Scene stack logic

3 files changed, 82 insertions, 20 deletions

diff --git a/src/scenes/mainMenu.c b/src/scenes/mainMenu.c
index 07ba34d..31b52c0 100644
--- a/src/scenes/mainMenu.c
+++ b/src/scenes/mainMenu.c
@@ -1,9 +1,27 @@
 #include <raylib.h>
+#include <stdlib.h>
+#include "scenes.h"
 
-void MainMenuUpdate() {
+bool updateMainMenu(void *self) {
+    return true;
 }
 
-void MainMenuDraw() {
+bool drawMainMenu(void *self) {
     ClearBackground(SKYBLUE);
-    DrawText("MAIN MENU", 10, 10, 30, BLACK);
+    DrawText("Main menu", 0, 0, 100, BLACK);
+    return true;
+}
+
+void deinitMainMenu(void *self) {
+    TraceLog(LOG_INFO, "Deleting a main menu");
+    free((Scene *)self);
+}
+
+Scene *CreateMainMenu() {
+    TraceLog(LOG_INFO, "Creating a main menu");
+    Scene *outp = malloc(sizeof(Scene));
+    outp->Update = updateMainMenu;
+    outp->Draw = drawMainMenu;
+    outp->Deint = deinitMainMenu;
+    return outp;
 }
diff --git a/src/scenes/sceneManager.c b/src/scenes/sceneManager.c
index 4d42ed9..bb70864 100644
--- a/src/scenes/sceneManager.c
+++ b/src/scenes/sceneManager.c
@@ -1,14 +1,45 @@
 #include "scenes.h"
+#include <stdlib.h>
+#include <sys/types.h>
 
-void UpdateScene(enum SCENE scene) {
-    switch (scene) {
-        case MAIN_MENU: MainMenuUpdate();
-    }
+Scene **sceneStack = NULL;
+uint sceneStackDepth = 0;
+
+Scene *getCurrentScene() {
+    if (sceneStackDepth == 0) return false;
+    return sceneStack[sceneStackDepth - 1];
+}
+
+bool InitSceneStack() {
+    sceneStack = malloc(sizeof(Scene) * SCENE_STACK_SIZE);
+    return sceneStack != NULL;
+}
+
+bool AddScene(Scene *newScene) {
+    if (newScene == NULL || sceneStackDepth == SCENE_STACK_SIZE)
+        return false;
+
+    sceneStack[sceneStackDepth] = newScene;
+    sceneStackDepth += 1;
+
+    return true;
 }
 
-void DrawScene(enum SCENE scene) {
-    switch (scene) {
-        case MAIN_MENU: MainMenuDraw();
-    }
+void DeleteSceneFromStack() {
+    Scene *currentScene = getCurrentScene();
+    if (currentScene == NULL) return;
+    currentScene->Deint(currentScene);
+    sceneStack[--sceneStackDepth] = NULL;
 }
 
+bool DrawScene() {
+    Scene *currentScene = getCurrentScene();
+    if (currentScene == NULL) return false;
+    return currentScene->Draw(currentScene);
+}
+
+bool UpdateScene() {
+    Scene *currentScene = getCurrentScene();
+    if (currentScene == NULL) return false;
+    return currentScene->Update(currentScene);
+}
diff --git a/src/scenes/scenes.h b/src/scenes/scenes.h
index 88295e6..7ad34af 100644
--- a/src/scenes/scenes.h
+++ b/src/scenes/scenes.h
@@ -1,17 +1,30 @@
+#include <stdbool.h>
+
 #ifndef SCENES_H
 #define SCENES_H
 
-/// The scene that the action should be executed upon
-enum SCENE {
-    MAIN_MENU,
-};
+#define SCENE_STACK_SIZE 16
+
+/// This structure represents a scene that is stored in a stack.
+/// The main appeal of this data type is dynamic creation of different
+/// scenes that don't depend on global state
+typedef struct {
+    bool (*Update)(void *self);
+    bool (*Draw)(void *self);
+    void (*Deint)(void *self);
+    /// A generic pointer to whatever data the scene needs. You will have to
+    /// cast it yourself
+    void *data;
+} Scene;
+
+bool InitSceneStack();
 
-void DrawScene(enum SCENE scene);
-void UpdateScene(enum SCENE scene);
+bool AddScene(Scene *newScene);
+void DeleteSceneFromStack();
 
+bool DrawScene();
+bool UpdateScene();
 
-// ========== MAIN MENU ==========
-void MainMenuUpdate();
-void MainMenuDraw();
+Scene *CreateMainMenu();
 
 #endif // SCENES_H