1 // SuperTux - Pulsing Light
2 // Copyright (C) 2006 Christoph Sommer <christoph.sommer@2006.expires.deltadevelopment.de>
4 // This program is free software: you can redistribute it and/or modify
5 // it under the terms of the GNU General Public License as published by
6 // the Free Software Foundation, either version 3 of the License, or
7 // (at your option) any later version.
9 // This program is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License
15 // along with this program. If not, see <http://www.gnu.org/licenses/>.
17 #include "object/pulsing_light.hpp"
20 #include "math/random_generator.hpp"
22 PulsingLight::PulsingLight(const Vector& center, float cycle_len_, float min_alpha_, float max_alpha_, const Color& color_) :
23 Light(center, color_),
24 min_alpha(min_alpha_),
25 max_alpha(max_alpha_),
26 cycle_len(cycle_len_),
29 assert(cycle_len > 0);
31 // start with random phase offset
32 t = gameRandom.randf(0.0, cycle_len);
35 PulsingLight::~PulsingLight()
40 PulsingLight::update(float elapsed_time)
42 Light::update(elapsed_time);
45 if (t > cycle_len) t -= cycle_len;
49 PulsingLight::draw(DrawingContext& context)
51 Color old_color = color;
53 color.alpha *= min_alpha + ((max_alpha - min_alpha) * cos(2 * M_PI * t / cycle_len));