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

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
   2 <!-- saved from url=(0013)about:internet -->
   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>glBlendEquation</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glBlendEquation"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glBlendEquation — specify the equation used for both the RGB blend equation and the Alpha blend equation</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">glBlendEquation</b>(</code></td><td>GLenum  </td><td><var class="pdparam">mode</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>mode</code></em></span></dt><dd><p>
   4                     specifies how source and destination colors are combined.
   5                     It must be <code class="constant">GL_FUNC_ADD</code>, <code class="constant">GL_FUNC_SUBTRACT</code>,
   6                     <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>, <code class="constant">GL_MIN</code>, <code class="constant">GL_MAX</code>.
   7                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
   8             The blend equations determine how a new pixel (the ''source'' color)
   9             is combined with a pixel already in the framebuffer (the ''destination''
  10             color).  This function sets both the RGB blend equation and the alpha
  11             blend equation to a single equation.
  12         </p><p>
  13             These equations use the source and destination blend factors
  14             specified by either <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a> or
  15             <a class="citerefentry" href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>.
  16             See <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a> or <a class="citerefentry" href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>
  17             for a description of the various blend factors.
  18         </p><p>
  19             In the equations that follow, source and destination
  20             color components are referred to as
  21             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  22
  23                 <mml:mfenced open="(" close=")">
  24                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  25                     <mml:mi mathvariant="italic">s</mml:mi>
  26                     </mml:msub>
  27                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  28                     <mml:mi mathvariant="italic">s</mml:mi>
  29                     </mml:msub>
  30                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  31                     <mml:mi mathvariant="italic">s</mml:mi>
  32                     </mml:msub>
  33                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  34                     <mml:mi mathvariant="italic">s</mml:mi>
  35                     </mml:msub>
  36                 </mml:mfenced>
  37             </mml:math>
  38             and
  39             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  40
  41                 <mml:mfenced open="(" close=")">
  42                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  43                     <mml:mi mathvariant="italic">d</mml:mi>
  44                     </mml:msub>
  45                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  46                     <mml:mi mathvariant="italic">d</mml:mi>
  47                     </mml:msub>
  48                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  49                     <mml:mi mathvariant="italic">d</mml:mi>
  50                     </mml:msub>
  51                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  52                     <mml:mi mathvariant="italic">d</mml:mi>
  53                     </mml:msub>
  54                 </mml:mfenced>
  55             </mml:math>,
  56             respectively.
  57             The result color is referred to as
  58             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  59
  60                 <mml:mfenced open="(" close=")">
  61                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  62                     <mml:mi mathvariant="italic">r</mml:mi>
  63                     </mml:msub>
  64                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  65                     <mml:mi mathvariant="italic">r</mml:mi>
  66                     </mml:msub>
  67                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  68                     <mml:mi mathvariant="italic">r</mml:mi>
  69                     </mml:msub>
  70                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  71                     <mml:mi mathvariant="italic">r</mml:mi>
  72                     </mml:msub>
  73                 </mml:mfenced>
  74             </mml:math>.
  75             The source and destination blend factors are denoted
  76             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  77
  78                 <mml:mfenced open="(" close=")">
  79                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  80                     <mml:mi mathvariant="italic">R</mml:mi>
  81                     </mml:msub>
  82                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  83                     <mml:mi mathvariant="italic">G</mml:mi>
  84                     </mml:msub>
  85                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  86                     <mml:mi mathvariant="italic">B</mml:mi>
  87                     </mml:msub>
  88                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  89                     <mml:mi mathvariant="italic">A</mml:mi>
  90                     </mml:msub>
  91                 </mml:mfenced>
  92             </mml:math>
  93             and
  94             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  95
  96                 <mml:mfenced open="(" close=")">
  97                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
  98                     <mml:mi mathvariant="italic">R</mml:mi>
  99                     </mml:msub>
 100                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 101                     <mml:mi mathvariant="italic">G</mml:mi>
 102                     </mml:msub>
 103                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 104                     <mml:mi mathvariant="italic">B</mml:mi>
 105                     </mml:msub>
 106                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 107                     <mml:mi mathvariant="italic">A</mml:mi>
 108                     </mml:msub>
 109                 </mml:mfenced>
 110             </mml:math>,
 111             respectively.
