storm_streak

Additive billboard streak for rain, splash droplets and sparks: a card that turns about its own Y axis toward the camera (zero_billboard_streak). Colour comes from the element's data0.rgb, which is HDR so sparks can run hotter than 1, and an element whose colour fades to black vanishes (below 0.002 in every channel it is discarded). Across the card the streak is rounded (1 - across^2), so a thin card shows a soft edge; along it a bright head gives way to a long soft tail. The storm's lightning lifts every card by ambient + flash * flash_gain, which makes falling rain flicker into view in every strike. Distance fades the streak by exp(-distance * fog), the streak fades in between 1.5 and 9 units from the camera, and the result is scaled by gain.

The storm graph (storm/storm.procGraph) builds three additive materials from it:

For each, the graph turns the particle onto its velocity, sets its length from its speed and writes data0 as a colour times a fade that takes a slow particle to black: wind-driven rain in a cool blue at random brightness, splash droplets thrown up where rain lands, and strike sparks cooling from (11, 9, 6) to black. In the Procgen Effects Showcase world, the fx_storm scene plays the graph.

The shader includes @builtin::shaderModules.billboard.

Properties

Lanes