__iimmaaggiinngg extension is supported, the RGBA components copied from the framebuffer may be processed by the imaging pipeline. See ggllTTeexxIImmaaggee11DD for specific details.
GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if the texture array has not been defined by a previous ggllTTeexxIImmaaggee11DD or ggllCCooppyyTTeexxIImmaaggee11DD operation.
GGLL__IINNVVAALLIIDD__VVAALLUUEE is generated if _l_e_v_e_l is less than 0.
GGLL__IINNVVAALLIIDD__VVAALLUUEE may be generated if _l_e_v_e_l$>log sub 2$ _m_a_x, where _m_a_x is the returned value of GGLL__MMAAXX__TTEEXXTTUURREE__SSIIZZEE.
GGLL__IINNVVAALLIIDD__VVAALLUUEE is generated if _y$ ~<~ ~-b$ or if _w_i_d_t_h$ ~<~ ~-b$, where $b$ is the border width of the texture array.
GGLL__IINNVVAALLIIDD__VVAALLUUEE is generated if $"xoffset" ~<~ ~-b$, or $("xoffset"~+~"width") ~>~ (w-b)$, where $w$ is the GGLL__TTEEXXTTUURREE__WWIIDDTTHH, and $b$ is the GGLL__TTEEXXTTUURREE__BBOORRDDEERR of the texture image being modified. Note that $w$ includes twice the border width.