upstream-doc/man3/xhtml/glBlendEquation.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
   3 <!-- saved from url=(0013)about:internet -->
   4 <?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" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glBlendEquation</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></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"><p><code class="funcdef">void <b class="fsfunc">glBlendEquation</b>(</code>GLenum <var class="pdparam">mode</var><code>)</code>;</p></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>
   5                     specifies how source and destination colors are combined.
   6                     It must be <code class="constant">GL_FUNC_ADD</code>, <code class="constant">GL_FUNC_SUBTRACT</code>,
   7                     <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>, <code class="constant">GL_MIN</code>, <code class="constant">GL_MAX</code>.
   8                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
   9             The blend equations determine how a new pixel (the ''source'' color)
  10             is combined with a pixel already in the framebuffer (the ''destination''
  11             color).  This function sets both the RGB blend equation and the alpha
  12             blend equation to a single equation.
  13         </p><p>
  14             These equations use the source and destination blend factors
  15             specified by either <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a> or
  16             <a href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>.
  17             See <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a> or <a href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>
  18             for a description of the various blend factors.
  19         </p><p>
  20             In the equations that follow, source and destination
  21             color components are referred to as
  22             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  23
  24                 <mml:mfenced open="(" close=")">
  25                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  26                     <mml:mi mathvariant="italic">s</mml:mi>
  27                     </mml:msub>
  28                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  29                     <mml:mi mathvariant="italic">s</mml:mi>
  30                     </mml:msub>
  31                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  32                     <mml:mi mathvariant="italic">s</mml:mi>
  33                     </mml:msub>
  34                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  35                     <mml:mi mathvariant="italic">s</mml:mi>
  36                     </mml:msub>
  37                 </mml:mfenced>
  38             </mml:math>
  39             and
  40             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  41
  42                 <mml:mfenced open="(" close=")">
  43                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  44                     <mml:mi mathvariant="italic">d</mml:mi>
  45                     </mml:msub>
  46                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  47                     <mml:mi mathvariant="italic">d</mml:mi>
  48                     </mml:msub>
  49                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  50                     <mml:mi mathvariant="italic">d</mml:mi>
  51                     </mml:msub>
  52                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  53                     <mml:mi mathvariant="italic">d</mml:mi>
  54                     </mml:msub>
  55                 </mml:mfenced>
  56             </mml:math>,
  57             respectively.
  58             The result color is referred to as
  59             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  60
  61                 <mml:mfenced open="(" close=")">
  62                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
  63                     <mml:mi mathvariant="italic">r</mml:mi>
  64                     </mml:msub>
  65                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
  66                     <mml:mi mathvariant="italic">r</mml:mi>
  67                     </mml:msub>
  68                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
  69                     <mml:mi mathvariant="italic">r</mml:mi>
  70                     </mml:msub>
  71                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
  72                     <mml:mi mathvariant="italic">r</mml:mi>
  73                     </mml:msub>
  74                 </mml:mfenced>
  75             </mml:math>.
  76             The source and destination blend factors are denoted
  77             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  78
  79                 <mml:mfenced open="(" close=")">
  80                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  81                     <mml:mi mathvariant="italic">R</mml:mi>
  82                     </mml:msub>
  83                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  84                     <mml:mi mathvariant="italic">G</mml:mi>
  85                     </mml:msub>
  86                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  87                     <mml:mi mathvariant="italic">B</mml:mi>
  88                     </mml:msub>
  89                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
  90                     <mml:mi mathvariant="italic">A</mml:mi>
  91                     </mml:msub>
  92                 </mml:mfenced>
  93             </mml:math>
  94             and
  95             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  96
  97                 <mml:mfenced open="(" close=")">
  98                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
  99                     <mml:mi mathvariant="italic">R</mml:mi>
 100                     </mml:msub>
 101                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 102                     <mml:mi mathvariant="italic">G</mml:mi>
 103                     </mml:msub>
 104                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 105                     <mml:mi mathvariant="italic">B</mml:mi>
 106                     </mml:msub>
 107                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 108                     <mml:mi mathvariant="italic">A</mml:mi>
 109                     </mml:msub>
 110                 </mml:mfenced>
 111             </mml:math>,
 112             respectively.
 113             For these equations all color components are understood to have values
 114             in the range
 115             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 116
 117                 <mml:mfenced open="[" close="]">
 118                     <mml:mn>0</mml:mn>
 119                     <mml:mn>1</mml:mn>
 120                 </mml:mfenced>
 121             </mml:math>.
