Tetris.cpp

#include "settings.h"
#include "Tetris.h"
// #include "Entropy.h"

// using the NES game as a guidepost is a little slow, this speeds it up
const bool SKIP_A_BIT_BROTHER=true;

const uint8_t DEBOUNCE_VALUE = 10;

// I just switched to interrupt-driven inputs so it's a little messy
// button flags represent whether or not a button was pressed this tick
volatile static uint8_t buttonFlags=0b11111111;
// time of the current frame render
static uint32_t frameTime = millis();
// timestamp of when the button started being held
static uint32_t leftButton = 0;
static uint32_t rightButton = 0;
static uint32_t upButton = 0;

#define LEFT_BUTTON_FLAG (!(buttonFlags & (1 << LEFT_BUTTON)))
#define RIGHT_BUTTON_FLAG (!(buttonFlags & (1 << RIGHT_BUTTON)))
#define MIDDLE_BUTTON_FLAG (!(buttonFlags & (1 << MIDDLE_BUTTON)))

// interrupt script
ISR(PCINT0_vect)
{
    // static vars are only initialized once
    static uint16_t debounceLeft = millis();
    static uint16_t debounceRight = millis();
    static uint16_t debounceMiddle = millis();

    const uint16_t now = millis();

    // first add any low pins to the register
    buttonFlags &= PINB;

    // then examine PINB and rectify which buttons are actually being held right now
    if (!(PINB & (1 << LEFT_BUTTON))) {
      if (now - debounceLeft > DEBOUNCE_VALUE) {
        debounceLeft = now;
        if (!leftButton) {
          leftButton = frameTime;
        }
      }
    } else {
      // TODO 0 as a sentinel value sometimes doesn't work
      leftButton = 0;
    }

    if (!(PINB & (1 << MIDDLE_BUTTON))) {
      if (now - debounceMiddle > DEBOUNCE_VALUE) {
        debounceMiddle = now;
        if (!upButton) {
          upButton = frameTime;
        }
      }
    } else {
      upButton = 0;
    }

    if (!(PINB & (1 << RIGHT_BUTTON))) {
      if (now - debounceRight > DEBOUNCE_VALUE) {
        debounceRight = now;
        if (!rightButton) {
          rightButton = frameTime;
        }
      }
    } else {
      rightButton = 0;
    }
}

const uint8_t BOARD_WIDTH = 8;
const uint8_t BOARD_HEIGHT = 32;

const uint8_t STARTING_PIECE_WIDTH = 4;
const uint8_t STARTING_PIECE_HEIGHT = 34;

const bool RENDER_SMALL = false;

// TODO can just be one macro with an input of which button to check
// also predicating this on one frame not passing means we drop inputs if its going too slow. might want to rethink
// TODO make millis_per_frame * 12 bit shift? check specification
#define REPEAT_DELAY 250
#define SHOULD_MOVE_LEFT (LEFT_BUTTON_FLAG || (leftButton && frameTime - leftButton > REPEAT_DELAY))
#define SHOULD_ROTATE (RIGHT_BUTTON_FLAG || (rightButton && frameTime - rightButton > REPEAT_DELAY))
#define SHOULD_MOVE_RIGHT (MIDDLE_BUTTON_FLAG || (upButton && frameTime - upButton > REPEAT_DELAY))


#define ALL_THREE_BUTTONS_HELD (SHOULD_MOVE_LEFT && SHOULD_MOVE_RIGHT && SHOULD_ROTATE)  //  (buttonFlags == 0b00011010)
// cut down on features since digispark has a bootloader
// #define DIGISPARK

// TODO these will not spawn at the same heights, but rotate (hopefully) correctly
// about their axis. if I move them to all spawn at the same height, they will
// lose that axis rotation. I need to reorder so that the first or last
// pixel is always the lowest pixel, so that I may use that in my program
// to spawn them all at the same height
const uint8_t uniqueShapes = 7;
const Shape Tetris::shapes[uniqueShapes * 4] PROGMEM = {
  { { { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 1 } } }, // square 1
  { { { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 1 } } }, // square 2
  { { { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 1 } } }, // square 3
  { { { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 1 } } }, // square 4

