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      1 /*
      2  * Mesa 3-D graphics library
      3  *
      4  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included
     14  * in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 
     26 /**
     27  * \file m_matrix.c
     28  * Matrix operations.
     29  *
     30  * \note
     31  * -# 4x4 transformation matrices are stored in memory in column major order.
     32  * -# Points/vertices are to be thought of as column vectors.
     33  * -# Transformation of a point p by a matrix M is: p' = M * p
     34  */
     35 
     36 
     37 #include "c99_math.h"
     38 #include "main/glheader.h"
     39 #include "main/imports.h"
     40 #include "main/macros.h"
     41 
     42 #include "m_matrix.h"
     43 
     44 
     45 /**
     46  * \defgroup MatFlags MAT_FLAG_XXX-flags
     47  *
     48  * Bitmasks to indicate different kinds of 4x4 matrices in GLmatrix::flags
     49  */
     50 /*@{*/
     51 #define MAT_FLAG_IDENTITY       0     /**< is an identity matrix flag.
     52                                        *   (Not actually used - the identity
     53                                        *   matrix is identified by the absence
     54                                        *   of all other flags.)
     55                                        */
     56 #define MAT_FLAG_GENERAL        0x1   /**< is a general matrix flag */
     57 #define MAT_FLAG_ROTATION       0x2   /**< is a rotation matrix flag */
     58 #define MAT_FLAG_TRANSLATION    0x4   /**< is a translation matrix flag */
     59 #define MAT_FLAG_UNIFORM_SCALE  0x8   /**< is an uniform scaling matrix flag */
     60 #define MAT_FLAG_GENERAL_SCALE  0x10  /**< is a general scaling matrix flag */
     61 #define MAT_FLAG_GENERAL_3D     0x20  /**< general 3D matrix flag */
     62 #define MAT_FLAG_PERSPECTIVE    0x40  /**< is a perspective proj matrix flag */
     63 #define MAT_FLAG_SINGULAR       0x80  /**< is a singular matrix flag */
     64 #define MAT_DIRTY_TYPE          0x100  /**< matrix type is dirty */
     65 #define MAT_DIRTY_FLAGS         0x200  /**< matrix flags are dirty */
     66 #define MAT_DIRTY_INVERSE       0x400  /**< matrix inverse is dirty */
     67 
     68 /** angle preserving matrix flags mask */
     69 #define MAT_FLAGS_ANGLE_PRESERVING (MAT_FLAG_ROTATION | \
     70 				    MAT_FLAG_TRANSLATION | \
     71 				    MAT_FLAG_UNIFORM_SCALE)
     72 
     73 /** geometry related matrix flags mask */
     74 #define MAT_FLAGS_GEOMETRY (MAT_FLAG_GENERAL | \
     75 			    MAT_FLAG_ROTATION | \
     76 			    MAT_FLAG_TRANSLATION | \
     77 			    MAT_FLAG_UNIFORM_SCALE | \
     78 			    MAT_FLAG_GENERAL_SCALE | \
     79 			    MAT_FLAG_GENERAL_3D | \
     80 			    MAT_FLAG_PERSPECTIVE | \
     81 	                    MAT_FLAG_SINGULAR)
     82 
     83 /** length preserving matrix flags mask */
     84 #define MAT_FLAGS_LENGTH_PRESERVING (MAT_FLAG_ROTATION | \
     85 				     MAT_FLAG_TRANSLATION)
     86 
     87 
     88 /** 3D (non-perspective) matrix flags mask */
     89 #define MAT_FLAGS_3D (MAT_FLAG_ROTATION | \
     90 		      MAT_FLAG_TRANSLATION | \
     91 		      MAT_FLAG_UNIFORM_SCALE | \
     92 		      MAT_FLAG_GENERAL_SCALE | \
     93 		      MAT_FLAG_GENERAL_3D)
     94 
     95 /** dirty matrix flags mask */
     96 #define MAT_DIRTY          (MAT_DIRTY_TYPE | \
     97 			    MAT_DIRTY_FLAGS | \
     98 			    MAT_DIRTY_INVERSE)
     99 
    100 /*@}*/
    101 
    102 
    103 /**
    104  * Test geometry related matrix flags.
    105  *
    106  * \param mat a pointer to a GLmatrix structure.
    107  * \param a flags mask.
    108  *
    109  * \returns non-zero if all geometry related matrix flags are contained within
    110  * the mask, or zero otherwise.
    111  */
    112 #define TEST_MAT_FLAGS(mat, a)  \
    113     ((MAT_FLAGS_GEOMETRY & (~(a)) & ((mat)->flags) ) == 0)
    114 
    115 
    116 
    117 /**
    118  * Names of the corresponding GLmatrixtype values.
    119  */
    120 static const char *types[] = {
    121    "MATRIX_GENERAL",
    122    "MATRIX_IDENTITY",
    123    "MATRIX_3D_NO_ROT",
    124    "MATRIX_PERSPECTIVE",
    125    "MATRIX_2D",
    126    "MATRIX_2D_NO_ROT",
    127    "MATRIX_3D"
    128 };
    129 
    130 
    131 /**
    132  * Identity matrix.
    133  */
    134 static const GLfloat Identity[16] = {
    135    1.0, 0.0, 0.0, 0.0,
    136    0.0, 1.0, 0.0, 0.0,
    137    0.0, 0.0, 1.0, 0.0,
    138    0.0, 0.0, 0.0, 1.0
    139 };
    140 
    141 
    142 
    143 /**********************************************************************/
    144 /** \name Matrix multiplication */
    145 /*@{*/
    146 
    147 #define A(row,col)  a[(col<<2)+row]
    148 #define B(row,col)  b[(col<<2)+row]
    149 #define P(row,col)  product[(col<<2)+row]
    150 
    151 /**
    152  * Perform a full 4x4 matrix multiplication.
    153  *
    154  * \param a matrix.
    155  * \param b matrix.
    156  * \param product will receive the product of \p a and \p b.
    157  *
    158  * \warning Is assumed that \p product != \p b. \p product == \p a is allowed.
    159  *
    160  * \note KW: 4*16 = 64 multiplications
    161  *
    162  * \author This \c matmul was contributed by Thomas Malik
    163  */
    164 static void matmul4( GLfloat *product, const GLfloat *a, const GLfloat *b )
    165 {
    166    GLint i;
    167    for (i = 0; i < 4; i++) {
    168       const GLfloat ai0=A(i,0),  ai1=A(i,1),  ai2=A(i,2),  ai3=A(i,3);
    169       P(i,0) = ai0 * B(0,0) + ai1 * B(1,0) + ai2 * B(2,0) + ai3 * B(3,0);
    170       P(i,1) = ai0 * B(0,1) + ai1 * B(1,1) + ai2 * B(2,1) + ai3 * B(3,1);
    171       P(i,2) = ai0 * B(0,2) + ai1 * B(1,2) + ai2 * B(2,2) + ai3 * B(3,2);
    172       P(i,3) = ai0 * B(0,3) + ai1 * B(1,3) + ai2 * B(2,3) + ai3 * B(3,3);
    173    }
    174 }
    175 
    176 /**
    177  * Multiply two matrices known to occupy only the top three rows, such
    178  * as typical model matrices, and orthogonal matrices.
    179  *
    180  * \param a matrix.
    181  * \param b matrix.
    182  * \param product will receive the product of \p a and \p b.
    183  */
    184 static void matmul34( GLfloat *product, const GLfloat *a, const GLfloat *b )
    185 {
    186    GLint i;
    187    for (i = 0; i < 3; i++) {
    188       const GLfloat ai0=A(i,0),  ai1=A(i,1),  ai2=A(i,2),  ai3=A(i,3);
    189       P(i,0) = ai0 * B(0,0) + ai1 * B(1,0) + ai2 * B(2,0);
    190       P(i,1) = ai0 * B(0,1) + ai1 * B(1,1) + ai2 * B(2,1);
    191       P(i,2) = ai0 * B(0,2) + ai1 * B(1,2) + ai2 * B(2,2);
    192       P(i,3) = ai0 * B(0,3) + ai1 * B(1,3) + ai2 * B(2,3) + ai3;
    193    }
    194    P(3,0) = 0;
    195    P(3,1) = 0;
    196    P(3,2) = 0;
    197    P(3,3) = 1;
    198 }
    199 
    200 #undef A
    201 #undef B
    202 #undef P
    203 
    204 /**
    205  * Multiply a matrix by an array of floats with known properties.
    206  *
    207  * \param mat pointer to a GLmatrix structure containing the left multiplication
    208  * matrix, and that will receive the product result.
    209  * \param m right multiplication matrix array.
    210  * \param flags flags of the matrix \p m.
