src/cave/particle.cpp

   1 /*
   2  * Copyright (c) 2007-2013, Czirkos Zoltan http://code.google.com/p/gdash/
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <glib.h>
  18
  19 #include "cave/particle.hpp"
  20
  21 ParticleSet::ParticleSet(int count, float size, float opacity, float p0x, float p0y, float dp0x, float dp0y, float v0x, float v0y, float dvx, float dvy, const GdColor &color)
  22   : color(color)
  23   , life(1000)
  24   , is_new(true)
  25   , size(size)
  26   , opacity(opacity)
  27   , particles(count) {
  28     for (size_t i = 0; i < particles.size(); ++i) {
  29         Particle &p = particles[i];
  30         p.px = p0x + g_random_double_range(-dp0x, dp0x);
  31         p.py = p0y + g_random_double_range(-dp0y, dp0y);
  32         p.vx = v0x + g_random_double_range(-dvx, dvx);
  33         p.vy = v0y + g_random_double_range(-dvy, dvy);
  34     }
  35 }
  36
  37
  38 void ParticleSet::move(int dt_ms) {
  39     float dt = dt_ms/1000.0;
  40
  41     for (size_t i = 0; i < particles.size(); ++i) {
  42         Particle &p = particles[i];
  43         p.px += p.vx * dt;
  44         p.py += p.vy * dt;
  45     }
  46
  47     life -= dt_ms;
  48 }
  49
  50
  51 void ParticleSet::normalize(double factor) {
  52     if (!is_new)
  53         return;
  54     is_new = false;
  55
  56     size *= factor;
  57     for (size_t i = 0; i < particles.size(); ++i) {
  58         Particle &p = particles[i];
  59         p.px *= factor;
  60         p.py *= factor;
  61         p.vx *= factor;
  62         p.vy *= factor;
  63     }
  64 }