From 38a40eb2e43b29195edbfae044f5d3c59ed3c693 Mon Sep 17 00:00:00 2001
From: hkz <tabaglio@posteo.net>
Date: Fri, 18 Jul 2025 09:12:17 +0200
Subject: [PATCH] Fix logic

---
 src/game_graphics.c | 21 ++++++++++++++++++++-
 src/game_graphics.h |  1 +
 src/game_logic.c    | 17 ++++++++---------
 src/main.c          | 11 ++++++++---
 4 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/src/game_graphics.c b/src/game_graphics.c
index 2c1d188..13f028b 100644
--- a/src/game_graphics.c
+++ b/src/game_graphics.c
@@ -8,6 +8,7 @@
 #include "line_data.h"
 #include "game_logic.h"
 #include "tiles.h"
+#include "monitor_subroutines.h"
 
 #define SCREEN_WIDTH_B 40
 #define GRID_CELL_SIDE 35
@@ -45,13 +46,31 @@ void draw_game_background(void) {
 	
 }
 
+// This will draw directly to the front buffer
+void ddraw_single_tile(uint8_t offset) {
+	uint8_t* grid = get_front_grid();
+	if(!grid[offset]) return; // The tile is not there, nothing to do
+	
+	const uint8_t *tile_data = tiles + (TILE_WIDTH_BYTES * TILE_HEIGHT * (grid[offset] - 1));
+	
+	uint8_t col = offset % GRID_SIDE;
+	uint8_t row = offset / GRID_SIDE;
+	
+	uint8_t delay = 0xFF;
+	
+	for(uint8_t h = 0; h < TILE_HEIGHT; h++) {
+		memcpy(front_buf + line_offset_map[TOP_OFFSET + 7 + (row * GRID_CELL_SIDE) + h] + LEFT_OFFSET_B + 1 + (col * GRID_CELL_SIDE/7), 
+			tile_data + (TILE_WIDTH_BYTES * h), TILE_WIDTH_BYTES);
+		WAIT(48);
+	}
+}
+
 void draw_tiles(void) {
 	uint8_t* grid = get_front_grid();
 	
 	// Clear the grid so we'll be able to draw the boxes on
 	clear_box(GRID_SIDE * (GRID_CELL_SIDE/7) + 1, (GRID_SIDE * GRID_CELL_SIDE) + 6, LEFT_OFFSET_B, TOP_OFFSET + 1, back_buf);
 
-
 	for (uint8_t tile = 0; tile < GRID_SIDE * GRID_SIDE; tile++) {
 		if(grid[tile]) {
 			const uint8_t *tile_data = tiles + (TILE_WIDTH_BYTES * TILE_HEIGHT * (grid[tile] - 1));
diff --git a/src/game_graphics.h b/src/game_graphics.h
index 18d4653..fbcafed 100644
--- a/src/game_graphics.h
+++ b/src/game_graphics.h
@@ -5,5 +5,6 @@
 
 void draw_game_background(void);
 void draw_tiles(void);
+void ddraw_single_tile(uint8_t offset);
 
 #endif /* _GAME_GRAPHICS_HEADER_ */
diff --git a/src/game_logic.c b/src/game_logic.c
index 3b532b0..5316a74 100644
--- a/src/game_logic.c
+++ b/src/game_logic.c
@@ -35,19 +35,18 @@ uint8_t *get_front_grid(void) {
 
 uint8_t add_random_tile(void) {
 	uint16_t rand = lfsr_update();
-	uint8_t tile_val = (rand & 0x000F) > 0x0D ? 2 : 1; // 90% chance of a tile of type 1 (a "2"), 10% of a type 2 (a "4")
+	uint8_t tile_val = (rand & 0x000F) > 0x0D ? 2 : 1; // ~90% chance of a tile of type 1 (a "2"), 10% of a type 2 (a "4")
 	uint8_t rand_offset = rand >> 8;
-	uint8_t tile_placed = 0;
 	
-	for (int8_t offset = 0; offset < GRID_SIDE * GRID_SIDE; offset++) {
-		if (!front_grid[(offset + rand_offset)%(GRID_SIDE * GRID_SIDE)]) {
-			front_grid[(offset + rand_offset)%(GRID_SIDE * GRID_SIDE)] = tile_val;
-			tile_placed = 1;
-			break;
+	for (uint8_t offset = 0; offset < GRID_SIDE * GRID_SIDE; offset++) {
+		uint8_t rand_off = (offset + rand_offset)%(GRID_SIDE * GRID_SIDE);
+		if (!front_grid[rand_off]) {
+			front_grid[rand_off] = tile_val;
+			return rand_off + 1;
 		}
 	}
 	
-	return tile_placed; // Return 0 if we were not able to place the tile
+	return 0; // Return 0 if we were not able to place the tile, else we return (offset + 1) to indicate where the tile was placed
 }
 
 game_state step_game(step_direction dir) {	
@@ -123,7 +122,7 @@ game_state step_game(step_direction dir) {
 					state.score += ((uint16_t)1) << back_grid[current_offset];
 					state.done += back_grid[current_offset] == 11 ? 1 : 0;
 					break;
-				}
+				} else if (front_grid[sub_col_offset]) break;
 			}
 		}
 	}
diff --git a/src/main.c b/src/main.c
index 76158ae..bcaecab 100644
--- a/src/main.c
+++ b/src/main.c
@@ -64,10 +64,15 @@ __task int main(void) {
 			// If we have finished, break out of this loop
 			if(state.done) break;
 			
-			// Unable to add a tile. We lost!!!
-			if(!add_random_tile()) break;
-			
+			// Draw the moved sprites
 			draw_tiles();
+			
+			// Unable to add a tile. We lost!!!
+			uint8_t random_tile_off = add_random_tile();
+			if(!random_tile_off) break;
+			
+			// Draw the new tile directly on the front buffer
+			ddraw_single_tile(random_tile_off - 1);
 		}
 
 	};