 122
 123         </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>
 124                         Mode
 125                         </strong></span></th><th align="left"><span class="bold"><strong>
 126                         RGB Components
 127                         </strong></span></th><th align="left"><span class="bold"><strong>
 128                         Alpha Component
 129                         </strong></span></th></tr></thead><tbody><tr><td align="left">
 130                         <code class="constant">GL_FUNC_ADD</code>
 131                         </td><td align="left">
 132                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 133
 134                             <mml:mrow>
 135                                 <mml:mi mathvariant="italic">Rr</mml:mi>
 136                                 <mml:mo>=</mml:mo>
 137                                 <mml:mrow>
 138                                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 139                                     <mml:mi mathvariant="italic">s</mml:mi>
 140                                     </mml:msub>
 141                                     <mml:mo>⁢</mml:mo>
 142                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 143                                     <mml:mi mathvariant="italic">R</mml:mi>
 144                                     </mml:msub>
 145                                     <mml:mo>+</mml:mo>
 146                                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 147                                     <mml:mi mathvariant="italic">d</mml:mi>
 148                                     </mml:msub>
 149                                     <mml:mo>⁢</mml:mo>
 150                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 151                                     <mml:mi mathvariant="italic">R</mml:mi>
 152                                     </mml:msub>
 153                                 </mml:mrow>
 154                             </mml:mrow>
 155                         </mml:math></div>
 156                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 157
 158                             <mml:mrow>
 159                                 <mml:mi mathvariant="italic">Gr</mml:mi>
 160                                 <mml:mo>=</mml:mo>
 161                                 <mml:mrow>
 162                                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 163                                     <mml:mi mathvariant="italic">s</mml:mi>
 164                                     </mml:msub>
 165                                     <mml:mo>⁢</mml:mo>
 166                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 167                                     <mml:mi mathvariant="italic">G</mml:mi>
 168                                     </mml:msub>
 169                                     <mml:mo>+</mml:mo>
 170                                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 171                                     <mml:mi mathvariant="italic">d</mml:mi>
 172                                     </mml:msub>
 173                                     <mml:mo>⁢</mml:mo>
 174                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 175                                     <mml:mi mathvariant="italic">G</mml:mi>
 176                                     </mml:msub>
 177                                 </mml:mrow>
 178                             </mml:mrow>
 179                         </mml:math></div>
 180                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 181
 182                             <mml:mrow>
 183                                 <mml:mi mathvariant="italic">Br</mml:mi>
 184                                 <mml:mo>=</mml:mo>
 185                                 <mml:mrow>
 186                                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 187                                     <mml:mi mathvariant="italic">s</mml:mi>
 188                                     </mml:msub>
 189                                     <mml:mo>⁢</mml:mo>
 190                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 191                                     <mml:mi mathvariant="italic">B</mml:mi>
 192                                     </mml:msub>
 193                                     <mml:mo>+</mml:mo>
 194                                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 195                                     <mml:mi mathvariant="italic">d</mml:mi>
 196                                     </mml:msub>
 197                                     <mml:mo>⁢</mml:mo>
 198                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 199                                     <mml:mi mathvariant="italic">B</mml:mi>
 200                                     </mml:msub>
 201                                 </mml:mrow>
 202                             </mml:mrow>
 203                         </mml:math></div>
 204                         </td><td align="left">
 205                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 206
 207                             <mml:mrow>
 208                                 <mml:mi mathvariant="italic">Ar</mml:mi>
 209                                 <mml:mo>=</mml:mo>
 210                                 <mml:mrow>
 211                                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 212                                     <mml:mi mathvariant="italic">s</mml:mi>
 213                                     </mml:msub>
 214                                     <mml:mo>⁢</mml:mo>
 215                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 216                                     <mml:mi mathvariant="italic">A</mml:mi>
 217                                     </mml:msub>
 218                                     <mml:mo>+</mml:mo>
 219                                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 220                                     <mml:mi mathvariant="italic">d</mml:mi>
 221                                     </mml:msub>
 222                                     <mml:mo>⁢</mml:mo>
 223                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 224                                     <mml:mi mathvariant="italic">A</mml:mi>
 225                                     </mml:msub>
 226                                 </mml:mrow>
 227                             </mml:mrow>
 228                         </mml:math></div>
 229                         </td></tr><tr><td align="left">
 230                         <code class="constant">GL_FUNC_SUBTRACT</code>
 231                         </td><td align="left">
 232                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 233
 234                             <mml:mrow>
