How many checkpoints are fully met. The engine samples this before and after
each step's latch pass: an increase is TOUR progress, which is the only
progress signal a tour has. Pixel-level change is not — a tour section
can latch while the frame looks identical (a tree expanding inside a narrow
panel, a chip toggling), and returning to a prior state is often required
(open→cancel, A→B→A). See the loop-reset in the engine's main loop.
How many checkpoints are fully met. The engine samples this before and after each step's latch pass: an increase is TOUR progress, which is the only progress signal a tour has. Pixel-level change is not — a tour section can latch while the frame looks identical (a tree expanding inside a narrow panel, a chip toggling), and returning to a prior state is often required (open→cancel, A→B→A). See the loop-reset in the engine's main loop.