dragon_smoke

Alpha-blended rolling black smoke puff for the dragon_breath graph. data0 = (life, seed, size, 0). Sooty and near-black, underlit orange by the fire only while young.

Each puff is a zero_billboard card turned by its seed and slowly rotated over its life. A domain-warped four-octave value noise drifting with time breaks up a soft disc. The puff fades in over the first 18 percent of its life and out between 0.45 and 1, at a peak opacity of 0.62. Its colour is a near-black (0.010, 0.009, 0.009) lifted by noise into dark grey as it ages, plus an orange underglow (1.6, 0.4, 0.08), weighted across the card by 0.5 - 0.5 * p.y and toward its thin edge, that decays with exp(-9 * life) squared, so only young smoke catches the fire.

The dragon_breath graph (dragon/dragon_breath.procGraph) draws its smoke output with it, transparent: smoke born where flame particles die, rolled by curl noise and drifting on a constant breeze, on cards that grow from 0.8 to 2.8 of their size over life. In the Procgen Effects Showcase world, the fx_breath scene plays that graph. All of its inputs arrive per particle on data0; properties.yaml holds properties: [].

The shader includes @builtin::shaderModules.billboard.

Lanes

Culling

vertexBoundsDilation (float, default 2.5): how far the vertex hook moves a vertex past the mesh, in world units. The culling bounds grow by it, so a card turned to face the camera stays inside them where it reaches past the mesh it was drawn from.