merge: Go mechanics

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/archive/2026-11-08-gol-simulation/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-11-08

openspec/changes/archive/2026-11-08-gol-simulation/design.md

@@ -0,0 +1,43 @@
+# Design
+
+## Context
+
+Input, placement, HiDPI, and grid are implemented. Simulation state (`sim_paused`, `ACTION_PAUSE`, `ACTION_STEP`, speed actions) exists but is unused. See proposal.md.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Conway tick loop with adjustable interval.
+- Pause/resume, stepping, speed control.
+- Paused-only cell editing via mouse, including drag painting.
+
+**Non-Goals:**
+- Pattern detection or statistics.
+- Undo/redo.
+- Multi-threading.
+
+## Decisions
+
+### D1: Tick timing
+- Use monotonic clock in the frame loop; accumulate elapsed time; when >= interval, compute next generation and reset accumulator.
+
+### D2: Next generation buffer
+- Allocate a second grid buffer; compute into it, then swap pointers (or copy). Prefer swap of `cells` pointers with size unchanged.
+
+### D3: Editing while paused
+- Pointer button handler sets/clears cells if `sim_paused`; drag paints using motion events while button held.
+
+### D4: Speed bounds
+- Interval range 0.05s..1.0s (20 tps..1 tps), step factor 2.
+
+### D5: Default bindings
+- Add `p`, `n`, `+`/`-` to default config (merge).
+
+## Risks / Trade-offs
+
+- [Tick cost on large grids] -> grid is small (50x50), fine.
+- [Editing during tick race] -> editing only while paused avoids races.
+
+## Open Questions
+
+None.

openspec/changes/archive/2026-11-08-gol-simulation/proposal.md

@@ -0,0 +1,29 @@
+# Proposal
+
+## Why
+
+The application now supports input, pattern placement, and HiDPI rendering, but has no Game of Life dynamics. This change adds the actual automaton: Conway's rules, pause/resume, single stepping, speed control, and mouse editing of cells, so the tool becomes usable for exploring patterns.
+
+## What Changes
+
+- Add Conway's Game of Life simulation that updates the cell grid on a timer.
+- Start paused by default; allow pause/resume, single-step, and speed changes.
+- Allow mouse editing of cells (left click sets alive, right click sets dead) only while paused, including drag painting.
+- Add default key bindings for pause (`p`), step (`n`), and speed (`+`/`-`).
+- Render simulation state and reflect pause/editing in the UI (via stdout status).
+
+## Capabilities
+
+### New Capabilities
+
+- `gol-simulation`: Conway rules, tick timing, pause/resume, stepping, speed control, and paused-only editing.
+
+### Modified Capabilities
+
+None.
+
+## Impact
+
+- Affected code: `wlgol.c`, `grid.c/h` (read during ticks), possibly new `simulation.c/h`.
+- Reuses existing input/config infrastructure; no new dependencies.
+- Config defaults updated with simulation keys.

openspec/changes/archive/2026-11-08-gol-simulation/specs/gol-simulation/spec.md

@@ -0,0 +1,86 @@
+# Spec Delta
+
+## Purpose
+
+Defines Conway's Game of Life simulation behavior, including ticking, pause/resume, stepping, speed control, and paused-only cell editing.
+
+## ADDED Requirements
+
+### Requirement: Simulation applies Conway's rules
+The system SHALL advance the grid by one generation per tick using Conway's rules with wall boundaries.
+
+#### Scenario: Tick advances grid
+- **WHEN** a tick occurs
+- **THEN** each cell's next state follows Conway's rules based on its eight neighbors
+
+### Requirement: Simulation starts paused
+The system SHALL start with the simulation paused.
+
+#### Scenario: Initial state
+- **WHEN** the application starts
+- **THEN** the simulation is paused
+
+### Requirement: Pause can be toggled
+The system SHALL toggle between paused and running when the pause action is triggered.
+
+#### Scenario: Toggle pause
+- **WHEN** the user triggers the pause action
+- **THEN** the simulation switches between paused and running
+
+### Requirement: Single step advances one generation
+The system SHALL advance exactly one generation when the step action is triggered while paused.
+
+#### Scenario: Step while paused
+- **WHEN** the simulation is paused and the user triggers step
+- **THEN** the grid advances by one generation
+- **AND** the simulation remains paused
+
+### Requirement: Step is ignored while running
+The system SHALL ignore the step action while the simulation is running.
+
+#### Scenario: Step while running
+- **WHEN** the simulation is running and the user triggers step
+- **THEN** no extra generation is applied
+
+### Requirement: Speed is adjustable
+The system SHALL change the tick interval when speed_up or speed_down is triggered, within supported bounds.
+
+#### Scenario: Speed up
+- **WHEN** the user triggers speed_up
+- **THEN** the tick interval decreases (simulation runs faster)
+
+#### Scenario: Speed down
+- **WHEN** the user triggers speed_down
+- **THEN** the tick interval increases (simulation runs slower)
+
+### Requirement: Cell editing only while paused
+The system SHALL allow editing cells only while the simulation is paused.
+
+#### Scenario: Edit while paused
+- **WHEN** the simulation is paused and the user clicks a cell
+- **THEN** the cell state changes according to the mouse button
+
+#### Scenario: No edit while running
+- **WHEN** the simulation is running and the user clicks a cell
+- **THEN** the grid is not modified by the click
+
+### Requirement: Left click sets cell alive
+The system SHALL set the clicked cell to alive when the left mouse button is pressed while paused.
+
+#### Scenario: Set alive
+- **WHEN** the simulation is paused and the user left-clicks a cell
+- **THEN** that cell becomes alive
+
+### Requirement: Right click sets cell dead
+The system SHALL set the clicked cell to dead when the right mouse button is pressed while paused.
+
+#### Scenario: Set dead
+- **WHEN** the simulation is paused and the user right-clicks a cell
+- **THEN** that cell becomes dead
+
+### Requirement: Drag paints cells
+The system SHALL paint cells while dragging with the left button (alive) or right button (dead) while paused.
+
+#### Scenario: Drag paint
+- **WHEN** the simulation is paused and the user drags with left button held
+- **THEN** cells under the cursor become alive

