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<HTML><BODY><PRE>     <STRONG>NAME</STRONG>	  <STRONG>glTexParameterf,</STRONG> <STRONG>glTexParameteri,</STRONG> <STRONG>glTexParameterfv,</STRONG>	  <STRONG>glTexParameteriv</STRONG> - set texture parameters     <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>	  void <STRONG>glTexParameterf</STRONG>(	GLenum <EM>target</EM>,				GLenum <EM>pname</EM>,				GLfloat	<EM>param</EM> )	  void <STRONG>glTexParameteri</STRONG>(	GLenum <EM>target</EM>,				GLenum <EM>pname</EM>,				GLint <EM>param</EM> )     <STRONG>PARAMETERS</STRONG>	  <EM>target</EM>  Specifies the	target texture,	which must be either		  <STRONG>GL_TEXTURE_1D</STRONG>	or <STRONG>GL_TEXTURE_2D</STRONG>.	  <EM>pname</EM>	  Specifies the	symbolic name of a single-valued		  texture parameter.  <EM>pname</EM> can	be one of the		  following:  <STRONG>GL_TEXTURE_MIN_FILTER</STRONG>,		  <STRONG>GL_TEXTURE_MAG_FILTER</STRONG>, <STRONG>GL_TEXTURE_WRAP_S</STRONG>,		  <STRONG>GL_TEXTURE_WRAP_T</STRONG>, or	<STRONG>GL_TEXTURE_PRIORITY</STRONG>.	  <EM>param</EM>	  Specifies the	value of <EM>pname</EM>.     <STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>	  void <STRONG>glTexParameterfv</STRONG>( GLenum	<EM>target</EM>,				 GLenum	<EM>pname</EM>,				 const GLfloat *<EM>params</EM> )	  void <STRONG>glTexParameteriv</STRONG>( GLenum	<EM>target</EM>,				 GLenum	<EM>pname</EM>,				 const GLint *<EM>params</EM> )     <STRONG>PARAMETERS</STRONG>	  <EM>target</EM>	       Specifies the target texture, which must	be either	       <STRONG>GL_TEXTURE_1D</STRONG> or	<STRONG>GL_TEXTURE_2D</STRONG>.	  <EM>pname</EM>	       Specifies the symbolic name of a	texture	parameter.	       <EM>pname</EM> can be one	of the following:	       <STRONG>GL_TEXTURE_MIN_FILTER</STRONG>, <STRONG>GL_TEXTURE_MAG_FILTER</STRONG>,	       <STRONG>GL_TEXTURE_WRAP_S</STRONG>, <STRONG>GL_TEXTURE_WRAP_T</STRONG>,	       <STRONG>GL_TEXTURE_BORDER_COLOR</STRONG>,	or <STRONG>GL_TEXTURE_PRIORITY</STRONG>.	  <EM>params</EM>	       Specifies a pointer to an array where the value or	       values of <EM>pname</EM> are stored.     <STRONG>DESCRIPTION</STRONG>	  Texture mapping is a technique that applies an image onto an	  object's surface as if the image were	a decal	or cellophane	  shrink-wrap. The image is created in texture space, with an	  (s, t) coordinate system. A texture is a one-	or two-	  dimensional image and	a set of parameters that determine how	  samples are derived from the image.	  <STRONG>glTexParameter</STRONG> assigns the value or values in	<EM>params</EM> to the	  texture parameter specified as <EM>pname</EM>.	<EM>target</EM> defines the	  target texture, either <STRONG>GL_TEXTURE_1D</STRONG> or <STRONG>GL_TEXTURE_2D</STRONG>.  The	  following symbols are	accepted in <EM>pname</EM>:	  <STRONG>GL_TEXTURE_MIN_FILTER</STRONG>		    The	texture	minifying function is used whenever		    the	pixel being textured maps to an	area greater		    than one texture element. There are	six defined		    minifying functions.  Two of them use the nearest		    one	or nearest four	texture	elements to compute		    the	texture	value. The other four use mipmaps.		    A mipmap is	an ordered set of arrays representing		    the	same image at progressively lower resolutions.		    If the texture has dimensions 2nx2m, there are		    max(n,m)+1 mipmaps.	The first mipmap is the		    original texture, with dimensions 2nx2m. Each		    subsequent mipmap has dimensions 2k-1x2l-1,	where		    2kx2l are the dimensions of	the previous mipmap,		    until either k=0 or	l=0.  At that point,		    subsequent mipmaps have dimension 1x2l-1 or	2k-1x1		    until the final mipmap, which has dimension	1x1.		    To define the mipmaps, call	<STRONG>glTexImage1D</STRONG>,		    <STRONG>glTexImage2D</STRONG>, <STRONG>glCopyTexImage1D</STRONG>, or		    <STRONG>glCopyTexImage2D</STRONG> with the <EM>level</EM> argument		    indicating the order of the	mipmaps.  