    211  *
    212  * Joins both flags and marks the type and inverse as dirty.  Calls matmul34()
    213  * if both matrices are 3D, or matmul4() otherwise.
    214  */
    215 static void matrix_multf( GLmatrix *mat, const GLfloat *m, GLuint flags )
    216 {
    217    mat->flags |= (flags | MAT_DIRTY_TYPE | MAT_DIRTY_INVERSE);
    218 
    219    if (TEST_MAT_FLAGS(mat, MAT_FLAGS_3D))
    220       matmul34( mat->m, mat->m, m );
    221    else
    222       matmul4( mat->m, mat->m, m );
    223 }
    224 
    225 /**
    226  * Matrix multiplication.
    227  *
    228  * \param dest destination matrix.
    229  * \param a left matrix.
    230  * \param b right matrix.
    231  *
    232  * Joins both flags and marks the type and inverse as dirty.  Calls matmul34()
    233  * if both matrices are 3D, or matmul4() otherwise.
    234  */
    235 void
    236 _math_matrix_mul_matrix( GLmatrix *dest, const GLmatrix *a, const GLmatrix *b )
    237 {
    238    dest->flags = (a->flags |
    239 		  b->flags |
    240 		  MAT_DIRTY_TYPE |
    241 		  MAT_DIRTY_INVERSE);
    242 
    243    if (TEST_MAT_FLAGS(dest, MAT_FLAGS_3D))
    244       matmul34( dest->m, a->m, b->m );
    245    else
    246       matmul4( dest->m, a->m, b->m );
    247 }
    248 
    249 /**
    250  * Matrix multiplication.
    251  *
    252  * \param dest left and destination matrix.
    253  * \param m right matrix array.
    254  *
    255  * Marks the matrix flags with general flag, and type and inverse dirty flags.
    256  * Calls matmul4() for the multiplication.
    257  */
    258 void
    259 _math_matrix_mul_floats( GLmatrix *dest, const GLfloat *m )
    260 {
    261    dest->flags |= (MAT_FLAG_GENERAL |
    262 		   MAT_DIRTY_TYPE |
    263 		   MAT_DIRTY_INVERSE |
    264                    MAT_DIRTY_FLAGS);
    265 
    266    matmul4( dest->m, dest->m, m );
    267 }
    268 
    269 /*@}*/
    270 
    271 
    272 /**********************************************************************/
    273 /** \name Matrix output */
    274 /*@{*/
    275 
    276 /**
    277  * Print a matrix array.
    278  *
    279  * \param m matrix array.
    280  *
    281  * Called by _math_matrix_print() to print a matrix or its inverse.
    282  */
    283 static void print_matrix_floats( const GLfloat m[16] )
    284 {
    285    int i;
    286    for (i=0;i<4;i++) {
    287       _mesa_debug(NULL,"\t%f %f %f %f\n", m[i], m[4+i], m[8+i], m[12+i] );
    288    }
    289 }
    290 
    291 /**
    292  * Dumps the contents of a GLmatrix structure.
    293  *
    294  * \param m pointer to the GLmatrix structure.
    295  */
    296 void
    297 _math_matrix_print( const GLmatrix *m )
    298 {
    299    GLfloat prod[16];
    300 
    301    _mesa_debug(NULL, "Matrix type: %s, flags: %x\n", types[m->type], m->flags);
    302    print_matrix_floats(m->m);
    303    _mesa_debug(NULL, "Inverse: \n");
    304    print_matrix_floats(m->inv);
    305    matmul4(prod, m->m, m->inv);
    306    _mesa_debug(NULL, "Mat * Inverse:\n");
    307    print_matrix_floats(prod);
    308 }
    309 
    310 /*@}*/
    311 
    312 
    313 /**
    314  * References an element of 4x4 matrix.
    315  *
    316  * \param m matrix array.
    317  * \param c column of the desired element.
    318  * \param r row of the desired element.
    319  *
    320  * \return value of the desired element.
    321  *
    322  * Calculate the linear storage index of the element and references it.
    323  */
    324 #define MAT(m,r,c) (m)[(c)*4+(r)]
    325 
    326 
    327 /**********************************************************************/
    328 /** \name Matrix inversion */
    329 /*@{*/
    330 
    331 /**
    332  * Swaps the values of two floating point variables.
    333  *
    334  * Used by invert_matrix_general() to swap the row pointers.
    335  */
    336 #define SWAP_ROWS(a, b) { GLfloat *_tmp = a; (a)=(b); (b)=_tmp; }
    337 
    338 /**
    339  * Compute inverse of 4x4 transformation matrix.
    340  *
    341  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    342  * stored in the GLmatrix::inv attribute.
    343  *
    344  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    345  *
    346  * \author
    347  * Code contributed by Jacques Leroy jle (at) star.be
    348  *
    349  * Calculates the inverse matrix by performing the gaussian matrix reduction
    350  * with partial pivoting followed by back/substitution with the loops manually
    351  * unrolled.
    352  */
    353 static GLboolean invert_matrix_general( GLmatrix *mat )
    354 {
    355    const GLfloat *m = mat->m;
    356    GLfloat *out = mat->inv;
    357    GLfloat wtmp[4][8];
    358    GLfloat m0, m1, m2, m3, s;
    359    GLfloat *r0, *r1, *r2, *r3;
    360 
    361    r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
    362 
    363    r0[0] = MAT(m,0,0), r0[1] = MAT(m,0,1),
    364    r0[2] = MAT(m,0,2), r0[3] = MAT(m,0,3),
    365    r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,
    366 
    367    r1[0] = MAT(m,1,0), r1[1] = MAT(m,1,1),
    368    r1[2] = MAT(m,1,2), r1[3] = MAT(m,1,3),
    369    r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,
    370 
    371    r2[0] = MAT(m,2,0), r2[1] = MAT(m,2,1),
    372    r2[2] = MAT(m,2,2), r2[3] = MAT(m,2,3),
    373    r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,
    374 
    375    r3[0] = MAT(m,3,0), r3[1] = MAT(m,3,1),
    376    r3[2] = MAT(m,3,2), r3[3] = MAT(m,3,3),
    377    r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;
    378 
    379    /* choose pivot - or die */
    380    if (fabsf(r3[0])>fabsf(r2[0])) SWAP_ROWS(r3, r2);
    381    if (fabsf(r2[0])>fabsf(r1[0])) SWAP_ROWS(r2, r1);
    382    if (fabsf(r1[0])>fabsf(r0[0])) SWAP_ROWS(r1, r0);
    383    if (0.0F == r0[0])  return GL_FALSE;
    384 
    385    /* eliminate first variable     */
    386    m1 = r1[0]/r0[0]; m2 = r2[0]/r0[0]; m3 = r3[0]/r0[0];
    387    s = r0[1]; r1[1] -= m1 * s; r2[1] -= m2 * s; r3[1] -= m3 * s;
    388    s = r0[2]; r1[2] -= m1 * s; r2[2] -= m2 * s; r3[2] -= m3 * s;
    389    s = r0[3]; r1[3] -= m1 * s; r2[3] -= m2 * s; r3[3] -= m3 * s;
    390    s = r0[4];
    391    if (s != 0.0F) { r1[4] -= m1 * s; r2[4] -= m2 * s; r3[4] -= m3 * s; }
    392    s = r0[5];
    393    if (s != 0.0F) { r1[5] -= m1 * s; r2[5] -= m2 * s; r3[5] -= m3 * s; }
    394    s = r0[6];
    395    if (s != 0.0F) { r1[6] -= m1 * s; r2[6] -= m2 * s; r3[6] -= m3 * s; }
    396    s = r0[7];
    397    if (s != 0.0F) { r1[7] -= m1 * s; r2[7] -= m2 * s; r3[7] -= m3 * s; }
    398 
    399    /* choose pivot - or die */
    400    if (fabsf(r3[1])>fabsf(r2[1])) SWAP_ROWS(r3, r2);
    401    if (fabsf(r2[1])>fabsf(r1[1])) SWAP_ROWS(r2, r1);
    402    if (0.0F == r1[1])  return GL_FALSE;
    403 
    404    /* eliminate second variable */
    405    m2 = r2[1]/r1[1]; m3 = r3[1]/r1[1];
    406    r2[2] -= m2 * r1[2]; r3[2] -= m3 * r1[2];
    407    r2[3] -= m2 * r1[3]; r3[3] -= m3 * r1[3];
    408    s = r1[4]; if (0.0F != s) { r2[4] -= m2 * s; r3[4] -= m3 * s; }
    409    s = r1[5]; if (0.0F != s) { r2[5] -= m2 * s; r3[5] -= m3 * s; }
    410    s = r1[6]; if (0.0F != s) { r2[6] -= m2 * s; r3[6] -= m3 * s; }
    411    s = r1[7]; if (0.0F != s) { r2[7] -= m2 * s; r3[7] -= m3 * s; }
    412 
    413    /* choose pivot - or die */
    414    if (fabsf(r3[2])>fabsf(r2[2])) SWAP_ROWS(r3, r2);
    415    if (0.0F == r2[2])  return GL_FALSE;
    416 
    417    /* eliminate third variable */
    418    m3 = r3[2]/r2[2];
    419    r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
    420    r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6],
    421    r3[7] -= m3 * r2[7];
    422 
    423    /* last check */
    424    if (0.0F == r3[3]) return GL_FALSE;
    425 
    426    s = 1.0F/r3[3];             /* now back substitute row 3 */
    427    r3[4] *= s; r3[5] *= s; r3[6] *= s; r3[7] *= s;
    428 
    429    m2 = r2[3];                 /* now back substitute row 2 */
    430    s  = 1.0F/r2[2];
    431    r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
    432    r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
    433    m1 = r1[3];
    434    r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
    435    r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
    436    m0 = r0[3];
    437    r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
    438    r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
    439 
    440    m1 = r1[2];                 /* now back substitute row 1 */
    441    s  = 1.0F/r1[1];
    442    r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
    443    r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
    444    m0 = r0[2];
    445    r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
    446    r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
    447 
    448    m0 = r0[1];                 /* now back substitute row 0 */
    449    s  = 1.0F/r0[0];
    450    r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
    451    r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
    452 
    453    MAT(out,0,0) = r0[4]; MAT(out,0,1) = r0[5],
    454    MAT(out,0,2) = r0[6]; MAT(out,0,3) = r0[7],
    455    MAT(out,1,0) = r1[4]; MAT(out,1,1) = r1[5],
    456    MAT(out,1,2) = r1[6]; MAT(out,1,3) = r1[7],
    457    MAT(out,2,0) = r2[4]; MAT(out,2,1) = r2[5],
    458    MAT(out,2,2) = r2[6]; MAT(out,2,3) = r2[7],
    459    MAT(out,3,0) = r3[4]; MAT(out,3,1) = r3[5],
    460    MAT(out,3,2) = r3[6]; MAT(out,3,3) = r3[7];
    461 
    462    return GL_TRUE;
    463 }
    464 #undef SWAP_ROWS
    465 
    466 /**
    467  * Compute inverse of a general 3d transformation matrix.
