Snow Demo

Little snow Demo, uses also the Lights.

Download: Snow.zip

BUTTON_MENU = reset the Snow

BUTTON_A = 160x128, index

BUTTON_B= 80x64, index

BUTTON_UP = Temperature + 

BUTTON_DOWN = Temperature -

BUTTON_LEFT = Speed -

BUTTON_RIGHT = Speed +

#include 
#define NUM_PARTICLES 1300
#define MAX_TTL 2000
#define MIN_TTL MAX_TTL/2
int particleCount = 0;
typedef struct {
byte x;
byte y;
int ttl;
byte color;
} particle;
particle particles[NUM_PARTICLES];
int temperature = 1;
byte snowSpeed = 1;
void setup()
{
gb.begin();
gb.lights.clear();
randomSeed(analogRead(A2));
gb.display.init(160, 128, ColorMode::index);
resetParticles();
}
void loop() {
while (!gb.update());
gb.display.clear();
if (gb.buttons.pressed(BUTTON_A)) {
gb.display.init(160, 128, ColorMode::index);
}
if (gb.buttons.pressed(BUTTON_B)) {
gb.display.init(80, 64, ColorMode::index);
}
if (gb.buttons.pressed(BUTTON_MENU)) {
resetParticles();
}
if (gb.buttons.pressed(BUTTON_UP)) {
if (temperature < 50)
temperature++;
}
if (gb.buttons.pressed(BUTTON_DOWN)) {
if (temperature > -50)
temperature--;
}
if (gb.buttons.pressed(BUTTON_LEFT)) {
if (snowSpeed < 10)
snowSpeed++;
}
if (gb.buttons.pressed(BUTTON_RIGHT)) {
if (snowSpeed > 0)
snowSpeed--;
}
if ((random(0, snowSpeed) + 1) == 1 && (10 - snowSpeed) != 0)
createParticles();
drawParticles();
updateParticles();
gb.display.print("T:");
gb.display.print(temperature);
gb.display.println("C");
gb.display.print("S:");
gb.display.println(10 - snowSpeed);
}
void resetParticles() {
gb.display.clear();
gb.lights.clear();
for (int i = 0; i < NUM_PARTICLES; i++) {
particles[i].x = -1;
particles[i].y = -1;
}
particleCount = 0;
}
void createParticles() {
if (particleCount < NUM_PARTICLES) {
initParticles(particleCount);
particleCount++;
}
}
void initParticles(int n) {
if (n < NUM_PARTICLES) {
particles[n].x = random(0, gb.display.width() - 1);
particles[n].y = 1;
particles[n].ttl = random(MIN_TTL, MAX_TTL);
particles[n].color = 0;
}
}
void updateParticles() {
for (int i = 0; i < particleCount; i++) {
if (particles[i].y >= 0 && particles[i].y < gb.display.height() - 1) {
if ((int)gb.display.getPixel(particles[i].x , particles[i].y + 1) == (int)BLACK) {
particles[i].y++;
}
else {
if (((int)gb.display.getPixel(particles[i].x - 1 , particles[i].y + 1) == (int)BLACK && (int)gb.display.getPixel(particles[i].x - 1 , particles[i].y) == (int)BLACK) && ((int)gb.display.getPixel(particles[i].x + 1 , particles[i].y + 1) == (int)BLACK && (int)gb.display.getPixel(particles[i].x + 1 , particles[i].y) == (int)BLACK)) {
if (random(0, 2) >= 1)
particles[i].x--;
else
particles[i].x++;
} else {
if ((int)gb.display.getPixel(particles[i].x - 1 , particles[i].y + 1) == (int)BLACK && (int)gb.display.getPixel(particles[i].x - 1 , particles[i].y) == (int)BLACK) {
particles[i].x--;
if (random(0, 2) >= 1)
gb.lights.drawPixel(0, random(0, 5), WHITE);
else
gb.lights.drawPixel(0, random(0, 5), BLACK);
}
if ((int)gb.display.getPixel(particles[i].x + 1 , particles[i].y + 1) == (int)BLACK && (int)gb.display.getPixel(particles[i].x + 1 , particles[i].y) == (int)BLACK) {
particles[i].x++;
if (random(0, 2) >= 1)
gb.lights.drawPixel(1, random(0, 5), WHITE);
else
gb.lights.drawPixel(1, random(0, 5), BLACK);
}
}
}
}
if (particles[i].ttl > 0) {
if (particles[i].ttl <= MAX_TTL)
particles[i].ttl = particles[i].ttl - temperature;
else {
particles[i].ttl = MAX_TTL;
particles[i].color = 0;
}
  if (particles[i].ttl &lt; MAX_TTL / 4)
    particles[i].color = 3;
  else if (particles[i].ttl &lt; MAX_TTL / 3)
    particles[i].color = 2;
  else if (particles[i].ttl &lt; MAX_TTL / 2)
    particles[i].color = 1;
}
else {
  initParticles(i);
}

if (particles[i].y &lt; 0 &amp;&amp; particles[i].y &gt; gb.display.height() - 1)
  initParticles(i);

}
}
void drawParticles() {
for (int i = 0; i < particleCount; i++) {
if (particles[i].x >= 0 && particles[i].y >= 0 && particles[i].x < gb.display.width() && particles[i].y < gb.display.height()) {
if (particles[i].color == 0)
gb.display.drawPixel(particles[i].x, particles[i].y, WHITE);
if (particles[i].color == 1)
gb.display.drawPixel(particles[i].x, particles[i].y, LIGHTBLUE);
if (particles[i].color == 2)
gb.display.drawPixel(particles[i].x, particles[i].y, BLUE);
if (particles[i].color == 3)
gb.display.drawPixel(particles[i].x, particles[i].y, DARKBLUE);
} else {
initParticles(i);
}
}
}