From e2819385781fb26188b7560fb325aea62f454e7d Mon Sep 17 00:00:00 2001
From: Dendy Faist <dendy@fai.st>
Date: Sat, 7 Oct 2023 20:38:27 +0200
Subject: [PATCH] Add timer to line clearing

---
 src/Game.zig      | 26 +++++++++++++++++++++++++-
 src/Game/Grid.zig | 36 +++++++++++++++++++++++++++++-------
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/Game.zig b/src/Game.zig
index 68f0e22..0dbd808 100644
--- a/src/Game.zig
+++ b/src/Game.zig
@@ -56,6 +56,7 @@ timer_left_das: Timer,
 timer_right_arr: Timer,
 timer_right_das: Timer,
 timer_gravity: Timer,
+timer_line_clear: Timer,
 
 needs_reinit: bool = false,
 
@@ -75,6 +76,7 @@ pub fn init(renderer: *Renderer.Renderer) Self {
         .timer_right_arr = Timer.init(0.05),
         .timer_right_das = Timer.init(0.2),
         .timer_gravity = Timer.init(0.3),
+        .timer_line_clear = Timer.init(1),
     };
 
     // Get a piece from the bag
@@ -85,6 +87,10 @@ pub fn init(renderer: *Renderer.Renderer) Self {
 
 // Main Game loop
 pub fn tick(self: *Self) State {
+    if (self.timer_line_clear.started and !self.timer_line_clear.finished()) {
+        self.renderer.render(self.*);
+        return self.state;
+    }
 
     // TIMERS
     // Dropping a piece
@@ -209,7 +215,25 @@ pub fn tick(self: *Self) State {
         }
     }
 
-    self.score += self.grid.clearLines();
+    // Check for empty lines. If there are, then start the clearing sequence
+    if (!self.timer_line_clear.started) {
+        if (self.grid.updateLinesToClear()) {
+            self.timer_line_clear.start();
+        }
+    }
+    // Don't go and clear them until the timer has finished
+    else if (self.timer_line_clear.finished()) {
+        const clear_score = self.grid.clearLines();
+        if (clear_score > 0) {
+            self.timer_line_clear.stop();
+            self.score += clear_score;
+        } else {
+            std.debug.print("WARNING: Clear line timer stopped but there was nothign to clear. This situation isn't valid\n", .{});
+        }
+    }
+    // NOTE: If for some reason game doesn't stop and another line has been cleared
+    //       before the timer reached the end, that line will be processed right after
+    //       the timer stops. Behaviour shouldn't get any funkier than that.
 
     self.renderer.render(self.*);
 
diff --git a/src/Game/Grid.zig b/src/Game/Grid.zig
index e71f1a4..5611afc 100644
--- a/src/Game/Grid.zig
+++ b/src/Game/Grid.zig
@@ -15,6 +15,7 @@ pub const buffer = 10;
 
 cells: [nrows][ncolumns]Cell,
 topped: bool = false,
+lines_to_clear: [nrows]bool = .{false} ** nrows,
 
 pub fn init() Self {
     var self = Self{
@@ -30,23 +31,44 @@ pub fn init() Self {
     return self;
 }
 
-pub fn clearLines(self: *Self) u8 {
-    var ncleared: u8 = 0;
+pub fn updateLinesToClear(self: *Self) bool {
+    var ret: bool = false;
+
+    // Look at each row
     for (self.cells, 0..) |_, y| {
+        // Look at each cell in the line
         for (self.cells[y], 0..) |cell_x, x| {
             if (cell_x.free) {
+                // It is free, this line isn't to be cleared
                 break;
             } else {
                 // Reached the end of the column?
                 if (x == self.cells[y].len - 1) {
-                    // Delete current row and bring the others down
-                    for (self.cells[1..y], 0..) |_, i| {
-                        self.cells[y - i] = self.cells[y - i - 1];
-                    }
-                    ncleared += 1;
+                    self.lines_to_clear[y] = true;
+                    ret = true;
                 }
             }
         }
     }
+
+    return ret;
+}
+
+pub fn clearLines(self: *Self) u8 {
+    var ncleared: u8 = 0;
+
+    // Go line by line, checking if any of them needs to be cleared
+    for (self.lines_to_clear, 0..) |_, y| {
+        if (self.lines_to_clear[y]) {
+            // Delete current row and bring the others down
+            for (self.cells[1..y], 0..) |_, i| {
+                self.cells[y - i] = self.cells[y - i - 1];
+            }
+            ncleared += 1;
+        }
+    }
+
+    self.lines_to_clear = .{false} ** nrows;
+
     return ncleared;
 }