/usr/share/gtk-doc/html/cogl/cogl-Matrices.html is in libcogl-doc 1.16.2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Matrices</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="index.html" title="Cogl Reference Manual">
<link rel="up" href="ch01.html" title="Cogl - a modern 3D graphics API">
<link rel="prev" href="cogl-Vertex-Buffers.html" title="Vertex Buffers">
<link rel="next" href="cogl-Shaders-and-Programmable-Pipeline.html" title="Shaders and Programmable Pipeline">
<meta name="generator" content="GTK-Doc V1.19 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2">
<tr valign="middle">
<td><a accesskey="p" href="cogl-Vertex-Buffers.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
<td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
<th width="100%" align="center">Cogl Reference Manual</th>
<td><a accesskey="n" href="cogl-Shaders-and-Programmable-Pipeline.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
</tr>
<tr><td colspan="5" class="shortcuts">
<a href="#cogl-Matrices.synopsis" class="shortcut">Top</a>
|
<a href="#cogl-Matrices.description" class="shortcut">Description</a>
</td></tr>
</table>
<div class="refentry">
<a name="cogl-Matrices"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="cogl-Matrices.top_of_page"></a>Matrices</span></h2>
<p>Matrices — Functions for initializing and manipulating 4x4 matrices</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsynopsisdiv">
<a name="cogl-Matrices.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis"> <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix">CoglMatrix</a>;
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-init-identity" title="cogl_matrix_init_identity ()">cogl_matrix_init_identity</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
<a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="returnvalue">CoglMatrix</span></a> * <a class="link" href="cogl-Matrices.html#cogl-matrix-copy" title="cogl_matrix_copy ()">cogl_matrix_copy</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
<span class="returnvalue">CoglBool</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-equal" title="cogl_matrix_equal ()">cogl_matrix_equal</a> (<em class="parameter"><code>const <span class="type">void</span> *v1</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *v2</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-free" title="cogl_matrix_free ()">cogl_matrix_free</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-frustum" title="cogl_matrix_frustum ()">cogl_matrix_frustum</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> left</code></em>,
<em class="parameter"><code><span class="type">float</span> right</code></em>,
<em class="parameter"><code><span class="type">float</span> bottom</code></em>,
<em class="parameter"><code><span class="type">float</span> top</code></em>,
<em class="parameter"><code><span class="type">float</span> z_near</code></em>,
<em class="parameter"><code><span class="type">float</span> z_far</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-ortho" title="cogl_matrix_ortho ()">cogl_matrix_ortho</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> left</code></em>,
<em class="parameter"><code><span class="type">float</span> right</code></em>,
<em class="parameter"><code><span class="type">float</span> bottom</code></em>,
<em class="parameter"><code><span class="type">float</span> top</code></em>,
<em class="parameter"><code><span class="type">float</span> near</code></em>,
<em class="parameter"><code><span class="type">float</span> far</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-perspective" title="cogl_matrix_perspective ()">cogl_matrix_perspective</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> fov_y</code></em>,
<em class="parameter"><code><span class="type">float</span> aspect</code></em>,
<em class="parameter"><code><span class="type">float</span> z_near</code></em>,
<em class="parameter"><code><span class="type">float</span> z_far</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-multiply" title="cogl_matrix_multiply ()">cogl_matrix_multiply</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *result</code></em>,
<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *a</code></em>,
<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *b</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-rotate" title="cogl_matrix_rotate ()">cogl_matrix_rotate</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> angle</code></em>,
<em class="parameter"><code><span class="type">float</span> x</code></em>,
