storm_ground

Surface shader for sodden ground: churned earth, rock, puddles with animated rain rings, and the lightning bolt's reflection in the pools (flash, bolt_pos). Everything is computed from the world XZ position in a surface() function that fills a PbrSurface.

A height field of PCG-hashed value-noise fBm gives the relief and its normal, which flattens out between 40 and 160 units from the camera. Puddles fill the low ground, clustered by a broad noise, scaled by wet and puddles; they fade in across a square band 9 to 16 units out from (center_x, center_z), leaving drier ground around the keep standing there. Two layers of rain rings (cells 0.55 and 0.83 wide, 1.15 and 0.85 drops per cell per second) bend the normal on every wet patch, most strongly in the pools. The albedo mixes dark earth, grey rock patches and dead grass, is darkened by wet, and goes near-black in the pools; roughness runs from 0.72 dry to 0.30 wet and 0.03 in the pools, and reflectance is 0.55.

The strike's reflection traces the reflected view ray toward the vertical column above bolt_pos and adds a blue-white streak (0.55, 0.66, 1.0) in the pools, scaled by a fresnel term and by flash. Distance haze 1 - exp(-distance * fog) fades the ground into the colour (0.052, 0.066, 0.092), the same haze colour storm_sky puts on its horizon, brightened slightly by the flash.

The storm_ground material (storm/materials/storm_ground.material) sets (center_x, center_z) to (-100, 220), where the keep stands, and keeps the defaults for the rest; the fx_storm scene's ground draws with it. The StormDirector component writes the material's flash and bolt_pos whenever the strike lighting changes.

Properties