Open Source Tomb Raider Engine
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Matrix.cpp 15KB

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  1. /* -*- Mode: C++; tab-width: 3; indent-tabs-mode: t; c-basic-offset: 3 -*- */
  2. /*================================================================
  3. *
  4. * Project : Freyja
  5. * Author : Terry 'Mongoose' Hendrix II
  6. * Website : http://www.westga.edu/~stu7440/
  7. * Email : stu7440@westga.edu
  8. * Object : Matrix
  9. * License : No use w/o permission (C) 2002 Mongoose
  10. * Comments: 3d Matrix class
  11. *
  12. *
  13. * This file was generated using Mongoose's C++
  14. * template generator script. <stu7440@westga.edu>
  15. *
  16. *-- History -------------------------------------------------
  17. *
  18. * 2002.05.11:
  19. * Mongoose - Created
  20. =================================================================*/
  21. #include <stdio.h>
  22. #include <math.h>
  23. #include <Matrix.h>
  24. ////////////////////////////////////////////////////////////
  25. // Constructors
  26. ////////////////////////////////////////////////////////////
  27. Matrix::Matrix()
  28. {
  29. setIdentity();
  30. }
  31. Matrix::Matrix(matrix_t m)
  32. {
  33. setMatrix(m);
  34. }
  35. Matrix::Matrix(Quaternion &q)
  36. {
  37. matrix_t m;
  38. q.getMatrix(m);
  39. setMatrix(m);
  40. }
  41. Matrix::~Matrix()
  42. {
  43. }
  44. ////////////////////////////////////////////////////////////
  45. // Public Accessors
  46. ////////////////////////////////////////////////////////////
  47. bool Matrix::getInvert(matrix_t out)
  48. {
  49. matrix_t m;
  50. #ifdef COLUMN_ORDER
  51. getMatrix(m);
  52. #else
  53. getTransposeMatrix(m);
  54. #endif
  55. /* Mongoose: This code was from a Jeff Lander tutorial which was based
  56. on MESA GL's InvertMatrix */
  57. /* NB. OpenGL Matrices are COLUMN major. */
  58. #define SWAP_ROWS(a, b) { float *_tmp = a; (a)=(b); (b)=_tmp; }
  59. #define MAT(m,r,c) (m)[(c)*4+(r)]
  60. float wtmp[4][8];
  61. float m0, m1, m2, m3, s;
  62. float *r0, *r1, *r2, *r3;
  63. r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
  64. r0[0] = MAT(m,0,0), r0[1] = MAT(m,0,1),
  65. r0[2] = MAT(m,0,2), r0[3] = MAT(m,0,3),
  66. r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,
  67. r1[0] = MAT(m,1,0), r1[1] = MAT(m,1,1),
  68. r1[2] = MAT(m,1,2), r1[3] = MAT(m,1,3),
  69. r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,
  70. r2[0] = MAT(m,2,0), r2[1] = MAT(m,2,1),
  71. r2[2] = MAT(m,2,2), r2[3] = MAT(m,2,3),
  72. r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,
  73. r3[0] = MAT(m,3,0), r3[1] = MAT(m,3,1),
  74. r3[2] = MAT(m,3,2), r3[3] = MAT(m,3,3),
  75. r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;
  76. /* choose pivot - or die */