 112             For these equations all color components are understood to have values
 113             in the range
 114             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 115
 116                 <mml:mfenced open="[" close="]">
 117                     <mml:mn>0</mml:mn>
 118                     <mml:mn>1</mml:mn>
 119                 </mml:mfenced>
 120             </mml:math>.
 121
 122         </p><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="left" /><col align="left" /></colgroup><thead><tr><th align="left"><span class="bold"><strong>
 123                         Mode
 124                         </strong></span></th><th align="left"><span class="bold"><strong>
 125                         RGB Components
 126                         </strong></span></th><th align="left"><span class="bold"><strong>
 127                         Alpha Component
 128                         </strong></span></th></tr></thead><tbody><tr><td align="left">
 129                         <code class="constant">GL_FUNC_ADD</code>
 130                         </td><td align="left">
 131                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 132
 133                             <mml:mrow>
 134                                 <mml:mi mathvariant="italic">Rr</mml:mi>
 135                                 <mml:mo>=</mml:mo>
 136                                 <mml:mrow>
 137                                                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 138                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 139                                                                         </mml:msub>
 140                                                                         <mml:mo>⁢</mml:mo>
 141                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 142                                                                         <mml:mi mathvariant="italic">R</mml:mi>
 143                                                                         </mml:msub>
 144                                                                         <mml:mo>+</mml:mo>
 145                                                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 146                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 147                                                                         </mml:msub>
 148                                                                         <mml:mo>⁢</mml:mo>
 149                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 150                                                                         <mml:mi mathvariant="italic">R</mml:mi>
 151                                                                         </mml:msub>
 152                                 </mml:mrow>
 153                             </mml:mrow>
 154                         </mml:math></div>
 155                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 156
 157                             <mml:mrow>
 158                                 <mml:mi mathvariant="italic">Gr</mml:mi>
 159                                 <mml:mo>=</mml:mo>
 160                                 <mml:mrow>
 161                                                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 162                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 163                                                                         </mml:msub>
 164                                                                         <mml:mo>⁢</mml:mo>
 165                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 166                                                                         <mml:mi mathvariant="italic">G</mml:mi>
 167                                                                         </mml:msub>
 168                                                                         <mml:mo>+</mml:mo>
 169                                                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 170                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 171                                                                         </mml:msub>
 172                                                                         <mml:mo>⁢</mml:mo>
 173                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 174                                                                         <mml:mi mathvariant="italic">G</mml:mi>
 175                                                                         </mml:msub>
 176                                 </mml:mrow>
 177                             </mml:mrow>
 178                         </mml:math></div>
 179                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 180
 181                             <mml:mrow>
 182                                 <mml:mi mathvariant="italic">Br</mml:mi>
 183                                 <mml:mo>=</mml:mo>
 184                                 <mml:mrow>
 185                                                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 186                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 187                                                                         </mml:msub>
 188                                                                         <mml:mo>⁢</mml:mo>
 189                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 190                                                                         <mml:mi mathvariant="italic">B</mml:mi>
 191                                                                         </mml:msub>
 192                                                                         <mml:mo>+</mml:mo>
 193                                                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 194                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 195                                                                         </mml:msub>
 196                                                                         <mml:mo>⁢</mml:mo>
 197                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 198                                                                         <mml:mi mathvariant="italic">B</mml:mi>
 199                                                                         </mml:msub>
 200                                 </mml:mrow>
 201                             </mml:mrow>
 202                         </mml:math></div>
 203                         </td><td align="left">
 204                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 205
 206                             <mml:mrow>
 207                                 <mml:mi mathvariant="italic">Ar</mml:mi>
 208                                 <mml:mo>=</mml:mo>
 209                                 <mml:mrow>
 210                                                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 211                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 212                                                                         </mml:msub>
 213                                                                         <mml:mo>⁢</mml:mo>
 214                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 215                                                                         <mml:mi mathvariant="italic">A</mml:mi>
 216                                                                         </mml:msub>
 217                                                                         <mml:mo>+</mml:mo>
 218                                                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 219                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 220                                                                         </mml:msub>
 221                                                                         <mml:mo>⁢</mml:mo>