 235                                 <mml:mi mathvariant="italic">Rr</mml:mi>
 236                                 <mml:mo>=</mml:mo>
 237                                 <mml:mrow>
 238                                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 239                                     <mml:mi mathvariant="italic">s</mml:mi>
 240                                     </mml:msub>
 241                                     <mml:mo>⁢</mml:mo>
 242                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 243                                     <mml:mi mathvariant="italic">R</mml:mi>
 244                                     </mml:msub>
 245                                     <mml:mo>-</mml:mo>
 246                                     <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 247                                     <mml:mi mathvariant="italic">d</mml:mi>
 248                                     </mml:msub>
 249                                     <mml:mo>⁢</mml:mo>
 250                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 251                                     <mml:mi mathvariant="italic">R</mml:mi>
 252                                     </mml:msub>
 253                                 </mml:mrow>
 254                             </mml:mrow>
 255                         </mml:math></div>
 256                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 257
 258                             <mml:mrow>
 259                                 <mml:mi mathvariant="italic">Gr</mml:mi>
 260                                 <mml:mo>=</mml:mo>
 261                                 <mml:mrow>
 262                                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 263                                     <mml:mi mathvariant="italic">s</mml:mi>
 264                                     </mml:msub>
 265                                     <mml:mo>⁢</mml:mo>
 266                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 267                                     <mml:mi mathvariant="italic">G</mml:mi>
 268                                     </mml:msub>
 269                                     <mml:mo>-</mml:mo>
 270                                     <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 271                                     <mml:mi mathvariant="italic">d</mml:mi>
 272                                     </mml:msub>
 273                                     <mml:mo>⁢</mml:mo>
 274                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 275                                     <mml:mi mathvariant="italic">G</mml:mi>
 276                                     </mml:msub>
 277                                 </mml:mrow>
 278                             </mml:mrow>
 279                         </mml:math></div>
 280                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 281
 282                             <mml:mrow>
 283                                 <mml:mi mathvariant="italic">Br</mml:mi>
 284                                 <mml:mo>=</mml:mo>
 285                                 <mml:mrow>
 286                                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 287                                     <mml:mi mathvariant="italic">s</mml:mi>
 288                                     </mml:msub>
 289                                     <mml:mo>⁢</mml:mo>
 290                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 291                                     <mml:mi mathvariant="italic">B</mml:mi>
 292                                     </mml:msub>
 293                                     <mml:mo>-</mml:mo>
 294                                     <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 295                                     <mml:mi mathvariant="italic">d</mml:mi>
 296                                     </mml:msub>
 297                                     <mml:mo>⁢</mml:mo>
 298                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 299                                     <mml:mi mathvariant="italic">B</mml:mi>
 300                                     </mml:msub>
 301                                 </mml:mrow>
 302                             </mml:mrow>
 303                         </mml:math></div>
 304                         </td><td align="left">
 305                         <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 306
 307                             <mml:mrow>
 308                                 <mml:mi mathvariant="italic">Ar</mml:mi>
 309                                 <mml:mo>=</mml:mo>
 310                                 <mml:mrow>
 311                                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 312                                     <mml:mi mathvariant="italic">s</mml:mi>
 313                                     </mml:msub>
 314                                     <mml:mo>⁢</mml:mo>
 315                                     <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 316                                     <mml:mi mathvariant="italic">A</mml:mi>
 317                                     </mml:msub>
 318                                     <mml:mo>-</mml:mo>
 319                                     <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 320                                     <mml:mi mathvariant="italic">d</mml:mi>
 321                                     </mml:msub>
 322                                     <mml:mo>⁢</mml:mo>
 323                                     <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 324                                     <mml:mi mathvariant="italic">A</mml:mi>
 325                                     </mml:msub>
 326                                 </mml:mrow>
 327                             </mml:mrow>
 328                         </mml:math></div>
 329                         </td></tr><tr><td align="left">
 330                         <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>
 331                         </td><td align="left">
 332                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 333
 334                                 <mml:mrow>
 335                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 336                                     <mml:mo>=</mml:mo>
 337                                     <mml:mrow>
 338                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 339                                         <mml:mi mathvariant="italic">d</mml:mi>
 340                                         </mml:msub>
 341                                         <mml:mo>⁢</mml:mo>
 342                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 343                                         <mml:mi mathvariant="italic">R</mml:mi>
