Merge pull request thecardkid#28 from thecardkid/hn/ghosting

ADD: ghost piece that shows where tetromino will end up

src/block_factory.c

@@ -32,6 +32,7 @@ void spawn(State* s) {
  n = rand() % NUM_BLOCKS;
  }
  s->next = n;
+ project_ghost(s);
  } else {
  s->mode = SHUTDOWN;
  }

src/controller.c

@@ -39,8 +39,15 @@ void run_mode(Movement* net_move, State* s, int* frame_counter) {
  // Collect desired total movement in this frame
  aggregate_movement(net_move, s, frame_counter);
 
+ // Clear interactables such as the block and ghost
+ clear_block(s);
+ clear_ghost(s);
+
  // Perform movement
  if (!move_block(s, net_move)) {
+ // Draw block before we reassign its pointer
+ draw_block(s);
+
  // Block was unable to make any valid downwards move.
 
  // Perform row clear if needed and update score
@@ -50,6 +57,10 @@ void run_mode(Movement* net_move, State* s, int* frame_counter) {
  spawn(s);
  }
 
+ // Draw block and ghost to grid
+ draw_ghost(s);
+ draw_block(s);
+
  // Rendering loop
  clear();
  render(s);
@@ -212,14 +223,6 @@ void act_on_user_input(
 }
 
 int move_block(State* s, Movement* m) {
- // Clear cells occupied by the block
- for (int i = 0; i < 4; i++) {
- int x = s->block->cells[i][0] + s->block->x;
- int y = s->block->cells[i][1] + s->block->y;
-
- s->grid[x][y] = EMPTY;
- }
-
  // Flags
  int applied_move = 1;
  int can_move_vert = 1;
@@ -238,7 +241,7 @@ int move_block(State* s, Movement* m) {
  int y = s->block->cells[i][1] + s->block->y;
 
  // Conditions where move is invalid
- if (!in_grid(x, y + m->y) || s->grid[x][y + m->y] != EMPTY) {
+ if (!in_grid(x, y + m->y) || ((s->grid[x][y + m->y] != EMPTY) && (s->grid[x][y + m->y] != GHOST))) {
  can_move_vert = 0;
  break;
  }
@@ -304,13 +307,8 @@ int move_block(State* s, Movement* m) {
  }
  }
 
- // Set cells occupied by block to correct color
- for (int i = 0; i < 4; i++) {
- int x = s->block->cells[i][0] + s->block->x;
- int y = s->block->cells[i][1] + s->block->y;
-
- s->grid[x][y] = s->block->color;
- }
+ // Recalculate ghost position
+ project_ghost(s);
 
  return can_move_vert;
 }

src/renderer.c

@@ -16,6 +16,7 @@ void set_up_screen() {
  init_pair(GREEN, COLOR_GREEN, COLOR_BLACK);
  init_pair(PURPLE, COLOR_MAGENTA, COLOR_BLACK);
  init_pair(RED, COLOR_RED, COLOR_BLACK);
+ init_pair(GHOST, COLOR_BLACK, COLOR_WHITE);
 }
 
 void display_grid(int grid[GRID_W][GRID_H]) {
@@ -26,7 +27,13 @@ void display_grid(int grid[GRID_W][GRID_H]) {
  for (int x = 0; x < GRID_W; x++) {
  if ((block = grid[x][y]) != EMPTY) {
  attron(COLOR_PAIR(block));
- printw("@");
+
+ if (block == GHOST) {
+ printw(" ");
+ } else {
+ printw("@");
+ }
+
  attroff(COLOR_PAIR(block));
  } else {
  printw(" ");

src/scorer.c

@@ -37,21 +37,6 @@ int is_empty(int grid[GRID_W][GRID_H]) {
  return 1;
 }
 
-void compute_heights(State* s) {
- int h;
-
- // recompute row heights
- for (int c=0; c<GRID_W; c++) {
- h = 0;
- for (int r=GRID_H-1; r>=0; r--) {
- if (s->grid[c][r] != EMPTY) {
- h = GRID_H - r;
- }
- }
- s->heights[c] = h;
- }
-}
-
 void score_block(State* s) {
  s->score += 10 * (s->level);
 }
@@ -110,6 +95,5 @@ void clear_rows(State* s) {
 void update_score(State* s) {
  score_block(s);
  clear_rows(s);
- compute_heights(s);
 }
 