    468  *
    469  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    470  * stored in the GLmatrix::inv attribute.
    471  *
    472  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    473  *
    474  * \author Adapted from graphics gems II.
    475  *
    476  * Calculates the inverse of the upper left by first calculating its
    477  * determinant and multiplying it to the symmetric adjust matrix of each
    478  * element. Finally deals with the translation part by transforming the
    479  * original translation vector using by the calculated submatrix inverse.
    480  */
    481 static GLboolean invert_matrix_3d_general( GLmatrix *mat )
    482 {
    483    const GLfloat *in = mat->m;
    484    GLfloat *out = mat->inv;
    485    GLfloat pos, neg, t;
    486    GLfloat det;
    487 
    488    /* Calculate the determinant of upper left 3x3 submatrix and
    489     * determine if the matrix is singular.
    490     */
    491    pos = neg = 0.0;
    492    t =  MAT(in,0,0) * MAT(in,1,1) * MAT(in,2,2);
    493    if (t >= 0.0F) pos += t; else neg += t;
    494 
    495    t =  MAT(in,1,0) * MAT(in,2,1) * MAT(in,0,2);
    496    if (t >= 0.0F) pos += t; else neg += t;
    497 
    498    t =  MAT(in,2,0) * MAT(in,0,1) * MAT(in,1,2);
    499    if (t >= 0.0F) pos += t; else neg += t;
    500 
    501    t = -MAT(in,2,0) * MAT(in,1,1) * MAT(in,0,2);
    502    if (t >= 0.0F) pos += t; else neg += t;
    503 
    504    t = -MAT(in,1,0) * MAT(in,0,1) * MAT(in,2,2);
    505    if (t >= 0.0F) pos += t; else neg += t;
    506 
    507    t = -MAT(in,0,0) * MAT(in,2,1) * MAT(in,1,2);
    508    if (t >= 0.0F) pos += t; else neg += t;
    509 
    510    det = pos + neg;
    511 
    512    if (fabsf(det) < 1e-25F)
    513       return GL_FALSE;
    514 
    515    det = 1.0F / det;
    516    MAT(out,0,0) = (  (MAT(in,1,1)*MAT(in,2,2) - MAT(in,2,1)*MAT(in,1,2) )*det);
    517    MAT(out,0,1) = (- (MAT(in,0,1)*MAT(in,2,2) - MAT(in,2,1)*MAT(in,0,2) )*det);
    518    MAT(out,0,2) = (  (MAT(in,0,1)*MAT(in,1,2) - MAT(in,1,1)*MAT(in,0,2) )*det);
    519    MAT(out,1,0) = (- (MAT(in,1,0)*MAT(in,2,2) - MAT(in,2,0)*MAT(in,1,2) )*det);
    520    MAT(out,1,1) = (  (MAT(in,0,0)*MAT(in,2,2) - MAT(in,2,0)*MAT(in,0,2) )*det);
    521    MAT(out,1,2) = (- (MAT(in,0,0)*MAT(in,1,2) - MAT(in,1,0)*MAT(in,0,2) )*det);
    522    MAT(out,2,0) = (  (MAT(in,1,0)*MAT(in,2,1) - MAT(in,2,0)*MAT(in,1,1) )*det);
    523    MAT(out,2,1) = (- (MAT(in,0,0)*MAT(in,2,1) - MAT(in,2,0)*MAT(in,0,1) )*det);
    524    MAT(out,2,2) = (  (MAT(in,0,0)*MAT(in,1,1) - MAT(in,1,0)*MAT(in,0,1) )*det);
    525 
    526    /* Do the translation part */
    527    MAT(out,0,3) = - (MAT(in,0,3) * MAT(out,0,0) +
    528 		     MAT(in,1,3) * MAT(out,0,1) +
    529 		     MAT(in,2,3) * MAT(out,0,2) );
    530    MAT(out,1,3) = - (MAT(in,0,3) * MAT(out,1,0) +
    531 		     MAT(in,1,3) * MAT(out,1,1) +
    532 		     MAT(in,2,3) * MAT(out,1,2) );
    533    MAT(out,2,3) = - (MAT(in,0,3) * MAT(out,2,0) +
    534 		     MAT(in,1,3) * MAT(out,2,1) +
    535 		     MAT(in,2,3) * MAT(out,2,2) );
    536 
    537    return GL_TRUE;
    538 }
    539 
    540 /**
    541  * Compute inverse of a 3d transformation matrix.
    542  *
    543  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    544  * stored in the GLmatrix::inv attribute.
    545  *
    546  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    547  *
    548  * If the matrix is not an angle preserving matrix then calls
    549  * invert_matrix_3d_general for the actual calculation. Otherwise calculates
    550  * the inverse matrix analyzing and inverting each of the scaling, rotation and
    551  * translation parts.
