Compound oscillation demo for ESP32

CompoundOscillation.ino

// Compound oscillation demo for ESP32
// Loosely coded by tobozo (c+) apr 2022 -
// Inspired by this GIF
//   - https://twitter.com/bayraitt/status/1514499189975134210

#include <ESP32-Chimera-Core.h> // https://github.com/tobozo/ESP32-Chimera-Core

static LGFX &tft(M5.Lcd);
static LGFX_Sprite* spriteLines   = new LGFX_Sprite( &tft );
static LGFX_Sprite* spriteMix     = new LGFX_Sprite( &tft );
static LGFX_Sprite* spriteBullets = new LGFX_Sprite( &tft );

static constexpr const int gridSize = 6;
static constexpr const int gridMargin = 10;
static constexpr const uint32_t bgcolor = 0x4d4845U;
static constexpr const uint32_t hgcolor = 0xffffffU;
static constexpr const uint32_t fgcolor = 0x888888U;

float angle = 0;

int sqWidth;
int sqSize;
int offsetX = gridMargin;
int offsetY = gridMargin;
int spritePosX, spritePosY;


uint8_t blend(float a, float b, float bias=0.5)
{
  return  sqrt( ((1 - bias) * (a*a)) + ( bias * (b*b ) ) );
}


void drawGrid( float angle_offset = 0 )
{
  float xpos,ypos;
  float x, y;

  for( float h=0; h<=gridSize; h++ ) {
    for( float v=0; v<=gridSize; v++ ) {
      if( h == 0 && v == 0 ) continue;
      xpos = (h*sqWidth)+sqSize;
      ypos = (v*sqWidth)+sqSize;
      bool circle = false;
      uint16_t barcolor;

      uint16_t ch = map( h, 0, gridSize, 0, 255 );
      uint16_t cv = map( v, 0, gridSize, 0, 255 );

      if( v == 0 ) {
        x = xpos + cos( (angle * h + angle_offset) ) * sqSize;
        y = ypos + sin( (angle * h + angle_offset) ) * sqSize;
        barcolor = tft.color565( ch, 255-ch, 128 );
      } else if( h == 0 ) {
        x = xpos + cos( (angle * v + angle_offset) ) * sqSize;
        y = ypos + sin( (angle * v + angle_offset) ) * sqSize;
        barcolor = tft.color565( cv, 255-cv, 128 );
      } else {
        x = xpos + cos( (angle + angle_offset) * h ) * sqSize;
        y = ypos + sin( (angle + angle_offset) * v ) * sqSize;
        barcolor = tft.color565( blend(cv, ch), 255-blend(ch, cv), 128 );
      }

      spriteLines->drawPixel( offsetX+x, offsetY+y, barcolor );
    }
  }
}



void drawBullets( float angle_offset = 0 )
{
  float xpos,ypos;
  float x, y;

  for( float h=0; h<=gridSize; h++ ) {
    for( float v=0; v<=gridSize; v++ ) {
      if( h == 0 && v == 0 ) continue;
      xpos = (h*sqWidth)+sqSize;
      ypos = (v*sqWidth)+sqSize;

      if( v == 0 ) {
        x = xpos + cos( (angle * h + angle_offset) ) * sqSize;
        y = ypos + sin( (angle * h + angle_offset) ) * sqSize;
      } else if( h == 0 ) {
        x = xpos + cos( (angle * v + angle_offset) ) * sqSize;
        y = ypos + sin( (angle * v + angle_offset) ) * sqSize;
      } else {
        x = xpos + cos( (angle + angle_offset) * h ) * sqSize;
        y = ypos + sin( (angle + angle_offset) * v ) * sqSize;
      }

      spriteBullets->fillCircle( offsetX+x, offsetY+y, 2, 1 );
    }
  }

  spriteLines->pushSprite( spriteMix, 0, 0 );
  spriteBullets->pushSprite( spriteMix, 0, 0, 0 );
  spriteMix->pushSprite( spritePosX, spritePosY );
  spriteBullets->fillSprite( 0 );

}


void setupSprites()
{
  uint16_t squareSize = tft.height();
  sqWidth = (squareSize-gridMargin ) / (gridSize+1);
  sqSize = (sqWidth/2)-4;

  spriteLines->setColorDepth( 8 );
  if( ! spriteLines->createSprite( squareSize, squareSize ) ) {
    Serial.println("Can't create spriteLines, halting");
    while(1);
  }
  spriteLines->fillSprite(bgcolor);


  spriteMix->setColorDepth( 8 );
  if( ! spriteMix->createSprite( squareSize, squareSize ) ) {
    Serial.println("Can't create spriteMix, halting");
    while(1);
  }
  spriteMix->fillSprite(bgcolor);


  spriteBullets->setColorDepth( 1 );
  spriteBullets->setPaletteColor( 0, bgcolor );
  spriteBullets->setPaletteColor( 1, hgcolor );
  if( ! spriteBullets->createSprite( squareSize, squareSize ) ) {
    Serial.println("Can't create spriteBullets, halting");
    while(1);
  }
  spriteBullets->fillSprite(0);

  spritePosX = tft.width()/2  - spriteMix->width()/2;
  spritePosY = tft.height()/2 - spriteMix->height()/2;
}



void setup()
{
  M5.begin();

  setupSprites();

  // fill the grid, only needs one pass
  // also animate bullets
  for( float a=0; a<2*PI*gridSize; a +=.02 ) {
    angle = fmod( a, 2*PI );
    drawGrid();
    drawBullets();
  }
}


void loop()
{
  drawBullets();
  angle = fmod( angle, 2*PI );
  angle += .02;
}