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- // SuperTux - Pulsing Light
- // Copyright (C) 2006 Christoph Sommer <christoph.sommer@2006.expires.deltadevelopment.de>
- //
- // This program 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.
- //
- // This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
- #include "object/pulsing_light.hpp"
- #include <assert.h>
- #include <math.h>
- #include "math/random.hpp"
- #include "math/util.hpp"
- PulsingLight::PulsingLight(const Vector& center, float cycle_len_, float min_alpha_, float max_alpha_, const Color& color_) :
- Light(center, color_),
- min_alpha(min_alpha_),
- max_alpha(max_alpha_),
- cycle_len(cycle_len_),
- t(0)
- {
- assert(cycle_len > 0);
- // start with random phase offset
- t = graphicsRandom.randf(0.0, cycle_len);
- }
- PulsingLight::~PulsingLight()
- {
- }
- void
- PulsingLight::update(float dt_sec)
- {
- Light::update(dt_sec);
- t += dt_sec;
- if (t > cycle_len) t -= cycle_len;
- }
- void
- PulsingLight::draw(DrawingContext& context)
- {
- Color old_color = color;
- color.alpha *= min_alpha + ((max_alpha - min_alpha) * cosf(math::TAU * t / cycle_len));
- Light::draw(context);
- color = old_color;
- }
- /* EOF */
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