  { { { -1, 1 }, { -1, 0 }, { 0, 0 }, { 1, 0 } } }, // L 1
  { { { 0, -1 }, { 0, 0 }, { 0, 1 }, { 1, 1 } } }, // L 2
  { { { -1, 0 }, { 0, 0 }, { 1, 0 }, { 1, -1 } } }, // L 3
  { { { -1, -1 }, { 0, -1 }, { 0, 0 }, { 0, 1 } } }, // L 4

  { { { -1, 0 }, { 0, 0 }, { 1, 0 }, { 1, 1 } } }, // J 1
  { { { 0, 1 }, { 0, 0 }, { 0, -1 }, { 1, -1 } } }, // J 2
  { { { -1, -1 }, { -1, 0 }, { 0, 0 }, { 1, 0 } } }, // J 3
  { { { -1, 1 }, { 0, 1 }, { 0, 0 }, { 0, -1 } } }, // J 4

  { { { -1, 0 }, { 0, 0 }, { 0, -1 }, { 1, -1 } } }, // S 1
  { { { 0, -1 }, { 0, 0 }, { 1, 0 }, { 1, 1 } } }, // S 2
  { { { -1, 1 }, { 0, 1 }, { 0, 0 }, { 1, 0 } } }, // S 3
  { { { -1, -1 }, { -1, 0 }, { 0, 0 }, { 0, 1 } } }, // S 4

  { { { -1, 0 }, { 0, 0 }, { 0, -1 }, { 1, 0 } } }, // T 1
  { { { 0, -1 }, { 0, 0 }, { 0, 1 }, { 1, 0 } } }, // T 2
  { { { -1, 0 }, { 0, 0 }, { 0, 1 }, { 1, 0 } } }, // T 3
  { { { -1, 0 }, { 0, -1 }, { 0, 0 }, { 0, 1 } } }, // T 4

  { { { -1, -1 }, { 0, -1 }, { 0, 0 }, { 1, 0 } } }, // Z 1
  { { { 0, 1 }, { 0, 0 }, { 1, 0 }, { 1, -1 } } }, // Z 2
  { { { -1, 0 }, { 0, 0 }, { 0, 1 }, { 1, 1 } } }, // Z 3
  { { { -1, 1 }, { -1, 0 }, { 0, 0 }, { 0, -1 } } }, // Z 4

  { { { -2, 0 }, { -1, 0 }, { 0, 0 }, { 1, 0 } } }, // I 1
  { { { 0, 2 }, { 0, 1 }, { 0, 0 }, { 0, -1 } } }, // I 2
  { { { -2, 1 }, { -1, 1 }, { 0, 1 }, { 1, 1 } } }, // I 3
  { { { -1, -2 }, { -1, -1 }, { -1, 0 }, { -1, 1 } } }, // I 4
};

// static, so initialized to 0s anyways
uint8_t Tetris::board[BOARD_HEIGHT] = {
  0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,
};
// initialized elsewhere instead of reading from progmem here
Shape Tetris::shape = { { { 0, 0 }, { 0, 1 }, { 1, 0 }, { 1, 1 } } };
// square 1
// initialized elsewhere
static uint8_t Tetris::shapeIndex = 1;

const uint8_t Tetris::numShapes = sizeof(Tetris::shapes) / sizeof(Tetris::shapes[0]); // 28

// TODO use 3 + 800 / (16 + x*x) to determine required frames. recalculate on increase in score? or just use as function

