mat.c File Reference

4 x 4 Matrix manipulation functions... More...

#include "common.h"
#include <stdio.h>
#include <math.h>
#include <strings.h>
#include "machine.h"
#include "bu.h"
#include "vmath.h"
#include "bn.h"

Include dependency graph for mat.c:

Go to the source code of this file.

Functions

void bn_mat_print_guts (const char *title, const mat_t m, char *obuf)

void bn_mat_print (const char *title, const mat_t m)

double bn_atan2 (double y, double x)

A wrapper for the system atan2(). On the Silicon Graphics, and perhaps on others, x==0 incorrectly returns infinity.

void bn_mat_mul (register mat_t o, register const mat_t a, register const mat_t b)

Multiply matrix "a" by "b" and store the result in "o". NOTE: This is different from multiplying "b" by "a" (most of the time!) NOTE: "o" must not be the same as either of the inputs.

void bn_mat_mul2 (register const mat_t i, register mat_t o)

A convenience wrapper for bn_mat_mul() to update a matrix in place. The arugment ordering is confusing either way.

void bn_mat_mul3 (mat_t o, const mat_t a, const mat_t b, const mat_t c)

void bn_mat_mul4 (mat_t ao, const mat_t a, const mat_t b, const mat_t c, const mat_t d)

void bn_matXvec (register vect_t ov, register const mat_t im, register const vect_t iv)

Multiply the matrix "im" by the vector "iv" and store the result in the vector "ov". Note this is post-multiply, and operates on 4-tuples. Use MAT4X3VEC() to operate on 3-tuples.

void bn_mat_inv (register mat_t output, const mat_t input)

int bn_mat_inverse (register mat_t output, const mat_t input)

void bn_htov_move (register vect_t v, register const vect_t h)

void bn_mat_trn (mat_t om, register const mat_t im)

void bn_mat_ae (register fastf_t *m, double azimuth, double elev)

void bn_ae_vec (fastf_t *azp, fastf_t *elp, const vect_t v)

void bn_aet_vec (fastf_t *az, fastf_t *el, fastf_t *twist, fastf_t *vec_ae, fastf_t *vec_twist, fastf_t accuracy)

Find the azimuth, elevation, and twist from two vectors. Vec_ae is in the direction of view (+z in mged view) and vec_twist points to the viewers right (+x in mged view). Accuracy (degrees) is used to stabilze flutter between equivalent extremes of atan2(), and to snap twist to zero when elevation is near +/- 90.

void bn_mat_angles (register fastf_t *mat, double alpha_in, double beta_in, double ggamma_in)

void bn_mat_angles_rad (register mat_t mat, double alpha, double beta, double ggamma)

This routine builds a Homogeneous rotation matrix, given alpha, beta, and gamma as angles of rotation, in radians.

void bn_eigen2x2 (fastf_t *val1, fastf_t *val2, fastf_t *vec1, fastf_t *vec2, fastf_t a, fastf_t b, fastf_t c)

void bn_vec_perp (vect_t new, const vect_t old)

Given a vector, create another vector which is perpendicular to it. The output vector will have unit length only if the input vector did.

void bn_mat_fromto (mat_t m, const vect_t from, const vect_t to)

Given two vectors, compute a rotation matrix that will transform space by the angle between the two. There are many candidate matricies.

void bn_mat_xrot (fastf_t *m, double sinx, double cosx)

void bn_mat_yrot (fastf_t *m, double siny, double cosy)

Given the sin and cos of a Y rotation angle, produce the rotation matrix.

void bn_mat_zrot (fastf_t *m, double sinz, double cosz)

Given the sin and cos of a Z rotation angle, produce the rotation matrix.

void bn_mat_lookat (mat_t rot, const vect_t dir, int yflip)

void bn_vec_ortho (register vect_t out, register const vect_t in)

Given a vector, create another vector which is perpendicular to it, and with unit length. This algorithm taken from Gift's arvec.f; a faster algorithm may be possible.

int bn_mat_scale_about_pt (mat_t mat, const point_t pt, const double scale)

Build a matrix to scale uniformly around a given point.

void bn_mat_xform_about_pt (mat_t mat, const mat_t xform, const point_t pt)

Build a matrix to apply arbitary 4x4 transformation around a given point.

int bn_mat_is_equal (const mat_t a, const mat_t b, const struct bn_tol *tol)

int bn_mat_is_identity (const mat_t m)

void bn_mat_arb_rot (mat_t m, const point_t pt, const vect_t dir, const fastf_t ang)

Construct a transformation matrix for rotation about an arbitrary axis.

matp_t bn_mat_dup (const mat_t in)

int bn_mat_ck (const char *title, const mat_t m)

fastf_t bn_mat_det3 (const mat_t m)

fastf_t bn_mat_determinant (const mat_t m)

int bn_mat_is_non_unif (const mat_t m)

Variables

const mat_t bn_mat_identity

Detailed Description

4 x 4 Matrix manipulation functions...

bn_atan2() Wrapper for library atan2()
(deprecated) bn_mat_zero( &m ) Fill matrix m with zeros
(deprecated) bn_mat_idn( &m ) Fill matrix m with identity matrix
(deprecated) bn_mat_copy( &o, &i ) Copy matrix i to matrix o
bn_mat_mul( &o, &i1, &i2 ) Multiply i1 by i2 and store in o
bn_mat_mul2( &i, &o )
bn_matXvec( &ov, &m, &iv ) Multiply m by vector iv, store in ov
bn_mat_inv( &om, &im ) Invert matrix im, store result in om
bn_mat_print( &title, &m ) Print matrix (with title) on stderr.
bn_mat_trn( &o, &i ) Transpose matrix i into matrix o
bn_mat_ae( &o, azimuth, elev) Make rot matrix from azimuth+elevation
bn_ae_vec( &az, &el, v ) Find az/elev from dir vector
bn_aet_vec( &az, &el, &twist, v1, v2 ) Find az,el,twist from two vectors
bn_mat_angles( &o, alpha, beta, gama ) Make rot matrix from angles
bn_eigen2x2() Eigen values and vectors
bn_mat_lookat Make rot mat: xform from D to -Z
bn_mat_fromto Make rot mat: xform from A to
bn_mat_arb_rot( &m, pt, dir, ang) Make rot mat about axis (pt,dir), through ang
bn_mat_is_equal() Is mat a equal to mat b?

Matrix array elements have the following positions in the matrix:

                                |  0  1  2  3 |         | 0 |
          [ 0 1 2 3 ]           |  4  5  6  7 |         | 1 |
                                |  8  9 10 11 |         | 2 |
                                | 12 13 14 15 |         | 3 |

preVector (vect_t) Matrix (mat_t) postVector (vect_t)

Author:

Robert S. Miles

Michael John Muuss

Lee A. Butler

Source: The U. S. Army Research Laboratory
Aberdeen Proving Ground, Maryland 21005-5068 USA

Definition in file mat.c.

Function Documentation

void bn_mat_print_guts ( const char * title,

const mat_t m,

char * obuf

)

Definition at line 105 of file mat.c.
Referenced by bn_mat_print(), and bn_tcl_mat_print().

void bn_mat_print ( const char * title,

const mat_t m

)

B N _ M A T _ P R I N T
Definition at line 136 of file mat.c.
References bn_mat_print_guts(), and bu_log().
Referenced by bn_mat_ck(), bn_mat_inv(), db_do_anim(), db_shader_mat(), nmg_flatten_face(), rt_dsp_shot(), rt_ehy_print(), rt_ell_print(), rt_epa_print(), rt_eto_print(), rt_part_print(), rt_rec_print(), rt_rhc_print(), rt_rpc_print(), rt_sph_print(), rt_submodel_import(), rt_submodel_import5(), rt_submodel_print(), rt_tgc_print(), and rt_tor_print().
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double bn_atan2 ( double y,

double x

)

