glTextureSubImage1D

glTexSubImage1D: man4/glTexSubImage1D.xml

Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable or disable one-dimensional texturing, call glEnable and glDisable with argument GL_TEXTURE_1D. glTexSubImage1D and glTextureSubImage1D redefine a contiguous subregion of an existing one-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. 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 width of 0, but such a specification has no effect. If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target (see glBindBuffer ) while a texture image is specified, pixels is treated as a byte offset into the buffer object's data store.

glPixelStore modes affect texture images. glTexSubImage1D and glTextureSubImage1D specify a one-dimensional subtexture for the current texture unit, specified with glActiveTexture. GL_STENCIL_INDEX is accepted for format only if the GL version is 4.4 or higher.