Spawn entities on the ground if snap is on

Previously, entities always appeared in the middle of the screen
with an unlocked y-axis. Now, they will appear on the ground
if snapping is enabled and the ground is in sight.

macrovision.js

@@ -5572,9 +5572,12 @@ function prepareEntities() {
             if (config.lockYAxis) {
                 yOffset = getVerticalOffset();
             } else {
-                yOffset = config.lockYAxis
-                    ? 0
-                    : config.height.toNumber("meters") / 2;
+                // Snap to the ground if it's visible.
+                if (config.groundSnap && pos2pix({x: 0, y: 0}).y < canvasHeight + 50) {
+                    yOffset = -config.y;
+                } else {
+                    yOffset = config.height.toNumber("meters") / 2;
+                }
             }
             displayEntity(
                 newEntity,