| 1 | <?xml version="1.0" encoding="UTF-8"?> |
| 2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN" |
| 3 | "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd"> |
| 4 | <refentry id="glGetActiveUniform"> |
| 5 | <refmeta> |
| 6 | <refentrytitle>glGetActiveUniform</refentrytitle> |
| 7 | <manvolnum>3G</manvolnum> |
| 8 | </refmeta> |
| 9 | <refnamediv> |
| 10 | <refname>glGetActiveUniform</refname> |
| 11 | <refpurpose>Returns information about an active uniform variable for the specified program object</refpurpose> |
| 12 | </refnamediv> |
| 13 | <refsynopsisdiv><title>C Specification</title> |
| 14 | <funcsynopsis> |
| 15 | <funcprototype> |
| 16 | <funcdef>void <function>glGetActiveUniform</function></funcdef> |
| 17 | <paramdef>GLuint <parameter>program</parameter></paramdef> |
| 18 | <paramdef>GLuint <parameter>index</parameter></paramdef> |
| 19 | <paramdef>GLsizei <parameter>bufSize</parameter></paramdef> |
| 20 | <paramdef>GLsizei *<parameter>length</parameter></paramdef> |
| 21 | <paramdef>GLint *<parameter>size</parameter></paramdef> |
| 22 | <paramdef>GLenum *<parameter>type</parameter></paramdef> |
| 23 | <paramdef>GLchar *<parameter>name</parameter></paramdef> |
| 24 | </funcprototype> |
| 25 | </funcsynopsis> |
| 26 | </refsynopsisdiv> |
| 27 | <refsect1 id="parameters"><title>Parameters</title> |
| 28 | <variablelist> |
| 29 | <varlistentry> |
| 30 | <term><parameter>program</parameter></term> |
| 31 | <listitem> |
| 32 | <para>Specifies the program object to be |
| 33 | queried.</para> |
| 34 | </listitem> |
| 35 | </varlistentry> |
| 36 | <varlistentry> |
| 37 | <term><parameter>index</parameter></term> |
| 38 | <listitem> |
| 39 | <para>Specifies the index of the uniform variable to |
| 40 | be queried.</para> |
| 41 | </listitem> |
| 42 | </varlistentry> |
| 43 | <varlistentry> |
| 44 | <term><parameter>bufSize</parameter></term> |
| 45 | <listitem> |
| 46 | <para>Specifies the maximum number of characters |
| 47 | OpenGL is allowed to write in the character buffer |
| 48 | indicated by <parameter>name</parameter>.</para> |
| 49 | </listitem> |
| 50 | </varlistentry> |
| 51 | <varlistentry> |
| 52 | <term><parameter>length</parameter></term> |
| 53 | <listitem> |
| 54 | <para>Returns the number of characters actually |
| 55 | written by OpenGL in the string indicated by |
| 56 | <parameter>name</parameter> (excluding the null |
| 57 | terminator) if a value other than |
| 58 | <constant>NULL</constant> is passed.</para> |
| 59 | </listitem> |
| 60 | </varlistentry> |
| 61 | <varlistentry> |
| 62 | <term><parameter>size</parameter></term> |
| 63 | <listitem> |
| 64 | <para>Returns the size of the uniform |
| 65 | variable.</para> |
| 66 | </listitem> |
| 67 | </varlistentry> |
| 68 | <varlistentry> |
| 69 | <term><parameter>type</parameter></term> |
| 70 | <listitem> |
| 71 | <para>Returns the data type of the uniform |
| 72 | variable.</para> |
| 73 | </listitem> |
| 74 | </varlistentry> |
| 75 | <varlistentry> |
| 76 | <term><parameter>name</parameter></term> |
| 77 | <listitem> |
| 78 | <para>Returns a null terminated string containing |
| 79 | the name of the uniform variable.</para> |
| 80 | </listitem> |
| 81 | </varlistentry> |
| 82 | </variablelist> |
| 83 | </refsect1> |