 222                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 223                                                                         <mml:mi mathvariant="italic">A</mml:mi>
 224                                                                         </mml:msub>
 225                                 </mml:mrow>
 226                             </mml:mrow>
 227                         </mml:math></div>
 228                         </td></tr><tr><td align="left">
 229                         <code class="constant">GL_FUNC_SUBTRACT</code>
 230                         </td><td align="left">
 231                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 232
 233                             <mml:mrow>
 234                                 <mml:mi mathvariant="italic">Rr</mml:mi>
 235                                 <mml:mo>=</mml:mo>
 236                                 <mml:mrow>
 237                                                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 238                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 239                                                                         </mml:msub>
 240                                                                         <mml:mo>⁢</mml:mo>
 241                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 242                                                                         <mml:mi mathvariant="italic">R</mml:mi>
 243                                                                         </mml:msub>
 244                                                                         <mml:mo>-</mml:mo>
 245                                                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 246                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 247                                                                         </mml:msub>
 248                                                                         <mml:mo>⁢</mml:mo>
 249                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 250                                                                         <mml:mi mathvariant="italic">R</mml:mi>
 251                                                                         </mml:msub>
 252                                 </mml:mrow>
 253                             </mml:mrow>
 254                         </mml:math></div>
 255                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 256
 257                             <mml:mrow>
 258                                 <mml:mi mathvariant="italic">Gr</mml:mi>
 259                                 <mml:mo>=</mml:mo>
 260                                 <mml:mrow>
 261                                                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 262                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 263                                                                         </mml:msub>
 264                                                                         <mml:mo>⁢</mml:mo>
 265                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 266                                                                         <mml:mi mathvariant="italic">G</mml:mi>
 267                                                                         </mml:msub>
 268                                                                         <mml:mo>-</mml:mo>
 269                                                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 270                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 271                                                                         </mml:msub>
 272                                                                         <mml:mo>⁢</mml:mo>
 273                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 274                                                                         <mml:mi mathvariant="italic">G</mml:mi>
 275                                                                         </mml:msub>
 276                                 </mml:mrow>
 277                             </mml:mrow>
 278                         </mml:math></div>
 279                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 280
 281                             <mml:mrow>
 282                                 <mml:mi mathvariant="italic">Br</mml:mi>
 283                                 <mml:mo>=</mml:mo>
 284                                 <mml:mrow>
 285                                                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 286                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 287                                                                         </mml:msub>
 288                                                                         <mml:mo>⁢</mml:mo>
 289                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 290                                                                         <mml:mi mathvariant="italic">B</mml:mi>
 291                                                                         </mml:msub>
 292                                                                         <mml:mo>-</mml:mo>
 293                                                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 294                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 295                                                                         </mml:msub>
 296                                                                         <mml:mo>⁢</mml:mo>
 297                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 298                                                                         <mml:mi mathvariant="italic">B</mml:mi>
 299                                                                         </mml:msub>
 300                                 </mml:mrow>
 301                             </mml:mrow>
 302                         </mml:math></div>
 303                         </td><td align="left">
 304                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 305
 306                             <mml:mrow>
 307                                 <mml:mi mathvariant="italic">Ar</mml:mi>
 308                                 <mml:mo>=</mml:mo>
 309                                 <mml:mrow>
 310                                                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 311                                                                         <mml:mi mathvariant="italic">s</mml:mi>
 312                                                                         </mml:msub>
 313                                                                         <mml:mo>⁢</mml:mo>
 314                                                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 315                                                                         <mml:mi mathvariant="italic">A</mml:mi>
 316                                                                         </mml:msub>
 317                                                                         <mml:mo>-</mml:mo>
 318                                                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 319                                                                         <mml:mi mathvariant="italic">d</mml:mi>
 320                                                                         </mml:msub>
 321                                                                         <mml:mo>⁢</mml:mo>
 322                                                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 323                                                                         <mml:mi mathvariant="italic">A</mml:mi>
 324                                                                         </mml:msub>
 325                                 </mml:mrow>
 326                             </mml:mrow>
 327                         </mml:math></div>
 328                         </td></tr><tr><td align="left">
