upstream-man-pages/man2/xhtml/glGetTexEnv.xml

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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glGetTexEnv</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetTexEnv"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetTexEnv — return texture environment parameters</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetTexEnvfv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLfloat *  </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div><p></p><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetTexEnviv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLint *  </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
   4                     Specifies a texture environment. May be
   5                     <code class="constant">GL_TEXTURE_ENV</code>,
   6                     <code class="constant">GL_TEXTURE_FILTER_CONTROL</code>, or
   7                     <code class="constant">GL_POINT_SPRITE</code>.
   8                 </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
   9                     Specifies the symbolic name of a texture environment parameter.
  10                     Accepted values are <code class="constant">GL_TEXTURE_ENV_MODE</code>, <code class="constant">GL_TEXTURE_ENV_COLOR</code>,
  11                     <code class="constant">GL_TEXTURE_LOD_BIAS</code>,
  12                     <code class="constant">GL_COMBINE_RGB</code>,
  13                     <code class="constant">GL_COMBINE_ALPHA</code>,
  14                     <code class="constant">GL_SRC0_RGB</code>,
  15                     <code class="constant">GL_SRC1_RGB</code>,
  16                     <code class="constant">GL_SRC2_RGB</code>,
  17                     <code class="constant">GL_SRC0_ALPHA</code>,
  18                     <code class="constant">GL_SRC1_ALPHA</code>,
  19                     <code class="constant">GL_SRC2_ALPHA</code>,
  20                     <code class="constant">GL_OPERAND0_RGB</code>,
  21                     <code class="constant">GL_OPERAND1_RGB</code>,
  22                     <code class="constant">GL_OPERAND2_RGB</code>,
  23                     <code class="constant">GL_OPERAND0_ALPHA</code>,
  24                     <code class="constant">GL_OPERAND1_ALPHA</code>,
  25                     <code class="constant">GL_OPERAND2_ALPHA</code>,
  26                     <code class="constant">GL_RGB_SCALE</code>,
  27                     <code class="constant">GL_ALPHA_SCALE</code>, or
  28                     <code class="constant">GL_COORD_REPLACE</code>.
  29                 </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>
  30                     Returns the requested data.
  31                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  32             <code class="function">glGetTexEnv</code> returns in <em class="parameter"><code>params</code></em> selected values of a texture environment that
  33             was specified with <a class="citerefentry" href="glTexEnv.xml"><span class="citerefentry"><span class="refentrytitle">glTexEnv</span></span></a>.
  34             <em class="parameter"><code>target</code></em> specifies a texture environment.
  35         </p><p>
  36             When <em class="parameter"><code>target</code></em> is <code class="constant">GL_TEXTURE_FILTER_CONTROL</code>,
  37             <em class="parameter"><code>pname</code></em> must be <code class="constant">GL_TEXTURE_LOD_BIAS</code>.
  38             When <em class="parameter"><code>target</code></em> is <code class="constant">GL_POINT_SPRITE</code>,
  39             <em class="parameter"><code>pname</code></em> must be <code class="constant">GL_COORD_REPLACE</code>.
  40             When <em class="parameter"><code>target</code></em> is
  41             <code class="constant">GL_TEXTURE_ENV</code>, <em class="parameter"><code>pname</code></em> can be <code class="constant">GL_TEXTURE_ENV_MODE</code>,
  42             <code class="constant">GL_TEXTURE_ENV_COLOR</code>, <code class="constant">GL_COMBINE_RGB</code>, <code class="constant">GL_COMBINE_ALPHA</code>,
  43             <code class="constant">GL_RGB_SCALE</code>, <code class="constant">GL_ALPHA_SCALE</code>,
  44             <code class="constant">GL_SRC0_RGB</code>, <code class="constant">GL_SRC1_RGB</code>, <code class="constant">GL_SRC2_RGB</code>,
  45             <code class="constant">GL_SRC0_ALPHA</code>, <code class="constant">GL_SRC1_ALPHA</code>, or <code class="constant">GL_SRC2_ALPHA</code>.
