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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> |