//PlazINT  -  Fast Plasma Generator using Integer Math Only
//Edmund "Skorn" Horn
//March 4,2013
//Version 1.0 adapted for OctoWS2811Lib (tested, working...)


#include <OctoWS2811.h>

//OctoWS2811 Defn. Stuff
#define COLS_LEDs 60  // all of the following params need to be adjusted for screen size
#define ROWS_LEDs 16  // LED_LAYOUT assumed 0 if ROWS_LEDs > 8
#define LEDS_PER_STRIP (COLS_LEDs * (ROWS_LEDs / 8))

DMAMEM int displayMemory[LEDS_PER_STRIP*6];
int drawingMemory[LEDS_PER_STRIP*6];
const int config = WS2811_GRB | WS2811_800kHz;
OctoWS2811 leds(LEDS_PER_STRIP, displayMemory, drawingMemory, config);

//Byte val 2PI Cosine Wave, offset by 1 PI 
//supports fast trig calcs and smooth LED fading/pulsing.
uint8_t const cos_wave[256] PROGMEM =  
{0,0,0,0,1,1,1,2,2,3,4,5,6,6,8,9,10,11,12,14,15,17,18,20,22,23,25,27,29,31,33,35,38,40,42,
45,47,49,52,54,57,60,62,65,68,71,73,76,79,82,85,88,91,94,97,100,103,106,109,113,116,119,
122,125,128,131,135,138,141,144,147,150,153,156,159,162,165,168,171,174,177,180,183,186,
189,191,194,197,199,202,204,207,209,212,214,216,218,221,223,225,227,229,231,232,234,236,
238,239,241,242,243,245,246,247,248,249,250,251,252,252,253,253,254,254,255,255,255,255,
255,255,255,255,254,254,253,253,252,252,251,250,249,248,247,246,245,243,242,241,239,238,
236,234,232,231,229,227,225,223,221,218,216,214,212,209,207,204,202,199,197,194,191,189,
186,183,180,177,174,171,168,165,162,159,156,153,150,147,144,141,138,135,131,128,125,122,
119,116,113,109,106,103,100,97,94,91,88,85,82,79,76,73,71,68,65,62,60,57,54,52,49,47,45,
42,40,38,35,33,31,29,27,25,23,22,20,18,17,15,14,12,11,10,9,8,6,6,5,4,3,2,2,1,1,1,0,0,0,0
};


//Gamma Correction Curve
uint8_t const exp_gamma[256] PROGMEM =
{0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,3,3,3,3,3,
4,4,4,4,4,5,5,5,5,5,6,6,6,7,7,7,7,8,8,8,9,9,9,10,10,10,11,11,12,12,12,13,13,14,14,14,15,15,
16,16,17,17,18,18,19,19,20,20,21,21,22,23,23,24,24,25,26,26,27,28,28,29,30,30,31,32,32,33,
34,35,35,36,37,38,39,39,40,41,42,43,44,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,
61,62,63,64,65,66,67,68,70,71,72,73,74,75,77,78,79,80,82,83,84,85,87,89,91,92,93,95,96,98,
99,100,101,102,105,106,108,109,111,112,114,115,117,118,120,121,123,125,126,128,130,131,133,
135,136,138,140,142,143,145,147,149,151,152,154,156,158,160,162,164,165,167,169,171,173,175,
177,179,181,183,185,187,190,192,194,196,198,200,202,204,207,209,211,213,216,218,220,222,225,
227,229,232,234,236,239,241,244,246,249,251,253,254,255
};


void setup()
{
  pinMode(13, OUTPUT);
  leds.begin();
  leds.show();
}


void loop()
{
  unsigned long frameCount=25500;  // arbitrary seed to calculate the three time displacement variables t,t2,t3
  while(1) {
    frameCount++ ; 
    uint16_t t = fastCosineCalc((42 * frameCount)/100);  //time displacement - fiddle with these til it looks good...
    uint16_t t2 = fastCosineCalc((35 * frameCount)/100); 
    uint16_t t3 = fastCosineCalc((38 * frameCount)/100);

    for (uint8_t y = 0; y < ROWS_LEDs; y++) {
      int left2Right, pixelIndex;
      if (((y % (ROWS_LEDs/8)) & 1) == 0) {
        left2Right = 1;
        pixelIndex = y * COLS_LEDs;
      } else {
        left2Right = -1;
        pixelIndex = (y + 1) * COLS_LEDs - 1;
      }
      for (uint8_t x = 0; x < COLS_LEDs ; x++) {
        //Calculate 3 seperate plasma waves, one for each color channel
        uint8_t r = fastCosineCalc(((x << 3) + (t >> 1) + fastCosineCalc((t2 + (y << 3)))));
        uint8_t g = fastCosineCalc(((y << 3) + t + fastCosineCalc(((t3 >> 2) + (x << 3)))));
        uint8_t b = fastCosineCalc(((y << 3) + t2 + fastCosineCalc((t + x + (g >> 2)))));
        //uncomment the following to enable gamma correction
        //r=pgm_read_byte_near(exp_gamma+r);  
        //g=pgm_read_byte_near(exp_gamma+g);
        //b=pgm_read_byte_near(exp_gamma+b);
        leds.setPixel(pixelIndex, ((r << 16) | (g << 8) | b));
	pixelIndex += left2Right;
      }
    }
    digitalWrite(13, HIGH);
    leds.show();  // not sure if this function is needed  to update each frame
    digitalWrite(13, LOW);
  }
}


inline uint8_t fastCosineCalc( uint16_t preWrapVal)
{
  uint8_t wrapVal = (preWrapVal % 255);
  if (wrapVal<0) wrapVal=255+wrapVal;
  return (pgm_read_byte_near(cos_wave+wrapVal)); 
}