A wrapper for the system atan2(). On the Silicon Graphics, and perhaps on others, x==0 incorrectly returns infinity.
B N _ A T A N 2
Definition at line 152 of file mat.c.
Referenced by bn_ae_vec(), bn_aet_vec(), rt_ell_uv(), rt_part_uv(), and rt_sph_uv().

void bn_mat_mul ( register mat_t o,

register const mat_t a,

register const mat_t b

)

Multiply matrix "a" by "b" and store the result in "o". NOTE: This is different from multiplying "b" by "a" (most of the time!) NOTE: "o" must not be the same as either of the inputs.
B N _ M A T _ M U L
Definition at line 227 of file mat.c.
Referenced by bn_mat_arb_rot(), bn_mat_fromto(), bn_mat_lookat(), bn_mat_mul2(), bn_mat_mul3(), bn_mat_mul4(), bn_mat_scale_about_pt(), bn_mat_xform_about_pt(), bn_math_cmd(), bn_vlist_3string(), db_apply_state_from_memb(), db_do_anim(), db_follow_path(), db_shader_mat(), db_tree_mul_dbleaf(), Do_copy_membs(), rt_comb_import5(), rt_ebm_import(), rt_ebm_import5(), rt_ehy_curve(), rt_ehy_prep(), rt_ehy_tess(), rt_ell_prep(), rt_ell_tess(), rt_ell_tnurb(), rt_epa_curve(), rt_epa_prep(), rt_linear_pipe_prep(), rt_part_prep(), rt_part_tess(), rt_rec_prep(), rt_rhc_prep(), rt_rpc_prep(), rt_superell_prep(), rt_tgc_curve(), rt_tgc_prep(), rt_tgc_tnurb(), rt_vol_import(), rt_vol_import5(), tp_3axis(), tp_3symbol(), vo_rot(), vo_update(), wdb_ocenter_cmd(), wdb_orotate_cmd(), wdb_oscale_cmd(), and wdb_otranslate_cmd().

void bn_mat_mul2 ( register const mat_t i,

register mat_t o

)

A convenience wrapper for bn_mat_mul() to update a matrix in place. The arugment ordering is confusing either way.
B N _ M A T _ M U L 2
o = i * o
Definition at line 260 of file mat.c.
References bn_mat_mul(), and MAT_COPY.
Referenced by bn_mat_arb_rot(), vo_mat_aet(), and vo_rot().
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void bn_mat_mul3 ( mat_t o,

const mat_t a,

const mat_t b,

const mat_t c

)

B N _ M A T _ M U L 3
o = a * b * c
The output matrix may be the same as 'b' or 'c', but may not be 'a'.
Definition at line 276 of file mat.c.
References bn_mat_mul().
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void bn_mat_mul4 ( mat_t ao,

const mat_t a,

const mat_t b,

const mat_t c,

const mat_t d

)

B N _ M A T _ M U L 4
o = a * b * c * d
The output matrix may be the same as any input matrix.
Definition at line 292 of file mat.c.
References bn_mat_mul().
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void bn_matXvec ( register vect_t ov,

register const mat_t im,

register const vect_t iv

)

Multiply the matrix "im" by the vector "iv" and store the result in the vector "ov". Note this is post-multiply, and operates on 4-tuples. Use MAT4X3VEC() to operate on 3-tuples.
B N _ M A T X V E C
Definition at line 309 of file mat.c.

void bn_mat_inv ( register mat_t output,

const mat_t input

)

