added input modifier use case sample

fxgl-samples/src/main/java/sandbox/InputModifierSample.java

@@ -0,0 +1,74 @@
+/*
+ * FXGL - JavaFX Game Library. The MIT License (MIT).
+ * Copyright (c) AlmasB ([email protected]).
+ * See LICENSE for details.
+ */
+
+package sandbox;
+
+import com.almasb.fxgl.app.GameApplication;
+import com.almasb.fxgl.app.GameSettings;
+import com.almasb.fxgl.entity.Entity;
+import com.almasb.fxgl.input.KeyTrigger;
+import com.almasb.fxgl.input.TriggerListener;
+import javafx.scene.input.KeyCode;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Rectangle;
+
+import static com.almasb.fxgl.dsl.FXGL.*;
+
+/**
+ *
+ */
+public class InputModifierSample extends GameApplication {
+
+    private Entity e;
+    private double speedMult = 1.0;
+
+    @Override
+    protected void initSettings(GameSettings settings) {
+        settings.setWidth(1280);
+        settings.setHeight(720);
+    }
+
+    @Override
+    protected void initInput() {
+        getInput().addTriggerListener(new TriggerListener() {
+            @Override
+            protected void onKeyBegin(KeyTrigger keyTrigger) {
+                if (keyTrigger.getKey() == KeyCode.SHIFT) {
+                    speedMult = 3.0;
+                }
+            }
+
+            @Override
+            protected void onKey(KeyTrigger keyTrigger) {
+                switch (keyTrigger.getKey()) {
+                    case W -> { e.translateY(-speedMult * 1); }
+                    case S -> { e.translateY(speedMult * 1); }
+                    case A -> { e.translateX(-speedMult * 1); }
+                    case D -> { e.translateX(speedMult * 1); }
+                }
+            }
+
+            @Override
+            protected void onKeyEnd(KeyTrigger keyTrigger) {
+                if (keyTrigger.getKey() == KeyCode.SHIFT) {
+                    speedMult = 1.0;
+                }
+            }
+        });
+    }
+
+    @Override
+    protected void initGame() {
+        e = entityBuilder()
+                .at(150, 150)
+                .view(new Rectangle(40, 40, Color.BLUE))
+                .buildAndAttach();
+    }
+
+    public static void main(String[] args) {
+        launch(args);
+    }
+}