<em class="parameter"><code><span class="type">float</span> y</code></em>,
<em class="parameter"><code><span class="type">float</span> z</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-translate" title="cogl_matrix_translate ()">cogl_matrix_translate</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> x</code></em>,
<em class="parameter"><code><span class="type">float</span> y</code></em>,
<em class="parameter"><code><span class="type">float</span> z</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-scale" title="cogl_matrix_scale ()">cogl_matrix_scale</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> sx</code></em>,
<em class="parameter"><code><span class="type">float</span> sy</code></em>,
<em class="parameter"><code><span class="type">float</span> sz</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-transpose" title="cogl_matrix_transpose ()">cogl_matrix_transpose</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-init-from-array" title="cogl_matrix_init_from_array ()">cogl_matrix_init_from_array</a> (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code>const <span class="type">float</span> *array</code></em>);
const <span class="returnvalue">float</span> * <a class="link" href="cogl-Matrices.html#cogl-matrix-get-array" title="cogl_matrix_get_array ()">cogl_matrix_get_array</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
<span class="returnvalue">CoglBool</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-get-inverse" title="cogl_matrix_get_inverse ()">cogl_matrix_get_inverse</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *inverse</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-transform-point" title="cogl_matrix_transform_point ()">cogl_matrix_transform_point</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> *x</code></em>,
<em class="parameter"><code><span class="type">float</span> *y</code></em>,
<em class="parameter"><code><span class="type">float</span> *z</code></em>,
<em class="parameter"><code><span class="type">float</span> *w</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-project-points" title="cogl_matrix_project_points ()">cogl_matrix_project_points</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">int</span> n_components</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_in</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *points_in</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_out</code></em>,
<em class="parameter"><code><span class="type">void</span> *points_out</code></em>,
<em class="parameter"><code><span class="type">int</span> n_points</code></em>);
<span class="returnvalue">void</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-transform-points" title="cogl_matrix_transform_points ()">cogl_matrix_transform_points</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">int</span> n_components</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_in</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *points_in</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_out</code></em>,
<em class="parameter"><code><span class="type">void</span> *points_out</code></em>,
<em class="parameter"><code><span class="type">int</span> n_points</code></em>);
<span class="returnvalue">CoglBool</span> <a class="link" href="cogl-Matrices.html#cogl-matrix-is-identity" title="cogl_matrix_is_identity ()">cogl_matrix_is_identity</a> (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);
</pre>
</div>
<div class="refsect1">
<a name="cogl-Matrices.description"></a><h2>Description</h2>
<p>
Matrices are used in Cogl to describe affine model-view transforms, texture
transforms, and projective transforms. This exposes a utility API that can
be used for direct manipulation of these matrices.
</p>
</div>
<div class="refsect1">
<a name="cogl-Matrices.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="CoglMatrix"></a><h3>CoglMatrix</h3>
<pre class="programlisting">typedef struct {
/* column 0 */
float xx;
float yx;
float zx;
float wx;
/* column 1 */
float xy;
float yy;
float zy;
float wy;
/* column 2 */
float xz;
float yz;
float zz;
float wz;
/* column 3 */
float xw;
float yw;
float zw;
float ww;
} CoglMatrix;
</pre>
<p>
A CoglMatrix holds a 4x4 transform matrix. This is a single precision,
column-major matrix which means it is compatible with what OpenGL expects.
</p>
<p>
A CoglMatrix can represent transforms such as, rotations, scaling,
translation, sheering, and linear projections. You can combine these
transforms by multiplying multiple matrices in the order you want them
applied.
