Class MouseDistanceMeasurementsControl

Mouse-driven creation of DistanceMeasurements on a DistanceMeasurementTool.

Workflow

• activate attaches pointermove + click to the tool's View canvas.
• As the cursor moves over geometry the control shows a small hover dot at the picked world point (or hides it on a miss).
• First click captures the origin anchor and starts a "draft" measurement that follows the cursor.
• Second click commits the target anchor and adds the finished measurement to DistanceMeasurementTool.measurements.
• Esc cancels an in-progress measurement.

Repeats until deactivate (or destroy) is called.

Picking goes through DistanceMeasurementTool.picker — the same BVH-based path the rest of the demo helpers use, so it doesn't fight the GPU pick pipeline.

The control is single-shot per pair — re-activation starts fresh, even if the previous activation left a half-built measurement around (it is discarded).