Tetris::Tetris(SSD1306Device* _oled) {
  oled = _oled;
  position = { STARTING_PIECE_WIDTH, STARTING_PIECE_HEIGHT };
}

uint32_t Tetris::run() {
  main();
  end();
  return score*10;
}

void Tetris::main() {
  assignRandomShape();
  uint32_t lastTickTime = millis();

  bool exit = false;

  while (!exit) {

    uint16_t millis_per_tick = getMillisPerTick();

    // if it's not a frame where we move downwards, don't even check for collision
    if ((millis() - lastTickTime > millis_per_tick) || ALL_THREE_BUTTONS_HELD) {
      // hacky short circuit to incoporate immediate auto-down into the old event loop
      if (ALL_THREE_BUTTONS_HELD) {
        // clear board of current piece, it'll probably be outside the envelope so do it twice
        renderBoard(false, false);
        renderBoard(false, false);
        while(!checkCollision({ 0, -1})) {
          // movePiece has frameTime in it now. besides, this is more correct
          position.y--;
        }
      }

      if(!checkCollision({ 0, -1})) {
        movePiece(true);
        resetButtons();
        renderBoard();
      } else {
        resetButtons();
        // no collisions above the plane of play
        if (position.y >= BOARD_HEIGHT) break;
        // re-add piece back in its new final resting place
        // from this point until we spawnNewPiece we're in a bit of a weird state, with the piece on the board. can't renderBoard(false, true) in this state or we will lose that
        addOrRemovePiece(true);
        // write once more to get rid of a nasty double buffer bug introduced when I stopped rendering the full screen
        // pieces will bounce if they hit but don't complete a row
        renderBoard(false, false);
        // check to see if any rows are full and need to be culled
        // needs to be done before we spawn a new piece, once again, due to rendering tricks
        // its so much faster though, totally worth it
        checkForFullRows();
        // spawn a new piece
        spawnNewPiece();
        // check for game over
        if (checkCollision({ 0, -1})) {
          exit = true;
        }
      }
      // always reset lastTickTime after we trigger
      lastTickTime = millis();
    } else {
      movePiece(false);
      resetButtons();
      renderBoard();
    }
  }
}

// close to original NES implementation
uint16_t Tetris::getMillisPerTick() {
  if (level < 9) {
    return 800 - level * 80;
  } else if (level < 28) {
    return 100 - (level - 9) * 5;
  } else {
    return 1;
  }
}


void Tetris::resetButtons() {
  // buttonFlags needs to be reset to detect new button presses
  // we do this here instead of in movePiece because that doesn't always get
  // called by the main loop
  buttonFlags=0b11111111;

  // every frame needs a unique identifier to tie inputs to
  // we change this right after we move things so we catch the maximum button
  // presses
  frameTime = millis();
}

void Tetris::movePiece(bool moveDown) {
  if (moveDown) {
    position.y--;
  }

  if (SHOULD_MOVE_LEFT) {
    if (!checkCollision({ -1, 0 })) {
      --position.x;
    }
  } else if (SHOULD_MOVE_RIGHT) {
    if (!checkCollision({ 1, 0 })) {
      ++position.x;
    }
  }

  // you should always be able to rotate, even if you click other buttons
  if (SHOULD_ROTATE) {
    rotatePiece();
  }
}

void Tetris::end() {
  // reset board in case
  // memset(board, 0x00, 32);
}

void Tetris::spawnNewPiece() {
  assignRandomShape();
  // I organized the shapes so that the first pixel is always one of the leftmost,
  // and the last is always one of the rightmost. if I'm going with random positions
  // I can use that here to dynamically change my bounds
  position.x = STARTING_PIECE_WIDTH;
  position.y = STARTING_PIECE_HEIGHT;
}

// regular tetris supposedly generates the next shapes 7 at a time
// but uh, this works too
void Tetris::assignRandomShape() {
  static bool shapesAlreadyUsed[uniqueShapes] = {false, false, false, false, false, false, false};

  // count how many shapes we haven't used this "bag" yet
  uint8_t spotsLeft = 0;
  for(uint8_t i = 0; i < uniqueShapes; i++) {
    if (!shapesAlreadyUsed[i]) {
      spotsLeft++;
    }
  }

