feat(examples): add Conway's Game of Life SDL2 app

examples/SDL2_Life/.gitignore

@@ -0,0 +1 @@
+life

examples/SDL2_Life/Makefile

@@ -0,0 +1,18 @@
+CC       ?= gcc
+CFLAGS   ?= -std=c11 -Wall -Wextra -O2
+PKGS     := sdl2
+PKG_CFLAGS := $(shell pkg-config --cflags $(PKGS))
+PKG_LIBS   := $(shell pkg-config --libs $(PKGS))
+
+TARGET := life
+SRC    := main.c
+
+all: $(TARGET)
+
+$(TARGET): $(SRC)
+	$(CC) $(CFLAGS) $(PKG_CFLAGS) $(SRC) -o $(TARGET) $(PKG_LIBS)
+
+clean:
+	rm -f $(TARGET)
+
+.PHONY: all clean

examples/SDL2_Life/main.c

@@ -0,0 +1,139 @@
+/*
+ * Conway's Game of Life for CardputerZero (320x170, SDL2).
+ *
+ * Ported from the Phoebe LVGL app (app_life). A toroidal cellular automaton
+ * that auto-reseeds when the population stalls, goes extinct, or ages out.
+ * No network or sensors. Cells are drawn as filled rects scaled to the panel.
+ *
+ * Keys: SPACE reseed, P pause, ESC / Q quit.
+ */
+#include <SDL2/SDL.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+#define SCREEN_W 320
+#define SCREEN_H 170
+
+/* Grid: cells are CELL x CELL px. 80x42 grid at CELL=4 fills 320x168. */
+#define CELL 4
+#define GW   (SCREEN_W / CELL)   /* 80 */
+#define GH   (SCREEN_H / CELL)   /* 42 */
+
+#define STEP_MS 90               /* generation interval */
+
+static uint8_t cur[GW * GH];
+static uint8_t nxt[GW * GH];
+
+static uint32_t rng_state;
+static uint32_t xrand(void) {
+    uint32_t x = rng_state;
+    x ^= x << 13; x ^= x >> 17; x ^= x << 5;
+    rng_state = x;
+    return x;
+}
+
+static int gen, stall, prev_pop;
+
+static void seed(void) {
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    rng_state ^= ((uint32_t)ts.tv_nsec * 2654435761u) | 1u;
+    for (int i = 0; i < GW * GH; i++)
+        cur[i] = (xrand() % 100) < 28 ? 1 : 0;
+    gen = 0;
+    stall = 0;
+    prev_pop = -1;
+}
+
+static void step(void) {
+    int pop = 0;
+    for (int y = 0; y < GH; y++) {
+        const int yu = (y + GH - 1) % GH;
+        const int yd = (y + 1) % GH;
+        for (int x = 0; x < GW; x++) {
+            const int xl = (x + GW - 1) % GW;
+            const int xr = (x + 1) % GW;
+            const int n = cur[yu * GW + xl] + cur[yu * GW + x] + cur[yu * GW + xr]
+                        + cur[y  * GW + xl]                    + cur[y  * GW + xr]
+                        + cur[yd * GW + xl] + cur[yd * GW + x] + cur[yd * GW + xr];
+            const uint8_t alive = cur[y * GW + x];
+            const uint8_t next = (n == 3 || (alive && n == 2)) ? 1 : 0;
+            nxt[y * GW + x] = next;
+            pop += next;
+        }
+    }
+    memcpy(cur, nxt, sizeof(cur));
+
+    if (pop == prev_pop) stall++;
+    else stall = 0;
+    prev_pop = pop;
+    if (pop == 0 || stall > 14 || ++gen > 600) seed();
+}
+
+static void draw(SDL_Renderer *ren) {
+    SDL_SetRenderDrawColor(ren, 0, 0, 0, 255);   /* COLOR_BG */
+    SDL_RenderClear(ren);
+    SDL_SetRenderDrawColor(ren, 0x99, 0xFF, 0x00, 255); /* COLOR_ACCENT */
+    for (int y = 0; y < GH; y++) {
+        for (int x = 0; x < GW; x++) {
+            if (!cur[y * GW + x]) continue;
+            SDL_Rect r = { x * CELL, y * CELL, CELL - 1, CELL - 1 };
+            SDL_RenderFillRect(ren, &r);
+        }
+    }
+    SDL_RenderPresent(ren);
+}
+
+int main(int argc, char **argv) {
+    (void)argc; (void)argv;
+
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS) != 0) {
+        fprintf(stderr, "SDL_Init: %s\n", SDL_GetError());
+        return 1;
+    }
+
+    SDL_Window *win = SDL_CreateWindow("Life",
+        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+        SCREEN_W, SCREEN_H, SDL_WINDOW_BORDERLESS);
+    if (!win) { fprintf(stderr, "SDL_CreateWindow: %s\n", SDL_GetError());
+                SDL_Quit(); return 1; }
+
+    SDL_Renderer *ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_SOFTWARE);
+    if (!ren) { fprintf(stderr, "SDL_CreateRenderer: %s\n", SDL_GetError());
+                SDL_DestroyWindow(win); SDL_Quit(); return 1; }
+
+    rng_state = 0x2545f491u;
+    seed();
+
+    int running = 1, paused = 0;
+    Uint32 last_step = SDL_GetTicks();
+    while (running) {
+        Uint32 now = SDL_GetTicks();
+        SDL_Event ev;
+        while (SDL_PollEvent(&ev)) {
+            if (ev.type == SDL_QUIT) running = 0;
+            else if (ev.type == SDL_KEYDOWN) {
+                SDL_Keycode k = ev.key.keysym.sym;
+                if (k == SDLK_ESCAPE || k == SDLK_q) running = 0;
+                else if (k == SDLK_SPACE) seed();
+                else if (k == SDLK_p) paused = !paused;
+            }
+        }
+
+        if (!paused && now - last_step >= STEP_MS) {
+            step();
+            last_step = now;
+        }
+        draw(ren);
+
+        Uint32 elapsed = SDL_GetTicks() - now;
+        if (elapsed < 16) SDL_Delay(16 - elapsed);
+    }
+
+    SDL_DestroyRenderer(ren);
+    SDL_DestroyWindow(win);
+    SDL_Quit();
+    return 0;
+}

