Add quick drop for blocks with a preview of where the current block will fall (#7)

Author: scottnm

demo/14-quick-drop.gif

@@ -81,8 +81,10 @@
 
 ![Image of increased fall speed](demo/13-fallspeed.gif)
 
-- [ ] Handle quick fall
-- [ ] Show piece fall preview
+- [X] [Handle quick drop and show drop preview](https://github.com/scottnm/tetrust/commit/FILL)
+
+![Image of quick drop and drop preview](demo/14-quick-drop.gif)
+
 - [ ] Add start screen
 - [ ] Add high score logging
 - [ ] Add high score screen from start

readme.md

@@ -141,7 +141,7 @@ impl GameState {
                             self.game_phase = GamePhase::StartNextBlock
                         }
                     } else {
-                        self.active_block_pos.y += 1;
+                        self.move_active_block_down();
                     }
                 }
 
@@ -151,7 +151,7 @@ impl GameState {
         }
     }
 
-    pub fn move_block_horizontal(&mut self, horizontal_motion: i32) {
+    pub fn move_active_block_horizontal(&mut self, horizontal_motion: i32) {
         match self.game_phase {
             GamePhase::MoveBlock => {
                 if self.can_active_block_move(horizontal_motion) {
@@ -162,6 +162,16 @@ impl GameState {
         }
     }
 
+    pub fn move_active_block_down(&mut self) {
+        self.active_block_pos.y += 1;
+    }
+
+    pub fn quick_drop(&mut self) {
+        while !self.has_active_block_landed() {
+            self.move_active_block_down();
+        }
+    }
+
     pub fn rotate_block(&mut self, relative_rotation: i32) {
         // no rotation means no rotation. noop.
         if relative_rotation == 0 {

src/game.rs

@@ -113,51 +113,56 @@ fn main() {
     let mut last_frame_time = time::Instant::now();
     let mut last_input_handled = time::Instant::now();
 
-    const BOARD_RECT: Rect = Rect {
-        left: 1,
-        top: 1,
-        width: 10,
+    // standard tetris board size
+    const BOARD_WIDTH: i32 = 10;
+    const BOARD_HEIGHT: i32 = 20;
+
+    let (window_height, window_width) = window.get_max_yx();
+    let board_rect: Rect = Rect {
+        left: (window_width / 2) - BOARD_WIDTH - 2, // arrange the board on the left side of the middle of the screen
+        top: (window_height - BOARD_HEIGHT) / 2,    // center the board within the window
+        width: BOARD_WIDTH,
         height: 20,
     };
 
-    const BOARD_FRAME_RECT: Rect = Rect {
-        left: BOARD_RECT.left - 1,
-        top: BOARD_RECT.top - 1,
-        width: BOARD_RECT.width + 2,
-        height: BOARD_RECT.height + 2,
+    let board_frame_rect: Rect = Rect {
+        left: board_rect.left - 1,
+        top: board_rect.top - 1,
+        width: board_rect.width + 2,
+        height: board_rect.height + 2,
     };
 
-    const TITLE_RECT: Rect = Rect {
-        left: BOARD_FRAME_RECT.right() + 2,
-        top: BOARD_FRAME_RECT.top,
+    let title_rect: Rect = Rect {
+        left: board_frame_rect.right() + 2,
+        top: board_frame_rect.top,
         width: (TITLE.len() + 4) as i32,
         height: 3,
     };
 
-    const PREVIEW_FRAME_RECT: Rect = Rect {
-        left: TITLE_RECT.left,
-        top: TITLE_RECT.bottom() + 2,
+    let preview_frame_rect: Rect = Rect {
+        left: title_rect.left,
+        top: title_rect.bottom() + 2,
         width: 6,
         height: 6,
     };
 
-    const PREVIEW_RECT: Rect = Rect {
-        left: PREVIEW_FRAME_RECT.left + 1,
-        top: PREVIEW_FRAME_RECT.top + 1,
-        width: PREVIEW_FRAME_RECT.width - 2,
-        height: PREVIEW_FRAME_RECT.height - 2,
+    let preview_rect: Rect = Rect {
+        left: preview_frame_rect.left + 1,
+        top: preview_frame_rect.top + 1,
+        width: preview_frame_rect.width - 2,
+        height: preview_frame_rect.height - 2,
     };
 
-    const SCORE_FRAME_RECT: Rect = Rect {
-        left: PREVIEW_FRAME_RECT.left,
-        top: PREVIEW_FRAME_RECT.bottom() + 2,
+    let score_frame_rect: Rect = Rect {
+        left: preview_frame_rect.left,
+        top: preview_frame_rect.bottom() + 2,
         width: 14,
         height: 4,
     };
 
     let mut game_state = GameState::new(
-        BOARD_RECT.width,
-        BOARD_RECT.height,
+        board_rect.width,
+        board_rect.height,
         Box::new(ThreadRangeRng::new()),
     );
 
