More efficient array setup

Projects Programming
11

Here is a quick pass at changing from 32-bit floats to 8-bit velocity and 16-bit position. This makes each particle 48 bits instead of 128 bits. It should also speed up the math since most is done in 32-bit integers instead of floats.

#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define SCREEN_ADDRESS 0x3C
#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C

#define xRBound 128
#define xLBound 0
#define yDBound 64
#define yUBound 0

#define particles 20

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

struct Particle
{
  int8_t dx; // Velocity in tenths of a pixel per step (+/-12.7 pixels)
  int8_t dy; // Velocity in tenths of a pixel per step (+/-12.7 pixels)
  int16_t xPos; // Position in hundredths of a pixel (+/-320.00 pixels)
  int16_t yPos; // Position in hundredths of a pixel (+/-320.00 pixels)
} Particles[particles];

int radius = 0;
int mass = 1;

const float DEG2RAD = PI / 180.0;
const float RAD2DEG = 180.0 / PI;

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(1, INPUT);
  randomSeed(analogRead(1));
  display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS);
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(0);
  display.clearDisplay();
  startParticlesRandom();
  //  startParticlesFine();
}

void loop()
{
  displayParticles();
  moveParticles();
  //  collisionCheck();
  delay(10);
}


void collisionCheck()
{
  for (int i = 0; i < particles; i++)
  {
    int32_t x1 = Particles[i].xPos;
    int32_t y1 = Particles[i].yPos;

    for (int j = 0; j < particles; j++)
    {
      if (i == j) continue;

      int32_t dx = Particles[j].xPos - x1;
      int32_t dy = Particles[j].yPos - y1;

      float distance = sqrt((dx * dx / 100) + (dy * dy / 100));
      if (distance - radius * 2 <= 1)
      {
        //Input complex physics equation that I don't understand yet so that particles will bounce and transfer energy
      }
    }
  }
}


void startParticlesRandom()
{
  for (int i = 0; i < particles; i++)
  {
    Particles[i].yPos = random(yUBound + radius, yDBound - radius);
    Particles[i].xPos = random(xLBound + radius, xRBound - radius);
    Particles[i].dx = random(-120, +120);
    Particles[i].dy = random(-120, +120);
    //    Serial.print("particle ");
    //    Serial.print(i);
    //    Serial.println(" set!");
  }
}

void startParticlesFine()
{
  Particles[0].yPos = (yDBound / 2) * 100;
  Particles[1].yPos = (yDBound / 2) * 100;
  Particles[0].xPos = 5 * 100;
  Particles[1].xPos = 123 * 100;
  Particles[0].dx = 15;
  Particles[1].dx = -5;
  Particles[0].dy = 15;
  Particles[1].dy = -5;
}

void moveParticles()
{
  for (int i = 0; i < particles; i++)
  {
    if (Particles[i].yPos / 100 >= yDBound - radius || Particles[i].yPos / 100 <= yUBound + radius)
    {
      Particles[i].dy *= -1;
    }
    if (Particles[i].xPos / 100 >= xRBound - radius || Particles[i].xPos / 100 <= xLBound + radius)
    {
      Particles[i].dx *= -1;
    }
    
    // Convert velocity in 10th to position change in 100ths
    Particles[i].yPos += Particles[i].dy * 10;
    Particles[i].xPos += Particles[i].dx * 10;
  }
}


void displayParticles()
{
  display.clearDisplay();
  for (int i = 0; i < particles; i++)
  {
    // Convert hundredths of a pixel to pixels
    int x = Particles[i].xPos / 100;
    int y = Particles[i].yPos / 100;
    display.drawCircle(x, y, radius, WHITE);
  }
  display.display();
}