B N _ M A T _ I N V
The matrix pointed at by "input" is inverted and stored in the area pointed at by "output".
Calls bu_bomb if matrix is singular.
Definition at line 335 of file mat.c.
References bn_mat_inverse(), bn_mat_print(), bu_bomb(), and bu_log().
Referenced by bn_math_cmd(), db_region_mat(), nmg_snurb_is_planar(), rt_dsp_import5(), rt_ebm_prep(), rt_ell_tess(), rt_ell_tnurb(), rt_eto_prep(), rt_extrude_prep(), rt_hf_to_dsp(), rt_part_tess(), rt_submodel_prep(), rt_tor_prep(), rt_vol_prep(), vo_mrotPoint_cmd(), vo_rot(), vo_update(), vo_viewDir_cmd(), wdb_ocenter_cmd(), wdb_orotate_cmd(), wdb_oscale_cmd(), and wdb_otranslate_cmd().
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int bn_mat_inverse ( register mat_t output,

const mat_t input

)

B N _ M A T _ I N V E R S E
The matrix pointed at by "input" is inverted and stored in the area pointed at by "output".
Invert a 4-by-4 matrix using Algorithm 120 from ACM. This is a modified Gauss-Jordan alogorithm Note: Inversion is done in place, with 3 work vectors

Returns:
1 if OK.
0 if matrix is singular.

Definition at line 361 of file mat.c.
References FAST, LOCAL, and MAT_COPY.
Referenced by bn_mat_inv(), and rt_bend_pipe_prep().

void bn_htov_move ( register vect_t v,

register const vect_t h

)

B N _ H T O V _ M O V E
Takes a pointer to [x,y,z,w], and converts it to an ordinary vector [x/w, y/w, z/w]. Optimization for the case of w==1 is performed.
Definition at line 466 of file mat.c.
References bu_log(), SMALL_FASTF, W, X, Y, and Z.
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void bn_mat_trn ( mat_t om,

register const mat_t im

)

B N _ M A T _ T R N
Definition at line 491 of file mat.c.
Referenced by bn_mat_fromto(), bn_math_cmd(), rt_ehy_plot(), rt_ehy_prep(), rt_ehy_tess(), rt_ell_prep(), rt_ell_tess(), rt_ell_tnurb(), rt_epa_plot(), rt_epa_prep(), rt_epa_tess(), rt_linear_pipe_prep(), rt_part_prep(), rt_part_tess(), rt_rec_prep(), rt_rhc_plot(), rt_rhc_prep(), rt_rhc_tess(), rt_rpc_plot(), rt_rpc_prep(), rt_rpc_tess(), and rt_superell_prep().

void bn_mat_ae ( register fastf_t * m,

double azimuth,

double elev

)

B N _ M A T _ A E
Compute a 4x4 rotation matrix given Azimuth and Elevation.
Azimuth is +X, Elevation is +Z, both in degrees.
Formula due to Doug Gwyn, BRL.
Definition at line 526 of file mat.c.
References bn_degtorad, and LOCAL.

void bn_ae_vec ( fastf_t * azp,

fastf_t * elp,

const vect_t v

)

B N _ A E _ V E C
Find the azimuth and elevation angles that correspond to the direction (not including twist) given by a direction vector.
Definition at line 565 of file mat.c.
References bn_atan2(), bn_radtodeg, X, Y, and Z.
Referenced by bn_aet_vec(), bn_math_cmd(), db_tree_describe(), db_tree_flatten_describe(), and vo_lookat_cmd().
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void bn_aet_vec ( fastf_t * az,

fastf_t * el,

fastf_t * twist,

fastf_t * vec_ae,

fastf_t * vec_twist,

fastf_t accuracy

)

Find the azimuth, elevation, and twist from two vectors. Vec_ae is in the direction of view (+z in mged view) and vec_twist points to the viewers right (+x in mged view). Accuracy (degrees) is used to stabilze flutter between equivalent extremes of atan2(), and to snap twist to zero when elevation is near +/- 90.
B N _ A E T _ V E C
Definition at line 589 of file mat.c.
References bn_ae_vec(), bn_atan2(), bn_radtodeg, NEAR_ZERO, VCROSS, VDOT, VSET, VUNITIZE, X, and Y.
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void bn_mat_angles ( register fastf_t * mat,

double alpha_in,

double beta_in,

double ggamma_in

)