| 84 | <refsect1 id="description"><title>Description</title> |
| 85 | <para><function>glGetActiveUniform</function> returns |
| 86 | information about an active uniform variable in the program |
| 87 | object specified by <parameter>program</parameter>. The number |
| 88 | of active uniform variables can be obtained by calling |
| 89 | <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> |
| 90 | with the value <constant>GL_ACTIVE_UNIFORMS</constant>. A value |
| 91 | of 0 for <parameter>index</parameter> selects the first active |
| 92 | uniform variable. Permissible values for |
| 93 | <parameter>index</parameter> range from 0 to the number of |
| 94 | active uniform variables minus 1.</para> |
| 95 | |
| 96 | <para>Shaders may use either built-in uniform variables, |
| 97 | user-defined uniform variables, or both. Built-in uniform |
| 98 | variables have a prefix of "gl_" and reference |
| 99 | existing OpenGL state or values derived from such state (e.g., |
| 100 | <parameter>gl_DepthRangeParameters</parameter>, see the OpenGL |
| 101 | Shading Language specification for a complete list.) |
| 102 | User-defined uniform variables have arbitrary names and obtain |
| 103 | their values from the application through calls to |
| 104 | <citerefentry><refentrytitle>glUniform</refentrytitle></citerefentry>. |
| 105 | A uniform variable (either built-in or user-defined) is |
| 106 | considered active if it is determined during the link operation |
| 107 | that it may be accessed during program execution. Therefore, |
| 108 | <parameter>program</parameter> should have previously been the |
| 109 | target of a call to |
| 110 | <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry>, |
| 111 | but it is not necessary for it to have been linked |
| 112 | successfully.</para> |
| 113 | |
| 114 | <para>The size of the character buffer required to store the |
| 115 | longest uniform variable name in <parameter>program</parameter> |
| 116 | can be obtained by calling |
| 117 | <citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> |
| 118 | with the value |
| 119 | <constant>GL_ACTIVE_UNIFORM_MAX_LENGTH</constant>. This value |
| 120 | should be used to allocate a buffer of sufficient size to store |
| 121 | the returned uniform variable name. The size of this character |
| 122 | buffer is passed in <parameter>bufSize</parameter>, and a |
| 123 | pointer to this character buffer is passed in |
| 124 | <parameter>name.</parameter></para> |
| 125 | |
| 126 | <para><function>glGetActiveUniform</function> returns the name |
| 127 | of the uniform variable indicated by |
| 128 | <parameter>index</parameter>, storing it in the character buffer |
| 129 | specified by <parameter>name</parameter>. The string returned |
| 130 | will be null terminated. The actual number of characters written |
| 131 | into this buffer is returned in <parameter>length</parameter>, |
| 132 | and this count does not include the null termination character. |
| 133 | If the length of the returned string is not required, a value of |
| 134 | <constant>NULL</constant> can be passed in the |
| 135 | <parameter>length</parameter> argument.</para> |
| 136 | |
| 137 | <para>The <parameter>type</parameter> |
| 138 | argument will return a pointer to the uniform variable's data |
