starfield.cpp

#include <iostream>

#include "sdl_compat.h"
#include "starfield.h"
#include "geom.h"
#include "defines.h"

using namespace std;


Star::Star(float x, float y, int ls)
:Object(x, y, 1, 1){
    lifespan = ls;
    color = map_rgb(rand()%255, rand()%255, rand()%255);

    counter = rand() % (lifespan);
}

void Star::update(int w, int h){
    if (counter > lifespan){
        counter = 0;
        pos.x = rand() % int(w);
        pos.y = rand() % int(h);
    }
    counter++;
}

void Star::draw(){
    float scaledCounter = float(counter) / (lifespan);
    float scale = 4*(scaledCounter - scaledCounter*scaledCounter);
    GameColor star_color = map_rgb_f(scale, scale, scale);
    draw_filled_ellipse(pos.x, pos.y, width, height, star_color);
}

void Starfield::init(int w, int h){
    stars.clear();
    window_width = w;
    window_height = h;
    num_stars = 75 + rand() % 50;
    int posx, posy, lifespan, delay;
    for(int i = 0; i < num_stars; i++){
        posx = rand() % int(window_width);
        posy = rand() % int(window_height);
        //cout << posx << posy << endl;
        lifespan = 75 + rand() % 500;
        stars.push_back(Star(
            posx, posy, lifespan
        ));
    }
}


void Starfield::update(void){
    for(auto& star : stars){
        star.update(window_width, window_height);
    }
}

void Starfield::draw(void){
    for(auto& star : stars){
        star.draw();
    }
}