  // if there are none, reset
  if (spotsLeft == 0) {
    for(uint8_t j = 0; j < uniqueShapes; j++) {
      shapesAlreadyUsed[j] = false;
    }
    spotsLeft = 7;
  }

  // find the spot we want to take
  // Entropy is more accurate but causing issues for other games due to Arduino's
  // code loading magic
  // uint8_t spot = Entropy.random(spotsLeft);
  uint8_t spot = rand() % spotsLeft;

  // and find the actual shape in the array
  int8_t openSpotCounter = -1;
  uint8_t k = 0;
  for (k; k < uniqueShapes; k++) {
    if (shapesAlreadyUsed[k]) {
      continue;
    }

    openSpotCounter++;

    // >= for 0th case
    if (openSpotCounter == spot) {
      break;
    }
  }

  shapesAlreadyUsed[k] = true;

  assignShape((k << 2));

  // static uint8_t index = 0;
  // assignShape(index++); // (rand()) % numShapes
  // assignShape(((uint8_t)rand()) % numShapes);
}

void Tetris::assignShape(uint8_t index) {
  if (index > 28) score += 13;
  shapeIndex = index;
  // load shape from progmem into ram since we need it everywhere
  memcpy_P(&shape, &shapes[shapeIndex], sizeof(Shape));
}

// really
void Tetris::checkForFullRows() {
  // to calculate the score
  uint8_t linesCleared = 0;
  uint8_t y = (int8_t)(position.y) - 3 < 0 ? 0 : position.y - 3;
  while(y < BOARD_HEIGHT) {
    if (board[y] == 0xFF) {
      linesCleared++;
      // to calculate the level
      incrementLines();
      for (uint8_t yy = y; yy < BOARD_HEIGHT - 1; yy++) {
        board[yy] = board[yy+1];
      }

      // doesn't work sporadically, not sure why. seems to be when 2 or more lines finish
      // memmove((void*)(board + y), (void*)(board + y + 1), 1);
      // could do if extraScore == 1 since we only have to do this once -
      // the first time, when there might be stuff in the top row that
      // gets duplicated - but meh
      board[BOARD_HEIGHT-1] = 0x00;
      // we could move this out of the loop but it creates a nice effect
      renderBoard(true, false);
    } else {
      ++y;
    }
  }

  // get rid of double render problems
  renderBoard(true, false);
  incrementScore(linesCleared);
}

void Tetris::incrementScore(uint8_t lines) {
  uint8_t extraScore = 0;

  switch(lines) {
    case 1:
      extraScore = 4;
      break;
    case 2:
      extraScore = 10;
      break;
    case 3:
      extraScore = 30;
      break;
    case 4:
      extraScore = 120;
  }

  score += extraScore * (level + 1);
}

void Tetris::incrementLines() {
  lines++;
  const uint8_t levelMultiplier = SKIP_A_BIT_BROTHER ? 5 : 10;

  if (lines >= (level + 1) * levelMultiplier) {
    lines = 0;
    level++;
  }
}

void Tetris::rotatePiece() {
  // bitshift division yeah yeah yeah
  const uint8_t shapeQuotient = shapeIndex >> 2;
  const uint8_t shapeRemainder = shapeIndex % 4;

  const uint8_t oldIndex = shapeIndex;

  assignShape(shapeQuotient * 4 + ((shapeRemainder + 1) % 4));

  // if the new shape collides
  if (checkCollision({ 0, 0 })) {
    // and moving it to the right doesn't help
    if (checkCollision({1, 0})) {
      // and moving it to the left doesn't help
      if (checkCollision({-1, 0})) {
        // switch back to the old shape
        assignShape(oldIndex);
      } else {
        // left was clear, just move left
        --position.x;
      }
    } else {
      // right was clear, just move right
      ++position.x;
    }
  }
}