| 139 | type. The symbolic constants returned for uniform types are shown in the |
| 140 | table below. |
| 141 | <informaltable frame="topbot"> |
| 142 | <tgroup cols="2" align="left"> |
| 143 | <colspec colwidth="1.1*" /> |
| 144 | <colspec colwidth="1*" /> |
| 145 | <thead> |
| 146 | <row> |
| 147 | <entry rowsep="1" align="left"><emphasis role="bold"> |
| 148 | Returned Symbolic Contant |
| 149 | </emphasis></entry> |
| 150 | <entry rowsep="1" align="left"><emphasis role="bold"> |
| 151 | Shader Uniform Type |
| 152 | </emphasis></entry> |
| 153 | </row> |
| 154 | </thead> |
| 155 | <tbody> |
| 156 | <row> |
| 157 | <entry align="left"> |
| 158 | <constant>GL_FLOAT</constant> |
| 159 | </entry> |
| 160 | <entry align="left"> |
| 161 | <constant>float</constant> |
| 162 | </entry> |
| 163 | </row> |
| 164 | <row> |
| 165 | <entry align="left"> |
| 166 | <constant>GL_FLOAT_VEC2</constant> |
| 167 | </entry> |
| 168 | <entry align="left"> |
| 169 | <constant>vec2</constant> |
| 170 | </entry> |
| 171 | </row> |
| 172 | <row> |
| 173 | <entry align="left"> |
| 174 | <constant>GL_FLOAT_VEC3</constant> |
| 175 | </entry> |
| 176 | <entry align="left"> |
| 177 | <constant>vec3</constant> |
| 178 | </entry> |
| 179 | </row> |
| 180 | <row> |
| 181 | <entry align="left"> |
| 182 | <constant>GL_FLOAT_VEC4</constant> |
| 183 | </entry> |
| 184 | <entry align="left"> |
| 185 | <constant>vec4</constant> |
| 186 | </entry> |
| 187 | </row> |
| 188 | <row> |
| 189 | <entry align="left"> |
| 190 | <constant>GL_INT</constant> |
| 191 | </entry> |
| 192 | <entry align="left"> |
| 193 | <constant>int</constant> |
| 194 | </entry> |
| 195 | </row> |
| 196 | <row> |
| 197 | <entry align="left"> |
| 198 | <constant>GL_INT_VEC2</constant> |
| 199 | </entry> |
| 200 | <entry align="left"> |
| 201 | <constant>ivec2</constant> |
| 202 | </entry> |
| 203 | </row> |
| 204 | <row> |
| 205 | <entry align="left"> |
| 206 | <constant>GL_INT_VEC3</constant> |
| 207 | </entry> |
| 208 | <entry align="left"> |
| 209 | <constant>ivec3</constant> |
| 210 | </entry> |
| 211 | </row> |
| 212 | <row> |
| 213 | <entry align="left"> |
| 214 | <constant>GL_INT_VEC4</constant> |
| 215 | </entry> |
| 216 | <entry align="left"> |
| 217 | <constant>ivec4</constant> |
| 218 | </entry> |
| 219 | </row> |
| 220 | <row> |
| 221 | <entry align="left"> |
| 222 | <constant>GL_UNSIGNED_INT</constant> |
| 223 | </entry> |
| 224 | <entry align="left"> |
| 225 | <constant>unsigned int</constant> |
| 226 | </entry> |
| 227 | </row> |
| 228 | <row> |
| 229 | <entry align="left"> |
| 230 | <constant>GL_UNSIGNED_INT_VEC2</constant> |
| 231 | </entry> |
| 232 | <entry align="left"> |
| 233 | <constant>uvec2</constant> |
| 234 | </entry> |
| 235 | </row> |
| 236 | <row> |
| 237 | <entry align="left"> |
| 238 | <constant>GL_UNSIGNED_INT_VEC3</constant> |
| 239 | </entry> |
| 240 | <entry align="left"> |
| 241 | <constant>uvec3</constant> |
| 242 | </entry> |
| 243 | </row> |
| 244 | <row> |
| 245 | <entry align="left"> |
| 246 | <constant>GL_UNSIGNED_INT_VEC4</constant> |
| 247 | </entry> |
| 248 | <entry align="left"> |
| 249 | <constant>uvec4</constant> |
| 250 | </entry> |
| 251 | </row> |
| 252 | <row> |
| 253 | <entry align="left"> |
| 254 | <constant>GL_BOOL</constant> |
| 255 | </entry> |
