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<HTML><BODY><PRE>     <STRONG>NAME</STRONG>	  <STRONG>glGetTexImage</STRONG>	- return a texture image     <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>	  void <STRONG>glGetTexImage</STRONG>( GLenum <EM>target</EM>,			      GLint <EM>level</EM>,			      GLenum <EM>format</EM>,			      GLenum <EM>type</EM>,			      GLvoid *<EM>pixels</EM> )     <STRONG>PARAMETERS</STRONG>	  <EM>target</EM>  Specifies which texture is to	be obtained.		  <STRONG>GL_TEXTURE_1D</STRONG>	and <STRONG>GL_TEXTURE_2D</STRONG> are accepted.	  <EM>level</EM>	  Specifies the	level-of-detail	number of the desired		  image.  Level	0 is the base image level.  Level n is		  the nth mipmap reduction image.	  <EM>format</EM>  Specifies a pixel format for the returned data.  The		  supported formats are	<STRONG>GL_RED</STRONG>,	<STRONG>GL_GREEN</STRONG>, <STRONG>GL_BLUE</STRONG>,		  <STRONG>GL_ALPHA</STRONG>, <STRONG>GL_RGB</STRONG>, <STRONG>GL_RGBA</STRONG>, <STRONG>GL_LUMINANCE</STRONG>, and		  <STRONG>GL_LUMINANCE_ALPHA</STRONG>.	  <EM>type</EM>	  Specifies a pixel type for the returned data.	 The		  supported types are <STRONG>GL_UNSIGNED_BYTE</STRONG>,	<STRONG>GL_BYTE</STRONG>,		  <STRONG>GL_UNSIGNED_SHORT</STRONG>, <STRONG>GL_SHORT</STRONG>, <STRONG>GL_UNSIGNED_INT</STRONG>,		  <STRONG>GL_INT</STRONG>, and <STRONG>GL_FLOAT</STRONG>.	  <EM>pixels</EM>  Returns the texture image.  Should be	a pointer to		  an array of the type specified by <EM>type</EM>.     <STRONG>DESCRIPTION</STRONG>	  <STRONG>glGetTexImage</STRONG>	returns	a texture image	into <EM>pixels</EM>.  <EM>target</EM>	  specifies whether the	desired	texture	image is one specified	  by <STRONG>glTexImage1D</STRONG> (<STRONG>GL_TEXTURE_1D</STRONG>) or by	<STRONG>glTexImage2D</STRONG>	  (<STRONG>GL_TEXTURE_2D</STRONG>).  <EM>level</EM> specifies the	level-of-detail	number	  of the desired image.	 <EM>format</EM>	and <EM>type</EM> specify the format	  and type of the desired image	array.	See the	reference	  pages	<STRONG>glTexImage1D</STRONG> and <STRONG>glDrawPixels</STRONG> for a description	of the	  acceptable values for	the <EM>format</EM> and <EM>type</EM> parameters,	  respectively.	  To understand	the operation of <STRONG>glGetTexImage</STRONG>,	consider the	  selected internal four-component texture image to be an RGBA	  color	buffer the size	of the image.  The semantics of	  <STRONG>glGetTexImage</STRONG>	are then identical to those of <STRONG>glReadPixels</STRONG>	  called with the same <EM>format</EM> and <EM>type</EM>,	with <EM>x</EM> and <EM>y</EM> set to 0,	  <EM>width</EM>	set to the width of the	texture	image (including	  border if one	was specified),	and <EM>height</EM> set to 1 for	1D	  images, or to	the height of the texture image	(including	  border if one	was specified) for 2D images.  Because the	  internal texture image is an RGBA image, pixel formats	  <STRONG>GL_COLOR_INDEX</STRONG>, <STRONG>GL_STENCIL_INDEX</STRONG>, and	<STRONG>GL_DEPTH_COMPONENT</STRONG> are	  not accepted,	and pixel type <STRONG>GL_BITMAP</STRONG> is not	accepted.	  If the selected texture image	does not contain four	  components, the following mappings are applied.  Single-	  component textures are treated as RGBA buffers with red set	  to the single-component value, green set to 0,  blue set to	  0, and alpha set to 1.  Two-component	textures are treated	  as RGBA buffers with red set to the value of component zero,	  alpha	set to the value of component one, and green and blue	  set to 0.  Finally, three-component textures are treated as	  RGBA buffers with red	set to component zero, green set to	  component one, blue set to component two, and	alpha set to	  1.	  To determine the required size of <EM>pixels</EM>, use	  <STRONG>glGetTexLevelParameter</STRONG> to determine the dimensions of	the	  internal texture image, then scale the required number of	  pixels by the	storage	required for each pixel, based on	  <EM>format</EM> and <EM>type</EM>.  Be sure to take the	pixel storage	  parameters into account, especially <STRONG>GL_PACK_ALIGNMENT</STRONG>.     <STRONG>NOTES</STRONG>	  If an	error is generated, no change is made to the contents	  of <EM>pixels</EM>.     <STRONG>ERRORS</STRONG>	  <STRONG>GL_INVALID_ENUM</STRONG> is generated if <EM>target</EM>, <EM>format</EM>, or <EM>type</EM> is	  not an accepted value.	  <STRONG>GL_INVALID_VALUE</STRONG> is generated	if <EM>level</EM> is less than 0.	  <STRONG>GL_INVALID_VALUE</STRONG> may be generated if <EM>level</EM> is	greater	than	  log max, where max is	the returned value of	  <STRONG>GL_MAX_TEXTURE_SIZE</STRONG>.	  <STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glGetTexImage</STRONG> is	  executed between the execution of <STRONG>glBegin</STRONG> and	the	  corresponding	execution of <STRONG>glEnd</STRONG>.     <STRONG>ASSOCIATED</STRONG>	<STRONG>GETS</STRONG>	  <STRONG>glGetTexLevelParameter</STRONG> with argument <STRONG>GL_TEXTURE_WIDTH</STRONG>	  <STRONG>glGetTexLevelParameter</STRONG> with argument <STRONG>GL_TEXTURE_HEIGHT</STRONG>	  <STRONG>glGetTexLevelParameter</STRONG> with argument <STRONG>GL_TEXTURE_BORDER</STRONG>	  <STRONG>glGetTexLevelParameter</STRONG> with argument <STRONG>GL_TEXTURE_COMPONENTS</STRONG>	  <STRONG>glGet</STRONG>	with arguments <STRONG>GL_PACK_ALIGNMENT</STRONG> and others     <STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>	  <STRONG>glDrawPixels</STRONG>,	<STRONG>glReadPixels</STRONG>, <STRONG>glTexEnv</STRONG>,	<STRONG>glTexGen</STRONG>,	  <STRONG>glTexImage1D</STRONG>,	<STRONG>glTexImage2D</STRONG>, <STRONG>glTexSubImage1D</STRONG>,	  <STRONG>glTexSubImage2D</STRONG>, <STRONG>glTexParameter</STRONG></PRE></BODY></HTML>
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