Hot reloading: WIP Got something working

Makefile

@@ -3,7 +3,7 @@ CC=gcc
 
 .PHONY: build clean run all
 
-all: main dod
+all: main dod boids_main
 
 main: main.c lib.h sprites.o sprites.h game_data.h ./lib/libraylib.a
 	$(CC) $(CFLAGS) -Iinclude/ -lm main.c -o main sprites.o ./lib/libraylib.a
@@ -14,15 +14,15 @@ sprites.o: sprites.c sprites.h lib.h
 dod: dod.c ./lib/libraylib.a
 	$(CC) $(CFLAGS) -Iinclude/ -lm dod.c -o dod ./lib/libraylib.a
 
-boids_main: boids_main.c lib.h ./lib/libraylib.a
-	$(CC) $(CFLAGS) -Iinclude/ -lm $< -o $@ ./lib/libraylib.a
+boids_main: boids_main.c lib.h ./lib/libraylib.a libboids.so
+	$(CC) $(CFLAGS) -Iinclude/ -fPIC -ldl -lm $< -o $@ ./lib/libraylib.a
 
 libboids.so: boids_game.c boids_game.h lib.h
-	$(CC) $(CFLAGS) -Iinclude/ -lm -c $< -o $@
+	$(CC) $(CFLAGS) -shared -fPIC -Iinclude/ -lm -lOpenGL $< -o $@ ./lib/libraylib.a
 
 run: all
 	./main
 
 clean:
-	rm -vf main
+	rm -vf *.so *.o main boids_main dod
 

boids_game.c

@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <stdio.h>
 #include "include/raylib.h"
 #include "include/raymath.h"
 #include "boids_game.h"
@@ -6,7 +7,6 @@
 
 #define SCREEN_WIDTH 1300
 #define SCREEN_HEIGHT 1080
-#define NUM_BOIDS 16
 
 typedef struct Boid {
     Point position;
@@ -22,7 +22,11 @@ typedef struct GameState {
     float max_force;
 } GameState;
 
-GameState *init() {
+static GameState *init() {
+    InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Boids");
+
+    SetTargetFPS(60);
+
     GameState *state = malloc(sizeof(struct GameApi));
     state->num_boids = 16;
     state->max_speed = 5.0f;
@@ -44,22 +48,23 @@ GameState *init() {
         boid->acceleration = (Vector2){0};
     }
 
+    printf("I loaded the contents\n");
     return state;
 }
 
-void finalize(GameState *state) {
+static void finalize(GameState *state) {
     (void)state;
 }
 
-void reload(GameState *state) {
+static void reload(GameState *state) {
     (void)state;
 }
 
-void unload(GameState *state) {
+static void unload(GameState *state) {
     (void)state;
 }
 
-void step(GameState *state) {
+static void step(GameState *state) {
     // Process Input
     if (IsMouseButtonPressed(0)) {
         Vector2 mouse_pos = GetMousePosition();
@@ -68,7 +73,7 @@ void step(GameState *state) {
 
 
     // Update
-    for (int i = 0; i < NUM_BOIDS; i++) {
+    for (int i = 0; i < state->num_boids; i++) {
         Boid *boid = &state->boids[i];
         if (state->target_pos.tag == SOME) {
             Vector2 desired = Vector2Subtract(state->target_pos.some.point, boid->position);
@@ -92,11 +97,20 @@ void step(GameState *state) {
         // want to get distracted with that
         // DrawTriangle(Vector2 v1, Vector2 v2, Vector2 v3, GREEN);
         // DrawTriangleLines(Vector2 v1, Vector2 v2, Vector2 v3, GREEN);
-        for (int i = 0; i < NUM_BOIDS; i++) {
+        for (int i = 0; i < state->num_boids; i++) {
             Boid *boid = &state->boids[i];
             DrawCircle(boid->position.x, boid->position.y, 27, BLACK);
             DrawCircle(boid->position.x, boid->position.y, 20, GREEN);
         }
+
     }
     EndDrawing();
 }
+
+const struct GameApi GAME_API = {
+    .init = init,
+    .reload = reload,
+    .step = step,
+    .unload = unload,
+    .finalize = finalize
+};

boids_game.h

@@ -3,11 +3,11 @@
 struct GameState;
 
 typedef struct GameApi {
-    struct GameApi *(*init)();
-    void (*finalize) (struct GameApi *state);
-    void (*reload) (struct GameApi *state);
-    void (*unload) (struct GameApi *state);
-    void (*step) (struct GameApi *state);
+    struct GameState *(*init)();
+    void (*finalize) (struct GameState *state);
+    void (*reload) (struct GameState *state);
+    void (*unload) (struct GameState *state);
+    void (*step) (struct GameState *state);
 } GameApi;
 
-extern const struct GameApi GAME_API;
+extern const GameApi GAME_API;

boids_main.c

@@ -24,6 +24,27 @@ struct Game {
 };
 #define MAX_EVENTS 1
 
+void load_game(struct Game *game) {
+    void *handle = dlopen(GAME_LIB, RTLD_NOW);
+
+    if (handle) {
+        game->handle = handle; 
+        const struct GameApi *api = dlsym(game->handle, "GAME_API");
+        if (api != NULL) {
+            printf("Loaded API, calling init()\n");
+            game->api = *api;
+            game->state = game->api.init();
+        } else {
+            printf("Failed to load API\n");
+            dlclose(game->handle);
+        }
+    } else {
+        fprintf(stderr, "Error loading %s\n", GAME_LIB);
+        fprintf(stderr, "Error was: %s\n", dlerror());
+        exit(1);
+    }
+}
+
 int main(void) {
     int fd = inotify_init();
     if (fd < 0) {
@@ -42,17 +63,15 @@ int main(void) {
     event.events = EPOLLIN;
     event.data.fd = fd;
 
-    // register inotify fd with epoll
     if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event) == -1) {
         fprintf(stderr, "Error adding inotify descriptor to epoll\n");
     }
 
-    InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Boids");
-
-    SetTargetFPS(TARGET_FPS);
-
     struct epoll_event events[MAX_EVENTS];
 
+    struct Game game = {0};
+    load_game(&game);
+
     while (!WindowShouldClose()) {
         int nfds = epoll_wait(epollfd, events, MAX_EVENTS, 0);
         if (nfds == -1) {
@@ -63,13 +82,12 @@ int main(void) {
         for (int n = 0; n < nfds; ++n) {
             if (events[n].data.fd == fd) {
                 printf("SO has been updated!\n");
+                // This clears the inotify queue so we don't get any more events
                 read(fd, epoll_buf, sizeof(epoll_buf));
             }
         }
 
-        BeginDrawing();
-        ClearBackground(BEIGE);
-        EndDrawing();
+        game.api.step(game.state);
     }
 
     inotify_rm_watch(fd, wd);

hours.org

@@ -16,6 +16,7 @@ CLOCK: [2024-01-06 Sat 11:00]--[2024-01-06 Sat 13:10] =>  2:10
 :END:
 ** <2024-01-09 Tue>
 :LOGBOOK:
+CLOCK: [2024-01-09 Tue 21:28]
 CLOCK: [2024-01-09 Tue 19:30]--[2024-01-09 Tue 20:31] =>  1:01
 CLOCK: [2024-01-09 Tue 10:45]--[2024-01-09 Tue 11:15] =>  0:30
 :END: