ab_water

The water in Ashbloom's crater: a blend-queue surface that reads the lit opaque scene standing behind it through zero::scene_color and bends it through its own animated ripple gradient, and reads the depth already drawn under it through zero::scene_depth so the colour darkens with real water depth over the stone.

One shader serves three surfaces — the sunken pool, the sheet pouring over a terrace lip, and the slurry running in the stone channels. What separates them is property values: flow_x/flow_z for a current, slurry for the grey ash load movement II carries, under_amount/under_color for the pool lit from beneath while the garden is glowing, rain_amount for the expanding rings rain pocks the surface with.

The vertex hook displaces the surface for real (off v.time, so the previous-frame evaluation reports the swell's true velocity), which is what moves the silhouette against the basin lip and puts the water into the motion-vector buffer.

Lighting is the engine's, called with a black albedo — what comes back is the specular response alone, so the moon lays its line on the water in movement I and the blooms standing over it do in movement III.

It declares no textures and no storage buffers, so it costs nothing of a material's 9 sampled-texture / 1 storage-buffer budget.

Author a material for it with render = { blend = "alphaBlend", cull = "none" } and set castsShadows = false on the Model — a transparent material is still built with depth writes on.