</p>
<p>
The transformation of a vertex (x, y, z, w) by a CoglMatrix is given by:
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
x_new = xx * x + xy * y + xz * z + xw * w
y_new = yx * x + yy * y + yz * z + yw * w
z_new = zx * x + zy * y + zz * z + zw * w
w_new = wx * x + wy * y + wz * z + ww * w
</pre></div>
<p>
</p>
<p>
Where w is normally 1
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>You must consider the members of the CoglMatrix structure read only,
and all matrix modifications must be done via the cogl_matrix API. This
allows Cogl to annotate the matrices internally. Violation of this will give
undefined results. If you need to initialize a matrix with a constant other
than the identity matrix you can use <a class="link" href="cogl-Matrices.html#cogl-matrix-init-from-array" title="cogl_matrix_init_from_array ()"><code class="function">cogl_matrix_init_from_array()</code></a>.</div>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-init-identity"></a><h3>cogl_matrix_init_identity ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_init_identity (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Resets matrix to the identity matrix:
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
.xx=1; .xy=0; .xz=0; .xw=0;
.yx=0; .yy=1; .yz=0; .yw=0;
.zx=0; .zy=0; .zz=1; .zw=0;
.wx=0; .wy=0; .wz=0; .ww=1;
</pre></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-copy"></a><h3>cogl_matrix_copy ()</h3>
<pre class="programlisting"><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="returnvalue">CoglMatrix</span></a> * cogl_matrix_copy (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Allocates a new <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> on the heap and initializes it with
the same values as <em class="parameter"><code>matrix</code></em>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix you want to copy</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>A newly allocated <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> which
should be freed using <a class="link" href="cogl-Matrices.html#cogl-matrix-free" title="cogl_matrix_free ()"><code class="function">cogl_matrix_free()</code></a>. <span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 1.6</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-equal"></a><h3>cogl_matrix_equal ()</h3>
<pre class="programlisting"><span class="returnvalue">CoglBool</span> cogl_matrix_equal (<em class="parameter"><code>const <span class="type">void</span> *v1</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *v2</code></em>);</pre>
<p>
Compares two matrices to see if they represent the same
transformation. Although internally the matrices may have different
annotations associated with them and may potentially have a cached
inverse matrix these are not considered in the comparison.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>v1</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>v2</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 1.4</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-free"></a><h3>cogl_matrix_free ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_free (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Frees a <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> that was previously allocated via a call to
<a class="link" href="cogl-Matrices.html#cogl-matrix-copy" title="cogl_matrix_copy ()"><code class="function">cogl_matrix_copy()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix you want to free</td>
</tr></tbody>
</table></div>
<p class="since">Since 1.6</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-frustum"></a><h3>cogl_matrix_frustum ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_frustum (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> left</code></em>,
<em class="parameter"><code><span class="type">float</span> right</code></em>,
<em class="parameter"><code><span class="type">float</span> bottom</code></em>,
<em class="parameter"><code><span class="type">float</span> top</code></em>,
<em class="parameter"><code><span class="type">float</span> z_near</code></em>,
<em class="parameter"><code><span class="type">float</span> z_far</code></em>);</pre>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> by the given frustum perspective matrix.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>left</code></em> :</span></p></td>
<td>X position of the left clipping plane where it
intersects the near clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>right</code></em> :</span></p></td>
<td>X position of the right clipping plane where it
intersects the near clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>bottom</code></em> :</span></p></td>
<td>Y position of the bottom clipping plane where it
intersects the near clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>top</code></em> :</span></p></td>
<td>Y position of the top clipping plane where it intersects
the near clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z_near</code></em> :</span></p></td>
<td>The distance to the near clipping plane (Must be positive)</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z_far</code></em> :</span></p></td>
<td>The distance to the far clipping plane (Must be positive)</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-ortho"></a><h3>cogl_matrix_ortho ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_ortho (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> left</code></em>,
<em class="parameter"><code><span class="type">float</span> right</code></em>,
<em class="parameter"><code><span class="type">float</span> bottom</code></em>,
<em class="parameter"><code><span class="type">float</span> top</code></em>,
<em class="parameter"><code><span class="type">float</span> near</code></em>,
<em class="parameter"><code><span class="type">float</span> far</code></em>);</pre>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Warning</h3>
<p><code class="literal">cogl_matrix_ortho</code> has been deprecated since version 1.10 and should not be used in newly-written code. Use <code class="function">cogl_matrix_orthographic()</code></p>
</div>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> by a parallel projection matrix.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>left</code></em> :</span></p></td>
<td>The coordinate for the left clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>right</code></em> :</span></p></td>
<td>The coordinate for the right clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>bottom</code></em> :</span></p></td>
<td>The coordinate for the bottom clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>top</code></em> :</span></p></td>
<td>The coordinate for the top clipping plane</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>near</code></em> :</span></p></td>
<td>The <span class="emphasis"><em>distance</em></span> to the near clipping
plane (will be <span class="emphasis"><em>negative</em></span> if the plane is
behind the viewer)</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>far</code></em> :</span></p></td>
<td>The <span class="emphasis"><em>distance</em></span> to the far clipping
plane (will be <span class="emphasis"><em>negative</em></span> if the plane is