    552  */
    553 static GLboolean invert_matrix_3d( GLmatrix *mat )
    554 {
    555    const GLfloat *in = mat->m;
    556    GLfloat *out = mat->inv;
    557 
    558    if (!TEST_MAT_FLAGS(mat, MAT_FLAGS_ANGLE_PRESERVING)) {
    559       return invert_matrix_3d_general( mat );
    560    }
    561 
    562    if (mat->flags & MAT_FLAG_UNIFORM_SCALE) {
    563       GLfloat scale = (MAT(in,0,0) * MAT(in,0,0) +
    564                        MAT(in,0,1) * MAT(in,0,1) +
    565                        MAT(in,0,2) * MAT(in,0,2));
    566 
    567       if (scale == 0.0F)
    568          return GL_FALSE;
    569 
    570       scale = 1.0F / scale;
    571 
    572       /* Transpose and scale the 3 by 3 upper-left submatrix. */
    573       MAT(out,0,0) = scale * MAT(in,0,0);
    574       MAT(out,1,0) = scale * MAT(in,0,1);
    575       MAT(out,2,0) = scale * MAT(in,0,2);
    576       MAT(out,0,1) = scale * MAT(in,1,0);
    577       MAT(out,1,1) = scale * MAT(in,1,1);
    578       MAT(out,2,1) = scale * MAT(in,1,2);
    579       MAT(out,0,2) = scale * MAT(in,2,0);
    580       MAT(out,1,2) = scale * MAT(in,2,1);
    581       MAT(out,2,2) = scale * MAT(in,2,2);
    582    }
    583    else if (mat->flags & MAT_FLAG_ROTATION) {
    584       /* Transpose the 3 by 3 upper-left submatrix. */
    585       MAT(out,0,0) = MAT(in,0,0);
    586       MAT(out,1,0) = MAT(in,0,1);
    587       MAT(out,2,0) = MAT(in,0,2);
    588       MAT(out,0,1) = MAT(in,1,0);
    589       MAT(out,1,1) = MAT(in,1,1);
    590       MAT(out,2,1) = MAT(in,1,2);
    591       MAT(out,0,2) = MAT(in,2,0);
    592       MAT(out,1,2) = MAT(in,2,1);
    593       MAT(out,2,2) = MAT(in,2,2);
    594    }
    595    else {
    596       /* pure translation */
    597       memcpy( out, Identity, sizeof(Identity) );
    598       MAT(out,0,3) = - MAT(in,0,3);
    599       MAT(out,1,3) = - MAT(in,1,3);
    600       MAT(out,2,3) = - MAT(in,2,3);
    601       return GL_TRUE;
    602    }
    603 
    604    if (mat->flags & MAT_FLAG_TRANSLATION) {
    605       /* Do the translation part */
    606       MAT(out,0,3) = - (MAT(in,0,3) * MAT(out,0,0) +
    607 			MAT(in,1,3) * MAT(out,0,1) +
    608 			MAT(in,2,3) * MAT(out,0,2) );
    609       MAT(out,1,3) = - (MAT(in,0,3) * MAT(out,1,0) +
    610 			MAT(in,1,3) * MAT(out,1,1) +
    611 			MAT(in,2,3) * MAT(out,1,2) );
    612       MAT(out,2,3) = - (MAT(in,0,3) * MAT(out,2,0) +
    613 			MAT(in,1,3) * MAT(out,2,1) +
    614 			MAT(in,2,3) * MAT(out,2,2) );
    615    }
    616    else {
    617       MAT(out,0,3) = MAT(out,1,3) = MAT(out,2,3) = 0.0;
    618    }
    619 
    620    return GL_TRUE;
    621 }
    622 
    623 /**
    624  * Compute inverse of an identity transformation matrix.
    625  *
    626  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    627  * stored in the GLmatrix::inv attribute.
    628  *
    629  * \return always GL_TRUE.
    630  *
    631  * Simply copies Identity into GLmatrix::inv.
    632  */
    633 static GLboolean invert_matrix_identity( GLmatrix *mat )
    634 {
    635    memcpy( mat->inv, Identity, sizeof(Identity) );
    636    return GL_TRUE;
    637 }
    638 
    639 /**
    640  * Compute inverse of a no-rotation 3d transformation matrix.
    641  *
    642  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    643  * stored in the GLmatrix::inv attribute.
    644  *
    645  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    646  *
    647  * Calculates the
    648  */
    649 static GLboolean invert_matrix_3d_no_rot( GLmatrix *mat )
    650 {
    651    const GLfloat *in = mat->m;
    652    GLfloat *out = mat->inv;
    653 
    654    if (MAT(in,0,0) == 0 || MAT(in,1,1) == 0 || MAT(in,2,2) == 0 )
    655       return GL_FALSE;
    656 
    657    memcpy( out, Identity, sizeof(Identity) );
    658    MAT(out,0,0) = 1.0F / MAT(in,0,0);
    659    MAT(out,1,1) = 1.0F / MAT(in,1,1);
    660    MAT(out,2,2) = 1.0F / MAT(in,2,2);
    661 
    662    if (mat->flags & MAT_FLAG_TRANSLATION) {
    663       MAT(out,0,3) = - (MAT(in,0,3) * MAT(out,0,0));
    664       MAT(out,1,3) = - (MAT(in,1,3) * MAT(out,1,1));
    665       MAT(out,2,3) = - (MAT(in,2,3) * MAT(out,2,2));
    666    }
    667 
    668    return GL_TRUE;
    669 }
    670 
    671 /**
    672  * Compute inverse of a no-rotation 2d transformation matrix.
    673  *
    674  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    675  * stored in the GLmatrix::inv attribute.
    676  *
    677  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    678  *
    679  * Calculates the inverse matrix by applying the inverse scaling and
    680  * translation to the identity matrix.
    681  */
    682 static GLboolean invert_matrix_2d_no_rot( GLmatrix *mat )
    683 {
    684    const GLfloat *in = mat->m;
    685    GLfloat *out = mat->inv;
    686 
    687    if (MAT(in,0,0) == 0 || MAT(in,1,1) == 0)
    688       return GL_FALSE;
    689 
    690    memcpy( out, Identity, sizeof(Identity) );
    691    MAT(out,0,0) = 1.0F / MAT(in,0,0);
    692    MAT(out,1,1) = 1.0F / MAT(in,1,1);
    693 
    694    if (mat->flags & MAT_FLAG_TRANSLATION) {
    695       MAT(out,0,3) = - (MAT(in,0,3) * MAT(out,0,0));
    696       MAT(out,1,3) = - (MAT(in,1,3) * MAT(out,1,1));
    697    }
    698 
    699    return GL_TRUE;
    700 }
    701 
    702 #if 0
    703 /* broken */
    704 static GLboolean invert_matrix_perspective( GLmatrix *mat )
    705 {
    706    const GLfloat *in = mat->m;
    707    GLfloat *out = mat->inv;
    708 
    709    if (MAT(in,2,3) == 0)
    710       return GL_FALSE;
    711 
    712    memcpy( out, Identity, sizeof(Identity) );
    713 
    714    MAT(out,0,0) = 1.0F / MAT(in,0,0);
    715    MAT(out,1,1) = 1.0F / MAT(in,1,1);
    716 
    717    MAT(out,0,3) = MAT(in,0,2);
    718    MAT(out,1,3) = MAT(in,1,2);
    719 
    720    MAT(out,2,2) = 0;
    721    MAT(out,2,3) = -1;
    722 
    723    MAT(out,3,2) = 1.0F / MAT(in,2,3);
    724    MAT(out,3,3) = MAT(in,2,2) * MAT(out,3,2);
    725 
    726    return GL_TRUE;
    727 }
    728 #endif
    729 
    730 /**
    731  * Matrix inversion function pointer type.
    732  */
    733 typedef GLboolean (*inv_mat_func)( GLmatrix *mat );
    734 
    735 /**
    736  * Table of the matrix inversion functions according to the matrix type.
    737  */
    738 static inv_mat_func inv_mat_tab[7] = {
    739    invert_matrix_general,
    740    invert_matrix_identity,
    741    invert_matrix_3d_no_rot,
    742 #if 0
    743    /* Don't use this function for now - it fails when the projection matrix
    744     * is premultiplied by a translation (ala Chromium's tilesort SPU).
    745     */
    746    invert_matrix_perspective,
    747 #else
    748    invert_matrix_general,
    749 #endif
    750    invert_matrix_3d,		/* lazy! */
    751    invert_matrix_2d_no_rot,
    752    invert_matrix_3d
    753 };
    754 
    755 /**
    756  * Compute inverse of a transformation matrix.
    757  *
    758  * \param mat pointer to a GLmatrix structure. The matrix inverse will be
    759  * stored in the GLmatrix::inv attribute.
    760  *
    761  * \return GL_TRUE for success, GL_FALSE for failure (\p singular matrix).
    762  *
    763  * Calls the matrix inversion function in inv_mat_tab corresponding to the
    764  * given matrix type.  In case of failure, updates the MAT_FLAG_SINGULAR flag,
    765  * and copies the identity matrix into GLmatrix::inv.
    766  */
    767 static GLboolean matrix_invert( GLmatrix *mat )
    768 {
    769    if (inv_mat_tab[mat->type](mat)) {
    770       mat->flags &= ~MAT_FLAG_SINGULAR;
    771       return GL_TRUE;
    772    } else {
    773       mat->flags |= MAT_FLAG_SINGULAR;
    774       memcpy( mat->inv, Identity, sizeof(Identity) );
    775       return GL_FALSE;
    776    }
    777 }
    778 
    779 /*@}*/
    780 
    781 
    782 /**********************************************************************/
    783 /** \name Matrix generation */
    784 /*@{*/
    785 
    786 /**
    787  * Generate a 4x4 transformation matrix from glRotate parameters, and
    788  * post-multiply the input matrix by it.
    789  *
    790  * \author
    791  * This function was contributed by Erich Boleyn (erich (at) uruk.org).
    792  * Optimizations contributed by Rudolf Opalla (rudi (at) khm.de).