examples/SDL2_Life/packaging/build.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+set -euo pipefail
+make

examples/SDL2_Life/packaging/ci-deps.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+set -euo pipefail
+apt-get install -y libsdl2-dev

examples/SDL2_Life/packaging/meta.env

@@ -0,0 +1,9 @@
+PKG_NAME=sdl2-life
+PKG_VERSION=0.1
+PKG_REVISION=m5stack1
+PKG_DESC="Conway's Game of Life for CardputerZero (SDL2)"
+PKG_DEPENDS="libsdl2-2.0-0, libwayland-client0"
+APP_NAME="Game of Life"
+APP_EXEC=/usr/share/APPLaunch/bin/sdl2-life
+APP_TERMINAL=false
+APP_ICON=share/images/sdl2-life.png

examples/SDL2_Life/packaging/stage.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+install -D -m 0755 life "$STAGE$APP_INSTALL_DIR/life"
+
+# Wayland/KMSDRM launcher wrapper (see SDL2_HelloWorld for rationale).
+cat >"$STAGE$INSTALL_PREFIX/bin/$PKG_NAME" <<EOF
+#!/bin/sh
+LOG=/tmp/$PKG_NAME.log
+: >"\$LOG" 2>/dev/null || LOG=/dev/null
+
+if [ -z "\${XDG_RUNTIME_DIR:-}" ]; then
+    _uid=\$(id -u 2>/dev/null || echo 1000)
+    if [ -d "/run/user/\$_uid" ]; then
+        XDG_RUNTIME_DIR="/run/user/\$_uid"
+    elif [ -d "/run/user/1000" ]; then
+        XDG_RUNTIME_DIR="/run/user/1000"
+    fi
+    [ -n "\$XDG_RUNTIME_DIR" ] && export XDG_RUNTIME_DIR
+fi
+
+_wl_ok=0
+if [ -n "\${WAYLAND_DISPLAY:-}" ] && [ -n "\${XDG_RUNTIME_DIR:-}" ] && \\
+   [ -S "\$XDG_RUNTIME_DIR/\$WAYLAND_DISPLAY" ]; then
+    _wl_ok=1
+elif [ -n "\${XDG_RUNTIME_DIR:-}" ]; then
+    for _c in wayland-0 wayland-1; do
+        if [ -S "\$XDG_RUNTIME_DIR/\$_c" ]; then
+            WAYLAND_DISPLAY=\$_c
+            export WAYLAND_DISPLAY
+            _wl_ok=1
+            break
+        fi
+    done
+fi
+
+if [ -z "\${SDL_VIDEODRIVER:-}" ]; then
+    if [ "\$_wl_ok" = 1 ]; then
+        SDL_VIDEODRIVER=wayland
+    elif [ -e /dev/dri/card0 ]; then
+        SDL_VIDEODRIVER=kmsdrm
+    else
+        SDL_VIDEODRIVER=offscreen
+    fi
+    export SDL_VIDEODRIVER
+fi
+
+echo "[$PKG_NAME] driver=\$SDL_VIDEODRIVER WAYLAND_DISPLAY=\${WAYLAND_DISPLAY:-} XDG_RUNTIME_DIR=\${XDG_RUNTIME_DIR:-} uid=\$(id -u)" >>"\$LOG" 2>&1
+exec $APP_INSTALL_DIR/life "\$@" >>"\$LOG" 2>&1
+EOF
+chmod 0755 "$STAGE$INSTALL_PREFIX/bin/$PKG_NAME"