diff options
Diffstat (limited to 'libdimension/geometry.c')
| -rw-r--r-- | libdimension/geometry.c | 46 |
1 files changed, 17 insertions, 29 deletions
diff --git a/libdimension/geometry.c b/libdimension/geometry.c index 6d3652f..9f198b8 100644 --- a/libdimension/geometry.c +++ b/libdimension/geometry.c @@ -18,6 +18,11 @@ * <http://www.gnu.org/licenses/>. * *************************************************************************/ +/** + * @file + * Geometrical function implementations. + */ + #include "dimension.h" #include <math.h> @@ -58,7 +63,7 @@ dmnsn_rotation_matrix(dmnsn_vector theta) /* Two trig calls, 25 multiplications, 13 additions */ double angle = dmnsn_vector_norm(theta); - if (angle == 0.0) { + if (fabs(angle) < dmnsn_epsilon) { return dmnsn_identity_matrix(); } dmnsn_vector axis = dmnsn_vector_div(theta, angle); @@ -88,14 +93,14 @@ dmnsn_vector_axis_angle(dmnsn_vector v1, dmnsn_vector v2, dmnsn_vector axis) dmnsn_vector proj = dmnsn_vector_add(dmnsn_vector_proj(d, axis), v2); double projn = dmnsn_vector_norm(proj); - if (!projn) + if (fabs(projn) < dmnsn_epsilon) return 0.0; double c = dmnsn_vector_dot(dmnsn_vector_normalize(v1), dmnsn_vector_div(proj, projn)); double angle = acos(c); - if (dmnsn_vector_dot(dmnsn_vector_cross(v1, proj), axis) > 0) { + if (dmnsn_vector_dot(dmnsn_vector_cross(v1, proj), axis) > 0.0) { return angle; } else { return -angle; @@ -104,16 +109,25 @@ dmnsn_vector_axis_angle(dmnsn_vector v1, dmnsn_vector v2, dmnsn_vector axis) /* Matrix inversion helper functions */ +/** A 2x2 matrix for inversion by partitioning. */ typedef struct { double n[2][2]; } dmnsn_matrix2; +/** Construct a 2x2 matrix. */ static dmnsn_matrix2 dmnsn_new_matrix2(double a1, double a2, double b1, double b2); +/** Invert a 2x2 matrix. */ static dmnsn_matrix2 dmnsn_matrix2_inverse(dmnsn_matrix2 A); +/** Negate a 2x2 matrix. */ static dmnsn_matrix2 dmnsn_matrix2_negate(dmnsn_matrix2 A); +/** Subtract two 2x2 matricies. */ static dmnsn_matrix2 dmnsn_matrix2_sub(dmnsn_matrix2 lhs, dmnsn_matrix2 rhs); +/** Add two 2x2 matricies. */ static dmnsn_matrix2 dmnsn_matrix2_mul(dmnsn_matrix2 lhs, dmnsn_matrix2 rhs); +/** Invert a matrix with the slower cofactor algorithm, if partitioning + failed. */ static dmnsn_matrix dmnsn_matrix_inverse_generic(dmnsn_matrix A); +/** Get the [\p row, \p col] cofactor of A */ static double dmnsn_matrix_cofactor(dmnsn_matrix A, unsigned int row, unsigned int col); @@ -395,29 +409,3 @@ dmnsn_transform_bounding_box(dmnsn_matrix trans, dmnsn_bounding_box box) return ret; } - -/* Solve for the t value such that x0 + t*n = x */ -double -dmnsn_line_index(dmnsn_line l, dmnsn_vector x) -{ - /* nz + 1 divisions, nz additions */ - double d = 0.0; - unsigned int nz = 0; - - if (l.n.x != 0.0) { - d += (x.x - l.x0.x)/l.n.x; - ++nz; - } - - if (l.n.y != 0.0) { - d += (x.y - l.x0.y)/l.n.y; - ++nz; - } - - if (l.n.z != 0.0) { - d += (x.z - l.x0.z)/l.n.z; - ++nz; - } - - return d/nz; -} |