B N _ M A T _ A N G L E S
This routine builds a Homogeneous rotation matrix, given alpha, beta, and gamma as angles of rotation, in degrees.
Alpha is angle of rotation about the X axis, and is done third. Beta is angle of rotation about the Y axis, and is done second. Gamma is angle of rotation about Z axis, and is done first.
Definition at line 637 of file mat.c.
References bn_degtorad, LOCAL, and MAT_IDN.

void bn_mat_angles_rad ( register mat_t mat,

double alpha,

double beta,

double ggamma

)

This routine builds a Homogeneous rotation matrix, given alpha, beta, and gamma as angles of rotation, in radians.
B N _ M A T _ A N G L E S _ R A D
Alpha is angle of rotation about the X axis, and is done third. Beta is angle of rotation about the Y axis, and is done second. Gamma is angle of rotation about Z axis, and is done first.
Definition at line 705 of file mat.c.
References LOCAL, and MAT_IDN.

void bn_eigen2x2 ( fastf_t * val1,

fastf_t * val2,

fastf_t * vec1,

fastf_t * vec2,

fastf_t a,

fastf_t b,

fastf_t c

)

B N _ E I G E N 2 X 2
Find the eigenvalues and eigenvectors of a symmetric 2x2 matrix. ( a b ) ( b c )
The eigenvalue with the smallest absolute value is returned in val1, with its eigenvector in vec1.
Definition at line 756 of file mat.c.
References NEAR_ZERO, VSET, VUNITIZE, X, and Y.

void bn_vec_perp ( vect_t new,

const vect_t old

)

Given a vector, create another vector which is perpendicular to it. The output vector will have unit length only if the input vector did.
B N _ V E C _ P E R P
Definition at line 805 of file mat.c.
References LOCAL, VCROSS, VMOVE, VSETALL, X, Y, and Z.
Referenced by bn_mat_fromto(), bn_math_cmd(), nmg_eu_2vecs_perp(), nmg_to_tgc(), rt_grp_plot(), rt_hlf_plot(), and rt_hlf_prep().

void bn_mat_fromto ( mat_t m,

const vect_t from,

const vect_t to

)

Given two vectors, compute a rotation matrix that will transform space by the angle between the two. There are many candidate matricies.
B N _ M A T _ F R O M T O
The input 'from' and 'to' vectors need not be unit length. MAT4X3VEC( to, m, from ) is the identity that is created.
Definition at line 833 of file mat.c.
References A, bn_mat_mul(), bn_mat_trn(), bn_vec_perp(), bu_log(), M, MAT4X3VEC, MAT_IDN, Q, R, V3ARGS, VCROSS, VDOT, VMOVE, VSET, VUNITIZE, X, Y, and Z.
Referenced by bn_math_cmd(), nmg_flatten_face(), nmg_isect2d_prep(), rt_extrude_prep(), and rt_part_tess().
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void bn_mat_xrot ( fastf_t * m,

double sinx,

double cosx

)

B N _ M A T _ X R O T
Given the sin and cos of an X rotation angle, produce the rotation matrix.
Definition at line 912 of file mat.c.

void bn_mat_yrot ( fastf_t * m,

double siny,

double cosy

)

Given the sin and cos of a Y rotation angle, produce the rotation matrix.
B N _ M A T _ Y R O T
Definition at line 939 of file mat.c.

void bn_mat_zrot ( fastf_t * m,

double sinz,

double cosz

)

Given the sin and cos of a Z rotation angle, produce the rotation matrix.
B N _ M A T _ Z R O T
Definition at line 966 of file mat.c.

void bn_mat_lookat ( mat_t rot,

const vect_t dir,

int yflip

)

B N _ M A T _ L O O K A T
Given a direction vector D of unit length, product a matrix which rotates that vector D onto the -Z axis. This matrix will be suitable for use as a "model2view" matrix.
XXX This routine will fail if the vector is already more or less aligned with the Z axis.
This is done in several steps.
1) Rotate D about Z to match +X axis. Azimuth adjustment. 2) Rotate D about Y to match -Y axis. Elevation adjustment. 3) Rotate D about Z to make projection of X axis again point in the +X direction. Twist adjustment. 4) Optionally, flip sign on Y axis if original Z becomes inverted. This can be nice for static frames, but is astonishing when used in animation.