  77. if (fabs(r3[0])>fabs(r2[0])) SWAP_ROWS(r3, r2);
  78. if (fabs(r2[0])>fabs(r1[0])) SWAP_ROWS(r2, r1);
  79. if (fabs(r1[0])>fabs(r0[0])) SWAP_ROWS(r1, r0);
  80. if (0.0 == r0[0]) return false;
  81. /* eliminate first variable */
  82. m1 = r1[0]/r0[0]; m2 = r2[0]/r0[0]; m3 = r3[0]/r0[0];
  83. s = r0[1]; r1[1] -= m1 * s; r2[1] -= m2 * s; r3[1] -= m3 * s;
  84. s = r0[2]; r1[2] -= m1 * s; r2[2] -= m2 * s; r3[2] -= m3 * s;
  85. s = r0[3]; r1[3] -= m1 * s; r2[3] -= m2 * s; r3[3] -= m3 * s;
  86. s = r0[4];
  87. if (s != 0.0) { r1[4] -= m1 * s; r2[4] -= m2 * s; r3[4] -= m3 * s; }
  88. s = r0[5];
  89. if (s != 0.0) { r1[5] -= m1 * s; r2[5] -= m2 * s; r3[5] -= m3 * s; }
  90. s = r0[6];
  91. if (s != 0.0) { r1[6] -= m1 * s; r2[6] -= m2 * s; r3[6] -= m3 * s; }
  92. s = r0[7];
  93. if (s != 0.0) { r1[7] -= m1 * s; r2[7] -= m2 * s; r3[7] -= m3 * s; }
  94. /* choose pivot - or die */
  95. if (fabs(r3[1])>fabs(r2[1])) SWAP_ROWS(r3, r2);
  96. if (fabs(r2[1])>fabs(r1[1])) SWAP_ROWS(r2, r1);
  97. if (0.0 == r1[1]) return false;
  98. /* eliminate second variable */
  99. m2 = r2[1]/r1[1]; m3 = r3[1]/r1[1];
  100. r2[2] -= m2 * r1[2]; r3[2] -= m3 * r1[2];
  101. r2[3] -= m2 * r1[3]; r3[3] -= m3 * r1[3];
  102. s = r1[4]; if (0.0 != s) { r2[4] -= m2 * s; r3[4] -= m3 * s; }
  103. s = r1[5]; if (0.0 != s) { r2[5] -= m2 * s; r3[5] -= m3 * s; }
  104. s = r1[6]; if (0.0 != s) { r2[6] -= m2 * s; r3[6] -= m3 * s; }
  105. s = r1[7]; if (0.0 != s) { r2[7] -= m2 * s; r3[7] -= m3 * s; }
  106. /* choose pivot - or die */
  107. if (fabs(r3[2])>fabs(r2[2])) SWAP_ROWS(r3, r2);
  108. if (0.0 == r2[2]) return false;
  109. /* eliminate third variable */
  110. m3 = r3[2]/r2[2];
  111. r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
  112. r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6],
  113. r3[7] -= m3 * r2[7];
  114. /* last check */
  115. if (0.0 == r3[3]) return false;
  116. s = 1.0/r3[3]; /* now back substitute row 3 */
  117. r3[4] *= s; r3[5] *= s; r3[6] *= s; r3[7] *= s;
  118. m2 = r2[3]; /* now back substitute row 2 */
  119. s = 1.0/r2[2];
  120. r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
  121. r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
  122. m1 = r1[3];
  123. r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
  124. r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
  125. m0 = r0[3];
  126. r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
  127. r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
  128. m1 = r1[2]; /* now back substitute row 1 */
  129. s = 1.0/r1[1];
  130. r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
  131. r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
  132. m0 = r0[2];
  133. r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