    793  */
    794 void
    795 _math_matrix_rotate( GLmatrix *mat,
    796 		     GLfloat angle, GLfloat x, GLfloat y, GLfloat z )
    797 {
    798    GLfloat xx, yy, zz, xy, yz, zx, xs, ys, zs, one_c, s, c;
    799    GLfloat m[16];
    800    GLboolean optimized;
    801 
    802    s = sinf( angle * M_PI / 180.0 );
    803    c = cosf( angle * M_PI / 180.0 );
    804 
    805    memcpy(m, Identity, sizeof(Identity));
    806    optimized = GL_FALSE;
    807 
    808 #define M(row,col)  m[col*4+row]
    809 
    810    if (x == 0.0F) {
    811       if (y == 0.0F) {
    812          if (z != 0.0F) {
    813             optimized = GL_TRUE;
    814             /* rotate only around z-axis */
    815             M(0,0) = c;
    816             M(1,1) = c;
    817             if (z < 0.0F) {
    818                M(0,1) = s;
    819                M(1,0) = -s;
    820             }
    821             else {
    822                M(0,1) = -s;
    823                M(1,0) = s;
    824             }
    825          }
    826       }
    827       else if (z == 0.0F) {
    828          optimized = GL_TRUE;
    829          /* rotate only around y-axis */
    830          M(0,0) = c;
    831          M(2,2) = c;
    832          if (y < 0.0F) {
    833             M(0,2) = -s;
    834             M(2,0) = s;
    835          }
    836          else {
    837             M(0,2) = s;
    838             M(2,0) = -s;
    839          }
    840       }
    841    }
    842    else if (y == 0.0F) {
    843       if (z == 0.0F) {
    844          optimized = GL_TRUE;
    845          /* rotate only around x-axis */
    846          M(1,1) = c;
    847          M(2,2) = c;
    848          if (x < 0.0F) {
    849             M(1,2) = s;
    850             M(2,1) = -s;
    851          }
    852          else {
    853             M(1,2) = -s;
    854             M(2,1) = s;
    855          }
    856       }
    857    }
    858 
    859    if (!optimized) {
    860       const GLfloat mag = sqrtf(x * x + y * y + z * z);
    861 
    862       if (mag <= 1.0e-4F) {
    863          /* no rotation, leave mat as-is */
    864          return;
    865       }
    866 
    867       x /= mag;
    868       y /= mag;
    869       z /= mag;
    870 
    871 
    872       /*
    873        *     Arbitrary axis rotation matrix.
    874        *
    875        *  This is composed of 5 matrices, Rz, Ry, T, Ry', Rz', multiplied
    876        *  like so:  Rz * Ry * T * Ry' * Rz'.  T is the final rotation
    877        *  (which is about the X-axis), and the two composite transforms
    878        *  Ry' * Rz' and Rz * Ry are (respectively) the rotations necessary
    879        *  from the arbitrary axis to the X-axis then back.  They are
    880        *  all elementary rotations.
    881        *
    882        *  Rz' is a rotation about the Z-axis, to bring the axis vector
    883        *  into the x-z plane.  Then Ry' is applied, rotating about the
    884        *  Y-axis to bring the axis vector parallel with the X-axis.  The
    885        *  rotation about the X-axis is then performed.  Ry and Rz are
    886        *  simply the respective inverse transforms to bring the arbitrary
    887        *  axis back to its original orientation.  The first transforms
    888        *  Rz' and Ry' are considered inverses, since the data from the
    889        *  arbitrary axis gives you info on how to get to it, not how
    890        *  to get away from it, and an inverse must be applied.
    891        *
    892        *  The basic calculation used is to recognize that the arbitrary
    893        *  axis vector (x, y, z), since it is of unit length, actually
    894        *  represents the sines and cosines of the angles to rotate the
    895        *  X-axis to the same orientation, with theta being the angle about
    896        *  Z and phi the angle about Y (in the order described above)
    897        *  as follows:
    898        *
    899        *  cos ( theta ) = x / sqrt ( 1 - z^2 )
    900        *  sin ( theta ) = y / sqrt ( 1 - z^2 )
    901        *
    902        *  cos ( phi ) = sqrt ( 1 - z^2 )
    903        *  sin ( phi ) = z
    904        *
    905        *  Note that cos ( phi ) can further be inserted to the above
    906        *  formulas:
    907        *
    908        *  cos ( theta ) = x / cos ( phi )
    909        *  sin ( theta ) = y / sin ( phi )
    910        *
    911        *  ...etc.  Because of those relations and the standard trigonometric
    912        *  relations, it is pssible to reduce the transforms down to what
    913        *  is used below.  It may be that any primary axis chosen will give the
    914        *  same results (modulo a sign convention) using thie method.
    915        *
    916        *  Particularly nice is to notice that all divisions that might
    917        *  have caused trouble when parallel to certain planes or
    918        *  axis go away with care paid to reducing the expressions.
    919        *  After checking, it does perform correctly under all cases, since
    920        *  in all the cases of division where the denominator would have
    921        *  been zero, the numerator would have been zero as well, giving
    922        *  the expected result.
    923        */
    924 
    925       xx = x * x;
    926       yy = y * y;
    927       zz = z * z;
    928       xy = x * y;
    929       yz = y * z;
    930       zx = z * x;
    931       xs = x * s;
    932       ys = y * s;
    933       zs = z * s;
    934       one_c = 1.0F - c;
    935 
    936       /* We already hold the identity-matrix so we can skip some statements */
    937       M(0,0) = (one_c * xx) + c;
    938       M(0,1) = (one_c * xy) - zs;
    939       M(0,2) = (one_c * zx) + ys;
    940 /*    M(0,3) = 0.0F; */
    941 
    942       M(1,0) = (one_c * xy) + zs;
    943       M(1,1) = (one_c * yy) + c;
    944       M(1,2) = (one_c * yz) - xs;
    945 /*    M(1,3) = 0.0F; */
    946 
    947       M(2,0) = (one_c * zx) - ys;
    948       M(2,1) = (one_c * yz) + xs;
    949       M(2,2) = (one_c * zz) + c;
    950 /*    M(2,3) = 0.0F; */
    951 
    952 /*
    953       M(3,0) = 0.0F;
    954       M(3,1) = 0.0F;
    955       M(3,2) = 0.0F;
    956       M(3,3) = 1.0F;
    957 */
    958    }
    959 #undef M
    960 
    961    matrix_multf( mat, m, MAT_FLAG_ROTATION );
    962 }
    963 
    964 /**
    965  * Apply a perspective projection matrix.
    966  *
    967  * \param mat matrix to apply the projection.
    968  * \param left left clipping plane coordinate.
    969  * \param right right clipping plane coordinate.
    970  * \param bottom bottom clipping plane coordinate.
    971  * \param top top clipping plane coordinate.
    972  * \param nearval distance to the near clipping plane.
    973  * \param farval distance to the far clipping plane.
    974  *
    975  * Creates the projection matrix and multiplies it with \p mat, marking the
    976  * MAT_FLAG_PERSPECTIVE flag.
    977  */
    978 void
    979 _math_matrix_frustum( GLmatrix *mat,
    980 		      GLfloat left, GLfloat right,
    981 		      GLfloat bottom, GLfloat top,
    982 		      GLfloat nearval, GLfloat farval )
    983 {
    984    GLfloat x, y, a, b, c, d;
    985    GLfloat m[16];
    986 
    987    x = (2.0F*nearval) / (right-left);
    988    y = (2.0F*nearval) / (top-bottom);
    989    a = (right+left) / (right-left);
    990    b = (top+bottom) / (top-bottom);
    991    c = -(farval+nearval) / ( farval-nearval);
    992    d = -(2.0F*farval*nearval) / (farval-nearval);  /* error? */
    993 
    994 #define M(row,col)  m[col*4+row]
    995    M(0,0) = x;     M(0,1) = 0.0F;  M(0,2) = a;      M(0,3) = 0.0F;
    996    M(1,0) = 0.0F;  M(1,1) = y;     M(1,2) = b;      M(1,3) = 0.0F;
    997    M(2,0) = 0.0F;  M(2,1) = 0.0F;  M(2,2) = c;      M(2,3) = d;
    998    M(3,0) = 0.0F;  M(3,1) = 0.0F;  M(3,2) = -1.0F;  M(3,3) = 0.0F;
    999 #undef M
   1000 
   1001    matrix_multf( mat, m, MAT_FLAG_PERSPECTIVE );
   1002 }
   1003 
   1004 /**
   1005  * Apply an orthographic projection matrix.
   1006  *
   1007  * \param mat matrix to apply the projection.
   1008  * \param left left clipping plane coordinate.
   1009  * \param right right clipping plane coordinate.
   1010  * \param bottom bottom clipping plane coordinate.
   1011  * \param top top clipping plane coordinate.
   1012  * \param nearval distance to the near clipping plane.
   1013  * \param farval distance to the far clipping plane.
