feat(rm): add resource manager

SnapGames · Mar 3, 2023 · 28de2cd · 28de2cd
1 parent 0b9ac91
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diff --git a/app/src/main/java/fr/snapgames/demo/core/io/ResourceManager.java b/app/src/main/java/fr/snapgames/demo/core/io/ResourceManager.java
@@ -58,7 +58,8 @@ public static void load(String path) {
         if (!path.contains(".")) {
             return;
         }
-        switch (path.substring(path.lastIndexOf(".") + 1, path.length() - (path.lastIndexOf(".") + 1)).toUpperCase()) {
+        String ext = path.substring(path.lastIndexOf(".") + 1, path.length()).toUpperCase();
+        switch (ext) {
             case "PNG", "JPG", "GIF" -> {
                 BufferedImage img = null;
                 if (!cache.containsKey(path)) {

diff --git a/app/src/main/java/fr/snapgames/demo/gdemoapp/scenes/DemoScene.java b/app/src/main/java/fr/snapgames/demo/gdemoapp/scenes/DemoScene.java
@@ -4,6 +4,7 @@
 import fr.snapgames.demo.core.entity.*;
 import fr.snapgames.demo.core.gfx.RandomColor;
 import fr.snapgames.demo.core.gfx.Renderer;
+import fr.snapgames.demo.core.io.ResourceManager;
 import fr.snapgames.demo.core.math.Vector2D;
 import fr.snapgames.demo.core.physic.Material;
 import fr.snapgames.demo.core.scene.AbstractScene;
@@ -41,25 +42,10 @@ public DemoScene(Game g, String name) {
     }
 
 
-    /**
-     * Load a {@link BufferedImage} from a file path.
-     *
-     * @param pathToImage path to the image file.
-     * @return the corresponding {@link BufferedImage} instance.
-     */
-    private BufferedImage loadImage(String pathToImage) {
-        try {
-            return ImageIO.read(this.getClass().getResourceAsStream(pathToImage));
-        } catch (NullPointerException | IOException e) {
-            logger.severe("Unable to read image resource from " + pathToImage);
-        }
-        return null;
-    }
-
     @Override
     public void prepare(Game g) {
-        imageBackground = loadImage("/images/backgrounds/forest.jpg");
-        imagePlayer = loadImage("/images/sprites01.png");
+        imageBackground = ResourceManager.getImage("/images/backgrounds/forest.jpg");
+        imagePlayer = ResourceManager.getImage("/images/sprites01.png");
     }
 
     @Override

diff --git a/docs/chapter-10-adding_scene_and_scenemanager.md b/docs/chapter-10-adding_scene_and_scenemanager.md
@@ -16,7 +16,7 @@ The following diagram propose an implementation layering on a `Scene` interface,
 provide
 internal mechanism, and a `SceneManager`.
 
-![Implementation class diagram](https://www.plantuml.com/plantuml/png/TP11RkCm34NtEeLcby5CBk15aQ85kkgcEG4Z_Te295aWgQHeqRlNhemuJT0DORx_QDhSYH9hJT7yqG49jaGAsGp1moReC7ff3QboE5I561T9n3vHWWbPmQ_aOFVWOt1Omhr3nZDbwi4sf1AHa5NEbWpZgKdBblLD3NyO-o_ae85YUCUcx-PrVxlZ6FoK54OXli6EGNf3GovLhs4jVbN_MqGg0j_viHxYQdccqzdXxWNPWy5h7gICWiqPzD27IMQQK7imdyRGGPJ9gMt7kL_Qzl-Nrvc1QT8ZqjW4l2colnepypVPxVRknwdDPVETpbhNJ-KgMkOwcQly4hhAZAncX-nhYby0)
+![Implementation class diagram](http://www.plantuml.com/plantuml/png/TP11JWCn34NtEKNO5K4lC0jK118hDd02T_APiPHa8jkX2CJTwJIZjch59hBV_rxaRTH8hAReRcn4WY-HEBkH0to2ZLFGjf2PyBOQrFMHLFqB9IpZUu-CLyeqG1ndWtnGZuP_dB_ZpCOK-HkhePllRhlFYSC-AO92SeLx0TaLvLogNS9Qmgbwxn6fA48NfhgDfrOGsXqxqhqX1mZabBEMIR4wWW7sH0b2UzG6z-jqd7RjLuiRHrireTvy4_6uhAt3gKGaP5iCBRQUaQPMm9SXXuipTsxJhzSF1zFTCEkUfmCwxrmSB66dywl_X7qLGJQtGGurnJy0)
 
 ## Scene interface
 

diff --git a/docs/chapter-11-add_a_resource_manager.md b/docs/chapter-11-add_a_resource_manager.md
@@ -96,3 +96,55 @@ public class ResourceManager {
     }
 }
 ```
+## Using the ResourceManager
+
+In your own `Scene` implementation, you can now preload some resources in the `prepare()`
+method:
+
+```java
+class MyScene extends AbstractScene{
+
+    //...
+    @Override
+    public void prepare(Game g) {
+        // load resources int cache
+        ResourceManager.getImage("/images/backgrounds/forest.jpg");
+        ResourceManager.getImage("/images/sprites01.png");
+    }
+    //...
+}
+```
+
+And during the Scene creation using the `create()` method, you can get the preloaded resources :
+
+```java
+class MyScene extends AbstractScene {
+    //...
+    @Override
+    public void create(Game g) {
+        //...
+        // Create the main player entity.
+        var playerFrame1 = ResoureManager.getImage("/images/sprites01.png"); 
+        var playerFrame1 = imagePlayer.getSubimage(0, 0, 32, 32);
+        var player = (GameObject) new GameObject("player")
+                .setImage(playerFrame1);
+        //...
+    }
+    //...
+}
+```
+
+So each time you re-activate this scene, resources are already in cache, so no wait to display the scene.
+
+## Conclusion
+
+We add hee avery useful service to load and cache some resources. Then, those resources can be used or reused by mulitple scene,
+reducing the loading time.
+
+Like in the 10 previous episodes, you can access the code from the GitHub repository you already know
+now: https://github.com/SnapGames/game101 on
+tag [create-resource-manager](https://github.com/SnapGames/game101/releases/tag/create-resource-manager).
+
+That’s all falk!
+
+McG.