  134. r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
  135. m0 = r0[1]; /* now back substitute row 0 */
  136. s = 1.0/r0[0];
  137. r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
  138. r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
  139. MAT(out,0,0) = r0[4];
  140. MAT(out,0,1) = r0[5], MAT(out,0,2) = r0[6];
  141. MAT(out,0,3) = r0[7], MAT(out,1,0) = r1[4];
  142. MAT(out,1,1) = r1[5], MAT(out,1,2) = r1[6];
  143. MAT(out,1,3) = r1[7], MAT(out,2,0) = r2[4];
  144. MAT(out,2,1) = r2[5], MAT(out,2,2) = r2[6];
  145. MAT(out,2,3) = r2[7], MAT(out,3,0) = r3[4];
  146. MAT(out,3,1) = r3[5], MAT(out,3,2) = r3[6];
  147. MAT(out,3,3) = r3[7];
  148. return true;
  149. #undef MAT
  150. #undef SWAP_ROWS
  151. }
  152. void Matrix::getMatrix(matrix_t mat)
  153. {
  154. copy(mMatrix, mat);
  155. }
  156. void Matrix::getTransposeMatrix(matrix_t m)
  157. {
  158. m[ 0]= mMatrix[0]; m[ 1]= mMatrix[4]; m[ 2]= mMatrix[ 8]; m[ 3]=mMatrix[12];
  159. m[ 4]= mMatrix[1]; m[ 5]= mMatrix[5]; m[ 6]= mMatrix[ 9]; m[ 7]=mMatrix[13];
  160. m[ 8]= mMatrix[2]; m[ 9]= mMatrix[6]; m[10]= mMatrix[10]; m[11]=mMatrix[14];
  161. m[12]= mMatrix[3]; m[13]= mMatrix[7]; m[14]= mMatrix[11]; m[15]=mMatrix[15];
  162. }
  163. Matrix Matrix::multiply(const Matrix &a, const Matrix &b)
  164. {
  165. Matrix c;
  166. multiply(a.mMatrix, b.mMatrix, c.mMatrix);
  167. return c;
  168. }
  169. Matrix Matrix::operator *(const Matrix &a)
  170. {
  171. return multiply(a, *this);
  172. }
  173. Vector3d Matrix::operator *(Vector3d v)
  174. {
  175. vec_t x = v.mVec[0], y = v.mVec[1], z = v.mVec[2];
  176. #ifdef COLUMN_ORDER
  177. // Column order
  178. return Vector3d(mMatrix[0]*x + mMatrix[4]*y + mMatrix[ 8]*z + mMatrix[12],
  179. mMatrix[1]*x + mMatrix[5]*y + mMatrix[ 9]*z + mMatrix[13],
  180. mMatrix[2]*x + mMatrix[6]*y + mMatrix[10]*z + mMatrix[14]);
  181. #else
  182. // Row order
  183. return Vector3d(mMatrix[0]*x + mMatrix[1]*y + mMatrix[ 2]*z + mMatrix[ 3],
  184. mMatrix[4]*x + mMatrix[5]*y + mMatrix[ 6]*z + mMatrix[ 7],
  185. mMatrix[8]*x + mMatrix[9]*y + mMatrix[10]*z + mMatrix[11]);
  186. #endif
  187. }
  188. void Matrix::multiply3v(vec3_t v, vec3_t result)
  189. {
  190. vec_t x = v[0], y = v[1], z = v[2];
  191. result[0] = mMatrix[0]*x + mMatrix[1]*y + mMatrix[ 2]*z + mMatrix[ 3];
  192. result[1] = mMatrix[4]*x + mMatrix[5]*y + mMatrix[ 6]*z + mMatrix[ 7];
  193. result[2] = mMatrix[8]*x + mMatrix[9]*y + mMatrix[10]*z + mMatrix[11];
  194. }
  195. void Matrix::multiply4d(double *v, double *result)
  196. {
  197. double x = v[0], y = v[1], z = v[2], w = v[3];
  198. result[0] = mMatrix[ 0]*x + mMatrix[ 1]*y + mMatrix[ 2]*z + mMatrix[ 3]*w;
  199. result[1] = mMatrix[ 4]*x + mMatrix[ 5]*y + mMatrix[ 6]*z + mMatrix[ 7]*w;
  200. result[2] = mMatrix[ 8]*x + mMatrix[ 9]*y + mMatrix[10]*z + mMatrix[11]*w;
