implement view bobbing

core/src/main/java/wtf/beatrice/retrorender/engine/FpsCameraController.java

@@ -22,8 +22,14 @@ public class FpsCameraController {
     private float velocityY = 0f;
     private boolean grounded = false;
 
+    // view bobbing
+    private float bobTime    = 0f;
+    private float bobOffsetY = 0f;
+    private final float bobAmount = 0.04f; // amplitude in world units
+    private final float bobSpeed  = 16f;
+
     // --- approximation toggles
-    private final boolean retroQuantization = true;
+    private final boolean retroQuantization = false;
 
     // how coarse the rotation is (0.25f = round to 0.25°)
     private final float yawStepDegrees   = 0.2f;
@@ -104,6 +110,10 @@ public class FpsCameraController {
 
     /** Update each frame with delta time */
     public void update(float delta, World3D world) {
+        camera.position.y -= bobOffsetY;
+        bobOffsetY = 0f;
+
+
         if (!mouseCaptured) {
             return;
         }
@@ -307,6 +317,27 @@ public class FpsCameraController {
             camera.position.y = Math.round(camera.position.y * q) / q;
             camera.position.z = Math.round(camera.position.z * q) / q;
         }
+
+        // =========================================================
+        // 4) VIEW BOBBING (purely visual)
+        // =========================================================
+        // horizontal movement magnitude (world units per frame)
+        float horizLen = (float)Math.sqrt(moveX * moveX + moveZ * moveZ);
+
+        if (grounded && horizLen > 0.0001f) {
+            // scale bob speed by how fast you're moving
+            float speedFactor = horizLen / (settings.moveSpeed * delta + 1e-6f);
+            bobTime += delta * bobSpeed * speedFactor;
+
+            bobOffsetY = (float)Math.sin(bobTime) * bobAmount;
+        } else {
+            // not moving or in the air → relax bobbing back to zero
+            bobTime = 0f;
+            // optional: smooth return to 0 instead of snapping
+            bobOffsetY += (0f - bobOffsetY) * 10f * delta;
+        }
+
+        camera.position.y += bobOffsetY;
     }
     private void updateCameraDirection() {
         // build direction vector from yaw/pitch