 344                                         </mml:msub>
 345                                         <mml:mo>-</mml:mo>
 346                                         <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 347                                         <mml:mi mathvariant="italic">s</mml:mi>
 348                                         </mml:msub>
 349                                         <mml:mo>⁢</mml:mo>
 350                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 351                                         <mml:mi mathvariant="italic">R</mml:mi>
 352                                         </mml:msub>
 353                                     </mml:mrow>
 354                                 </mml:mrow>
 355                             </mml:math></div>
 356                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 357
 358                                 <mml:mrow>
 359                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 360                                     <mml:mo>=</mml:mo>
 361                                     <mml:mrow>
 362                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 363                                         <mml:mi mathvariant="italic">d</mml:mi>
 364                                         </mml:msub>
 365                                         <mml:mo>⁢</mml:mo>
 366                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 367                                         <mml:mi mathvariant="italic">G</mml:mi>
 368                                         </mml:msub>
 369                                         <mml:mo>-</mml:mo>
 370                                         <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 371                                         <mml:mi mathvariant="italic">s</mml:mi>
 372                                         </mml:msub>
 373                                         <mml:mo>⁢</mml:mo>
 374                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 375                                         <mml:mi mathvariant="italic">G</mml:mi>
 376                                         </mml:msub>
 377                                     </mml:mrow>
 378                                 </mml:mrow>
 379                             </mml:math></div>
 380                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 381
 382                                 <mml:mrow>
 383                                     <mml:mi mathvariant="italic">Br</mml:mi>
 384                                     <mml:mo>=</mml:mo>
 385                                     <mml:mrow>
 386                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 387                                         <mml:mi mathvariant="italic">d</mml:mi>
 388                                         </mml:msub>
 389                                         <mml:mo>⁢</mml:mo>
 390                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 391                                         <mml:mi mathvariant="italic">B</mml:mi>
 392                                         </mml:msub>
 393                                         <mml:mo>-</mml:mo>
 394                                         <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 395                                         <mml:mi mathvariant="italic">s</mml:mi>
 396                                         </mml:msub>
 397                                         <mml:mo>⁢</mml:mo>
 398                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 399                                         <mml:mi mathvariant="italic">B</mml:mi>
 400                                         </mml:msub>
 401                                     </mml:mrow>
 402                                 </mml:mrow>
 403                             </mml:math></div>
 404                         </td><td align="left">
 405                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 406
 407                                 <mml:mrow>
 408                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 409                                     <mml:mo>=</mml:mo>
 410                                     <mml:mrow>
 411                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 412                                         <mml:mi mathvariant="italic">d</mml:mi>
 413                                         </mml:msub>
 414                                         <mml:mo>⁢</mml:mo>
 415                                         <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
 416                                         <mml:mi mathvariant="italic">A</mml:mi>
 417                                         </mml:msub>
 418                                         <mml:mo>-</mml:mo>
 419                                         <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 420                                         <mml:mi mathvariant="italic">s</mml:mi>
 421                                         </mml:msub>
 422                                         <mml:mo>⁢</mml:mo>
 423                                         <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
 424                                         <mml:mi mathvariant="italic">A</mml:mi>
 425                                         </mml:msub>
 426                                     </mml:mrow>
 427                                 </mml:mrow>
 428                             </mml:math></div>
 429                         </td></tr><tr><td align="left">
 430                         <code class="constant">GL_MIN</code>
 431                         </td><td align="left">
 432                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 433
 434                                 <mml:mrow>
 435                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 436                                     <mml:mo>=</mml:mo>
 437                                     <mml:mrow>
 438                                         <mml:mi mathvariant="italic">min</mml:mi>
 439                                         <mml:mo>⁡</mml:mo>
 440                                         <mml:mfenced open="(" close=")">
 441                                             <mml:mrow>
 442                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 443                                                 <mml:mi mathvariant="italic">s</mml:mi>
 444                                                 </mml:msub>
 445                                             </mml:mrow>
 446                                             <mml:mrow>
 447                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 448                                                 <mml:mi mathvariant="italic">d</mml:mi>
 449                                                 </mml:msub>
