feat: add Game of Life simulation mechanics

Implement Conway rules with tick timing, pause/resume, single stepping,
speed control, and paused-only cell editing with drag painting. Update
default key bindings for pause/step/speed. Mark verification complete.

config.c

@@ -60,11 +60,14 @@ int config_parse_mods(const char *s, uint32_t *out_mods, char **out_key) {
     while (t) {
         char *tt = trim(t);
         if (*tt) {
+            char *alias = tt;
+            if (strcmp(tt, "+") == 0) alias = "plus";
+            else if (strcmp(tt, "-") == 0) alias = "minus";
             if (n == cap) {
                 cap = cap ? cap * 2 : 4;
                 toks = realloc(toks, cap * sizeof(char *));
             }
-            toks[n++] = strdup(tt);
+            toks[n++] = strdup(alias);
         }
         t = strtok_r(NULL, "+", &save);
     }
@@ -129,6 +132,10 @@ config_t config_defaults(void) {
         {"space", ACTION_ROTATE},
         {"escape", ACTION_CANCEL},
         {"ctrl+q", ACTION_QUIT},
+        {"p", ACTION_PAUSE},
+        {"n", ACTION_STEP},
+        {"+", ACTION_SPEED_UP},
+        {"-", ACTION_SPEED_DOWN},
     };
     int ndef = sizeof(defs) / sizeof(defs[0]);
     for (int i = 0; i < ndef; i++) {
@@ -152,7 +159,11 @@ static const char *default_file_content =
     "\"4\" = \"select:toad\"\n"
     "\"space\" = \"rotate\"\n"
     "\"escape\" = \"cancel\"\n"
-    "\"ctrl+q\" = \"quit\"\n";
+    "\"ctrl+q\" = \"quit\"\n"
+    "\"p\" = \"pause\"\n"
+    "\"n\" = \"step\"\n"
+    "\"+\" = \"speed_up\"\n"
+    "\"-\" = \"speed_down\"\n";
 
 int config_ensure_default_file(const char *path) {
     if (!path) return -1;

openspec/changes/gol-simulation/tasks.md

@@ -2,20 +2,20 @@
 
 ## 1. Simulation core
 
-- [ ] 1.1 Implement Conway tick using a second grid buffer and swap, verifying a known pattern (blinker) oscillates.
+- [x] 1.1 Implement Conway tick using a second grid buffer and swap, verifying a known pattern (blinker) oscillates.
-- [ ] 1.2 Add tick timing in the frame loop with adjustable interval, verifying ticks occur at configured rate.
+- [x] 1.2 Add tick timing in the frame loop with adjustable interval, verifying ticks occur at configured rate.
 
 ## 2. Controls
 
-- [ ] 2.1 Wire pause/step/speed actions to simulation state, verifying pause stops ticks and step advances one generation.
+- [x] 2.1 Wire pause/step/speed actions to simulation state, verifying pause stops ticks and step advances one generation.
-- [ ] 2.2 Add default key bindings for p/n/+/- and verify config tests pass.
+- [x] 2.2 Add default key bindings for p/n/+/- and verify config tests pass.
 
 ## 3. Editing
 
-- [ ] 3.1 Implement paused-only cell editing on left/right click, verifying clicks change cell state only when paused.
+- [x] 3.1 Implement paused-only cell editing on left/right click, verifying clicks change cell state only when paused.
-- [ ] 3.2 Implement drag painting while paused, verifying drag sets/clears cells.
+- [x] 3.2 Implement drag painting while paused, verifying drag sets/clears cells.
 
 ## 4. Verification
 
-- [ ] 4.1 Build and run ctest, verifying all tests pass.
+- [x] 4.1 Build and run ctest, verifying all tests pass.
-- [ ] 4.2 Manual run: verify pause, step, speed, editing, and Esc.
+- [x] 4.2 Manual run: verify pause, step, speed, editing, and Esc.

wlgol.c

@@ -48,11 +48,18 @@ double current_scale = 1.0;
 int need_resize = 1;
 
 grid_t grid;
+grid_t grid_back;
+int sim_paused = 1;
+double sim_interval = 0.05; /* 20 tps */
+double sim_accumulator = 0.0;
+struct timespec sim_last_time;
+int sim_time_initialized = 0;
+int mouse_left_down = 0;
+int mouse_right_down = 0;
 double cursor_x = 0, cursor_y = 0;
 int click_pending = 0;
 double click_x = 0, click_y = 0;
 int show_grid_lines = 1;
-int sim_paused = 1;
 struct timespec mytime;
 
 struct canvas
@@ -229,6 +236,8 @@ const struct wl_buffer_listener wl_buffer_listener = {
 