  46         </p><p>
  47             <em class="parameter"><code>pname</code></em> names a specific texture environment parameter, as follows:
  48         </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_ENV_MODE</code></span></dt><dd><p>
  49                         <em class="parameter"><code>params</code></em> returns the single-valued texture environment mode,
  50                         a symbolic constant. The initial value is <code class="constant">GL_MODULATE</code>.
  51                     </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_ENV_COLOR</code></span></dt><dd><p>
  52                         <em class="parameter"><code>params</code></em> returns four integer or floating-point values that are the
  53                         texture environment color.
  54                         Integer values,
  55                         when requested,
  56                         are linearly mapped from the internal floating-point representation
  57                         such that 1.0 maps to the most positive representable integer,
  58                         and
  59                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  60
  61                             <mml:mn>-1.0</mml:mn>
  62                         </mml:math>
  63                         maps to the most negative representable integer. The initial
  64                         value is (0, 0, 0, 0).
  65                     </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_LOD_BIAS</code></span></dt><dd><p>
  66                         <em class="parameter"><code>params</code></em> returns a single floating-point value that is the texture
  67                         level-of-detail bias.  The initial value is 0.
  68                     </p></dd><dt><span class="term"><code class="constant">GL_COMBINE_RGB</code></span></dt><dd><p>
  69                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the current
  70                         RGB combine mode.  The initial value is <code class="constant">GL_MODULATE</code>.
  71                     </p></dd><dt><span class="term"><code class="constant">GL_COMBINE_ALPHA</code></span></dt><dd><p>
  72                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the current
  73                         alpha combine mode.  The initial value is <code class="constant">GL_MODULATE</code>.
  74                     </p></dd><dt><span class="term"><code class="constant">GL_SRC0_RGB</code></span></dt><dd><p>
  75                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  76                         combiner zero's RGB source.  The initial value is <code class="constant">GL_TEXTURE</code>.
  77                     </p></dd><dt><span class="term"><code class="constant">GL_SRC1_RGB</code></span></dt><dd><p>
  78                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  79                         combiner one's RGB source.  The initial value is <code class="constant">GL_PREVIOUS</code>.
  80                     </p></dd><dt><span class="term"><code class="constant">GL_SRC2_RGB</code></span></dt><dd><p>
  81                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  82                         combiner two's RGB source.  The initial value is <code class="constant">GL_CONSTANT</code>.
  83                     </p></dd><dt><span class="term"><code class="constant">GL_SRC0_ALPHA</code></span></dt><dd><p>
  84                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  85                         combiner zero's alpha source.  The initial value is <code class="constant">GL_TEXTURE</code>.
  86                     </p></dd><dt><span class="term"><code class="constant">GL_SRC1_ALPHA</code></span></dt><dd><p>
  87                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  88                         combiner one's alpha source.  The initial value is <code class="constant">GL_PREVIOUS</code>.
  89                     </p></dd><dt><span class="term"><code class="constant">GL_SRC2_ALPHA</code></span></dt><dd><p>
  90                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  91                         combiner two's alpha source.  The initial value is <code class="constant">GL_CONSTANT</code>.
  92                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND0_RGB</code></span></dt><dd><p>
  93                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  94                         combiner zero's RGB operand.  The initial value is <code class="constant">GL_SRC_COLOR</code>.
  95                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND1_RGB</code></span></dt><dd><p>
  96                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
  97                         combiner one's RGB operand.  The initial value is <code class="constant">GL_SRC_COLOR</code>.
  98                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND2_RGB</code></span></dt><dd><p>
  99                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
 100                         combiner two's RGB operand.  The initial value is <code class="constant">GL_SRC_ALPHA</code>.
 101                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND0_ALPHA</code></span></dt><dd><p>
 102                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
 103                         combiner zero's alpha operand.  The initial value is <code class="constant">GL_SRC_ALPHA</code>.