 329                         <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>
 330                         </td><td align="left">
 331                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 332
 333                                 <mml:mrow>
 334                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 335                                     <mml:mo>=</mml:mo>
 336                                     <mml:mrow>
 337                                                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 338                                                                                 <mml:mi mathvariant="italic">d</mml:mi>
 339                                                                                 </mml:msub>
 340                                                                                 <mml:mo>⁢</mml:mo>
 341                                                                                 <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 342                                                                                 <mml:mi mathvariant="italic">R</mml:mi>
 343                                                                                 </mml:msub>
 344                                                                                 <mml:mo>-</mml:mo>
 345                                                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 346                                                                                 <mml:mi mathvariant="italic">s</mml:mi>
 347                                                                                 </mml:msub>
 348                                                                                 <mml:mo>⁢</mml:mo>
 349                                                                                 <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 350                                                                                 <mml:mi mathvariant="italic">R</mml:mi>
 351                                                                                 </mml:msub>
 352                                     </mml:mrow>
 353                                 </mml:mrow>
 354                             </mml:math></div>
 355                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 356
 357                                 <mml:mrow>
 358                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 359                                     <mml:mo>=</mml:mo>
 360                                     <mml:mrow>
 361                                                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 362                                                                                 <mml:mi mathvariant="italic">d</mml:mi>
 363                                                                                 </mml:msub>
 364                                                                                 <mml:mo>⁢</mml:mo>
 365                                                                                 <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 366                                                                                 <mml:mi mathvariant="italic">G</mml:mi>
 367                                                                                 </mml:msub>
 368                                                                                 <mml:mo>-</mml:mo>
 369                                                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 370                                                                                 <mml:mi mathvariant="italic">s</mml:mi>
 371                                                                                 </mml:msub>
 372                                                                                 <mml:mo>⁢</mml:mo>
 373                                                                                 <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 374                                                                                 <mml:mi mathvariant="italic">G</mml:mi>
 375                                                                                 </mml:msub>
 376                                     </mml:mrow>
 377                                 </mml:mrow>
 378                             </mml:math></div>
 379                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 380
 381                                 <mml:mrow>
 382                                     <mml:mi mathvariant="italic">Br</mml:mi>
 383                                     <mml:mo>=</mml:mo>
 384                                     <mml:mrow>
 385                                                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 386                                                                                 <mml:mi mathvariant="italic">d</mml:mi>
 387                                                                                 </mml:msub>
 388                                                                                 <mml:mo>⁢</mml:mo>
 389                                                                                 <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 390                                                                                 <mml:mi mathvariant="italic">B</mml:mi>
 391                                                                                 </mml:msub>
 392                                                                                 <mml:mo>-</mml:mo>
 393                                                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 394                                                                                 <mml:mi mathvariant="italic">s</mml:mi>
 395                                                                                 </mml:msub>
 396                                                                                 <mml:mo>⁢</mml:mo>
 397                                                                                 <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 398                                                                                 <mml:mi mathvariant="italic">B</mml:mi>
 399                                                                                 </mml:msub>
 400                                     </mml:mrow>
 401                                 </mml:mrow>
 402                             </mml:math></div>
 403                         </td><td align="left">
 404                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 405
 406                                 <mml:mrow>
 407                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 408                                     <mml:mo>=</mml:mo>
 409                                     <mml:mrow>
 410                                                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 411                                                                                 <mml:mi mathvariant="italic">d</mml:mi>
 412                                                                                 </mml:msub>
 413                                                                                 <mml:mo>⁢</mml:mo>
 414                                                                                 <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 415                                                                                 <mml:mi mathvariant="italic">A</mml:mi>
 416                                                                                 </mml:msub>
 417                                                                                 <mml:mo>-</mml:mo>
 418                                                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 419                                                                                 <mml:mi mathvariant="italic">s</mml:mi>
