Manager's office safe scene stacks on top of manager's office scene, instead of replacing it.

engine.h

@@ -1,26 +1,39 @@
-#define MAX_GAME_OBJECTS 100
-extern struct object {
+#define MAX_OBJECTS_PER_SCENE 30
+#define MAX_SCRIPTS_PER_SCENE 30
+#define MAX_STACKED_SCENES 5
+
+struct object {
 	int id; // 0 if slot unused
 	int x;
 	int y;
 	int width;
 	int height;
 	const char *pixels;
-} objects[MAX_GAME_OBJECTS];
+};
 
-#define MAX_GAME_SCRIPTS 100
 typedef void (*script_wake_fn)(struct script *scr, int wakeupMode, int arg1, int arg2, int arg3, int arg4);
 #define SCRIPT_HEADER \
 	int id /* 0 if slot unused */; \
 	int wakeupMode; \
 	script_wake_fn wakeupFn; \
 	int wakeupArg1; /* for SCRIPT_WAKEUP_OTHER_SCRIPT */
-extern struct script {
+struct script {
 	SCRIPT_HEADER
-
 	int vars[100];
+};
+
+typedef void (*scene_render_fn)(struct scene *s);
+void standard_scene_render(struct scene *s);
+extern struct scene {
+	int id;
+	struct object objects[MAX_OBJECTS_PER_SCENE];
+	struct script scripts[MAX_SCRIPTS_PER_SCENE];
+	scene_render_fn render_fn;
+	struct navmesh *navmesh; // defaults to non-null pointer to empty navmesh
+} scenes[MAX_STACKED_SCENES];
+extern int scene_depth; // number of stacked scenes
+#define top_scene scenes[scene_depth-1]
 
-} scripts[MAX_GAME_SCRIPTS];
 
 struct script_player_walk {
 	SCRIPT_HEADER
@@ -36,10 +49,12 @@ struct script_player_walk {
 
 
 // engine
-void transition_scene(int scene); // Immediately stops all event processing for current scene, which is unloaded before this function returns
+// Scene changes - even push - may discard remaining events for the scene.
+void push_scene(int scene);
+void replace_scene(int scene);
+void pop_scene();
 void scene_add_clickrect(int id, int x, int y, int width, int height);
 void scene_add_object(int id, int x, int y, int width, int height, const char *pixels);
-void scene_set_navmesh(struct navmesh *navmesh);
 struct object *find_object_by_id(int id);
 struct script *scene_add_script(int id, bool interrupt_existing);
 struct script *scene_get_script(int id);

game control flow.txt

@@ -0,0 +1,14 @@
+At first we had a single scene at a time. This can't support some features we want.
+
+We can have a stack of scenes.
+A scene is often a room but it can also be a modal dialog.
+When moving from one room to another it replaces the topmost scene but modal interactions push onto the stack.
+Example: Manager's office -> Access the safe -> Textbox -> Pause/quit menu.
+
+Hypothetically we could also have something like a dream world which keeps the outside-dream state on the stack.
+
+Scenes come in different types. A room is a typical scene. But we have minigames like the safe, textboxes and menus.
+All rooms should inherit some common behaviour like moving the player character.
+All menus should inherit menu behaviour. Neither applies to the safe cracking.
+
+Things from all scenes are rendered in scene stacking order.

game.cpp

@@ -30,6 +30,7 @@ extern struct navmesh navmesh_basement;
 #define OBJID_CLOSE_MODAL 12
 
 void scene_setup(int scene, int fromscene) {
+	top_scene.render_fn = standard_scene_render;
 	switch(scene) {
 	case SCENE_LOBBY:
 		scene_add_object(OBJID_BACKGROUND, 0, 0, BGWIDTH, BGHEIGHT, _binary_sprite_lobby_raw_start);
@@ -42,7 +43,7 @@ void scene_setup(int scene, int fromscene) {
 			scene_add_object(OBJID_PLAYER, 424, 575, 51, 111, _binary_sprite_stickman_raw_start);
 			break;
 		}
-		scene_set_navmesh(&navmesh_lobby);
+		top_scene.navmesh = &navmesh_lobby;
 		break;
 	case SCENE_MANAGERS_OFFICE:
 		scene_add_object(OBJID_BACKGROUND, 0, 0, BGWIDTH, BGHEIGHT, _binary_sprite_managers_office_raw_start);
@@ -63,10 +64,10 @@ void scene_setup(int scene, int fromscene) {
 			scene_add_object(OBJID_PLAYER, 424, 575, 51, 111, _binary_sprite_stickman_raw_start);
 			break;
 		}
-		scene_set_navmesh(&navmesh_managers_office);
+		top_scene.navmesh = &navmesh_managers_office;
 		break;
 	case SCENE_MANAGERS_OFFICE_SAFE:
-		scene_add_object(OBJID_BACKGROUND, 0, 0, BGWIDTH, BGHEIGHT, _binary_sprite_managers_office_safe_raw_start);
+		scene_add_object(OBJID_BACKGROUND, 248, 0, 787, BGHEIGHT, _binary_sprite_managers_office_safe_raw_start);
 		scene_add_object(OBJID_CLOSE_MODAL, 0, 0, 248, 800, nullptr);
 		scene_add_object(OBJID_CLOSE_MODAL, 1035, 0, 1280-1035, 800, nullptr);
 		break;
@@ -81,15 +82,20 @@ void scene_setup(int scene, int fromscene) {
 			scene_add_object(OBJID_PLAYER, 424, 575, 51, 111, _binary_sprite_stickman_raw_start);
 			break;
 		}
-		scene_set_navmesh(&navmesh_basement);
+		top_scene.navmesh = &navmesh_basement;
 		break;
 	}
 }
 
