| 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> |