Level	0 is		    the	original texture; level	max(n,m) is the	final		    1x1	mipmap.		    <EM>params</EM> supplies a function for minifying the		    texture as one of the following:		    <STRONG>GL_NEAREST</STRONG>			      Returns the value	of the texture element			      that is nearest (in Manhattan distance)			      to the center of the pixel being			      textured.		    <STRONG>GL_LINEAR</STRONG> Returns the weighted average of the four			      texture elements that are	closest	to the			      center of	the pixel being	textured.			      These can	include	border texture			      elements,	depending on the values	of			      <STRONG>GL_TEXTURE_WRAP_S</STRONG>	and <STRONG>GL_TEXTURE_WRAP_T</STRONG>,			      and on the exact mapping.		    <STRONG>GL_NEAREST_MIPMAP_NEAREST</STRONG>			      Chooses the mipmap that most closely			      matches the size of the pixel being			      textured and uses	the <STRONG>GL_NEAREST</STRONG>			      criterion	(the texture element nearest			      to the center of the pixel) to produce a			      texture value.		    <STRONG>GL_LINEAR_MIPMAP_NEAREST</STRONG>			      Chooses the mipmap that most closely			      matches the size of the pixel being			      textured and uses	the <STRONG>GL_LINEAR</STRONG>			      criterion	(a weighted average of the			      four texture elements that are closest			      to the center of the pixel) to produce a			      texture value.		    <STRONG>GL_NEAREST_MIPMAP_LINEAR</STRONG>			      Chooses the two mipmaps that most			      closely match the	size of	the pixel			      being textured and uses the <STRONG>GL_NEAREST</STRONG>			      criterion	(the texture element nearest			      to the center of the pixel) to produce a			      texture value from each mipmap. The			      final texture value is a weighted			      average of those two values.		    <STRONG>GL_LINEAR_MIPMAP_LINEAR</STRONG>			      Chooses the two mipmaps that most			      closely match the	size of	the pixel			      being textured and uses the <STRONG>GL_LINEAR</STRONG>			      criterion	(a weighted average of the			      four texture elements that are closest			      to the center of the pixel) to produce a			      texture value from each mipmap.  The			      final texture value is a weighted			      average of those two values.		    As more texture elements are sampled in the		    minification process, fewer	aliasing artifacts		    will be apparent. While the	<STRONG>GL_NEAREST</STRONG> and		    <STRONG>GL_LINEAR</STRONG> minification functions can be faster		    than the other four, they sample only one or four		    texture elements to	determine the texture value of		    the	pixel being rendered and can produce moire		    patterns or	ragged transitions. The	initial	value		    of <STRONG>GL_TEXTURE_MIN_FILTER</STRONG> is		    <STRONG>GL_NEAREST_MIPMAP_LINEAR</STRONG>.	  <STRONG>GL_TEXTURE_MAG_FILTER</STRONG>		    The	texture	magnification function is used when		    the	pixel being textured maps to an	area less than		    or equal to	one texture element.  It sets the		    texture magnification function to either		    <STRONG>GL_NEAREST</STRONG> or <STRONG>GL_LINEAR</STRONG> (see below). <STRONG>GL_NEAREST</STRONG> is		    generally faster than <STRONG>GL_LINEAR</STRONG>, but it can		    produce textured images with sharper edges because		    the	transition between texture elements is not as		    smooth. The	initial	value of <STRONG>GL_TEXTURE_MAG_FILTER</STRONG>		    is <STRONG>GL_LINEAR</STRONG>.		    <STRONG>GL_NEAREST</STRONG>			      Returns the value	of the texture element			      that is nearest (in Manhattan distance)			      to the center of the pixel being			      textured.		    <STRONG>GL_LINEAR</STRONG> Returns the weighted average of the four			      texture elements that are	closest	to the			      center of	the pixel being	textured.			      These can	include	border texture			      elements,	depending on the values	of			      <STRONG>GL_TEXTURE_WRAP_S</STRONG>	and <STRONG>GL_TEXTURE_WRAP_T</STRONG>,			      and on the exact mapping.	  <STRONG>GL_TEXTURE_WRAP_S</STRONG>		    Sets the wrap parameter for	texture	coordinate <EM>s</EM>		    to either <STRONG>GL_CLAMP</STRONG> or <STRONG>GL_REPEAT</STRONG>.  <STRONG>GL_CLAMP</STRONG> causes		    s coordinates to be	clamped	to the range [0,1] and		    is useful for preventing wrapping artifacts	when		    mapping a single image onto	an object. <STRONG>GL_REPEAT</STRONG>		    causes the integer part of the s coordinate	to be		    ignored; the GL uses only the fractional part,		    thereby creating a repeating pattern. Border		    texture elements are accessed only if wrapping is		    set	to <STRONG>GL_CLAMP</STRONG>.  Initially, <STRONG>GL_TEXTURE_WRAP_S</STRONG> is		    set	to <STRONG>GL_REPEAT</STRONG>.	  <STRONG>GL_TEXTURE_WRAP_T</STRONG>		    Sets the wrap parameter for	texture	coordinate <EM>t</EM>		    to either <STRONG>GL_CLAMP</STRONG> or <STRONG>GL_REPEAT</STRONG>.  See the		    discussion under <STRONG>GL_TEXTURE_WRAP_S</STRONG>.	Initially,		    <STRONG>GL_TEXTURE_WRAP_T</STRONG> is set to	<STRONG>GL_REPEAT</STRONG>.	  <STRONG>GL_TEXTURE_BORDER_COLOR</STRONG>		    Sets a border color.  <EM>params</EM> contains four values		    that comprise the RGBA color of the	texture		    border. Integer color components are interpreted		    linearly such that the most	positive integer maps		    to 1.0, and	the most negative integer maps to		    -1.0.  The values are clamped to the range [0,1]		    when they are specified.  Initially, the border		    color is (0, 0, 0, 0).	  <STRONG>GL_TEXTURE_PRIORITY</STRONG>		    Specifies the texture residence priority of	the		    currently bound texture.  Permissible values are		    in the range [0, 1].  See <STRONG>glPrioritizeTextures</STRONG> and		    <STRONG>glBindTexture</STRONG> for more information.     <STRONG>NOTES</STRONG>	  Suppose that a program has enabled texturing (by calling	  <STRONG>glEnable</STRONG> with	argument <STRONG>GL_TEXTURE_1D</STRONG> or <STRONG>GL_TEXTURE_2D</STRONG>) and	  has set <STRONG>GL_TEXTURE_MIN_FILTER</STRONG>	to one of the functions	that	  requires a mipmap.  If either	the dimensions of the texture	  images currently defined (with previous calls	to	  <STRONG>glTexImage1D</STRONG>,	<STRONG>glTexImage2D</STRONG>, <STRONG>glCopyTexImage1D</STRONG>,	or	  <STRONG>glCopyTexImage2D</STRONG>) do not follow the proper sequence for	  mipmaps (described above), or	there are fewer	texture	images	  defined than are needed, or the set of texture images	have	  differing numbers of texture components, then	it is as if	  texture mapping were disabled.	  Linear filtering accesses the	four nearest texture elements	  only in 2D textures.	In 1D textures,	linear filtering	  accesses the two nearest texture elements.     <STRONG>ERRORS</STRONG>	  <STRONG>GL_INVALID_ENUM</STRONG> is generated if <EM>target</EM> or <EM>pname</EM> is not one	  of the accepted defined values.	  <STRONG>GL_INVALID_ENUM</STRONG> is generated if <EM>params</EM> should	have a defined	  constant value (based	on the value of	<EM>pname</EM>) and does	not.	  <STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glTexParameter</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>glGetTexParameter</STRONG>	  <STRONG>glGetTexLevelParameter</STRONG>     <STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>	  <STRONG>glBindTexture</STRONG>, <STRONG>glCopyPixels</STRONG>, <STRONG>glCopyTexImage1D</STRONG>,	  <STRONG>glCopyTexImage2D</STRONG>, <STRONG>glCopyTexSubImage1D</STRONG>, <STRONG>glCopyTexSubImage2D</STRONG>,	  <STRONG>glDrawPixels</STRONG>,	<STRONG>glPixelStore</STRONG>, <STRONG>glPixelTransfer</STRONG>,	  <STRONG>glPrioritizeTextures</STRONG>,	<STRONG>glTexEnv</STRONG>, <STRONG>glTexGen</STRONG>, <STRONG>glTexImage1D</STRONG>,	  <STRONG>glTexImage2D</STRONG>,	<STRONG>glTexSubImage1D</STRONG>, <STRONG>glTexSubImage2D</STRONG></PRE></BODY></HTML>
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