gravity bugfix, update display_board signature

* Fix bug introduced in last commit when I tried to explicitly cast a uint
    to an int variable; it prevented the gravity check from ever activating,
    so pieces wouldn't ever actually be added to be board.
* Changed display_board to take TetrisBoard instead of TetrisBoard*

include/driver_tetris.h

@@ -39,7 +39,7 @@
                        waddch((w),' '|A_REVERSE|COLOR_PAIR(x))
 #define ADD_EMPTY(w) waddch((w), ' '); waddch((w), ' ')
 
-void display_board(WINDOW *w, TetrisBoard *b);
+void display_board(WINDOW *w, TetrisBoard b);
 void update_score(WINDOW *w, TetrisGame *tg);
 
 // Debug functions

src/driver_tetris.c

@@ -84,7 +84,7 @@ int main(void) {
         tg_tick(tg, move);
 
         // display board
-        display_board(g_win, &tg->active_board);
+        display_board(g_win, tg->active_board);
         update_score(s_win, tg);
 
         switch(getch()) {
@@ -161,7 +161,7 @@ int main(void) {
 /**
  * Draw board array presented by tetris game
 */
-void display_board(WINDOW *w, TetrisBoard *tb) {
+void display_board(WINDOW *w, TetrisBoard tb) {
 
     static struct timeval last_update;
 
@@ -179,8 +179,8 @@ void display_board(WINDOW *w, TetrisBoard *tb) {
             wmove(w, 1 + i, 1);
             for (int j = 0; j < TETRIS_COLS; j++) {
 
-                if (tb->board[i][j] >= 0) {
-                    ADD_BLOCK(w, tb->board[i][j]);
+                if (tb.board[i][j] >= 0) {
+                    ADD_BLOCK(w, tb.board[i][j]);
                 }
                 else {
                     ADD_EMPTY(w);
@@ -191,10 +191,11 @@ void display_board(WINDOW *w, TetrisBoard *tb) {
 
         last_update = curr_time_usec;
         wrefresh(w);
+
         #ifdef DEBUG_T
         // fprintf(gamelog, "display_board()\n");
         // print_board_state(*tb, gamelog);
-        fflush(gamelog);
+        // fflush(gamelog);
         #endif
 
         #ifdef DEBUG_T_WIN

tetris/tetris.c

@@ -411,7 +411,7 @@ bool check_do_piece_gravity(TetrisGame *tg) {
     // check if it's time for piece to be moved down
     int32_t time_diff_usec = get_elapsed_us(tg->last_gravity_tick_usec, curr_time_usec);
 
-    if (time_diff_usec > (int32_t)tg->gravity_tick_rate_usec) {
+    if (time_diff_usec > tg->gravity_tick_rate_usec) {
 
         // if can move down
         if(check_valid_move(tg, T_DOWN)) {