  201. result[3] = mMatrix[12]*x + mMatrix[13]*y + mMatrix[14]*z + mMatrix[15]*w;
  202. }
  203. void Matrix::multiply4v(vec4_t v, vec4_t result)
  204. {
  205. vec_t x = v[0], y = v[1], z = v[2], w = v[3];
  206. result[0] = mMatrix[ 0]*x + mMatrix[ 1]*y + mMatrix[ 2]*z + mMatrix[ 3]*w;
  207. result[1] = mMatrix[ 4]*x + mMatrix[ 5]*y + mMatrix[ 6]*z + mMatrix[ 7]*w;
  208. result[2] = mMatrix[ 8]*x + mMatrix[ 9]*y + mMatrix[10]*z + mMatrix[11]*w;
  209. result[3] = mMatrix[12]*x + mMatrix[13]*y + mMatrix[14]*z + mMatrix[15]*w;
  210. }
  211. void Matrix::print()
  212. {
  213. #ifdef COLUMN_ORDER
  214. printf("{\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n}\n",
  215. mMatrix[0], mMatrix[4], mMatrix[ 8], mMatrix[12],
  216. mMatrix[1], mMatrix[5], mMatrix[ 9], mMatrix[13],
  217. mMatrix[2], mMatrix[6], mMatrix[10], mMatrix[14],
  218. mMatrix[3], mMatrix[7], mMatrix[11], mMatrix[15]);
  219. #else
  220. printf("{\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n%f %f %f %f\n}\n",
  221. mMatrix[ 0], mMatrix[ 1], mMatrix[ 2], mMatrix[ 3],
  222. mMatrix[ 4], mMatrix[ 5], mMatrix[ 6], mMatrix[ 7],
  223. mMatrix[ 8], mMatrix[ 9], mMatrix[10], mMatrix[11],
  224. mMatrix[12], mMatrix[13], mMatrix[14], mMatrix[15]);
  225. #endif
  226. }
  227. bool Matrix::isIdentity()
  228. {
  229. // Hhhmm... floating point using direct comparisions
  230. if (mMatrix[ 0] == 1 && mMatrix[ 1] == 0 && mMatrix[ 2] == 0 &&
  231. mMatrix[ 3] == 0 && mMatrix[ 4] == 0 && mMatrix[ 5] == 1 &&
  232. mMatrix[ 6] == 0 && mMatrix[ 7] == 0 && mMatrix[ 8] == 0 &&
  233. mMatrix[ 9] == 0 && mMatrix[10] == 1 && mMatrix[11] == 0 &&
  234. mMatrix[12] == 0 && mMatrix[13] == 0 && mMatrix[14] == 0 &&
  235. mMatrix[15] == 1)
  236. return true;
  237. return false;
  238. }
  239. ////////////////////////////////////////////////////////////
  240. // Public Mutators
  241. ////////////////////////////////////////////////////////////
  242. void Matrix::setMatrix(matrix_t mat)
  243. {
  244. copy(mat, mMatrix);
  245. }
  246. void Matrix::setIdentity()
  247. {
  248. mMatrix[ 0] = 1; mMatrix[ 1] = 0; mMatrix[ 2] = 0; mMatrix[ 3] = 0;
  249. mMatrix[ 4] = 0; mMatrix[ 5] = 1; mMatrix[ 6] = 0; mMatrix[ 7] = 0;
  250. mMatrix[ 8] = 0; mMatrix[ 9] = 0; mMatrix[10] = 1; mMatrix[11] = 0;
  251. mMatrix[12] = 0; mMatrix[13] = 0; mMatrix[14] = 0; mMatrix[15] = 1;
  252. }
  253. void Matrix::scale(const vec_t *xyz)
  254. {
  255. scale(xyz[0], xyz[1], xyz[2]);
  256. }
  257. void Matrix::scale(vec_t sx, vec_t sy, vec_t sz)
  258. {
  259. matrix_t smatrix;
  260. matrix_t tmp;
  261. smatrix[ 0] = sx;smatrix[ 1] = 0; smatrix[ 2] = 0; smatrix[ 3] = 0;
  262. smatrix[ 4] = 0; smatrix[ 5] = sy;smatrix[ 6] = 0; smatrix[ 7] = 0;