src/utils.c

@@ -16,6 +16,70 @@ int in_grid(int x, int y) {
  return 1;
 }
 
+void clear_block(State* s) {
+ for (int i = 0; i < 4; i++) {
+ int x = s->block->cells[i][0] + s->block->x;
+ int y = s->block->cells[i][1] + s->block->y;
+
+ s->grid[x][y] = EMPTY;
+ }
+}
+
+void clear_ghost(State* s) {
+ for (int i = 0; i < 4; i++) {
+ int x = s->block->cells[i][0] + s->block->x;
+ int y = s->block->cells[i][1] + s->block->ghosty;
+
+ s->grid[x][y] = EMPTY;
+ }
+}
+
+void draw_block(State* s) {
+ for (int i = 0; i < 4; i++) {
+ int x = s->block->cells[i][0] + s->block->x;
+ int y = s->block->cells[i][1] + s->block->y;
+
+ s->grid[x][y] = s->block->color;
+ }
+}
+
+void draw_ghost(State* s) {
+ for (int i = 0; i < 4; i++) {
+ int x = s->block->cells[i][0] + s->block->x;
+ int y = s->block->cells[i][1] + s->block->ghosty;
+
+ s->grid[x][y] = GHOST;
+ }
+}
+
+void project_ghost(State* s) {
+ int ghost_y = s->block->y;
+
+ if (ghost_y > GRID_H-OFFSET) ghost_y = GRID_H-OFFSET;
+
+ // It can be assumed that the ghost fits in the starting position since
+ // it starts in the same place as the block.
+ while (ghost_y < GRID_H) {
+ int can_move_down = 1;
+ for (int i = 0; i < 4; i++) {
+ int x = s->block->cells[i][0] + s->block->x;
+ int y = s->block->cells[i][1] + ghost_y;
+
+ if(!in_grid(x, y+1) || s->grid[x][y+1] != EMPTY) {
+ can_move_down = 0;
+ }
+ }
+
+ if (can_move_down) {
+ ghost_y++;
+ } else {
+ break;
+ }
+ }
+
+ s->block->ghosty = ghost_y;
+}
+
 void increment_with_max(int* num, int max) {
  (*num)++;
  if (*num > max) {

src/utils.h

@@ -36,33 +36,12 @@ extern const int L_Block[4][2];
 extern const int rotation_matrix_R[2][2];
 extern const int rotation_matrix_L[2][2];
 
-/*
- * Checks whether coordinate is inside playable area
- */
-int in_grid(int x, int y);
-
-/*
- * Increment an integer by one without surpassing a specified maximum
- *
- * @param num: the integer to increment
- * @param max: the maximum value that the integer can be incremented to
- */
-void increment_with_max(int* num, int max);
-
-/*
- * Decrement an integer by one without surpassing a specified minimum
- *
- * @param num: the integer to deccrement
- * @param max: the minimum value that the integer can be deccremented to
- */
-void decrement_with_min(int* num, int min);
-
 /*
  * Taken from https://i.stack.imgur.com/JLRFu.png
  *
  * Not defined as enum class to allow implicit casting to int
  */
-typedef enum {EMPTY, CYAN, BLUE, WHITE, YELLOW, GREEN, PURPLE, RED} BlockColor;
+typedef enum {EMPTY, CYAN, BLUE, WHITE, YELLOW, GREEN, PURPLE, RED, GHOST} BlockColor;
 
 /*
  * Taken from http://tetris.wikia.com/wiki/Tetromino
@@ -84,15 +63,14 @@ typedef enum {RUNNING, PAUSED, CONFIRM_QUIT, SHUTDOWN, BOSS} Gamemode;
 */
 typedef struct {
  int cells[4][2];
- int x;
- int y;
+ int x, y;
+ int ghosty;
  BlockColor color;
  BlockType type;
 } Block;
 
 typedef struct {
  int grid[GRID_W][GRID_H];
- int heights[GRID_W];
  int score;
  int level;
  Gamemode mode; // 1: Game in progress 0: Game over
@@ -110,4 +88,56 @@ typedef struct {
  Rotation r;
 } Movement;
 
+/*
+ * Checks whether coordinate is inside playable area
+ */
+int in_grid(int x, int y);
+
+/*
+ * Set all cells occupied by playable block to EMPTY
+ */
+void clear_block(State* s);
+
+/*
+ * Set all cells occupied by playable block to the block's color
+ */
+void draw_block(State* s);
+
+/*
+ * Set all cells occupied by playable block's ghost to EMPTY
+ * Note: this implementation allows for overlap between playable block and
+ * its ghost, so this method may clear some cells of the playable block.
+ */
+void clear_ghost(State* s);
+
+/*
+ * Set all cells occupied by the playable block's ghost to the GHOST color.
+ * Note: since the ghost and playable block may overlap, the order in which
+ * their draw calls are made will determine which renders "ontop" of the other.
+ */
+void draw_ghost(State* s);
+
+/*
+ * Calculate and assign correct position for the ghost of the playable block.
+ * The correct position of the ghost is always the furthest down the block may
+ * travel before hitting any other block.
+ */
+void project_ghost(State* s);
+
+/*
+ * Increment an integer by one without surpassing a specified maximum
+ *
+ * @param num: the integer to increment
+ * @param max: the maximum value that the integer can be incremented to
+ */
+void increment_with_max(int* num, int max);
+
+/*
+ * Decrement an integer by one without surpassing a specified minimum
+ *
+ * @param num: the integer to deccrement
+ * @param max: the minimum value that the integer can be deccremented to
+ */
+void decrement_with_min(int* num, int min);
+
 #endif