   1014  *
   1015  * Creates the projection matrix and multiplies it with \p mat, marking the
   1016  * MAT_FLAG_GENERAL_SCALE and MAT_FLAG_TRANSLATION flags.
   1017  */
   1018 void
   1019 _math_matrix_ortho( GLmatrix *mat,
   1020 		    GLfloat left, GLfloat right,
   1021 		    GLfloat bottom, GLfloat top,
   1022 		    GLfloat nearval, GLfloat farval )
   1023 {
   1024    GLfloat m[16];
   1025 
   1026 #define M(row,col)  m[col*4+row]
   1027    M(0,0) = 2.0F / (right-left);
   1028    M(0,1) = 0.0F;
   1029    M(0,2) = 0.0F;
   1030    M(0,3) = -(right+left) / (right-left);
   1031 
   1032    M(1,0) = 0.0F;
   1033    M(1,1) = 2.0F / (top-bottom);
   1034    M(1,2) = 0.0F;
   1035    M(1,3) = -(top+bottom) / (top-bottom);
   1036 
   1037    M(2,0) = 0.0F;
   1038    M(2,1) = 0.0F;
   1039    M(2,2) = -2.0F / (farval-nearval);
   1040    M(2,3) = -(farval+nearval) / (farval-nearval);
   1041 
   1042    M(3,0) = 0.0F;
   1043    M(3,1) = 0.0F;
   1044    M(3,2) = 0.0F;
   1045    M(3,3) = 1.0F;
   1046 #undef M
   1047 
   1048    matrix_multf( mat, m, (MAT_FLAG_GENERAL_SCALE|MAT_FLAG_TRANSLATION));
   1049 }
   1050 
   1051 /**
   1052  * Multiply a matrix with a general scaling matrix.
   1053  *
   1054  * \param mat matrix.
   1055  * \param x x axis scale factor.
   1056  * \param y y axis scale factor.
   1057  * \param z z axis scale factor.
   1058  *
   1059  * Multiplies in-place the elements of \p mat by the scale factors. Checks if
   1060  * the scales factors are roughly the same, marking the MAT_FLAG_UNIFORM_SCALE
   1061  * flag, or MAT_FLAG_GENERAL_SCALE. Marks the MAT_DIRTY_TYPE and
   1062  * MAT_DIRTY_INVERSE dirty flags.
   1063  */
   1064 void
   1065 _math_matrix_scale( GLmatrix *mat, GLfloat x, GLfloat y, GLfloat z )
   1066 {
   1067    GLfloat *m = mat->m;
   1068    m[0] *= x;   m[4] *= y;   m[8]  *= z;
   1069    m[1] *= x;   m[5] *= y;   m[9]  *= z;
   1070    m[2] *= x;   m[6] *= y;   m[10] *= z;
   1071    m[3] *= x;   m[7] *= y;   m[11] *= z;
   1072 
   1073    if (fabsf(x - y) < 1e-8F && fabsf(x - z) < 1e-8F)
   1074       mat->flags |= MAT_FLAG_UNIFORM_SCALE;
   1075    else
   1076       mat->flags |= MAT_FLAG_GENERAL_SCALE;
   1077 
   1078    mat->flags |= (MAT_DIRTY_TYPE |
   1079 		  MAT_DIRTY_INVERSE);
   1080 }
   1081 
   1082 /**
   1083  * Multiply a matrix with a translation matrix.
   1084  *
   1085  * \param mat matrix.
   1086  * \param x translation vector x coordinate.
   1087  * \param y translation vector y coordinate.
   1088  * \param z translation vector z coordinate.
   1089  *
   1090  * Adds the translation coordinates to the elements of \p mat in-place.  Marks
   1091  * the MAT_FLAG_TRANSLATION flag, and the MAT_DIRTY_TYPE and MAT_DIRTY_INVERSE
   1092  * dirty flags.
   1093  */
   1094 void
   1095 _math_matrix_translate( GLmatrix *mat, GLfloat x, GLfloat y, GLfloat z )
   1096 {
   1097    GLfloat *m = mat->m;
   1098    m[12] = m[0] * x + m[4] * y + m[8]  * z + m[12];
   1099    m[13] = m[1] * x + m[5] * y + m[9]  * z + m[13];
   1100    m[14] = m[2] * x + m[6] * y + m[10] * z + m[14];
   1101    m[15] = m[3] * x + m[7] * y + m[11] * z + m[15];
   1102 
   1103    mat->flags |= (MAT_FLAG_TRANSLATION |
   1104 		  MAT_DIRTY_TYPE |
   1105 		  MAT_DIRTY_INVERSE);
   1106 }
   1107 
   1108 
   1109 /**
   1110  * Set matrix to do viewport and depthrange mapping.
   1111  * Transforms Normalized Device Coords to window/Z values.
   1112  */
   1113 void
   1114 _math_matrix_viewport(GLmatrix *m, const float scale[3],
   1115                       const float translate[3], double depthMax)
   1116 {
   1117    m->m[MAT_SX] = scale[0];
   1118    m->m[MAT_TX] = translate[0];
   1119    m->m[MAT_SY] = scale[1];
   1120    m->m[MAT_TY] = translate[1];
   1121    m->m[MAT_SZ] = depthMax*scale[2];
   1122    m->m[MAT_TZ] = depthMax*translate[2];
   1123    m->flags = MAT_FLAG_GENERAL_SCALE | MAT_FLAG_TRANSLATION;
   1124    m->type = MATRIX_3D_NO_ROT;
   1125 }
   1126 
   1127 
   1128 /**
   1129  * Set a matrix to the identity matrix.
   1130  *
   1131  * \param mat matrix.
   1132  *
   1133  * Copies ::Identity into \p GLmatrix::m, and into GLmatrix::inv if not NULL.
   1134  * Sets the matrix type to identity, and clear the dirty flags.
   1135  */
   1136 void
   1137 _math_matrix_set_identity( GLmatrix *mat )
   1138 {
   1139    memcpy( mat->m, Identity, sizeof(Identity) );
   1140    memcpy( mat->inv, Identity, sizeof(Identity) );
   1141 
   1142    mat->type = MATRIX_IDENTITY;
   1143    mat->flags &= ~(MAT_DIRTY_FLAGS|
   1144 		   MAT_DIRTY_TYPE|
   1145 		   MAT_DIRTY_INVERSE);
   1146 }
   1147 
   1148 /*@}*/
   1149 
   1150 
   1151 /**********************************************************************/
   1152 /** \name Matrix analysis */
   1153 /*@{*/
   1154 
   1155 #define ZERO(x) (1<<x)
   1156 #define ONE(x)  (1<<(x+16))
   1157 
   1158 #define MASK_NO_TRX      (ZERO(12) | ZERO(13) | ZERO(14))
   1159 #define MASK_NO_2D_SCALE ( ONE(0)  | ONE(5))
   1160 
   1161 #define MASK_IDENTITY    ( ONE(0)  | ZERO(4)  | ZERO(8)  | ZERO(12) |\
   1162 			  ZERO(1)  |  ONE(5)  | ZERO(9)  | ZERO(13) |\
   1163 			  ZERO(2)  | ZERO(6)  |  ONE(10) | ZERO(14) |\
   1164 			  ZERO(3)  | ZERO(7)  | ZERO(11) |  ONE(15) )
   1165 
   1166 #define MASK_2D_NO_ROT   (           ZERO(4)  | ZERO(8)  |           \
   1167 			  ZERO(1)  |            ZERO(9)  |           \
   1168 			  ZERO(2)  | ZERO(6)  |  ONE(10) | ZERO(14) |\
   1169 			  ZERO(3)  | ZERO(7)  | ZERO(11) |  ONE(15) )
   1170 
   1171 #define MASK_2D          (                      ZERO(8)  |           \
   1172 			                        ZERO(9)  |           \
   1173 			  ZERO(2)  | ZERO(6)  |  ONE(10) | ZERO(14) |\
   1174 			  ZERO(3)  | ZERO(7)  | ZERO(11) |  ONE(15) )
   1175 
   1176 
   1177 #define MASK_3D_NO_ROT   (           ZERO(4)  | ZERO(8)  |           \
   1178 			  ZERO(1)  |            ZERO(9)  |           \
   1179 			  ZERO(2)  | ZERO(6)  |                      \
   1180 			  ZERO(3)  | ZERO(7)  | ZERO(11) |  ONE(15) )
   1181 
   1182 #define MASK_3D          (                                           \
   1183 			                                             \
   1184 			                                             \
   1185 			  ZERO(3)  | ZERO(7)  | ZERO(11) |  ONE(15) )
   1186 
   1187 
   1188 #define MASK_PERSPECTIVE (           ZERO(4)  |            ZERO(12) |\
   1189 			  ZERO(1)  |                       ZERO(13) |\
   1190 			  ZERO(2)  | ZERO(6)  |                      \
   1191 			  ZERO(3)  | ZERO(7)  |            ZERO(15) )
   1192 
   1193 #define SQ(x) ((x)*(x))
   1194 
   1195 /**
   1196  * Determine type and flags from scratch.