Definition at line 1010 of file mat.c.
References bn_mat_mul(), bn_mat_yrot(), bn_mat_zrot(), bu_log(), MAT4X3VEC, MAT_COPY, MAT_IDN, VPRINT, VSET, X, Y, and Z.
Referenced by bn_math_cmd().
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void bn_vec_ortho ( register vect_t out,

register const vect_t in

)

Given a vector, create another vector which is perpendicular to it, and with unit length. This algorithm taken from Gift's arvec.f; a faster algorithm may be possible.
B N _ V E C _ O R T H O
Definition at line 1071 of file mat.c.
References FAST, NEAR_ZERO, SMALL, VPRINT, VSETALL, X, Y, and Z.
Referenced by bn_isect_line3_line3(), bn_math_cmd(), classify_seg(), isect_ray_snurb_face(), rt_arb_curve(), rt_arbn_curve(), rt_ars_curve(), rt_bot_curve(), rt_cline_curve(), rt_cline_plot(), rt_cline_tess(), rt_dsp_curve(), rt_ebm_curve(), rt_ehy_curve(), rt_ell_curve(), rt_epa_curve(), rt_eto_plot(), rt_eto_prep(), rt_eto_tess(), rt_hf_curve(), rt_hlf_curve(), rt_linear_pipe_prep(), rt_nmg_curve(), rt_nurb_curve(), rt_nurb_shot(), rt_part_curve(), rt_part_prep(), rt_pg_curve(), rt_pipe_curve(), rt_pipe_plot(), rt_rec_curve(), rt_rhc_curve(), rt_rpc_curve(), rt_sketch_curve(), rt_sph_curve(), rt_submodel_curve(), rt_tgc_curve(), rt_tor_export(), rt_tor_import5(), rt_vol_curve(), rt_xxx_curve(), tesselate_pipe_start(), and tp_3vector().

int bn_mat_scale_about_pt ( mat_t mat,

const point_t pt,

const double scale

)

Build a matrix to scale uniformly around a given point.
B N _ M A T _ S C A L E _ A B O U T _ P T

Returns:
-1 if scale is too small.
0 if OK.

Definition at line 1123 of file mat.c.
References bn_mat_mul(), MAT_DELTAS_VEC, MAT_DELTAS_VEC_NEG, MAT_IDN, MAT_ZERO, NEAR_ZERO, and SMALL.
Referenced by bn_mat_scale_about_pt_wrapper(), db_parse_1anim(), and wdb_oscale_cmd().
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void bn_mat_xform_about_pt ( mat_t mat,

const mat_t xform,

const point_t pt

)

Build a matrix to apply arbitary 4x4 transformation around a given point.
B N _ M A T _ X F O R M _ A B O U T _ P T
Definition at line 1152 of file mat.c.
References bn_mat_mul(), MAT_DELTAS_VEC, MAT_DELTAS_VEC_NEG, and MAT_IDN.
Referenced by bn_math_cmd(), vo_rot(), and wdb_orotate_cmd().
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int bn_mat_is_equal ( const mat_t a,

const mat_t b,

const struct bn_tol * tol

)

B N _ M A T _ I S _ E Q U A L

Returns:
0 When matrices are not equal
1 When matricies are equal

Definition at line 1174 of file mat.c.
References BN_CK_TOL, bn_tol::dist, NEAR_ZERO, and bn_tol::perp.
Referenced by rt_find_identical_solid(), rt_gettree_leaf(), and shoot_and_plot().

int bn_mat_is_identity ( const mat_t m )

B N _ M A T _ I S _ I D E N T I T Y
This routine is intended for detecting identity matricies read in from ascii or binary files, where the numbers are pure ones or zeros. This routine is *not* intended for tolerance-based "near-zero" comparisons; as such, it shouldn't be used on matrices which are the result of calculation.