  263. smatrix[ 8] = 0; smatrix[ 9] = 0; smatrix[10] = sz;smatrix[11] = 0;
  264. smatrix[12] = 0; smatrix[13] = 0; smatrix[14] = 0; smatrix[15] = 1;
  265. copy(mMatrix, tmp);
  266. multiply(tmp, smatrix, mMatrix);
  267. }
  268. void Matrix::rotate(const vec_t *xyz)
  269. {
  270. rotate(xyz[0], xyz[1], xyz[2]);
  271. }
  272. void Matrix::rotate(vec_t ax, vec_t ay, vec_t az)
  273. {
  274. matrix_t xmat, ymat, zmat, tmp, tmp2;
  275. xmat[ 0]=1; xmat[ 1]=0; xmat[ 2]=0; xmat[ 3]=0;
  276. xmat[ 4]=0; xmat[ 5]=cos(ax); xmat[ 6]=sin(ax); xmat[ 7]=0;
  277. xmat[ 8]=0; xmat[ 9]=-sin(ax); xmat[10]=cos(ax); xmat[11]=0;
  278. xmat[12]=0; xmat[13]=0; xmat[14]=0; xmat[15]=1;
  279. ymat[ 0]=cos(ay); ymat[ 1]=0; ymat[ 2]=-sin(ay); ymat[ 3]=0;
  280. ymat[ 4]=0; ymat[ 5]=1; ymat[ 6]=0; ymat[ 7]=0;
  281. ymat[ 8]=sin(ay); ymat[ 9]=0; ymat[10]=cos(ay); ymat[11]=0;
  282. ymat[12]=0; ymat[13]=0; ymat[14]=0; ymat[15]=1;
  283. zmat[ 0]=cos(az); zmat[ 1]=sin(az); zmat[ 2]=0; zmat[ 3]=0;
  284. zmat[ 4]=-sin(az); zmat[ 5]=cos(az); zmat[ 6]=0; zmat[ 7]=0;
  285. zmat[ 8]=0; zmat[ 9]=0; zmat[10]=1; zmat[11]=0;
  286. zmat[12]=0; zmat[13]=0; zmat[14]=0; zmat[15]=1;
  287. multiply(mMatrix, ymat, tmp);
  288. multiply(tmp, xmat, tmp2);
  289. multiply(tmp2, zmat, mMatrix);
  290. }
  291. void Matrix::translate(const vec_t *xyz)
  292. {
  293. translate(xyz[0], xyz[1], xyz[2]);
  294. }
  295. void Matrix::translate(vec_t tx, vec_t ty, vec_t tz)
  296. {
  297. matrix_t tmat, tmp;
  298. tmat[ 0]=1; tmat[ 1]=0; tmat[ 2]=0; tmat[ 3]=0;
  299. tmat[ 4]=0; tmat[ 5]=1; tmat[ 6]=0; tmat[ 7]=0;
  300. tmat[ 8]=0; tmat[ 9]=0; tmat[10]=1; tmat[11]=0;
  301. tmat[12]=tx; tmat[13]=ty; tmat[14]=tz; tmat[15]=1;
  302. copy(mMatrix, tmp);
  303. multiply(tmp, tmat, mMatrix);
  304. }
  305. ////////////////////////////////////////////////////////////
  306. // Private Accessors
  307. ////////////////////////////////////////////////////////////
  308. ////////////////////////////////////////////////////////////
  309. // Private Mutators
  310. ////////////////////////////////////////////////////////////
  311. void Matrix::copy(matrix_t source, matrix_t dest)
  312. {
  313. #ifdef FASTER_MATRIX
  314. memcpy(dest, source, sizeof(matrix_t));
  315. #else
  316. dest[ 0] = source[ 0];
  317. dest[ 1] = source[ 1];
  318. dest[ 2] = source[ 2];
  319. dest[ 3] = source[ 3];
  320. dest[ 4] = source[ 4];
  321. dest[ 5] = source[ 5];
  322. dest[ 6] = source[ 6];
  323. dest[ 7] = source[ 7];
  324. dest[ 8] = source[8];
  325. dest[ 9] = source[9];
  326. dest[10] = source[10];
  327. dest[11] = source[11];
  328. dest[12] = source[12];
  329. dest[13] = source[13];
  330. dest[14] = source[14];
  331. dest[15] = source[15];
  332. #endif
  333. }
  334. void Matrix::multiply(const matrix_t a, const matrix_t b, matrix_t result)