| 256 | <entry align="left"> |
| 257 | <constant>bool</constant> |
| 258 | </entry> |
| 259 | </row> |
| 260 | <row> |
| 261 | <entry align="left"> |
| 262 | <constant>GL_BOOL_VEC2</constant> |
| 263 | </entry> |
| 264 | <entry align="left"> |
| 265 | <constant>bvec2</constant> |
| 266 | </entry> |
| 267 | </row> |
| 268 | <row> |
| 269 | <entry align="left"> |
| 270 | <constant>GL_BOOL_VEC3</constant> |
| 271 | </entry> |
| 272 | <entry align="left"> |
| 273 | <constant>bvec3</constant> |
| 274 | </entry> |
| 275 | </row> |
| 276 | <row> |
| 277 | <entry align="left"> |
| 278 | <constant>GL_BOOL_VEC4</constant> |
| 279 | </entry> |
| 280 | <entry align="left"> |
| 281 | <constant>bvec4</constant> |
| 282 | </entry> |
| 283 | </row> |
| 284 | <row> |
| 285 | <entry align="left"> |
| 286 | <constant>GL_FLOAT_MAT2</constant> |
| 287 | </entry> |
| 288 | <entry align="left"> |
| 289 | <constant>mat2</constant> |
| 290 | </entry> |
| 291 | </row> |
| 292 | <row> |
| 293 | <entry align="left"> |
| 294 | <constant>GL_FLOAT_MAT3</constant> |
| 295 | </entry> |
| 296 | <entry align="left"> |
| 297 | <constant>mat3</constant> |
| 298 | </entry> |
| 299 | </row> |
| 300 | <row> |
| 301 | <entry align="left"> |
| 302 | <constant>GL_FLOAT_MAT4</constant> |
| 303 | </entry> |
| 304 | <entry align="left"> |
| 305 | <constant>mat4</constant> |
| 306 | </entry> |
| 307 | </row> |
| 308 | <row> |
| 309 | <entry align="left"> |
| 310 | <constant>GL_FLOAT_MAT2x3</constant> |
| 311 | </entry> |
| 312 | <entry align="left"> |
| 313 | <constant>mat2x3</constant> |
| 314 | </entry> |
| 315 | </row> |
| 316 | <row> |
| 317 | <entry align="left"> |
| 318 | <constant>GL_FLOAT_MAT2x4</constant> |
| 319 | </entry> |
| 320 | <entry align="left"> |
| 321 | <constant>mat2x4</constant> |
| 322 | </entry> |
| 323 | </row> |
| 324 | <row> |
| 325 | <entry align="left"> |
| 326 | <constant>GL_FLOAT_MAT3x2</constant> |
| 327 | </entry> |
| 328 | <entry align="left"> |
| 329 | <constant>mat3x2</constant> |
| 330 | </entry> |
| 331 | </row> |
| 332 | <row> |
| 333 | <entry align="left"> |
| 334 | <constant>GL_FLOAT_MAT3x4</constant> |
| 335 | </entry> |
| 336 | <entry align="left"> |
| 337 | <constant>mat3x4</constant> |
| 338 | </entry> |
| 339 | </row> |
| 340 | <row> |
| 341 | <entry align="left"> |
| 342 | <constant>GL_FLOAT_MAT4x2</constant> |
| 343 | </entry> |
| 344 | <entry align="left"> |
| 345 | <constant>mat4x2</constant> |
| 346 | </entry> |
| 347 | </row> |
| 348 | <row> |
| 349 | <entry align="left"> |
| 350 | <constant>GL_FLOAT_MAT4x3</constant> |
| 351 | </entry> |
| 352 | <entry align="left"> |
| 353 | <constant>mat4x3</constant> |
| 354 | </entry> |
| 355 | </row> |
| 356 | <row> |
| 357 | <entry align="left"> |
| 358 | <constant>GL_SAMPLER_1D</constant> |
| 359 | </entry> |
| 360 | <entry align="left"> |
| 361 | <constant>sampler1D</constant> |
| 362 | </entry> |
| 363 | </row> |
| 364 | <row> |
| 365 | <entry align="left"> |
| 366 | <constant>GL_SAMPLER_2D</constant> |
| 367 | </entry> |
| 368 | <entry align="left"> |
| 369 | <constant>sampler2D</constant> |
| 370 | </entry> |
| 371 | </row> |
| 372 | <row> |
| 373 | <entry align="left"> |
| 374 | <constant>GL_SAMPLER_3D</constant> |
| 375 | </entry> |
| 376 | <entry align="left"> |
| 377 | <constant>sampler3D</constant> |
