src/object/snow_particle_system.cpp

   1 //  SuperTux
   2 //  Copyright (C) 2006 Matthias Braun <matze@braunis.de>
   3 //
   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.
   8 //
   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.
  13 //
  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/>.
  16
  17 #include "object/snow_particle_system.hpp"
  18
  19 #include <math.h>
  20
  21 #include "math/random_generator.hpp"
  22 #include "supertux/globals.hpp"
  23 #include "video/drawing_context.hpp"
  24
  25 SnowParticleSystem::SnowParticleSystem()
  26 {
  27   snowimages[0] = Surface::create("images/objects/particles/snow2.png");
  28   snowimages[1] = Surface::create("images/objects/particles/snow1.png");
  29   snowimages[2] = Surface::create("images/objects/particles/snow0.png");
  30
  31   virtual_width = SCREEN_WIDTH * 2;
  32
  33   // create some random snowflakes
  34   size_t snowflakecount = size_t(virtual_width/10.0);
  35   for(size_t i=0; i<snowflakecount; ++i) {
  36     SnowParticle* particle = new SnowParticle;
  37     int snowsize = systemRandom.rand(3);
  38
  39     particle->pos.x = systemRandom.randf(virtual_width);
  40     particle->pos.y = systemRandom.randf(SCREEN_HEIGHT);
  41     particle->anchorx = particle->pos.x + (systemRandom.randf(-0.5, 0.5) * 16);
  42     particle->drift_speed = systemRandom.randf(-0.5, 0.5) * 0.3;
  43     particle->wobble = 0.0;
  44
  45     particle->texture = snowimages[snowsize];
  46
  47     particle->speed = 1 + (2 - snowsize)/2 + systemRandom.randf(1.8);
  48     particle->speed *= 20; // gravity
  49
  50     particles.push_back(particle);
  51   }
  52 }
  53
  54 void
  55 SnowParticleSystem::parse(const Reader& reader)
  56 {
  57   reader.get("z-pos", z_pos);
  58 }
  59
  60 SnowParticleSystem::~SnowParticleSystem()
  61 {
  62 }
  63
  64 void SnowParticleSystem::update(float elapsed_time)
  65 {
  66   std::vector<Particle*>::iterator i;
  67
  68   for(i = particles.begin(); i != particles.end(); ++i) {
  69     SnowParticle* particle = (SnowParticle*) *i;
  70     float anchor_delta;
  71
  72     particle->pos.y += particle->speed * elapsed_time;
  73     particle->pos.x += particle->wobble * elapsed_time /* * particle->speed * 0.125*/;
  74
  75     anchor_delta = (particle->anchorx - particle->pos.x);
  76     particle->wobble += (4 * anchor_delta * 0.05) + systemRandom.randf(-0.5, 0.5);
  77     particle->wobble *= 0.99f;
  78     particle->anchorx += particle->drift_speed * elapsed_time;
  79   }
  80 }
  81
  82 /* EOF */