  335. {
  336. /* Generated code for matrix mult */
  337. #ifdef COLUMN_ORDER
  338. /* Column order */
  339. result[ 0] = a[ 0] * b[ 0] + a[ 4] * b[ 1] + a[ 8] * b[ 2] + a[12] * b[ 3];
  340. result[ 1] = a[ 0] * b[ 4] + a[ 4] * b[ 5] + a[ 8] * b[ 6] + a[12] * b[ 7];
  341. result[ 2] = a[ 0] * b[ 8] + a[ 4] * b[ 9] + a[ 8] * b[10] + a[12] * b[11];
  342. result[ 3] = a[ 0] * b[12] + a[ 4] * b[13] + a[ 8] * b[14] + a[12] * b[15];
  343. result[ 4] = a[ 1] * b[ 0] + a[ 5] * b[ 1] + a[ 9] * b[ 2] + a[13] * b[ 3];
  344. result[ 5] = a[ 1] * b[ 4] + a[ 5] * b[ 5] + a[ 9] * b[ 6] + a[13] * b[ 7];
  345. result[ 6] = a[ 1] * b[ 8] + a[ 5] * b[ 9] + a[ 9] * b[10] + a[13] * b[11];
  346. result[ 7] = a[ 1] * b[12] + a[ 5] * b[13] + a[ 9] * b[14] + a[13] * b[15];
  347. result[ 8] = a[ 2] * b[ 0] + a[ 6] * b[ 1] + a[10] * b[ 2] + a[14] * b[ 3];
  348. result[ 9] = a[ 2] * b[ 4] + a[ 6] * b[ 5] + a[10] * b[ 6] + a[14] * b[ 7];
  349. result[10] = a[ 2] * b[ 8] + a[ 6] * b[ 9] + a[10] * b[10] + a[14] * b[11];
  350. result[11] = a[ 2] * b[12] + a[ 6] * b[13] + a[10] * b[14] + a[14] * b[15];
  351. result[12] = a[ 3] * b[ 0] + a[ 7] * b[ 1] + a[11] * b[ 2] + a[15] * b[ 3];
  352. result[13] = a[ 3] * b[ 4] + a[ 7] * b[ 5] + a[11] * b[ 6] + a[15] * b[ 7];
  353. result[14] = a[ 3] * b[ 8] + a[ 7] * b[ 9] + a[11] * b[10] + a[15] * b[11];
  354. result[15] = a[ 3] * b[12] + a[ 7] * b[13] + a[11] * b[14] + a[15] * b[15];
  355. #else
  356. /* Row order */
  357. result[ 0] = a[ 0] * b[ 0] + a[ 1] * b[ 4] + a[ 2] * b[ 8] + a[ 3] * b[12];
  358. result[ 1] = a[ 0] * b[ 1] + a[ 1] * b[ 5] + a[ 2] * b[ 9] + a[ 3] * b[13];
  359. result[ 2] = a[ 0] * b[ 2] + a[ 1] * b[ 6] + a[ 2] * b[10] + a[ 3] * b[14];
  360. result[ 3] = a[ 0] * b[ 3] + a[ 1] * b[ 7] + a[ 2] * b[11] + a[ 3] * b[15];
  361. result[ 4] = a[ 4] * b[ 0] + a[ 5] * b[ 4] + a[ 6] * b[ 8] + a[ 7] * b[12];
  362. result[ 5] = a[ 4] * b[ 1] + a[ 5] * b[ 5] + a[ 6] * b[ 9] + a[ 7] * b[13];
  363. result[ 6] = a[ 4] * b[ 2] + a[ 5] * b[ 6] + a[ 6] * b[10] + a[ 7] * b[14];
  364. result[ 7] = a[ 4] * b[ 3] + a[ 5] * b[ 7] + a[ 6] * b[11] + a[ 7] * b[15];
  365. result[ 8] = a[ 8] * b[ 0] + a[ 9] * b[ 4] + a[10] * b[ 8] + a[11] * b[12];
  366. result[ 9] = a[ 8] * b[ 1] + a[ 9] * b[ 5] + a[10] * b[ 9] + a[11] * b[13];
  367. result[10] = a[ 8] * b[ 2] + a[ 9] * b[ 6] + a[10] * b[10] + a[11] * b[14];
  368. result[11] = a[ 8] * b[ 3] + a[ 9] * b[ 7] + a[10] * b[11] + a[11] * b[15];
  369. result[12] = a[12] * b[ 0] + a[13] * b[ 4] + a[14] * b[ 8] + a[15] * b[12];
  370. result[13] = a[12] * b[ 1] + a[13] * b[ 5] + a[14] * b[ 9] + a[15] * b[13];
  371. result[14] = a[12] * b[ 2] + a[13] * b[ 6] + a[14] * b[10] + a[15] * b[14];
  372. result[15] = a[12] * b[ 3] + a[13] * b[ 7] + a[14] * b[11] + a[15] * b[15];
  373. #endif
  374. }