/*

  OLEDWave

  OLEDWave was written to utilize any 128x64 display.  This is a very simple example showing how to smoothly
  generate a Sine and Cosine function on an OLED Display. I have seen many complex and confusing examples.
  This code was written by Greg Stievenart with no claim to the information provided in this code.
  Please feel free to copy, modify and share. Freely published October 19, 2019

  The units in this example are broken down into an imaginary circle with a radius of 30. This number
  is multiplied by the Sine and the Cosine of the wave.

  EXAMPLE:

   60/2        **                      **                      **                        **
            *      *                *      *                *      *                  *      *
          *          *            *          *            *          *              *          *
       0 * ---------- * -------- * ---------- * -------- * ---------- * ---------- * ---------- *
                       *        *              *        *              *          *
                         *    *                  *    *                  *      *
  -60/2                    **                      **                       **

  More information about the Sine fuction: https://en.wikipedia.org/wiki/Sine

  This project is posted at: https://forum.arduino.cc/index.php?topic=625662.0
  
  Project inspired by post at: https://forum.arduino.cc/index.php?topic=27475.0
  
*/

#include <Wire.h>                               // requried to run I2C SH1106
#include <SPI.h>                                // requried to run I2C SH1106
#include <Adafruit_GFX.h>                       // https://github.com/adafruit/Adafruit-GFX-Library
#include <Adafruit_SH1106.h>                    // https://github.com/wonho-maker/Adafruit_SH1106

#define OLED_RESET 4

Adafruit_SH1106 display(OLED_RESET);            // reset required for SH1106

int hCenter = 32;                               // horizontal center of 64 / 2 = 32
int Radius = 30;                                // radius of circle
const float Pi = 3.14159265359;                 // Pi

void setup(){
 
  display.begin(SH1106_SWITCHCAPVCC, 0x3D);     // needed for SH1106 display
}

void loop(){

  display.clearDisplay();                       // clears display
  display.drawRect(0, 0, 120, 64, WHITE);       // draws border
  display.drawLine(0,30,120,30,WHITE);          // draws grid horizontal center
  display.drawLine(30,0,30,64,WHITE);           // draws grid vertical first
  display.drawLine(60,0,60,64,WHITE);           // draws grid vertical second
  display.drawLine(90,0,90,64,WHITE);           // draws grid vertical third

  for (int i=0; i<120; i++){                    // draws 120 pixels per loop
    
    float Angle = i * 3;                        // 120 X 3 = 360°
    int a = (hCenter + (sin(Angle * (Pi / 180)) * Radius));    // Pi/180 converts degrees to radians
    int b = (hCenter + (cos(Angle * (Pi / 180)) * Radius));    // Pi/180 converts degrees to radians

    display.drawPixel(i,a,WHITE);               // draws each pixel for Sine wave
    display.drawPixel(i,b,WHITE);               // draws each pixel for Cosine wave
    display.display();                          // displays new screen information
  }
}