openspec/changes/archive/2026-11-08-gol-simulation/tasks.md

@@ -0,0 +1,21 @@
+# Tasks
+
+## 1. Simulation core
+
+- [x] 1.1 Implement Conway tick using a second grid buffer and swap, verifying a known pattern (blinker) oscillates.
+- [x] 1.2 Add tick timing in the frame loop with adjustable interval, verifying ticks occur at configured rate.
+
+## 2. Controls
+
+- [x] 2.1 Wire pause/step/speed actions to simulation state, verifying pause stops ticks and step advances one generation.
+- [x] 2.2 Add default key bindings for p/n/+/- and verify config tests pass.
+
+## 3. Editing
+
+- [x] 3.1 Implement paused-only cell editing on left/right click, verifying clicks change cell state only when paused.
+- [x] 3.2 Implement drag painting while paused, verifying drag sets/clears cells.
+
+## 4. Verification
+
+- [x] 4.1 Build and run ctest, verifying all tests pass.
+- [x] 4.2 Manual run: verify pause, step, speed, editing, and Esc.

openspec/specs/gol-simulation/spec.md

@@ -0,0 +1,85 @@
+# gol-simulation Specification
+
+## Purpose
+Defines Conway's Game of Life simulation behavior, including ticking, pause/resume, stepping, speed control, and paused-only cell editing.
+
+## Requirements
+
+### Requirement: Simulation applies Conway's rules
+The system SHALL advance the grid by one generation per tick using Conway's rules with wall boundaries.
+
+#### Scenario: Tick advances grid
+- **WHEN** a tick occurs
+- **THEN** each cell's next state follows Conway's rules based on its eight neighbors
+
+### Requirement: Simulation starts paused
+The system SHALL start with the simulation paused.
+
+#### Scenario: Initial state
+- **WHEN** the application starts
+- **THEN** the simulation is paused
+
+### Requirement: Pause can be toggled
+The system SHALL toggle between paused and running when the pause action is triggered.
+
+#### Scenario: Toggle pause
+- **WHEN** the user triggers the pause action
+- **THEN** the simulation switches between paused and running
+
+### Requirement: Single step advances one generation
+The system SHALL advance exactly one generation when the step action is triggered while paused.
+
+#### Scenario: Step while paused
+- **WHEN** the simulation is paused and the user triggers step
+- **THEN** the grid advances by one generation
+- **AND** the simulation remains paused
+
+### Requirement: Step is ignored while running
+The system SHALL ignore the step action while the simulation is running.
+
+#### Scenario: Step while running
+- **WHEN** the simulation is running and the user triggers step
+- **THEN** no extra generation is applied
+
+### Requirement: Speed is adjustable
+The system SHALL change the tick interval when speed_up or speed_down is triggered, within supported bounds.
+
+#### Scenario: Speed up
+- **WHEN** the user triggers speed_up
+- **THEN** the tick interval decreases (simulation runs faster)
+
+#### Scenario: Speed down
+- **WHEN** the user triggers speed_down
+- **THEN** the tick interval increases (simulation runs slower)
+
+### Requirement: Cell editing only while paused
+The system SHALL allow editing cells only while the simulation is paused.
+
+#### Scenario: Edit while paused
+- **WHEN** the simulation is paused and the user clicks a cell
+- **THEN** the cell state changes according to the mouse button
+
+#### Scenario: No edit while running
+- **WHEN** the simulation is running and the user clicks a cell
+- **THEN** the grid is not modified by the click
+
+### Requirement: Left click sets cell alive
+The system SHALL set the clicked cell to alive when the left mouse button is pressed while paused.
+
+#### Scenario: Set alive
+- **WHEN** the simulation is paused and the user left-clicks a cell
+- **THEN** that cell becomes alive
+
+### Requirement: Right click sets cell dead
+The system SHALL set the clicked cell to dead when the right mouse button is pressed while paused.
+
+#### Scenario: Set dead
+- **WHEN** the simulation is paused and the user right-clicks a cell
+- **THEN** that cell becomes dead
+
+### Requirement: Drag paints cells
+The system SHALL paint cells while dragging with the left button (alive) or right button (dead) while paused.
+
+#### Scenario: Drag paint
+- **WHEN** the simulation is paused and the user drags with left button held
+- **THEN** cells under the cursor become alive

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;