   1197  *
   1198  * \param mat matrix.
   1199  *
   1200  * This is expensive enough to only want to do it once.
   1201  */
   1202 static void analyse_from_scratch( GLmatrix *mat )
   1203 {
   1204    const GLfloat *m = mat->m;
   1205    GLuint mask = 0;
   1206    GLuint i;
   1207 
   1208    for (i = 0 ; i < 16 ; i++) {
   1209       if (m[i] == 0.0F) mask |= (1<<i);
   1210    }
   1211 
   1212    if (m[0] == 1.0F) mask |= (1<<16);
   1213    if (m[5] == 1.0F) mask |= (1<<21);
   1214    if (m[10] == 1.0F) mask |= (1<<26);
   1215    if (m[15] == 1.0F) mask |= (1<<31);
   1216 
   1217    mat->flags &= ~MAT_FLAGS_GEOMETRY;
   1218 
   1219    /* Check for translation - no-one really cares
   1220     */
   1221    if ((mask & MASK_NO_TRX) != MASK_NO_TRX)
   1222       mat->flags |= MAT_FLAG_TRANSLATION;
   1223 
   1224    /* Do the real work
   1225     */
   1226    if (mask == (GLuint) MASK_IDENTITY) {
   1227       mat->type = MATRIX_IDENTITY;
   1228    }
   1229    else if ((mask & MASK_2D_NO_ROT) == (GLuint) MASK_2D_NO_ROT) {
   1230       mat->type = MATRIX_2D_NO_ROT;
   1231 
   1232       if ((mask & MASK_NO_2D_SCALE) != MASK_NO_2D_SCALE)
   1233 	 mat->flags |= MAT_FLAG_GENERAL_SCALE;
   1234    }
   1235    else if ((mask & MASK_2D) == (GLuint) MASK_2D) {
   1236       GLfloat mm = DOT2(m, m);
   1237       GLfloat m4m4 = DOT2(m+4,m+4);
   1238       GLfloat mm4 = DOT2(m,m+4);
   1239 
   1240       mat->type = MATRIX_2D;
   1241 
   1242       /* Check for scale */
   1243       if (SQ(mm-1) > SQ(1e-6F) ||
   1244 	  SQ(m4m4-1) > SQ(1e-6F))
   1245 	 mat->flags |= MAT_FLAG_GENERAL_SCALE;
   1246 
   1247       /* Check for rotation */
   1248       if (SQ(mm4) > SQ(1e-6F))
   1249 	 mat->flags |= MAT_FLAG_GENERAL_3D;
   1250       else
   1251 	 mat->flags |= MAT_FLAG_ROTATION;
   1252 
   1253    }
   1254    else if ((mask & MASK_3D_NO_ROT) == (GLuint) MASK_3D_NO_ROT) {
   1255       mat->type = MATRIX_3D_NO_ROT;
   1256 
   1257       /* Check for scale */
   1258       if (SQ(m[0]-m[5]) < SQ(1e-6F) &&
   1259 	  SQ(m[0]-m[10]) < SQ(1e-6F)) {
   1260 	 if (SQ(m[0]-1.0F) > SQ(1e-6F)) {
   1261 	    mat->flags |= MAT_FLAG_UNIFORM_SCALE;
   1262          }
   1263       }
   1264       else {
   1265 	 mat->flags |= MAT_FLAG_GENERAL_SCALE;
   1266       }
   1267    }
   1268    else if ((mask & MASK_3D) == (GLuint) MASK_3D) {
   1269       GLfloat c1 = DOT3(m,m);
   1270       GLfloat c2 = DOT3(m+4,m+4);
   1271       GLfloat c3 = DOT3(m+8,m+8);
   1272       GLfloat d1 = DOT3(m, m+4);
   1273       GLfloat cp[3];
   1274 
   1275       mat->type = MATRIX_3D;
   1276 
   1277       /* Check for scale */
   1278       if (SQ(c1-c2) < SQ(1e-6F) && SQ(c1-c3) < SQ(1e-6F)) {
   1279 	 if (SQ(c1-1.0F) > SQ(1e-6F))
   1280 	    mat->flags |= MAT_FLAG_UNIFORM_SCALE;
   1281 	 /* else no scale at all */
   1282       }
   1283       else {
   1284 	 mat->flags |= MAT_FLAG_GENERAL_SCALE;
   1285       }
   1286 
   1287       /* Check for rotation */
   1288       if (SQ(d1) < SQ(1e-6F)) {
   1289 	 CROSS3( cp, m, m+4 );
   1290 	 SUB_3V( cp, cp, (m+8) );
   1291 	 if (LEN_SQUARED_3FV(cp) < SQ(1e-6F))
   1292 	    mat->flags |= MAT_FLAG_ROTATION;
   1293 	 else
   1294 	    mat->flags |= MAT_FLAG_GENERAL_3D;
   1295       }
   1296       else {
   1297 	 mat->flags |= MAT_FLAG_GENERAL_3D; /* shear, etc */
   1298       }
   1299    }
   1300    else if ((mask & MASK_PERSPECTIVE) == MASK_PERSPECTIVE && m[11]==-1.0F) {
   1301       mat->type = MATRIX_PERSPECTIVE;
   1302       mat->flags |= MAT_FLAG_GENERAL;
   1303    }
   1304    else {
   1305       mat->type = MATRIX_GENERAL;
   1306       mat->flags |= MAT_FLAG_GENERAL;
   1307    }
   1308 }
   1309 
   1310 /**
   1311  * Analyze a matrix given that its flags are accurate.
   1312  *
   1313  * This is the more common operation, hopefully.
   1314  */
   1315 static void analyse_from_flags( GLmatrix *mat )
   1316 {
   1317    const GLfloat *m = mat->m;
   1318 
   1319    if (TEST_MAT_FLAGS(mat, 0)) {
   1320       mat->type = MATRIX_IDENTITY;
   1321    }
   1322    else if (TEST_MAT_FLAGS(mat, (MAT_FLAG_TRANSLATION |
   1323 				 MAT_FLAG_UNIFORM_SCALE |
   1324 				 MAT_FLAG_GENERAL_SCALE))) {
   1325       if ( m[10]==1.0F && m[14]==0.0F ) {
   1326 	 mat->type = MATRIX_2D_NO_ROT;
   1327       }
   1328       else {
   1329 	 mat->type = MATRIX_3D_NO_ROT;
   1330       }
   1331    }
   1332    else if (TEST_MAT_FLAGS(mat, MAT_FLAGS_3D)) {
   1333       if (                                 m[ 8]==0.0F
   1334             &&                             m[ 9]==0.0F
   1335             && m[2]==0.0F && m[6]==0.0F && m[10]==1.0F && m[14]==0.0F) {
   1336 	 mat->type = MATRIX_2D;
   1337       }
   1338       else {
   1339 	 mat->type = MATRIX_3D;
   1340       }
   1341    }
   1342    else if (                 m[4]==0.0F                 && m[12]==0.0F
   1343             && m[1]==0.0F                               && m[13]==0.0F
   1344             && m[2]==0.0F && m[6]==0.0F
   1345             && m[3]==0.0F && m[7]==0.0F && m[11]==-1.0F && m[15]==0.0F) {
   1346       mat->type = MATRIX_PERSPECTIVE;
   1347    }
   1348    else {
   1349       mat->type = MATRIX_GENERAL;
   1350    }
   1351 }
   1352 
   1353 /**
   1354  * Analyze and update a matrix.
   1355  *
   1356  * \param mat matrix.
   1357  *
   1358  * If the matrix type is dirty then calls either analyse_from_scratch() or
   1359  * analyse_from_flags() to determine its type, according to whether the flags
   1360  * are dirty or not, respectively. If the matrix has an inverse and it's dirty
   1361  * then calls matrix_invert(). Finally clears the dirty flags.
   1362  */
   1363 void
   1364 _math_matrix_analyse( GLmatrix *mat )
   1365 {
   1366    if (mat->flags & MAT_DIRTY_TYPE) {
   1367       if (mat->flags & MAT_DIRTY_FLAGS)
   1368 	 analyse_from_scratch( mat );
   1369       else
   1370 	 analyse_from_flags( mat );
   1371    }
   1372 
   1373    if (mat->inv && (mat->flags & MAT_DIRTY_INVERSE)) {
   1374       matrix_invert( mat );
   1375       mat->flags &= ~MAT_DIRTY_INVERSE;
   1376    }
   1377 
   1378    mat->flags &= ~(MAT_DIRTY_FLAGS | MAT_DIRTY_TYPE);
   1379 }
   1380 
   1381 /*@}*/
   1382 
   1383 
   1384 /**
   1385  * Test if the given matrix preserves vector lengths.