behind the viewer)</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-perspective"></a><h3>cogl_matrix_perspective ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_perspective (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> fov_y</code></em>,
<em class="parameter"><code><span class="type">float</span> aspect</code></em>,
<em class="parameter"><code><span class="type">float</span> z_near</code></em>,
<em class="parameter"><code><span class="type">float</span> z_far</code></em>);</pre>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> by the described perspective matrix
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>You should be careful not to have to great a <em class="parameter"><code>z_far</code></em> / <em class="parameter"><code>z_near</code></em>
ratio since that will reduce the effectiveness of depth testing
since there wont be enough precision to identify the depth of
objects near to each other.</div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>fov_y</code></em> :</span></p></td>
<td>Vertical field of view angle in degrees.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>aspect</code></em> :</span></p></td>
<td>The (width over height) aspect ratio for display</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z_near</code></em> :</span></p></td>
<td>The distance to the near clipping plane (Must be positive,
and must not be 0)</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z_far</code></em> :</span></p></td>
<td>The distance to the far clipping plane (Must be positive)</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-multiply"></a><h3>cogl_matrix_multiply ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_multiply (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *result</code></em>,
<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *a</code></em>,
<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *b</code></em>);</pre>
<p>
Multiplies the two supplied matrices together and stores
the resulting matrix inside <em class="parameter"><code>result</code></em>.
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>It is possible to multiply the <em class="parameter"><code>a</code></em> matrix in-place, so
<em class="parameter"><code>result</code></em> can be equal to <em class="parameter"><code>a</code></em> but can't be equal to <em class="parameter"><code>b</code></em>.</div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>result</code></em> :</span></p></td>
<td>The address of a 4x4 matrix to store the result in</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-rotate"></a><h3>cogl_matrix_rotate ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_rotate (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> angle</code></em>,
<em class="parameter"><code><span class="type">float</span> x</code></em>,
<em class="parameter"><code><span class="type">float</span> y</code></em>,
<em class="parameter"><code><span class="type">float</span> z</code></em>);</pre>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> with a rotation matrix that applies a rotation
of <em class="parameter"><code>angle</code></em> degrees around the specified 3D vector.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>angle</code></em> :</span></p></td>
<td>The angle you want to rotate in degrees</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>X component of your rotation vector</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>Y component of your rotation vector</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z</code></em> :</span></p></td>
<td>Z component of your rotation vector</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-translate"></a><h3>cogl_matrix_translate ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_translate (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> x</code></em>,
<em class="parameter"><code><span class="type">float</span> y</code></em>,
<em class="parameter"><code><span class="type">float</span> z</code></em>);</pre>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> with a transform matrix that translates along
the X, Y and Z axis.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>The X translation you want to apply</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>The Y translation you want to apply</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z</code></em> :</span></p></td>
<td>The Z translation you want to apply</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-scale"></a><h3>cogl_matrix_scale ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_scale (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> sx</code></em>,
<em class="parameter"><code><span class="type">float</span> sy</code></em>,
<em class="parameter"><code><span class="type">float</span> sz</code></em>);</pre>
<p>
Multiplies <em class="parameter"><code>matrix</code></em> with a transform matrix that scales along the X,
Y and Z axis.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>sx</code></em> :</span></p></td>
<td>The X scale factor</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>sy</code></em> :</span></p></td>
<td>The Y scale factor</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>sz</code></em> :</span></p></td>
<td>The Z scale factor</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-transpose"></a><h3>cogl_matrix_transpose ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_transpose (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Replaces <em class="parameter"><code>matrix</code></em> with its transpose. Ie, every element (i,j) in the
new matrix is taken from element (j,i) in the old matrix.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a>
</td>
</tr></tbody>
</table></div>
<p class="since">Since 1.10</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-init-from-array"></a><h3>cogl_matrix_init_from_array ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_init_from_array (<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code>const <span class="type">float</span> *array</code></em>);</pre>
<p>
Initializes <em class="parameter"><code>matrix</code></em> with the contents of <em class="parameter"><code>array</code></em>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>array</code></em> :</span></p></td>
<td>A linear array of 16 floats (column-major order)</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-get-array"></a><h3>cogl_matrix_get_array ()</h3>
<pre class="programlisting">const <span class="returnvalue">float</span> * cogl_matrix_get_array (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Casts <em class="parameter"><code>matrix</code></em> to a float array which can be directly passed to OpenGL.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a pointer to the float array</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-get-inverse"></a><h3>cogl_matrix_get_inverse ()</h3>
<pre class="programlisting"><span class="returnvalue">CoglBool</span> cogl_matrix_get_inverse (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *inverse</code></em>);</pre>
<p>
Gets the inverse transform of a given matrix and uses it to initialize
a new <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a>.