| 378 | </entry> |
| 379 | </row> |
| 380 | <row> |
| 381 | <entry align="left"> |
| 382 | <constant>GL_SAMPLER_CUBE</constant> |
| 383 | </entry> |
| 384 | <entry align="left"> |
| 385 | <constant>samplerCube</constant> |
| 386 | </entry> |
| 387 | </row> |
| 388 | <row> |
| 389 | <entry align="left"> |
| 390 | <constant>GL_SAMPLER_1D_SHADOW</constant> |
| 391 | </entry> |
| 392 | <entry align="left"> |
| 393 | <constant>sampler1DShadow</constant> |
| 394 | </entry> |
| 395 | </row> |
| 396 | <row> |
| 397 | <entry align="left"> |
| 398 | <constant>GL_SAMPLER_2D_SHADOW</constant> |
| 399 | </entry> |
| 400 | <entry align="left"> |
| 401 | <constant>sampler2DShadow</constant> |
| 402 | </entry> |
| 403 | </row> |
| 404 | <row> |
| 405 | <entry align="left"> |
| 406 | <constant>GL_SAMPLER_1D_ARRAY</constant> |
| 407 | </entry> |
| 408 | <entry align="left"> |
| 409 | <constant>sampler1DArray</constant> |
| 410 | </entry> |
| 411 | </row> |
| 412 | <row> |
| 413 | <entry align="left"> |
| 414 | <constant>GL_SAMPLER_2D_ARRAY</constant> |
| 415 | </entry> |
| 416 | <entry align="left"> |
| 417 | <constant>sampler2DArray</constant> |
| 418 | </entry> |
| 419 | </row> |
| 420 | <row> |
| 421 | <entry align="left"> |
| 422 | <constant>GL_SAMPLER_1D_ARRAY_SHADOW</constant> |
| 423 | </entry> |
| 424 | <entry align="left"> |
| 425 | <constant>sampler1DArrayShadow</constant> |
| 426 | </entry> |
| 427 | </row> |
| 428 | <row> |
| 429 | <entry align="left"> |
| 430 | <constant>GL_SAMPLER_2D_ARRAY_SHADOW</constant> |
| 431 | </entry> |
| 432 | <entry align="left"> |
| 433 | <constant>sampler2DArrayShadow</constant> |
| 434 | </entry> |
| 435 | </row> |
| 436 | <row> |
| 437 | <entry align="left"> |
| 438 | <constant>GL_SAMPLER_2D_MULTISAMPLE</constant> |
| 439 | </entry> |
| 440 | <entry align="left"> |
| 441 | <constant>sampler2DMS</constant> |
| 442 | </entry> |
| 443 | </row> |
| 444 | <row> |
| 445 | <entry align="left"> |
| 446 | <constant>GL_SAMPLER_2D_MULTISAMPLE_ARRAY</constant> |
| 447 | </entry> |
| 448 | <entry align="left"> |
| 449 | <constant>sampler2DMSArray</constant> |
| 450 | </entry> |
| 451 | </row> |
| 452 | <row> |
| 453 | <entry align="left"> |
| 454 | <constant>GL_SAMPLER_CUBE_SHADOW</constant> |
| 455 | </entry> |
| 456 | <entry align="left"> |
| 457 | <constant>samplerCubeShadow</constant> |
| 458 | </entry> |
| 459 | </row> |
| 460 | <row> |
| 461 | <entry align="left"> |
| 462 | <constant>GL_SAMPLER_BUFFER</constant> |
| 463 | </entry> |
| 464 | <entry align="left"> |
| 465 | <constant>samplerBuffer</constant> |
| 466 | </entry> |
| 467 | </row> |
| 468 | <row> |
| 469 | <entry align="left"> |
| 470 | <constant>GL_SAMPLER_2D_RECT</constant> |
| 471 | </entry> |
| 472 | <entry align="left"> |
| 473 | <constant>sampler2DRect</constant> |
| 474 | </entry> |
| 475 | </row> |
| 476 | <row> |
| 477 | <entry align="left"> |
| 478 | <constant>GL_SAMPLER_2D_RECT_SHADOW</constant> |
| 479 | </entry> |
| 480 | <entry align="left"> |
| 481 | <constant>sampler2DRectShadow</constant> |
| 482 | </entry> |
| 483 | </row> |
| 484 | <row> |
| 485 | <entry align="left"> |
| 486 | <constant>GL_INT_SAMPLER_1D</constant> |
| 487 | </entry> |
| 488 | <entry align="left"> |
| 489 | <constant>isampler1D</constant> |