 104                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND1_ALPHA</code></span></dt><dd><p>
 105                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
 106                         combiner one's alpha operand.  The initial value is <code class="constant">GL_SRC_ALPHA</code>.
 107                     </p></dd><dt><span class="term"><code class="constant">GL_OPERAND2_ALPHA</code></span></dt><dd><p>
 108                         <em class="parameter"><code>params</code></em> returns a single symbolic constant value representing the texture
 109                         combiner two's alpha operand.  The initial value is <code class="constant">GL_SRC_ALPHA</code>.
 110                     </p></dd><dt><span class="term"><code class="constant">GL_RGB_SCALE</code></span></dt><dd><p>
 111                         <em class="parameter"><code>params</code></em> returns a single floating-point value representing the current RGB
 112                         texture combiner scaling factor.  The initial value is 1.0.
 113                     </p></dd><dt><span class="term"><code class="constant">GL_ALPHA_SCALE</code></span></dt><dd><p>
 114                         <em class="parameter"><code>params</code></em> returns a single floating-point value representing the current alpha
 115                         texture combiner scaling factor.  The initial value is 1.0.
 116                     </p></dd><dt><span class="term"><code class="constant">GL_COORD_REPLACE</code></span></dt><dd><p>
 117                         <em class="parameter"><code>params</code></em> returns a single boolean value representing the current point sprite
 118                         texture coordinate replacement enable state.  The initial value is <code class="constant">GL_FALSE</code>.
 119                     </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 120             If an error is generated,
 121             no change is made to the contents of <em class="parameter"><code>params</code></em>.
 122         </p><p>
 123             For OpenGL versions 1.3 and greater, or when the <code class="code">ARB_multitexture</code> extension is supported, <code class="function">glGetTexEnv</code> returns
 124             the texture environment parameters for the active texture unit.
 125         </p><p>
 126             <code class="constant">GL_COMBINE_RGB</code>,
 127             <code class="constant">GL_COMBINE_ALPHA</code>,
 128             <code class="constant">GL_SRC0_RGB</code>,
 129             <code class="constant">GL_SRC1_RGB</code>,
 130             <code class="constant">GL_SRC2_RGB</code>,
 131             <code class="constant">GL_SRC0_ALPHA</code>,
 132             <code class="constant">GL_SRC1_ALPHA</code>,
 133             <code class="constant">GL_SRC2_ALPHA</code>,
 134             <code class="constant">GL_OPERAND0_RGB</code>,
 135             <code class="constant">GL_OPERAND1_RGB</code>,
 136             <code class="constant">GL_OPERAND2_RGB</code>,
 137             <code class="constant">GL_OPERAND0_ALPHA</code>,
 138             <code class="constant">GL_OPERAND1_ALPHA</code>,
 139             <code class="constant">GL_OPERAND2_ALPHA</code>,
 140             <code class="constant">GL_RGB_SCALE</code>, and
 141             <code class="constant">GL_ALPHA_SCALE</code> are available only if the GL version is 1.3 or greater.
 142         </p><p>
 143             <code class="constant">GL_TEXTURE_FILTER_CONTROL</code> and <code class="constant">GL_TEXTURE_LOD_BIAS</code> are available
 144             only if the GL version is 1.4 or greater.
 145         </p><p>
 146             <code class="constant">GL_POINT_SPRITE</code> and <code class="constant">GL_COORD_REPLACE</code> are available
 147             only if the GL version is 2.0 or greater.
 148         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 149             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> or <em class="parameter"><code>pname</code></em> is not an
 150             accepted value.
 151         </p><p>
 152             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetTexEnv</code>
 153             is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
 154             and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 155         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 156             <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
 157             <a class="citerefentry" href="glTexEnv.xml"><span class="citerefentry"><span class="refentrytitle">glTexEnv</span></span></a>
 158         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 159             Copyright <span class="trademark"></span>© 1991-2006
 160             Silicon Graphics, Inc. This document is licensed under the SGI
 161             Free Software B License. For details, see
 162             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 163         </p></div></div></body></html>