@@ -166,13 +171,15 @@ fn main() {
         move_right: bool,
         rot_left: bool,
         rot_right: bool,
+        drop: bool,
     }
 
     let mut inputs = Inputs {
         move_left: false,
         move_right: false,
         rot_left: false,
         rot_right: false,
+        drop: false,
     };
 
     let mut game_over_blit_timer = Option::<time::Instant>::None;
@@ -189,6 +196,7 @@ fn main() {
                 // check for movement inputs
                 'a' => inputs.move_left = true,
                 'd' => inputs.move_right = true,
+                's' => inputs.drop = true,
                 'j' => inputs.rot_left = true,
                 'l' => inputs.rot_right = true,
 
@@ -211,7 +219,7 @@ fn main() {
             if inputs.move_right {
                 horizontal_motion += 1;
             }
-            game_state.move_block_horizontal(horizontal_motion);
+            game_state.move_active_block_horizontal(horizontal_motion);
 
             let mut relative_rotation: i32 = 0;
             if inputs.rot_left {
@@ -222,11 +230,16 @@ fn main() {
             }
             game_state.rotate_block(relative_rotation);
 
+            if inputs.drop {
+                game_state.quick_drop();
+            }
+
             inputs = Inputs {
                 move_left: false,
                 move_right: false,
                 rot_left: false,
                 rot_right: false,
+                drop: false,
             };
         }
 
@@ -239,53 +252,65 @@ fn main() {
         window.erase();
 
         // Render the tetris title
-        draw_frame(&window, &TITLE_RECT);
-        draw_text_centered(&window, TITLE, TITLE_RECT.center_x(), TITLE_RECT.center_y());
+        draw_frame(&window, &title_rect);
+        draw_text_centered(&window, TITLE, title_rect.center_x(), title_rect.center_y());
 
         // Render next piece preview
         draw_text_centered(
             &window,
             "Next",
-            PREVIEW_FRAME_RECT.center_x(),
-            PREVIEW_FRAME_RECT.top - 1,
+            preview_frame_rect.center_x(),
+            preview_frame_rect.top - 1,
         );
-        draw_frame(&window, &PREVIEW_FRAME_RECT);
+        draw_frame(&window, &preview_frame_rect);
         render_block(
             &window,
             Vec2::zero(),
-            PREVIEW_RECT.left,
-            PREVIEW_RECT.top,
+            preview_rect.left,
+            preview_rect.top,
             game_state.preview_block(),
         );
 
         // Render the score pane
         draw_text_centered(
             &window,
             &format!("Level: {:05}", game_state.level()),
-            SCORE_FRAME_RECT.center_x(),
-            SCORE_FRAME_RECT.center_y() - 1,
+            score_frame_rect.center_x(),
+            score_frame_rect.center_y() - 1,
         );
         draw_text_centered(
             &window,
             &format!("Score: {:05}", game_state.score()),
-            SCORE_FRAME_RECT.center_x(),
-            SCORE_FRAME_RECT.center_y(),
+            score_frame_rect.center_x(),
+            score_frame_rect.center_y(),
         );
-        draw_frame(&window, &SCORE_FRAME_RECT);
+        draw_frame(&window, &score_frame_rect);
+
+        // Render the board frame
+        draw_frame(&window, &board_frame_rect);
 
         // Render the active piece
-        draw_frame(&window, &BOARD_FRAME_RECT);
         if let Some((block, block_pos)) = game_state.active_block() {
-            render_block(&window, block_pos, BOARD_RECT.left, BOARD_RECT.top, block);
+            // TOOD: mayhaps refactor this into its own helper?
+            // render the active piece's drop trail
+            for cell in &block.cells() {
+                let start_row = cell.y + block_pos.y;
+                let col = cell.x + block_pos.x;
+                for row in start_row..board_rect.height {
+                    window.mvaddch(row + board_rect.top, col + board_rect.left, '-');
+                }
+            }
+
+            render_block(&window, block_pos, board_rect.left, board_rect.top, block);
         }
 
         // Render the settled pieces
         game_state.for_each_settled_piece(|block_type: BlockType, cell_pos: Vec2| {
             render_cell(
                 &window,
                 cell_pos,
-                BOARD_RECT.left,
-                BOARD_RECT.top,
+                board_rect.left,
+                board_rect.top,
                 block_type,
             );
         });
@@ -306,8 +331,8 @@ fn main() {
             draw_text_centered(
                 &window,
                 "Game Over",
-                BOARD_RECT.center_x(),
-                BOARD_RECT.center_y(),
+                board_rect.center_x(),
+                board_rect.center_y(),
             );
             window.attroff(pancurses::A_BLINK);
         }
@@ -317,8 +342,8 @@ fn main() {
             draw_text_centered(
                 &window,
                 "PAUSE",
-                BOARD_RECT.center_x(),
-                BOARD_RECT.center_y(),
+                board_rect.center_x(),
+                board_rect.center_y(),
             );
             window.attroff(pancurses::A_BLINK);
         }