| 490 | </entry> |
| 491 | </row> |
| 492 | <row> |
| 493 | <entry align="left"> |
| 494 | <constant>GL_INT_SAMPLER_2D</constant> |
| 495 | </entry> |
| 496 | <entry align="left"> |
| 497 | <constant>isampler2D</constant> |
| 498 | </entry> |
| 499 | </row> |
| 500 | <row> |
| 501 | <entry align="left"> |
| 502 | <constant>GL_INT_SAMPLER_3D</constant> |
| 503 | </entry> |
| 504 | <entry align="left"> |
| 505 | <constant>isampler3D</constant> |
| 506 | </entry> |
| 507 | </row> |
| 508 | <row> |
| 509 | <entry align="left"> |
| 510 | <constant>GL_INT_SAMPLER_CUBE</constant> |
| 511 | </entry> |
| 512 | <entry align="left"> |
| 513 | <constant>isamplerCube</constant> |
| 514 | </entry> |
| 515 | </row> |
| 516 | <row> |
| 517 | <entry align="left"> |
| 518 | <constant>GL_INT_SAMPLER_1D_ARRAY</constant> |
| 519 | </entry> |
| 520 | <entry align="left"> |
| 521 | <constant>isampler1DArray</constant> |
| 522 | </entry> |
| 523 | </row> |
| 524 | <row> |
| 525 | <entry align="left"> |
| 526 | <constant>GL_INT_SAMPLER_2D_ARRAY</constant> |
| 527 | </entry> |
| 528 | <entry align="left"> |
| 529 | <constant>isampler2DArray</constant> |
| 530 | </entry> |
| 531 | </row> |
| 532 | <row> |
| 533 | <entry align="left"> |
| 534 | <constant>GL_INT_SAMPLER_2D_MULTISAMPLE</constant> |
| 535 | </entry> |
| 536 | <entry align="left"> |
| 537 | <constant>isampler2DMS</constant> |
| 538 | </entry> |
| 539 | </row> |
| 540 | <row> |
| 541 | <entry align="left"> |
| 542 | <constant>GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY</constant> |
| 543 | </entry> |
| 544 | <entry align="left"> |
| 545 | <constant>isampler2DMSArray</constant> |
| 546 | </entry> |
| 547 | </row> |
| 548 | <row> |
| 549 | <entry align="left"> |
| 550 | <constant>GL_INT_SAMPLER_BUFFER</constant> |
| 551 | </entry> |
| 552 | <entry align="left"> |
| 553 | <constant>isamplerBuffer</constant> |
| 554 | </entry> |
| 555 | </row> |
| 556 | <row> |
| 557 | <entry align="left"> |
| 558 | <constant>GL_INT_SAMPLER_2D_RECT</constant> |
| 559 | </entry> |
| 560 | <entry align="left"> |
| 561 | <constant>isampler2DRect</constant> |
| 562 | </entry> |
| 563 | </row> |
| 564 | <row> |
| 565 | <entry align="left"> |
| 566 | <constant>GL_UNSIGNED_INT_SAMPLER_1D</constant> |
| 567 | </entry> |
| 568 | <entry align="left"> |
| 569 | <constant>usampler1D</constant> |
| 570 | </entry> |
| 571 | </row> |
| 572 | <row> |
| 573 | <entry align="left"> |
| 574 | <constant>GL_UNSIGNED_INT_SAMPLER_2D</constant> |
| 575 | </entry> |
| 576 | <entry align="left"> |
| 577 | <constant>usampler2D</constant> |
| 578 | </entry> |
| 579 | </row> |
| 580 | <row> |
| 581 | <entry align="left"> |
| 582 | <constant>GL_UNSIGNED_INT_SAMPLER_3D</constant> |
| 583 | </entry> |
| 584 | <entry align="left"> |
| 585 | <constant>usampler3D</constant> |
| 586 | </entry> |
| 587 | </row> |
| 588 | <row> |
| 589 | <entry align="left"> |
| 590 | <constant>GL_UNSIGNED_INT_SAMPLER_CUBE</constant> |
| 591 | </entry> |
| 592 | <entry align="left"> |
| 593 | <constant>usamplerCube</constant> |
| 594 | </entry> |
| 595 | </row> |
| 596 | <row> |
| 597 | <entry align="left"> |
| 598 | <constant>GL_UNSIGNED_INT_SAMPLER_1D_ARRAY</constant> |
| 599 | </entry> |
| 600 | <entry align="left"> |
| 601 | <constant>usampler2DArray</constant> |
