Update orbit-camera.js

orbit-camera.js

@@ -341,6 +341,19 @@ OrbitCameraInputMouse.prototype.initialize = function () {
     this.panButtonDown = false;
     this.lastPoint = new pc.Vec2();
 };
+
+// Returns the resulting camera world position Y for a pivot
+OrbitCamera.prototype.worldCameraYForPivot = function(pivot) {
+    var quat = new pc.Quat();
+    quat.setFromEulerAngles(this._pitch, this._yaw, 0);
+    var forward = new pc.Vec3();
+    quat.transformVector(pc.Vec3.FORWARD, forward);
+    var camPos = pivot.clone();
+    camPos.add(forward.clone().scale(-this._distance));
+    return camPos.y;
+};
+
+
 OrbitCameraInputMouse.fromWorldPoint = new pc.Vec3();
 OrbitCameraInputMouse.toWorldPoint = new pc.Vec3();
 OrbitCameraInputMouse.worldDiff = new pc.Vec3();
@@ -353,7 +366,24 @@ OrbitCameraInputMouse.prototype.pan = function (screenPoint) {
     camera.screenToWorld(screenPoint.x, screenPoint.y, distance, fromWorldPoint);
     camera.screenToWorld(this.lastPoint.x, this.lastPoint.y, distance, toWorldPoint);
     worldDiff.sub2(toWorldPoint, fromWorldPoint);
-    this.orbitCamera.pivotPoint.add(worldDiff);
+
+    // Try proposed new pivot
+    var proposedPivot = this.orbitCamera.pivotPoint.clone().add(worldDiff);
+    var minY = this.orbitCamera.minY;
+    var resultingY = this.orbitCamera.worldCameraYForPivot(proposedPivot);
+    if (resultingY >= minY - 1e-4) {
+        this.orbitCamera.pivotPoint.add(worldDiff);
+    } else {
+        // Optionally, restrict only vertical panning
+        worldDiff.y = 0;
+        proposedPivot = this.orbitCamera.pivotPoint.clone().add(worldDiff);
+        resultingY = this.orbitCamera.worldCameraYForPivot(proposedPivot);
+        if (resultingY >= minY - 1e-4) {
+            this.orbitCamera.pivotPoint.add(worldDiff);
+        }
+        // else, do nothing (block pan)
+    }
+
     var pitchRadians = this.orbitCamera.pitch * pc.math.DEG_TO_RAD;
     var minPivotY = this.orbitCamera.distance * Math.sin(pitchRadians);
     if (this.orbitCamera.pivotPoint.y < minPivotY) {
@@ -512,7 +542,21 @@ OrbitCameraInputTouch.prototype.pan = function (midPoint) {
     camera.screenToWorld(midPoint.x, midPoint.y, distance, fromWorldPoint);
     camera.screenToWorld(this.lastPinchMidPoint.x, this.lastPinchMidPoint.y, distance, toWorldPoint);
     worldDiff.sub2(toWorldPoint, fromWorldPoint);
-    this.orbitCamera.pivotPoint.add(worldDiff);
+  
+    var proposedPivot = this.orbitCamera.pivotPoint.clone().add(worldDiff);
+    var minY = this.orbitCamera.minY;
+    var resultingY = this.orbitCamera.worldCameraYForPivot(proposedPivot);
+    if (resultingY >= minY - 1e-4) {
+      this.orbitCamera.pivotPoint.add(worldDiff);
+    } else {
+      worldDiff.y = 0;
+      proposedPivot = this.orbitCamera.pivotPoint.clone().add(worldDiff);
+      resultingY = this.orbitCamera.worldCameraYForPivot(proposedPivot);
+      if (resultingY >= minY - 1e-4) {
+        this.orbitCamera.pivotPoint.add(worldDiff);
+      }
+    }
+
     var pitchRadians = this.orbitCamera.pitch * pc.math.DEG_TO_RAD;
     var minPivotY = this.orbitCamera.distance * Math.sin(pitchRadians);
     if (this.orbitCamera.pivotPoint.y < minPivotY) {