 420                                                                                 </mml:msub>
 421                                                                                 <mml:mo>⁢</mml:mo>
 422                                                                                 <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 423                                                                                 <mml:mi mathvariant="italic">A</mml:mi>
 424                                                                                 </mml:msub>
 425                                     </mml:mrow>
 426                                 </mml:mrow>
 427                             </mml:math></div>
 428                         </td></tr><tr><td align="left">
 429                         <code class="constant">GL_MIN</code>
 430                         </td><td align="left">
 431                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 432
 433                                 <mml:mrow>
 434                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 435                                     <mml:mo>=</mml:mo>
 436                                     <mml:mrow>
 437                                         <mml:mi mathvariant="italic">min</mml:mi>
 438                                         <mml:mo>⁡</mml:mo>
 439                                         <mml:mfenced open="(" close=")">
 440                                             <mml:mrow>
 441                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 442                                                 <mml:mi mathvariant="italic">s</mml:mi>
 443                                                 </mml:msub>
 444                                             </mml:mrow>
 445                                             <mml:mrow>
 446                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 447                                                 <mml:mi mathvariant="italic">d</mml:mi>
 448                                                 </mml:msub>
 449                                             </mml:mrow>
 450                                         </mml:mfenced>
 451                                     </mml:mrow>
 452                                 </mml:mrow>
 453                             </mml:math></div>
 454                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 455
 456                                 <mml:mrow>
 457                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 458                                     <mml:mo>=</mml:mo>
 459                                     <mml:mrow>
 460                                         <mml:mi mathvariant="italic">min</mml:mi>
 461                                         <mml:mo>⁡</mml:mo>
 462                                         <mml:mfenced open="(" close=")">
 463                                             <mml:mrow>
 464                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 465                                                 <mml:mi mathvariant="italic">s</mml:mi>
 466                                                 </mml:msub>
 467                                             </mml:mrow>
 468                                             <mml:mrow>
 469                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 470                                                 <mml:mi mathvariant="italic">d</mml:mi>
 471                                                 </mml:msub>
 472                                             </mml:mrow>
 473                                         </mml:mfenced>
 474                                     </mml:mrow>
 475                                 </mml:mrow>
 476                             </mml:math></div>
 477                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 478
 479                                 <mml:mrow>
 480                                     <mml:mi mathvariant="italic">Br</mml:mi>
 481                                     <mml:mo>=</mml:mo>
 482                                     <mml:mrow>
 483                                         <mml:mi mathvariant="italic">min</mml:mi>
 484                                         <mml:mo>⁡</mml:mo>
 485                                         <mml:mfenced open="(" close=")">
 486                                             <mml:mrow>
 487                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 488                                                 <mml:mi mathvariant="italic">s</mml:mi>
 489                                                 </mml:msub>
 490                                             </mml:mrow>
 491                                             <mml:mrow>
 492                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 493                                                 <mml:mi mathvariant="italic">d</mml:mi>
 494                                                 </mml:msub>
 495                                             </mml:mrow>
 496                                         </mml:mfenced>
 497                                     </mml:mrow>
 498                                 </mml:mrow>
 499                             </mml:math></div>
 500                         </td><td align="left">
 501                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 502
 503                                 <mml:mrow>
 504                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 505                                     <mml:mo>=</mml:mo>
 506                                     <mml:mrow>
 507                                         <mml:mi mathvariant="italic">min</mml:mi>
 508                                         <mml:mo>⁡</mml:mo>
 509                                         <mml:mfenced open="(" close=")">
 510                                             <mml:mrow>
 511                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 512                                                 <mml:mi mathvariant="italic">s</mml:mi>
 513                                                 </mml:msub>
 514                                             </mml:mrow>
 515                                             <mml:mrow>
 516                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 517                                                 <mml:mi mathvariant="italic">d</mml:mi>
 518                                                 </mml:msub>
 519                                             </mml:mrow>
 520                                         </mml:mfenced>
 521                                     </mml:mrow>
 522                                 </mml:mrow>
 523                             </mml:math></div>
 524                         </td></tr><tr><td align="left">
 525                         <code class="constant">GL_MAX</code>
 526                         </td><td align="left">
 527                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 528
 529                                 <mml:mrow>
 530                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 531                                     <mml:mo>=</mml:mo>
 532                                     <mml:mrow>
 533                                         <mml:mi mathvariant="italic">max</mml:mi>
 534                                         <mml:mo>⁡</mml:mo>
 535                                         <mml:mfenced open="(" close=")">
 536                                             <mml:mrow>
 537                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 538                                                 <mml:mi mathvariant="italic">s</mml:mi>
 539                                                 </mml:msub>
 540                                             </mml:mrow>
 541                                             <mml:mrow>
 542                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 543                                                 <mml:mi mathvariant="italic">d</mml:mi>
 544                                                 </mml:msub>