 void redraw(); // forward declaration
 
+static void simulation_tick(void);
+
 static void handle_key(uint32_t key, uint32_t state, xkb_keysym_t sym, uint32_t mods, void *user_data)
 {
 	(void)key;
@@ -266,12 +275,25 @@ static void handle_key(uint32_t key, uint32_t state, xkb_keysym_t sym, uint32_t
 		break;
 	case ACTION_PAUSE:
 		sim_paused = !sim_paused;
+		sim_accumulator = 0;
+		printf("paused=%d\n", sim_paused);
 		break;
 	case ACTION_STEP:
-		printf("step requested\n");
+		if (sim_paused) {
+			simulation_tick();
+			printf("stepped\n");
+		}
 		break;
 	case ACTION_SPEED_UP:
+		sim_interval /= 2.0;
+		if (sim_interval < 0.025) sim_interval = 0.025;
+		printf("interval=%g\n", sim_interval);
+		break;
 	case ACTION_SPEED_DOWN:
+		sim_interval *= 2.0;
+		if (sim_interval > 1.0) sim_interval = 1.0;
+		printf("interval=%g\n", sim_interval);
+		break;
 	case ACTION_TOGGLE_GRID:
 		show_grid_lines = !show_grid_lines;
 		break;
@@ -283,12 +305,24 @@ static void handle_key(uint32_t key, uint32_t state, xkb_keysym_t sym, uint32_t
 static void handle_button(uint32_t button, uint32_t state, double x, double y, void *user_data)
 {
 	(void)user_data;
-	if (state != WL_POINTER_BUTTON_STATE_PRESSED) return;
+	if (button == BTN_LEFT) {
-	if (button != BTN_LEFT) return;
+		if (state == WL_POINTER_BUTTON_STATE_PRESSED) {
-	click_x = x;
+			mouse_left_down = 1;
-	click_y = y;
+			click_x = x;
-	click_pending = 1;
+			click_y = y;
-	printf("click at %.1f %.1f\n", x, y);
+			click_pending = 1;
+		} else {
+			mouse_left_down = 0;
+		}
+	}
+	if (button == BTN_RIGHT) {
+		if (state == WL_POINTER_BUTTON_STATE_PRESSED) {
+			mouse_right_down = 1;
+		} else {
+			mouse_right_down = 0;
+		}
+	}
+	printf("button %u state %u at %.1f %.1f\n", button, state, x, y);
 }
 
 void wl_callack_done(void *data, struct wl_callback *callback, uint32_t time)
@@ -342,6 +376,7 @@ static void canvas_resize(int log_w, int log_h, double scale) {
 	}
 
 	grid_resize(&grid, log_w / 8, log_h / 8);
+	grid_resize(&grid_back, grid.cols, grid.rows);
 	need_resize = 0;
 	printf("canvas resized logical=%dx%d phys=%dx%d scale=%g grid=%dx%d\n", log_w, log_h, phys_w, phys_h, scale, grid.cols, grid.rows);
 }
@@ -462,6 +497,39 @@ static void fill_rect(int x0, int y0, int w, int h, unsigned char r, unsigned ch
 	}
 }
 
+static int count_neighbors(int c, int r) {
+    int n = 0;
+    for (int dr = -1; dr <= 1; dr++) {
+        for (int dc = -1; dc <= 1; dc++) {
+            if (dr == 0 && dc == 0) continue;
+            n += grid_get(&grid, c + dc, r + dr);
+        }
+    }
+    return n;
+}
+
+static void simulation_tick(void) {
+    if (grid_back.cols != grid.cols || grid_back.rows != grid.rows) {
+        grid_free(&grid_back);
+        grid_init(&grid_back, grid.cols, grid.rows);
+    }
+    grid_clear(&grid_back);
+    for (int r = 0; r < grid.rows; r++) {
+        for (int c = 0; c < grid.cols; c++) {
+            int alive = grid_get(&grid, c, r);
+            int nb = count_neighbors(c, r);
+            int next = 0;
+            if (alive && (nb == 2 || nb == 3)) next = 1;
+            if (!alive && nb == 3) next = 1;
+            grid_set(&grid_back, c, r, next);
+        }
+    }
+    /* swap cell buffers */
+    unsigned char *tmp = grid.cells;
+    grid.cells = grid_back.cells;
+    grid_back.cells = tmp;
+}
+
 void redraw()
 {
 	if (need_resize) {
@@ -474,6 +542,35 @@ void redraw()
 	cursor_x = pointer_data.x;
 	cursor_y = pointer_data.y;
 
+	/* tick timing */
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	if (!sim_time_initialized) {
+		sim_last_time = now;
+		sim_time_initialized = 1;
+	}
+	double dt = (now.tv_sec - sim_last_time.tv_sec) + (now.tv_nsec - sim_last_time.tv_nsec) / 1e9;
+	sim_last_time = now;
+	if (!sim_paused) {
+		sim_accumulator += dt;
+		while (sim_accumulator >= sim_interval) {
+			simulation_tick();
+			sim_accumulator -= sim_interval;
+		}
+	}
+
+	/* paused-only editing */
+	if (sim_paused && active_tool < 0) {
+		if (mouse_left_down || mouse_right_down) {
+			int cx = (int)(cursor_x / 8.0);
+			int cy = (int)(cursor_y / 8.0);
+			if (cx >= 0 && cy >= 0 && cx < grid.cols && cy < grid.rows) {
+				if (mouse_left_down) grid_set(&grid, cx, cy, 1);
+				if (mouse_right_down) grid_set(&grid, cx, cy, 0);
+			}
+		}
+	}
+
 	/* handle pending click placement */
 	if (click_pending) {
 		click_pending = 0;