Returns:
0 non-identity
1 a perfect identity matrix

Definition at line 1234 of file mat.c.
References bn_mat_identity.
Referenced by db_tcl_tree_parse(), db_tree_counter(), rt_arbn_import5(), rt_comb_import5(), and rt_comb_v5_serialize().

void bn_mat_arb_rot ( mat_t m,

const point_t pt,

const vect_t dir,

const fastf_t ang

)

Construct a transformation matrix for rotation about an arbitrary axis.
B N _ M A T _ A R B _ R O T
The axis is defined by a point (pt) and a unit direction vector (dir). The angle of rotation is "ang"
Definition at line 1248 of file mat.c.
References bn_mat_mul(), bn_mat_mul2(), MAT_IDN, MDX, MDY, MDZ, X, Y, and Z.
Referenced by bn_math_cmd(), draw_pipe_bend(), tesselate_pipe_bend(), and vo_arot_cmd().
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matp_t bn_mat_dup ( const mat_t in )

B N _ M A T _ D U P
Return a pointer to a copy of the matrix in dynamically allocated memory.
Definition at line 1309 of file mat.c.
References bcopy, and bu_malloc().
Referenced by db_dup_subtree(), db_tcl_tree_parse(), db_tree_mul_dbleaf(), and rt_comb_import5().
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int bn_mat_ck ( const char * title,

const mat_t m

)

B N _ M A T _ C K
Check to ensure that a rotation matrix preserves axis perpendicularily. Note that not all matricies are rotation matricies.

Returns:
-1 FAIL
0 OK

Definition at line 1329 of file mat.c.
References A, bn_mat_print(), bu_bomb(), bu_debug, BU_DEBUG_COREDUMP, BU_DEBUG_MATH, bu_log(), MAT4X3VEC, NEAR_ZERO, VDIVIDE_TOL, VDOT, and VMOVE.
Referenced by db_recurse(), and db_tcl_tree_parse().
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fastf_t bn_mat_det3 ( const mat_t m )

B N _ M A T _ D E T 3
Calculates the determinant of the 3X3 "rotation" part of the passed matrix
Definition at line 1378 of file mat.c.
References FAST.

fastf_t bn_mat_determinant ( const mat_t m )

B N _ M A T _ D E T E R M I N A N T
Calculates the determinant of the 4X4 matrix
Definition at line 1396 of file mat.c.
Referenced by nmg_snurb_is_planar().

int bn_mat_is_non_unif ( const mat_t m )

Definition at line 1427 of file mat.c.
References MAGSQ.
Referenced by rt_tor_import5().

Variable Documentation

const mat_t bn_mat_identity

Initial value:
{ 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0 }

Definition at line 94 of file mat.c.
Referenced by bn_mat_is_identity(), db_tree_describe(), db_tree_flatten_describe(), rt_comb_export4(), rt_db_external5_to_internal5(), rt_db_get_internal(), rt_extrude_import(), rt_extrude_import5(), rt_gettree_leaf(), shoot_and_plot(), wdb_nmg_simplify_cmd(), and wdb_shells_cmd().