// two times we check collision: 1. to know if a brick hits another brick
// 2. to know if a rotation would fail.
// for #1 use a modifier of -1 to check underneath pixels.
// #2 just use 0
bool Tetris::checkCollision(Position delta) {
  for (uint8_t i = 0; i < PIXELS_IN_SHAPE; i++) {
    Position pixel = shape.pixels[i];
    Position newPosition = { position.x + pixel.x + delta.x, position.y + pixel.y + delta.y };

    // if we've hit the bottom it always collides
    // most collision checks are done with a delta - they are checking
    // if the piece moves to a location whether it collides or not.
    // the only exception is rotation checks, which just want to check
    // if the new rotated piece is occupying the same space as something.
    // hence < 0 instead of <= 0 for the 0 checks
    if (((int8_t)newPosition.y < 0 || ((int8_t)newPosition.x < 0) || (newPosition.x >= BOARD_WIDTH))) {
      // score += 12;
      return true;
    }

    // pixels above the play field do not collide. they will also buffer overflow lol
    if (newPosition.y < BOARD_HEIGHT) {
      uint8_t row = board[newPosition.y];

      // check underneath for blocks
      if (row & (0x01 << newPosition.x)) {
        return true;
      }
    }
  }

  return false;
}

// this method should not be called when a piece would interstect
void Tetris::addOrRemovePiece(bool add) {
  for (uint8_t i = 0; i < PIXELS_IN_SHAPE; i++) {
    Position pixel = shape.pixels[i];
    Position newPosition = { position.x + pixel.x, position.y + pixel.y };

    // check bounds, continue rendering the rest of the piece if we fail though
    if (newPosition.y > BOARD_HEIGHT || (int8_t)newPosition.y < 0) continue;
    if (newPosition.x > BOARD_WIDTH || (int8_t)newPosition.x < 0) continue;

    uint8_t* row = &board[(newPosition.y)];
    if (add) {
      *row |= 0x01 << (newPosition.x);
    } else {
      *row &= ~(0x01 << (newPosition.x));
    }
  }
}

// only call this function when the piece is in a good place
void Tetris::renderBoard(bool wholeScreen, bool addPiece) {
  // add piece to board
  if (addPiece) addOrRemovePiece(true);
  // wholeScreen = false;
  // reset to bottom left

  // no way in hell am I importing std
  // 6 works to get rid of double buffer problems, but 4 might as well
  uint8_t yMin = wholeScreen ? 0 : ((int8_t)(position.y) - 6 < 0 ? 0 : position.y - 6);
  uint8_t yMax = wholeScreen ? BOARD_HEIGHT : (position.y + 6 > BOARD_HEIGHT ? BOARD_HEIGHT : position.y + 6);

  oled->setCursor(yMin*4,0);

  for (uint8_t x = 0; x < (RENDER_SMALL ? 1 : BOARD_WIDTH >> 1); x++) {
    for (uint8_t y = yMin; y < yMax; y++) {
      // proceeding upwards, grab pixels 2x1 and write them to the screen
      uint8_t row = board[y];
      bool pixel1 = row & 0x01 << (x * 2 + 1);
      bool pixel2 = row & 0x01 << (x * 2);

      uint8_t block = pixel1 ? 0xF0 : 0x00;
      block |= pixel2 ? 0x0F : 0x00;

      // let the screen know there's data comin
      oled->startData();

      for (uint8_t i = 0; i < (RENDER_SMALL ? 1 : 4); i++){
        oled->sendData((RENDER_SMALL ? row : block));
        // cooperative multithreading amirite
      }

      oled->endData();
    }

    oled->setCursor(yMin*4,x+1);
  }
  if (RENDER_SMALL) delay(200);
  if (addPiece) addOrRemovePiece(false);

  // debugging
  // oled->setCursor(100,0);
  // oled->print(SHOULD_MOVE_LEFT);
  // oled->switchFrame();

  oled->switchFrame();
}