   1386  */
   1387 GLboolean
   1388 _math_matrix_is_length_preserving( const GLmatrix *m )
   1389 {
   1390    return TEST_MAT_FLAGS( m, MAT_FLAGS_LENGTH_PRESERVING);
   1391 }
   1392 
   1393 
   1394 /**
   1395  * Test if the given matrix does any rotation.
   1396  * (or perhaps if the upper-left 3x3 is non-identity)
   1397  */
   1398 GLboolean
   1399 _math_matrix_has_rotation( const GLmatrix *m )
   1400 {
   1401    if (m->flags & (MAT_FLAG_GENERAL |
   1402                    MAT_FLAG_ROTATION |
   1403                    MAT_FLAG_GENERAL_3D |
   1404                    MAT_FLAG_PERSPECTIVE))
   1405       return GL_TRUE;
   1406    else
   1407       return GL_FALSE;
   1408 }
   1409 
   1410 
   1411 GLboolean
   1412 _math_matrix_is_general_scale( const GLmatrix *m )
   1413 {
   1414    return (m->flags & MAT_FLAG_GENERAL_SCALE) ? GL_TRUE : GL_FALSE;
   1415 }
   1416 
   1417 
   1418 GLboolean
   1419 _math_matrix_is_dirty( const GLmatrix *m )
   1420 {
   1421    return (m->flags & MAT_DIRTY) ? GL_TRUE : GL_FALSE;
   1422 }
   1423 
   1424 
   1425 /**********************************************************************/
   1426 /** \name Matrix setup */
   1427 /*@{*/
   1428 
   1429 /**
   1430  * Copy a matrix.
   1431  *
   1432  * \param to destination matrix.
   1433  * \param from source matrix.
   1434  *
   1435  * Copies all fields in GLmatrix, creating an inverse array if necessary.
   1436  */
   1437 void
   1438 _math_matrix_copy( GLmatrix *to, const GLmatrix *from )
   1439 {
   1440    memcpy(to->m, from->m, 16 * sizeof(GLfloat));
   1441    memcpy(to->inv, from->inv, 16 * sizeof(GLfloat));
   1442    to->flags = from->flags;
   1443    to->type = from->type;
   1444 }
   1445 
   1446 /**
   1447  * Loads a matrix array into GLmatrix.
   1448  *
   1449  * \param m matrix array.
   1450  * \param mat matrix.
   1451  *
   1452  * Copies \p m into GLmatrix::m and marks the MAT_FLAG_GENERAL and MAT_DIRTY
   1453  * flags.
   1454  */
   1455 void
   1456 _math_matrix_loadf( GLmatrix *mat, const GLfloat *m )
   1457 {
   1458    memcpy( mat->m, m, 16*sizeof(GLfloat) );
   1459    mat->flags = (MAT_FLAG_GENERAL | MAT_DIRTY);
   1460 }
   1461 
   1462 /**
   1463  * Matrix constructor.
   1464  *
   1465  * \param m matrix.
   1466  *
   1467  * Initialize the GLmatrix fields.
   1468  */
   1469 void
   1470 _math_matrix_ctr( GLmatrix *m )
   1471 {
   1472    m->m = _mesa_align_malloc( 16 * sizeof(GLfloat), 16 );
   1473    if (m->m)
   1474       memcpy( m->m, Identity, sizeof(Identity) );
   1475    m->inv = _mesa_align_malloc( 16 * sizeof(GLfloat), 16 );
   1476    if (m->inv)
   1477       memcpy( m->inv, Identity, sizeof(Identity) );
   1478    m->type = MATRIX_IDENTITY;
   1479    m->flags = 0;
   1480 }
   1481 
   1482 /**
   1483  * Matrix destructor.
   1484  *
   1485  * \param m matrix.
   1486  *
   1487  * Frees the data in a GLmatrix.
   1488  */
   1489 void
   1490 _math_matrix_dtr( GLmatrix *m )
   1491 {
   1492    _mesa_align_free( m->m );
   1493    m->m = NULL;
   1494 
   1495    _mesa_align_free( m->inv );
   1496    m->inv = NULL;
   1497 }
   1498 
   1499 /*@}*/
   1500 
   1501 
   1502 /**********************************************************************/
   1503 /** \name Matrix transpose */
   1504 /*@{*/
   1505 
   1506 /**
   1507  * Transpose a GLfloat matrix.
   1508  *
   1509  * \param to destination array.
   1510  * \param from source array.
   1511  */
   1512 void
   1513 _math_transposef( GLfloat to[16], const GLfloat from[16] )
   1514 {
   1515    to[0] = from[0];
   1516    to[1] = from[4];
   1517    to[2] = from[8];
   1518    to[3] = from[12];
   1519    to[4] = from[1];
   1520    to[5] = from[5];
   1521    to[6] = from[9];
   1522    to[7] = from[13];
   1523    to[8] = from[2];
   1524    to[9] = from[6];
   1525    to[10] = from[10];
   1526    to[11] = from[14];
   1527    to[12] = from[3];
   1528    to[13] = from[7];
   1529    to[14] = from[11];
   1530    to[15] = from[15];
   1531 }
   1532 
   1533 /**
   1534  * Transpose a GLdouble matrix.
   1535  *
   1536  * \param to destination array.
   1537  * \param from source array.
   1538  */
   1539 void
   1540 _math_transposed( GLdouble to[16], const GLdouble from[16] )
   1541 {
   1542    to[0] = from[0];
   1543    to[1] = from[4];
   1544    to[2] = from[8];
   1545    to[3] = from[12];
   1546    to[4] = from[1];
   1547    to[5] = from[5];
   1548    to[6] = from[9];
   1549    to[7] = from[13];
   1550    to[8] = from[2];
   1551    to[9] = from[6];
   1552    to[10] = from[10];
   1553    to[11] = from[14];
   1554    to[12] = from[3];
   1555    to[13] = from[7];
   1556    to[14] = from[11];
   1557    to[15] = from[15];
   1558 }
   1559 
   1560 /**
   1561  * Transpose a GLdouble matrix and convert to GLfloat.
   1562  *
   1563  * \param to destination array.
   1564  * \param from source array.
   1565  */
   1566 void
   1567 _math_transposefd( GLfloat to[16], const GLdouble from[16] )
   1568 {
   1569    to[0] = (GLfloat) from[0];
   1570    to[1] = (GLfloat) from[4];
   1571    to[2] = (GLfloat) from[8];
   1572    to[3] = (GLfloat) from[12];
   1573    to[4] = (GLfloat) from[1];
   1574    to[5] = (GLfloat) from[5];
   1575    to[6] = (GLfloat) from[9];
   1576    to[7] = (GLfloat) from[13];
   1577    to[8] = (GLfloat) from[2];
   1578    to[9] = (GLfloat) from[6];
   1579    to[10] = (GLfloat) from[10];
   1580    to[11] = (GLfloat) from[14];
   1581    to[12] = (GLfloat) from[3];
   1582    to[13] = (GLfloat) from[7];
   1583    to[14] = (GLfloat) from[11];
   1584    to[15] = (GLfloat) from[15];
   1585 }
   1586 
   1587 /*@}*/
   1588 
   1589 
   1590 /**
   1591  * Transform a 4-element row vector (1x4 matrix) by a 4x4 matrix.  This
   1592  * function is used for transforming clipping plane equations and spotlight
   1593  * directions.
   1594  * Mathematically,  u = v * m.
   1595  * Input:  v - input vector
   1596  *         m - transformation matrix
   1597  * Output:  u - transformed vector
   1598  */
   1599 void
   1600 _mesa_transform_vector( GLfloat u[4], const GLfloat v[4], const GLfloat m[16] )
   1601 {
   1602    const GLfloat v0 = v[0], v1 = v[1], v2 = v[2], v3 = v[3];
   1603 #define M(row,col)  m[row + col*4]
   1604    u[0] = v0 * M(0,0) + v1 * M(1,0) + v2 * M(2,0) + v3 * M(3,0);
   1605    u[1] = v0 * M(0,1) + v1 * M(1,1) + v2 * M(2,1) + v3 * M(3,1);
   1606    u[2] = v0 * M(0,2) + v1 * M(1,2) + v2 * M(2,2) + v3 * M(3,2);
   1607    u[3] = v0 * M(0,3) + v1 * M(1,3) + v2 * M(2,3) + v3 * M(3,3);
   1608 #undef M
   1609 }
   1610