Added zoom functionality

src/client/java/wtf/hak/survivalfabric/features/Zoom.java

@@ -0,0 +1,52 @@
+package wtf.hak.survivalfabric.features;
+
+import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
+import net.fabricmc.fabric.api.client.keybinding.v1.KeyBindingHelper;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.option.KeyBinding;
+import net.minecraft.client.util.InputUtil;
+import net.minecraft.text.Text;
+import org.lwjgl.glfw.GLFW;
+import wtf.hak.survivalfabric.utils.MathUtils;
+
+public class Zoom {
+
+    private static final KeyBinding ZOOM_BIND = KeyBindingHelper.registerKeyBinding(new KeyBinding("key.survivalfabric.zoom", InputUtil.Type.KEYSYM, GLFW.GLFW_KEY_C, "category.survivalfabric.survivalfabric"));
+    private static final float INITIAL_ZOOM = 20f;
+
+    private static boolean SHOULD_ZOOM = false;
+    private static float ZOOM_STEP_VALUE = 2.5f;
+    private static int ZOOM_STEP = 0;
+
+    public static void register() {
+        ClientTickEvents.END_CLIENT_TICK.register(client -> {
+            if(ZOOM_BIND.isPressed())
+                SHOULD_ZOOM = true;
+            else {
+                SHOULD_ZOOM = false;
+                ZOOM_STEP = 0;
+            }
+        });
+    }
+
+    public static boolean isZooming() {
+        return SHOULD_ZOOM;
+    }
+
+    public static float getZoomFov() {
+        return INITIAL_ZOOM - -ZOOM_STEP * ZOOM_STEP_VALUE;
+    }
+
+    public static void modifyStep(int step) {
+        ZOOM_STEP += step;
+
+        // Clamp the zoom level so the FOV stays within [1, 110]
+        float zoomFov = getZoomFov();
+        if (zoomFov < 1) {
+            ZOOM_STEP = Math.round((1 - INITIAL_ZOOM) / ZOOM_STEP_VALUE)+1;
+        } else if (zoomFov > 110) {
+            ZOOM_STEP = Math.round((110 - INITIAL_ZOOM) / ZOOM_STEP_VALUE);
+        }
+        MinecraftClient.getInstance().player.sendMessage(Text.literal(ZOOM_STEP + ""), true);
+    }
+}