 static void transition_scene_on_walk_finish(struct script *scr, int wakeupMode, int arg1, int arg2, int arg3, int arg4) {
 	scr->id = 0;
-	if(wakeupMode == SCRIPT_WAKEUP_OTHER_SCRIPT)
-		transition_scene(scr->vars[0]);
+	if(wakeupMode == SCRIPT_WAKEUP_OTHER_SCRIPT) {
+		if(scr->vars[0] == SCENE_MANAGERS_OFFICE_SAFE) {
+			push_scene(scr->vars[0]);
+		} else {
+			replace_scene(scr->vars[0]);
+		}
+	}
 	else
 		assert(wakeupMode == SCRIPT_WAKEUP_OTHER_SCRIPT_INTERRUPTED);
 }
@@ -136,7 +142,7 @@ void onclick(int curscene, int objid) {
 	case SCENE_MANAGERS_OFFICE_SAFE:
 		switch(objid) {
 		case OBJID_CLOSE_MODAL:
-			transition_scene(SCENE_MANAGERS_OFFICE);
+			pop_scene();
 			return;
 		}
 		break;

pinetab2_framework.cpp

@@ -26,9 +26,8 @@
 static int touchscreen_fd;
 
 static struct navmesh null_navmesh = {0};
-struct navmesh *cur_navmesh = &null_navmesh;
-struct object objects[MAX_GAME_OBJECTS];
-struct script scripts[MAX_GAME_SCRIPTS];
+struct scene scenes[MAX_STACKED_SCENES];
+int scene_depth = 0;
 bool need_rerender = false;
 
 
@@ -162,26 +161,32 @@ static void blit(int x, int y, const struct sprite *spr) {
 	}
 }
 
-void scene_set_navmesh(struct navmesh *navmesh) {
-	cur_navmesh = navmesh;
-}
+static void scene_clear_and_setup(int scene, int fromscene) {
+	memset(&top_scene, 0, sizeof(top_scene));
+	top_scene.id = scene;
+	top_scene.navmesh = &null_navmesh;
 
-static uint32_t scene_generation_count = 0;
-static int curscene = -1;
-void transition_scene(int scene) {
-	int prevscene = curscene;
-	scene_generation_count++;
-	curscene = scene;
-	memset(objects, 0, sizeof objects);
-	memset(scripts, 0, sizeof scripts); // script state is local to scene, so no cancel notification
-	cur_navmesh = &null_navmesh;
-	scene_setup(scene, prevscene);
+	scene_setup(scene, fromscene);
+}
+void push_scene(int scene) {
+	scene_depth++;
+	if(scene_depth > MAX_STACKED_SCENES) error(1, 0, "maximum scene depth exceeded");
+	scene_clear_and_setup(scene, -1);
+}
+void replace_scene(int scene) {
+	scene_clear_and_setup(scene, top_scene.id);
+}
+void pop_scene() {
+	if(scene_depth == 1) error(1, 0, "no scenes left");
+	scene_depth--;
+	// any cleanup?
 }
 
 void scene_add_object(int id, int x, int y, int width, int height, const char *pixels) {
 	if(id == 0) error(1, 0, "scene_add_object: id 0 is invalid");
 
-	for(int i = 0; i < MAX_GAME_OBJECTS; i++) {
+	struct object *objects = top_scene.objects;
+	for(int i = 0; i < MAX_OBJECTS_PER_SCENE; i++) {
 		if(objects[i].id == 0) {
 			objects[i].id = id;
 			objects[i].x = x;
@@ -196,14 +201,16 @@ void scene_add_object(int id, int x, int y, int width, int height, const char *p
 }
 