Generated on Mon Sep 18 01:25:03 2006 for BRL-CAD by

1.4.6


Functions
void	bn_mat_print_guts (const char title, const mat_t m, char obuf)
void	bn_mat_print (const char *title, const mat_t m)
double	bn_atan2 (double y, double x)
	A wrapper for the system atan2(). On the Silicon Graphics, and perhaps on others, x==0 incorrectly returns infinity.
void	bn_mat_mul (register mat_t o, register const mat_t a, register const mat_t b)
	Multiply matrix "a" by "b" and store the result in "o". NOTE: This is different from multiplying "b" by "a" (most of the time!) NOTE: "o" must not be the same as either of the inputs.
void	bn_mat_mul2 (register const mat_t i, register mat_t o)
	A convenience wrapper for bn_mat_mul() to update a matrix in place. The arugment ordering is confusing either way.
void	bn_mat_mul3 (mat_t o, const mat_t a, const mat_t b, const mat_t c)
void	bn_mat_mul4 (mat_t ao, const mat_t a, const mat_t b, const mat_t c, const mat_t d)
void	bn_matXvec (register vect_t ov, register const mat_t im, register const vect_t iv)
	Multiply the matrix "im" by the vector "iv" and store the result in the vector "ov". Note this is post-multiply, and operates on 4-tuples. Use MAT4X3VEC() to operate on 3-tuples.
void	bn_mat_inv (register mat_t output, const mat_t input)
int	bn_mat_inverse (register mat_t output, const mat_t input)
void	bn_htov_move (register vect_t v, register const vect_t h)
void	bn_mat_trn (mat_t om, register const mat_t im)
void	bn_mat_ae (register fastf_t *m, double azimuth, double elev)
void	bn_ae_vec (fastf_t azp, fastf_t elp, const vect_t v)
void	bn_aet_vec (fastf_t az, fastf_t el, fastf_t twist, fastf_t vec_ae, fastf_t *vec_twist, fastf_t accuracy)
	Find the azimuth, elevation, and twist from two vectors. Vec_ae is in the direction of view (+z in mged view) and vec_twist points to the viewers right (+x in mged view). Accuracy (degrees) is used to stabilze flutter between equivalent extremes of atan2(), and to snap twist to zero when elevation is near +/- 90.
void	bn_mat_angles (register fastf_t *mat, double alpha_in, double beta_in, double ggamma_in)
void	bn_mat_angles_rad (register mat_t mat, double alpha, double beta, double ggamma)
	This routine builds a Homogeneous rotation matrix, given alpha, beta, and gamma as angles of rotation, in radians.
void	bn_eigen2x2 (fastf_t val1, fastf_t val2, fastf_t vec1, fastf_t vec2, fastf_t a, fastf_t b, fastf_t c)
void	bn_vec_perp (vect_t new, const vect_t old)
	Given a vector, create another vector which is perpendicular to it. The output vector will have unit length only if the input vector did.
void	bn_mat_fromto (mat_t m, const vect_t from, const vect_t to)
	Given two vectors, compute a rotation matrix that will transform space by the angle between the two. There are many candidate matricies.
void	bn_mat_xrot (fastf_t *m, double sinx, double cosx)
void	bn_mat_yrot (fastf_t *m, double siny, double cosy)
	Given the sin and cos of a Y rotation angle, produce the rotation matrix.
void	bn_mat_zrot (fastf_t *m, double sinz, double cosz)
	Given the sin and cos of a Z rotation angle, produce the rotation matrix.
void	bn_mat_lookat (mat_t rot, const vect_t dir, int yflip)
void	bn_vec_ortho (register vect_t out, register const vect_t in)
	Given a vector, create another vector which is perpendicular to it, and with unit length. This algorithm taken from Gift's arvec.f; a faster algorithm may be possible.
int	bn_mat_scale_about_pt (mat_t mat, const point_t pt, const double scale)
	Build a matrix to scale uniformly around a given point.
void	bn_mat_xform_about_pt (mat_t mat, const mat_t xform, const point_t pt)
	Build a matrix to apply arbitary 4x4 transformation around a given point.
int	bn_mat_is_equal (const mat_t a, const mat_t b, const struct bn_tol *tol)
int	bn_mat_is_identity (const mat_t m)
void	bn_mat_arb_rot (mat_t m, const point_t pt, const vect_t dir, const fastf_t ang)
	Construct a transformation matrix for rotation about an arbitrary axis.
matp_t	bn_mat_dup (const mat_t in)
int	bn_mat_ck (const char *title, const mat_t m)
fastf_t	bn_mat_det3 (const mat_t m)
fastf_t	bn_mat_determinant (const mat_t m)
int	bn_mat_is_non_unif (const mat_t m)
Variables
const mat_t	bn_mat_identity