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view scripts/plot/appearance/specular.m @ 21546:f7f97d7e9294
doc: Wrap m-file docstrings to 79 characters + newline (80 total).
* isrecording.m, soundsc.m, delaunay3.m, cell2mat.m, cumtrapz.m, del2.m,
inputParser.m, interp1.m, interp3.m, narginchk.m, profile.m,
validateattributes.m, delaunayn.m, tsearchn.m, voronoin.m, brighten.m,
cmunique.m, colorcube.m, imfinfo.m, imshow.m, edit.m, orderfields.m, run.m,
warning_ids.m, ode23.m, ode45.m, odeget.m, integrate_adaptive.m, kahan.m,
ode_struct_value_check.m, runge_kutta_23.m, fminunc.m, fsolve.m, fzero.m,
pkg.m, build.m, specular.m, view.m, bar.m, barh.m, contour3.m, isosurface.m,
line.m, pie.m, pie3.m, quiver3.m, scatter.m, scatter3.m, stem3.m, stemleaf.m,
surfl.m, tetramesh.m, isfigure.m, mkpp.m, pchip.m, residue.m, splinefit.m,
rmpref.m, unique.m, eigs.m, ilu.m, factor.m, factorial.m, gallery.m, hankel.m,
histc.m, ols.m, finv.m, fpdf.m, kruskal_wallis_test.m, weekday.m:
Wrap m-file docstrings to 79 characters + newline (80 total).
author | Rik <rik@octave.org> |
---|---|
date | Sun, 27 Mar 2016 15:50:01 -0700 |
parents | 516bb87ea72e |
children | bac0d6f07a3e |
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## Copyright (C) 2009-2015 Kai Habel ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {} {} specular (@var{sx}, @var{sy}, @var{sz}, @var{lv}, @var{vv}) ## @deftypefnx {} {} specular (@var{sx}, @var{sy}, @var{sz}, @var{lv}, @var{vv}, @var{se}) ## Calculate the specular reflection strength of a surface defined by the ## normal vector elements @var{sx}, @var{sy}, @var{sz} using Phong's ## approximation. ## ## The light source location and viewer location vectors are specified using ## parameters @var{lv} and @var{vv} respectively. The location vectors can ## given as 2-element vectors [azimuth, elevation] in degrees or as 3-element ## vectors [x, y, z]. ## ## An optional sixth argument specifies the specular exponent (spread) ## @var{se}. If not given, @var{se} defaults to 10. ## @seealso{diffuse, surfl} ## @end deftypefn ## Author: Kai Habel <kai.habel@gmx.de> function retval = specular (sx, sy, sz, lv, vv, se) if (nargin < 5 || nargin > 6) print_usage (); endif ## Check normal vectors if (! size_equal (sx, sy, sz)) error ("specular: SX, SY, and SZ must be the same size"); endif ## Check light vector (lv) argument if (! isvector (lv) || length (lv) < 2 || length (lv) > 3) error ("specular: light vector LV must be a 2- or 3-element vector"); elseif (length (lv) == 2) [lv(1), lv(2), lv(3)] = sph2cart (lv(1) * pi/180, lv(2) * pi/180, 1.0); endif ## Check view vector (vv) argument if (! isvector (vv) || length (vv) < 2 || length (lv) > 3) error ("specular: view vector VV must be a 2- or 3-element vector"); elseif (length (vv) == 2) [vv(1), vv(2), vv(3)] = sph2cart (vv(1) * pi / 180, vv(2) * pi / 180, 1.0); endif ## Check specular exponent (se) argument if (nargin < 6) se = 10; elseif (! (isnumeric (se) && numel (se) == 1 && se > 0)) error ("specular: exponent SE must be a positive scalar"); endif ## Normalize view and light vectors if (sum (abs (lv)) > 0) lv /= norm (lv); endif if (sum (abs (vv)) > 0) vv /= norm (vv); endif ## Calculate normal vector lengths and dot-products ns = sqrt (sx.^2 + sy.^2 + sz.^2); l_dot_n = (sx * lv(1) + sy * lv(2) + sz * lv(3)) ./ ns; v_dot_n = (sx * vv(1) + sy * vv(2) + sz * vv(3)) ./ ns; ## Calculate specular reflection using Phong's approximation retval = 2 * l_dot_n .* v_dot_n - dot (lv, vv); ## Set reflectance to zero if light is on the other side retval(l_dot_n < 0) = 0; ## Allow postive values only retval(retval < 0) = 0; retval .^= se; endfunction