Wet surfaces and puddles

#Patch a material

weather.patchMaterial(ground.material, { ground: true });   // puddles + full snow blanket
weather.patchMaterial(wallMaterial);                          // wetness, ripples, snow on ledges
weather.patchMaterial(leafMaterial, { sway: true });          // bends in the wind

patchMaterial(material, options?) returns the same material, so it can wrap a constructor call. It works through onBeforeCompile:

• Supported materials: MeshStandardMaterial and MeshPhysicalMaterial. Anything else logs a warning and is returned unchanged.
• Chains an existing onBeforeCompile, so it composes with other patches, including NatureGL Sky's cloud shadows.
• Idempotent. Patching the same material twice does nothing the second time.
• Instancing and batching aware. The world position used for puddles and shelter includes the instance transform.
• Materials are shared by reference: patch a material once and every mesh using it gets the weather.

#What every patched material gets

#ground: true

For roughly horizontal ground:

• Puddles fade in once wetness passes 30 % and are full at 75 %. Where they are depends on a world-space noise pattern, so they stay put as the camera moves. Puddles never form under snow or under shelter.
• The full snow blanket instead of ledge-only snow.
• Reflectivity for the SSR pass. In weather.render(), puddles reflect the scene, and the raindrop rings distort the reflection. On the plain path they reflect scene.environment, or a sky tint if there's no environment map.

#sway: true

For trees and bushes: vertices bend with the wind, more the higher they are above y = 0.6 m. Put the object's origin at its base. The demo patches its foliage and trunks this way.

wetness 0wetness 1

#Wetness is state

weather.wetness (the SurfaceWeather) holds the current wetness and snowCover, both 0–1. They are not targets: they change every frame, from the current weather.

weather.wetness.rate multiplies all of them. daylight comes from setLighting({ daylight }), or from the key light's height when you don't pass it.

#Setting it directly

weather.set({ wetness: 1 });                        // ease there over ~4.5 s, then natural again
weather.set({ wetness: 1, snowCover: 0 }, { instant: true });
weather.wetness.force(0.6, null, 1.5);              // ease to 0.6 over 1.5 s (the demo's slider)
weather.wetness.setImmediate(0, 0);                 // bone dry, right now
weather.wetness.puddles = false;                    // no puddles at all

Presets include wetness and snowCover, so loadPreset('downpour') eases the streets to fully wet, and loadPreset('clear') dries them.

#Puddle reflections

pipeline.ssr = falsepipeline.ssr = true

Screen-space reflections are part of weather.render(). The ray takes ssrSteps steps: 12 on low up to 28 on ultra. Rays that leave the screen fall back to the sky colours from setLighting({ skyHorizon, skyZenith }).

weather.render();              // the pipeline exists after the first render()
weather.pipeline.ssr = false;  // puddles reflect the sky colour only

#Your own shaders

The patch reads the shared uniform block, weather.uniforms. wet, cover, rain, puddle, wind and time are there, together with the occlusion map (heightTex, hArea, hTop, hNear, hFar, hFloor). Bind them by reference into a custom ShaderMaterial and they update every frame. This is advanced use, and the uniform names can change between versions.