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>Although the first parameter is annotated as const to indicate
that the transform it represents isn't modified this function may
technically save a copy of the inverse transform within the given
<a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> so that subsequent requests for the inverse transform may
avoid costly inversion calculations.</div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>inverse</code></em> :</span></p></td>
<td>The destination for a 4x4 inverse transformation matrix. <span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<code class="literal">TRUE</code> if the inverse was successfully calculated or <code class="literal">FALSE</code>
for degenerate transformations that can't be inverted (in this case the
<em class="parameter"><code>inverse</code></em> matrix will simply be initialized with the identity matrix)</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 1.2</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-transform-point"></a><h3>cogl_matrix_transform_point ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_transform_point (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">float</span> *x</code></em>,
<em class="parameter"><code><span class="type">float</span> *y</code></em>,
<em class="parameter"><code><span class="type">float</span> *z</code></em>,
<em class="parameter"><code><span class="type">float</span> *w</code></em>);</pre>
<p>
Transforms a point whos position is given and returned as four float
components.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A 4x4 transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>The X component of your points position. <span class="annotation">[<acronym title="Parameter for input and for returning results. Default is transfer full."><span class="acronym">inout</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>The Y component of your points position. <span class="annotation">[<acronym title="Parameter for input and for returning results. Default is transfer full."><span class="acronym">inout</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>z</code></em> :</span></p></td>
<td>The Z component of your points position. <span class="annotation">[<acronym title="Parameter for input and for returning results. Default is transfer full."><span class="acronym">inout</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>w</code></em> :</span></p></td>
<td>The W component of your points position. <span class="annotation">[<acronym title="Parameter for input and for returning results. Default is transfer full."><span class="acronym">inout</span></acronym>]</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-project-points"></a><h3>cogl_matrix_project_points ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_project_points (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">int</span> n_components</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_in</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *points_in</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_out</code></em>,
<em class="parameter"><code><span class="type">void</span> *points_out</code></em>,
<em class="parameter"><code><span class="type">int</span> n_points</code></em>);</pre>
<p>
Projects an array of input points and writes the result to another
array of output points. The input points can either have 2, 3 or 4
components each. The output points always have 4 components (known
as homogenous coordinates). The output array can simply point to
the input array to do the transform in-place.
</p>
<p>
Here's an example with differing input/output strides:
</p>
<div class="informalexample"><pre class="programlisting">
typedef struct {
float x,y;
uint8_t r,g,b,a;
float s,t,p;
} MyInVertex;
typedef struct {
uint8_t r,g,b,a;
float x,y,z;
} MyOutVertex;
MyInVertex vertices[N_VERTICES];
MyOutVertex results[N_VERTICES];
CoglMatrix matrix;
my_load_vertices (vertices);
my_get_matrix (&matrix);
cogl_matrix_project_points (&matrix,
2,
sizeof (MyInVertex),
&vertices[0].x,
sizeof (MyOutVertex),
&results[0].x,
N_VERTICES);
</pre></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A projection matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>n_components</code></em> :</span></p></td>
<td>The number of position components for each input point.