 450                                             </mml:mrow>
 451                                         </mml:mfenced>
 452                                     </mml:mrow>
 453                                 </mml:mrow>
 454                             </mml:math></div>
 455                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 456
 457                                 <mml:mrow>
 458                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 459                                     <mml:mo>=</mml:mo>
 460                                     <mml:mrow>
 461                                         <mml:mi mathvariant="italic">min</mml:mi>
 462                                         <mml:mo>⁡</mml:mo>
 463                                         <mml:mfenced open="(" close=")">
 464                                             <mml:mrow>
 465                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 466                                                 <mml:mi mathvariant="italic">s</mml:mi>
 467                                                 </mml:msub>
 468                                             </mml:mrow>
 469                                             <mml:mrow>
 470                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 471                                                 <mml:mi mathvariant="italic">d</mml:mi>
 472                                                 </mml:msub>
 473                                             </mml:mrow>
 474                                         </mml:mfenced>
 475                                     </mml:mrow>
 476                                 </mml:mrow>
 477                             </mml:math></div>
 478                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 479
 480                                 <mml:mrow>
 481                                     <mml:mi mathvariant="italic">Br</mml:mi>
 482                                     <mml:mo>=</mml:mo>
 483                                     <mml:mrow>
 484                                         <mml:mi mathvariant="italic">min</mml:mi>
 485                                         <mml:mo>⁡</mml:mo>
 486                                         <mml:mfenced open="(" close=")">
 487                                             <mml:mrow>
 488                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 489                                                 <mml:mi mathvariant="italic">s</mml:mi>
 490                                                 </mml:msub>
 491                                             </mml:mrow>
 492                                             <mml:mrow>
 493                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 494                                                 <mml:mi mathvariant="italic">d</mml:mi>
 495                                                 </mml:msub>
 496                                             </mml:mrow>
 497                                         </mml:mfenced>
 498                                     </mml:mrow>
 499                                 </mml:mrow>
 500                             </mml:math></div>
 501                         </td><td align="left">
 502                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 503
 504                                 <mml:mrow>
 505                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 506                                     <mml:mo>=</mml:mo>
 507                                     <mml:mrow>
 508                                         <mml:mi mathvariant="italic">min</mml:mi>
 509                                         <mml:mo>⁡</mml:mo>
 510                                         <mml:mfenced open="(" close=")">
 511                                             <mml:mrow>
 512                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 513                                                 <mml:mi mathvariant="italic">s</mml:mi>
 514                                                 </mml:msub>
 515                                             </mml:mrow>
 516                                             <mml:mrow>
 517                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 518                                                 <mml:mi mathvariant="italic">d</mml:mi>
 519                                                 </mml:msub>
 520                                             </mml:mrow>
 521                                         </mml:mfenced>
 522                                     </mml:mrow>
 523                                 </mml:mrow>
 524                             </mml:math></div>
 525                         </td></tr><tr><td align="left">
 526                         <code class="constant">GL_MAX</code>
 527                         </td><td align="left">
 528                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 529
 530                                 <mml:mrow>
 531                                     <mml:mi mathvariant="italic">Rr</mml:mi>
 532                                     <mml:mo>=</mml:mo>
 533                                     <mml:mrow>
 534                                         <mml:mi mathvariant="italic">max</mml:mi>
 535                                         <mml:mo>⁡</mml:mo>
 536                                         <mml:mfenced open="(" close=")">
 537                                             <mml:mrow>
 538                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 539                                                 <mml:mi mathvariant="italic">s</mml:mi>
 540                                                 </mml:msub>
 541                                             </mml:mrow>
 542                                             <mml:mrow>
 543                                                 <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
 544                                                 <mml:mi mathvariant="italic">d</mml:mi>
 545                                                 </mml:msub>
 546                                             </mml:mrow>
 547                                         </mml:mfenced>
 548                                     </mml:mrow>
 549                                 </mml:mrow>
 550                             </mml:math></div>
 551                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 552
 553                                 <mml:mrow>
 554                                     <mml:mi mathvariant="italic">Gr</mml:mi>
 555                                     <mml:mo>=</mml:mo>
 556                                     <mml:mrow>
 557                                         <mml:mi mathvariant="italic">max</mml:mi>
 558                                         <mml:mo>⁡</mml:mo>