| 602 | </entry> |
| 603 | </row> |
| 604 | <row> |
| 605 | <entry align="left"> |
| 606 | <constant>GL_UNSIGNED_INT_SAMPLER_2D_ARRAY</constant> |
| 607 | </entry> |
| 608 | <entry align="left"> |
| 609 | <constant>usampler2DArray</constant> |
| 610 | </entry> |
| 611 | </row> |
| 612 | <row> |
| 613 | <entry align="left"> |
| 614 | <constant>GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE</constant> |
| 615 | </entry> |
| 616 | <entry align="left"> |
| 617 | <constant>usampler2DMS</constant> |
| 618 | </entry> |
| 619 | </row> |
| 620 | <row> |
| 621 | <entry align="left"> |
| 622 | <constant>GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY</constant> |
| 623 | </entry> |
| 624 | <entry align="left"> |
| 625 | <constant>usampler2DMSArray</constant> |
| 626 | </entry> |
| 627 | </row> |
| 628 | <row> |
| 629 | <entry align="left"> |
| 630 | <constant>GL_UNSIGNED_INT_SAMPLER_BUFFER</constant> |
| 631 | </entry> |
| 632 | <entry align="left"> |
| 633 | <constant>usamplerBuffer</constant> |
| 634 | </entry> |
| 635 | </row> |
| 636 | <row> |
| 637 | <entry align="left"> |
| 638 | <constant>GL_UNSIGNED_INT_SAMPLER_2D_RECT</constant> |
| 639 | </entry> |
| 640 | <entry align="left"> |
| 641 | <constant>usampler2DRect</constant> |
| 642 | </entry> |
| 643 | </row> |
| 644 | </tbody> |
| 645 | </tgroup> |
| 646 | </informaltable> |
| 647 | </para> |
| 648 | |
| 649 | <para>If one or more elements of an array are active, the name |
| 650 | of the array is returned in <parameter>name</parameter>, the |
| 651 | type is returned in <parameter>type</parameter>, and the |
| 652 | <parameter>size</parameter> parameter returns the highest array |
| 653 | element index used, plus one, as determined by the compiler |
| 654 | and/or linker. Only one active uniform variable will be reported |
| 655 | for a uniform array.</para> |
| 656 | |
| 657 | <para>Uniform variables that are declared as structures or |
| 658 | arrays of structures will not be returned directly by this |
| 659 | function. Instead, each of these uniform variables will be |
| 660 | reduced to its fundamental components containing the |
| 661 | "." and "[]" operators such that each of the |
| 662 | names is valid as an argument to |
| 663 | <citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>. |
| 664 | Each of these reduced uniform variables is counted as one active |
| 665 | uniform variable and is assigned an index. A valid name cannot |
| 666 | be a structure, an array of structures, or a subcomponent of a |
| 667 | vector or matrix.</para> |
| 668 | |
| 669 | <para>The size of the uniform variable will be returned in |
| 670 | <parameter>size</parameter>. Uniform variables other than arrays |
| 671 | will have a size of 1. Structures and arrays of structures will |
| 672 | be reduced as described earlier, such that each of the names |
| 673 | returned will be a data type in the earlier list. If this |
| 674 | reduction results in an array, the size returned will be as |
| 675 | described for uniform arrays; otherwise, the size returned will |
| 676 | be 1.</para> |
| 677 | |
| 678 | <para>The list of active uniform variables may include both |
| 679 | built-in uniform variables (which begin with the prefix |
| 680 | "gl_") as well as user-defined uniform variable |