(either 2, 3 or 4)</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stride_in</code></em> :</span></p></td>
<td>The stride in bytes between input points.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>points_in</code></em> :</span></p></td>
<td>A pointer to the first component of the first input point.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stride_out</code></em> :</span></p></td>
<td>The stride in bytes between output points.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>points_out</code></em> :</span></p></td>
<td>A pointer to the first component of the first output point.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>n_points</code></em> :</span></p></td>
<td>The number of points to transform.</td>
</tr>
</tbody>
</table></div>
<p class="stability">Stability Level: Unstable</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-transform-points"></a><h3>cogl_matrix_transform_points ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> cogl_matrix_transform_points (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>,
<em class="parameter"><code><span class="type">int</span> n_components</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_in</code></em>,
<em class="parameter"><code>const <span class="type">void</span> *points_in</code></em>,
<em class="parameter"><code><span class="type">size_t</span> stride_out</code></em>,
<em class="parameter"><code><span class="type">void</span> *points_out</code></em>,
<em class="parameter"><code><span class="type">int</span> n_points</code></em>);</pre>
<p>
Transforms an array of input points and writes the result to
another array of output points. The input points can either have 2
or 3 components each. The output points always have 3 components.
The output array can simply point to the input array to do the
transform in-place.
</p>
<p>
If you need to transform 4 component points see
<a class="link" href="cogl-Matrices.html#cogl-matrix-project-points" title="cogl_matrix_project_points ()"><code class="function">cogl_matrix_project_points()</code></a>.
</p>
<p>
Here's an example with differing input/output strides:
</p>
<div class="informalexample"><pre class="programlisting">
typedef struct {
float x,y;
uint8_t r,g,b,a;
float s,t,p;
} MyInVertex;
typedef struct {
uint8_t r,g,b,a;
float x,y,z;
} MyOutVertex;
MyInVertex vertices[N_VERTICES];
MyOutVertex results[N_VERTICES];
CoglMatrix matrix;
my_load_vertices (vertices);
my_get_matrix (&matrix);
cogl_matrix_transform_points (&matrix,
2,
sizeof (MyInVertex),
&vertices[0].x,
sizeof (MyOutVertex),
&results[0].x,
N_VERTICES);
</pre></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A transformation matrix</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>n_components</code></em> :</span></p></td>
<td>The number of position components for each input point.
(either 2 or 3)</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stride_in</code></em> :</span></p></td>
<td>The stride in bytes between input points.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>points_in</code></em> :</span></p></td>
<td>A pointer to the first component of the first input point.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stride_out</code></em> :</span></p></td>
<td>The stride in bytes between output points.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>points_out</code></em> :</span></p></td>
<td>A pointer to the first component of the first output point.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>n_points</code></em> :</span></p></td>
<td>The number of points to transform.</td>
</tr>
</tbody>
</table></div>
<p class="stability">Stability Level: Unstable</p>
</div>
<hr>
<div class="refsect2">
<a name="cogl-matrix-is-identity"></a><h3>cogl_matrix_is_identity ()</h3>
<pre class="programlisting"><span class="returnvalue">CoglBool</span> cogl_matrix_is_identity (<em class="parameter"><code>const <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a> *matrix</code></em>);</pre>
<p>
Determines if the given matrix is an identity matrix.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>matrix</code></em> :</span></p></td>
<td>A <a class="link" href="cogl-Matrices.html#CoglMatrix" title="CoglMatrix"><span class="type">CoglMatrix</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<code class="literal">TRUE</code> if <em class="parameter"><code>matrix</code></em> is an identity matrix else <code class="literal">FALSE</code>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 1.8</p>
</div>
</div>
</div>
<div class="footer">
<hr>
Generated by GTK-Doc V1.19</div>
</body>
</html>
|