A journey from a simple class to a game with the Java language https://mcgivrer.github.io/fromClassToGame/ , and open Hub https://www.openhub.net/p/fromClassToGame.
As we now need more that just images to be displayed in our game, we need some other kind of resources like font, sound and so on, we need to add a ResourceManager which work consist in managing all this kind of resources.
First we are going to keep in memory all the resources, to retrieve them faster. So let’s set a Map to store those resources.
For convenient usage, we will also keep a rootPath variable pointing to the rootPath of execution class’s path.
We will use also a simplified version of the singleton pattern (only ONE ResourceManager to be instantiated at a time). The instance attribute will keep this singleton on.
As this service will be singleton, and we won’t need an instantiation, we will use only static attributes and methods.
public class ResourceManager {
private static final Logger logger = LoggerFactory.getLogger(ResourceManager.class);
private static Map<String, Object> resources = new HashMap<>();
private static String rootPath;
private ResourceManager() {
rootPath = ResourceManager.class.getClassLoader().getResource("/").toString();
}
}
public class ResourceManager {
...
private static BufferedImage readImage(String path) {
BufferedImage image = null;
try {
image = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream(path));
} catch (IOException e) {
logger.error("Unable to read image", e);
}
return image;
}
public static BufferedImage getImage(String imagePath) {
if (resources.containsKey(imagePath)) {
return (BufferedImage) resources.get(imagePath);
} else {
BufferedImage i = readImage(imagePath);
if (i != null) {
resources.put(imagePath, i);
}
return (BufferedImage) resources.get(imagePath);
}
}
}
Adding a 5 stars service that consists in slicing the image at getting time is added, and then store it in the cache:
First try to read image in the cache from the already existing readImage(String) method. and then Slice the image with the described rectangle with (x,y,w,h) where:
x is the horizontal position in the read image,y the vertical position in the read image,w the width of the image to be sliced,h the height of the image to be sliced. private static BufferedImage readImage(String imagePath, int x, int y, int w, int h) {
BufferedImage image = null;
image = readImage(imagePath).getSubimage(x, y, w, h);
return image;
}
And a trick to keep the image in cache memory, using an internalName added to the imagePath as key of this object in the cache.
public static BufferedImage getSlicedImage(String imagePath, String internalName, int x, int y, int w, int h) {
if (resources.containsKey(imagePath + ":" + internalName)) {
return (BufferedImage) resources.get(imagePath);
} else {
BufferedImage i = readImage(imagePath, x, y, w, h);
if (i != null) {
resources.put(imagePath + ":" + internalName, i);
}
return (BufferedImage) resources.get(imagePath + ":" + internalName);
}
}
public class ResourceManager {
private static final Logger logger = LoggerFactory.getLogger(ResourceManager.class);
private static Map<String, Object> resources = new HashMap<>();
private static String rootPath;
private ResourceManager() {
rootPath = ResourceManager.class.getClassLoader().getResource("/").toString();
}
private static Font readFont(String path) {
Font font = null;
try {
InputStream is = ResourceManager.class.getClassLoader().getResourceAsStream(path);
font = Font.createFont(Font.TRUETYPE_FONT, is);
} catch (FontFormatException | IOException e) {
logger.error("Unable to read font", e);
e.printStackTrace();
}
return font;
}
private static BufferedImage readImage(String path) {
BufferedImage image = null;
try {
image = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream(path));
} catch (IOException e) {
logger.error("Unable to read image", e);
}
return image;
}
private static BufferedImage readImage(String path, int x, int y, int w, int h) {
BufferedImage image = null;
try {
image = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream(path)).getSubimage(x, y, w, h);
} catch (IOException e) {
logger.error("Unable to read image", e);
}
return image;
}
public static Font getFont(String fontPath) {
Font f = null;
if (resources.containsKey(fontPath)) {
f = (Font) resources.get(fontPath);
} else {
f = readFont(fontPath);
if (f != null) {
resources.put(fontPath, f);
}
}
return f;
}
public static BufferedImage getImage(String imagePath) {
if (resources.containsKey(imagePath)) {
return (BufferedImage) resources.get(imagePath);
} else {
BufferedImage i = readImage(imagePath);
if (i != null) {
resources.put(imagePath, i);
}
return (BufferedImage) resources.get(imagePath);
}
}
public static BufferedImage getSlicedImage(String imagePath, String internalName, int x, int y, int w, int h) {
if (resources.containsKey(imagePath + ":" + internalName)) {
return (BufferedImage) resources.get(imagePath);
} else {
BufferedImage i = readImage(imagePath, x, y, w, h);
if (i != null) {
resources.put(imagePath + ":" + internalName, i);
}
return (BufferedImage) resources.get(imagePath + ":" + internalName);
}
}
}
Very simple to use it:
BufferedImage img = ResourceImage.getImage("images/my_image.png");
You can also slice an image at reading. The image will be store in the sliced version.
BufferedImage img = ResourceImage.getSlicedImage("images/my_image.png","myImage",0,0,16,16);
The my_image.png will be sliced at position 0,0 with a size of 16x16, and will be stored in resource cache as myImage.
To retrieve this image later, you will just have to get images/my_image.png:myImage.
Font myFont = ResourceImage.getFont("fonts/a_font.ttf");
You can directly modify the get font :
Font myFont = ResourceImage.getFont("fonts/a_font.ttf").defivedFont(14.0);
And that’s It !