 struct object *find_object_by_id(int id) {
-	for(int i = 0; i < MAX_GAME_OBJECTS; i++) {
+	struct object *objects = top_scene.objects;
+	for(int i = 0; i < MAX_OBJECTS_PER_SCENE; i++) {
 		if(objects[i].id == id)
 			return &objects[i];
 	}
 	return nullptr;
 }
 struct script *scene_add_script(int id, bool interrupt_existing) {
-	for(int i = 0; i < MAX_GAME_SCRIPTS; i++) {
+	struct script *scripts = top_scene.scripts;
+	for(int i = 0; i < MAX_SCRIPTS_PER_SCENE; i++) {
 		if(scripts[i].id == id && interrupt_existing) {
 			// interrupt existing script?
 			// player walk script is safe to trivially cancel, at least
@@ -310,6 +317,7 @@ static double is_point_in_tri(int x, int y, const struct navmesh_tri *tri) {
 static int find_navmesh_tri(int x, int y, int tolerance) {
 	int best_tri = -1;
 	double best_dist = tolerance;
+	struct navmesh *cur_navmesh = top_scene.navmesh;
 	for(int i = 0; i < cur_navmesh->num_tris; i++) {
 		double dist = is_point_in_tri(x, y, &cur_navmesh->tris[i]);
 		if(dist == 0)
@@ -347,12 +355,14 @@ void start_player_walk_to_point(int targetX, int targetY) {
 }
 
 void handle_tap(int x, int y) {
-	uint32_t gencount = scene_generation_count;
 	uint32_t walkgen = player_walk_generation;
-	for(int i = 0; i < MAX_GAME_OBJECTS; i++) {
+	int sceneid = top_scene.id;
+	struct navmesh *cur_navmesh = top_scene.navmesh;
+	struct object *objects = top_scene.objects;
+	for(int i = 0; i < MAX_OBJECTS_PER_SCENE; i++) {
 		if(objects[i].id && (unsigned int)(x - objects[i].x) < objects[i].width && (unsigned int)(y - objects[i].y) < objects[i].height) {
-			onclick(curscene, objects[i].id);
-			if(gencount != scene_generation_count) return; // early exit if scene changed, and don't walk the player either
+			onclick(sceneid, objects[i].id);
+			if(top_scene.id != sceneid) return; // early exit if scene changed, and don't walk the player either
 		}
 	}
 
@@ -385,6 +395,7 @@ static void update_player_walk_script_on_frame(struct script *scr, int wakeupMod
 		deliver_script_wakeup(SCRIPT_WAKEUP_OTHER_SCRIPT, script_id, SCRIPT_WAKEUP_OTHER_SCRIPT_INTERRUPTED, 0, 0, 0, 0);
 		return;
 	}
+	struct navmesh *cur_navmesh = top_scene.navmesh;
 
 	if(player_walk_script->currentNavmeshTri == -1) {
 		// something weird happened. just teleport player and end movement.
@@ -438,16 +449,26 @@ static void update_player_walk_script_on_frame(struct script *scr, int wakeupMod
 }
 
 bool deliver_script_wakeup(int wakeupMode, int wakeupArg1, int wakeupType, int arg1, int arg2, int arg3, int arg4) {
-	uint32_t gen = scene_generation_count;
-	for(int i = 0; i < MAX_GAME_SCRIPTS; i++) {
+	int scene = top_scene.id;
+	struct script *scripts = top_scene.scripts;
+	for(int i = 0; i < MAX_SCRIPTS_PER_SCENE; i++) {
 		if(scripts[i].id && scripts[i].wakeupMode == wakeupMode && scripts[i].wakeupArg1 == wakeupArg1) {
 			scripts[i].wakeupFn(&scripts[i], wakeupType, arg1, arg2, arg3, arg4);
-			if(scene_generation_count != gen) return true; // scene changed - abort early
+			if(scene_depth == 0 || top_scene.id != scene) return true; // scene changed - abort early
 		}
 	}
 	return false;
 }
 
+void standard_scene_render(scene *s) {
+	struct object *objects = s->objects;
+	for(int i = 0; i < MAX_OBJECTS_PER_SCENE; i++) {
+		if(objects[i].id != 0 && objects[i].pixels) {
+			struct sprite spr = {.width = objects[i].width, .height = objects[i].height, .pixels = (uint32_t*)objects[i].pixels};
+			blit(objects[i].x, objects[i].y, &spr);
+		}
+	}
+}
 
 int main(int argc, char **argv) {
 
@@ -520,7 +541,7 @@ int main(int argc, char **argv) {
 		if(timerfd_settime(timerfd, 0, &tspec, NULL) < 0) error(1, errno, "timerfd_settime");
 	}
 
-	transition_scene(SCENE_LOBBY);
+	push_scene(SCENE_LOBBY);
 
 	int cur_buffer = 0;
 
@@ -588,11 +609,8 @@ int main(int argc, char **argv) {
 			cur_buffer = 1-cur_buffer; // for testing, just keep writing into the same buffer
 			curfb = fbs[cur_buffer];
 
-			for(int i = 0; i < MAX_GAME_OBJECTS; i++) {
-				if(objects[i].id != 0 && objects[i].pixels) {
-					struct sprite spr = {.width = objects[i].width, .height = objects[i].height, .pixels = (uint32_t*)objects[i].pixels};
-					blit(objects[i].x, objects[i].y, &spr);
-				}
+			for(int s = 0; s < scene_depth; s++) {
+				scenes[s].render_fn(&scenes[s]);
 			}
 
 			struct drm_mode_crtc_page_flip flipcmd = {