 559                                         <mml:mfenced open="(" close=")">
 560                                             <mml:mrow>
 561                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 562                                                 <mml:mi mathvariant="italic">s</mml:mi>
 563                                                 </mml:msub>
 564                                             </mml:mrow>
 565                                             <mml:mrow>
 566                                                 <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
 567                                                 <mml:mi mathvariant="italic">d</mml:mi>
 568                                                 </mml:msub>
 569                                             </mml:mrow>
 570                                         </mml:mfenced>
 571                                     </mml:mrow>
 572                                 </mml:mrow>
 573                             </mml:math></div>
 574                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 575
 576                                 <mml:mrow>
 577                                     <mml:mi mathvariant="italic">Br</mml:mi>
 578                                     <mml:mo>=</mml:mo>
 579                                     <mml:mrow>
 580                                         <mml:mi mathvariant="italic">max</mml:mi>
 581                                         <mml:mo>⁡</mml:mo>
 582                                         <mml:mfenced open="(" close=")">
 583                                             <mml:mrow>
 584                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 585                                                 <mml:mi mathvariant="italic">s</mml:mi>
 586                                                 </mml:msub>
 587                                             </mml:mrow>
 588                                             <mml:mrow>
 589                                                 <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
 590                                                 <mml:mi mathvariant="italic">d</mml:mi>
 591                                                 </mml:msub>
 592                                             </mml:mrow>
 593                                         </mml:mfenced>
 594                                     </mml:mrow>
 595                                 </mml:mrow>
 596                             </mml:math></div>
 597                         </td><td align="left">
 598                             <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 599
 600                                 <mml:mrow>
 601                                     <mml:mi mathvariant="italic">Ar</mml:mi>
 602                                     <mml:mo>=</mml:mo>
 603                                     <mml:mrow>
 604                                         <mml:mi mathvariant="italic">max</mml:mi>
 605                                         <mml:mo>⁡</mml:mo>
 606                                         <mml:mfenced open="(" close=")">
 607                                             <mml:mrow>
 608                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 609                                                 <mml:mi mathvariant="italic">s</mml:mi>
 610                                                 </mml:msub>
 611                                             </mml:mrow>
 612                                             <mml:mrow>
 613                                                 <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
 614                                                 <mml:mi mathvariant="italic">d</mml:mi>
 615                                                 </mml:msub>
 616                                             </mml:mrow>
 617                                         </mml:mfenced>
 618                                     </mml:mrow>
 619                                 </mml:mrow>
 620                             </mml:math></div>
 621                         </td></tr></tbody></table></div><p>
 622         </p><p>
 623             The results of these equations are clamped to the range
 624                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 625
 626                             <mml:mfenced open="[" close="]">
 627                                 <mml:mn>0</mml:mn>
 628                                 <mml:mn>1</mml:mn>
 629                             </mml:mfenced>
 630                         </mml:math>.
 631         </p><p>
 632             The <code class="constant">GL_MIN</code> and <code class="constant">GL_MAX</code> equations are useful for applications
 633             that analyze image data (image thresholding against a constant color,
 634             for example).
 635             The <code class="constant">GL_FUNC_ADD</code> equation is useful
 636             for antialiasing and transparency, among other things.
 637         </p><p>
 638             Initially, both the RGB blend equation and the alpha blend equation are set to <code class="constant">GL_FUNC_ADD</code>.
 639         </p><p>
 640         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 641             The <code class="constant">GL_MIN</code>, and <code class="constant">GL_MAX</code> equations do not use
 642             the source or destination factors, only the source and destination colors.
 643         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 644             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not one of
 645             <code class="constant">GL_FUNC_ADD</code>, <code class="constant">GL_FUNC_SUBTRACT</code>, <code class="constant">GL_FUNC_REVERSE_SUBTRACT</code>,
 646             <code class="constant">GL_MAX</code>, or <code class="constant">GL_MIN</code>.
 647         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 648             <a 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>
 649          </p><p>
 650             <a 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>
 651          </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 652             <a href="glBlendColor.xml"><span class="citerefentry"><span class="refentrytitle">glBlendColor</span></span></a>,
 653             <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>
 654             <a href="glBlendFuncSeparate.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFuncSeparate</span></span></a>
 655         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 656             Copyright <span class="trademark"></span>© 1991-2006
 657             Silicon Graphics, Inc. This document is licensed under the SGI
 658             Free Software B License. For details, see
 659             <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 660         </p></div></div></body></html>