'grow' chaperone bounds up when moving playspace

src/overlaycontroller.cpp

@@ -559,7 +559,6 @@ void OverlayController::AddOffsetToCollisionBounds(float offset[3], bool commit)
 	// Apparently Valve sanity-checks the y-coordinates of the collision bounds (and only the y-coordinates)
 	// I can move the bounds on the xz-plane, I can make the "ceiling" of the chaperone cage lower/higher, but when I
 	// dare to set one single lower corner to something non-zero, every corner gets its y-coordinates reset to the defaults.
-	// I do it anyway, maybe it gets fixed in the future.
 	if (commit) {
 		vr::VRChaperoneSetup()->RevertWorkingCopy();
 	}
@@ -571,7 +570,13 @@ void OverlayController::AddOffsetToCollisionBounds(float offset[3], bool commit)
 		for (unsigned b = 0; b < collisionBoundsCount; b++) {
 			for (unsigned c = 0; c < 4; c++) {
 				collisionBounds[b].vCorners[c].v[0] += offset[0];
-				collisionBounds[b].vCorners[c].v[1] += offset[1];
+
+				// keep the lower corners on the ground so it doesn't reset all y cooridinates.
+				// this causes the caperone to "grow" up instead of not moving up at all.
+				// note that Valve still forces a minimum height so we can't go into the ground
+				if (collisionBounds[b].vCorners[c].v[1] != 0) {
+					collisionBounds[b].vCorners[c].v[1] += offset[1];
+				}
 				collisionBounds[b].vCorners[c].v[2] += offset[2];
 			}
 		}