| 681 | names.</para> |
| 682 | |
| 683 | <para>This function will return as much information as it can |
| 684 | about the specified active uniform variable. If no information |
| 685 | is available, <parameter>length</parameter> will be 0, and |
| 686 | <parameter>name</parameter> will be an empty string. This |
| 687 | situation could occur if this function is called after a link |
| 688 | operation that failed. If an error occurs, the return values |
| 689 | <parameter>length</parameter>, <parameter>size</parameter>, |
| 690 | <parameter>type</parameter>, and <parameter>name</parameter> |
| 691 | will be unmodified.</para> |
| 692 | </refsect1> |
| 693 | <refsect1 id="errors"><title>Errors</title> |
| 694 | <para><constant>GL_INVALID_VALUE</constant> is generated if |
| 695 | <parameter>program</parameter> is not a value generated by |
| 696 | OpenGL.</para> |
| 697 | |
| 698 | <para><constant>GL_INVALID_OPERATION</constant> is generated if |
| 699 | <parameter>program</parameter> is not a program object.</para> |
| 700 | |
| 701 | <para><constant>GL_INVALID_VALUE</constant> is generated if |
| 702 | <parameter>index</parameter> is greater than or equal to the |
| 703 | number of active uniform variables in |
| 704 | <parameter>program</parameter>.</para> |
| 705 | |
| 706 | <para><constant>GL_INVALID_VALUE</constant> is generated if |
| 707 | <parameter>bufSize</parameter> is less than 0.</para> |
| 708 | </refsect1> |
| 709 | <refsect1 id="associatedgets"><title>Associated Gets</title> |
| 710 | <para><citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> |
| 711 | with argument <constant>GL_MAX_VERTEX_UNIFORM_COMPONENTS</constant>, |
| 712 | <constant>GL_MAX_GEOMETRY_UNIFORM_COMPONENTS</constant>, |
| 713 | <constant>GL_MAX_FRAGMENT_UNIFORM_COMPONENTS</constant>, or |
| 714 | <constant>GL_MAX_COMBINED_UNIFORM_COMPONENTS</constant>.</para> |
| 715 | |
| 716 | <para><citerefentry><refentrytitle>glGetProgram</refentrytitle></citerefentry> |
| 717 | with argument <constant>GL_ACTIVE_UNIFORMS</constant> or |
| 718 | <constant>GL_ACTIVE_UNIFORM_MAX_LENGTH</constant>.</para> |
| 719 | |
| 720 | <para><citerefentry><refentrytitle>glIsProgram</refentrytitle></citerefentry></para> |
| 721 | </refsect1> |
| 722 | <refsect1 id="seealso"><title>See Also</title> |
| 723 | <para><citerefentry><refentrytitle>glGetUniform</refentrytitle></citerefentry>, |
| 724 | <citerefentry><refentrytitle>glGetUniformLocation</refentrytitle></citerefentry>, |
| 725 | <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry>, |
| 726 | <citerefentry><refentrytitle>glUniform</refentrytitle></citerefentry>, |
| 727 | <citerefentry><refentrytitle>glUseProgram</refentrytitle></citerefentry></para> |
| 728 | </refsect1> |
| 729 | <refsect1 id="Copyright"><title>Copyright</title> |
| 730 | <para> |
| 731 | Copyright <trademark class="copyright"></trademark> 2003-2005 3Dlabs Inc. Ltd. |
| 732 | Copyright <trademark class="copyright"></trademark> 2010 Khronos Group |
| 733 | This material may be distributed subject to the terms and conditions set forth in |
| 734 | the Open Publication License, v 1.0, 8 June 1999. |
| 735 | <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>. |
| 736 | </para> |
| 737 | </refsect1> |
| 738 | </refentry> |