 545                                             </mml:mrow>
 546                                         </mml:mfenced>
 547                                     </mml:mrow>
 548                                 </mml:mrow>
 549                             </mml:math></div>
 550                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 551
 552                                 <mml:mrow>
 553                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 554                                     <mml:mo>=</mml:mo>
 555                                     <mml:mrow>
 556                                         <mml:mi mathvariant="italic">max</mml:mi>
 557                                         <mml:mo>⁡</mml:mo>
 558                                         <mml:mfenced open="(" close=")">
 559                                             <mml:mrow>
 560                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 561                                                 <mml:mi mathvariant="italic">s</mml:mi>
 562                                                 </mml:msub>
 563                                             </mml:mrow>
 564                                             <mml:mrow>
 565                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 566                                                 <mml:mi mathvariant="italic">d</mml:mi>
 567                                                 </mml:msub>
 568                                             </mml:mrow>
 569                                         </mml:mfenced>
 570                                     </mml:mrow>
 571                                 </mml:mrow>
 572                             </mml:math></div>
 573                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 574
 575                                 <mml:mrow>
 576                                     <mml:mi mathvariant="italic">Br</mml:mi>
 577                                     <mml:mo>=</mml:mo>
 578                                     <mml:mrow>
 579                                         <mml:mi mathvariant="italic">max</mml:mi>
 580                                         <mml:mo>⁡</mml:mo>
 581                                         <mml:mfenced open="(" close=")">
 582                                             <mml:mrow>
 583                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 584                                                 <mml:mi mathvariant="italic">s</mml:mi>
 585                                                 </mml:msub>
 586                                             </mml:mrow>
 587                                             <mml:mrow>
 588                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 589                                                 <mml:mi mathvariant="italic">d</mml:mi>
 590                                                 </mml:msub>
 591                                             </mml:mrow>
 592                                         </mml:mfenced>
 593                                     </mml:mrow>
 594                                 </mml:mrow>
 595                             </mml:math></div>
 596                         </td><td align="left">
 597                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 598
 599                                 <mml:mrow>
 600                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 601                                     <mml:mo>=</mml:mo>
 602                                     <mml:mrow>
 603                                         <mml:mi mathvariant="italic">max</mml:mi>
 604                                         <mml:mo>⁡</mml:mo>
 605                                         <mml:mfenced open="(" close=")">
 606                                             <mml:mrow>
 607                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 608                                                 <mml:mi mathvariant="italic">s</mml:mi>
 609                                                 </mml:msub>
 610                                             </mml:mrow>
 611                                             <mml:mrow>
 612                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 613                                                 <mml:mi mathvariant="italic">d</mml:mi>
 614                                                 </mml:msub>
 615                                             </mml:mrow>
 616                                         </mml:mfenced>
 617                                     </mml:mrow>
 618                                 </mml:mrow>
 619                             </mml:math></div>
 620                         </td></tr></tbody></table></div><p>
 621         </p><p>
 622             The results of these equations are clamped to the range
 623                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 624
 625                             <mml:mfenced open="[" close="]">
 626                                 <mml:mn>0</mml:mn>
 627                                 <mml:mn>1</mml:mn>
 628                             </mml:mfenced>
 629                         </mml:math>.
 630         </p><p>
 631             The <code class="constant">GL_MIN</code> and <code class="constant">GL_MAX</code> equations are useful for applications
 632             that analyze image data (image thresholding against a constant color,
 633             for example).
 634             The <code class="constant">GL_FUNC_ADD</code> equation is useful
 635             for antialiasing and transparency, among other things.
 636         </p><p>
 637             Initially, both the RGB blend equation and the alpha blend equation are set to <code class="constant">GL_FUNC_ADD</code>.
 638         </p><p>
 639         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 640             The <code class="constant">GL_MIN</code>, and <code class="constant">GL_MAX</code> equations do not use
 641             the source or destination factors, only the source and destination colors.
 642         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 643             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not one of
 644             <code class="constant">GL_FUNC_ADD</code>, <code class="constant">GL_FUNC_SUBTRACT</code>, <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>,
 645             <code class="constant">GL_MAX</code>, or <code class="constant">GL_MIN</code>.
 646         </p><p>
 647             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glBlendEquation</code> is executed
 648             between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding
 649             execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 650         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 651             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with an argument of <code class="constant">GL_BLEND_EQUATION_RGB</code>
 652          </p><p>
 653             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with an argument of <code class="constant">GL_BLEND_EQUATION_ALPHA</code>
 654          </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 655             <a class="citerefentry" href="glGetString.xml"><span class="citerefentry"><span class="refentrytitle">glGetString</span></span></a>,
 656             <a class="citerefentry" href="glBlendColor.xml"><span class="citerefentry"><span class="refentrytitle">glBlendColor</span></span></a>,
 657             <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>
 658             <a class="citerefentry" href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>
 659         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 660             Copyright <span class="trademark"></span>© 1991-2006
 661             Silicon Graphics, Inc. This document is licensed under the SGI
 662             Free Software B License. For details, see
 663             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 664         </p></div></div></body></html>