// Main-pass vertex stage of falling leaves (`falling.rs`, a `FloraMaterial` with `falling` set): each card of a
// burst hangs where it grew until its moment, falls, tumbling and swinging, drifts with the wind,
// settles flat on the ground, lies there a while and shrinks away (`falling_common.wesl`). The
// fragment stage is the tree leaves' own (`fragment.wesl`), so a falling leaf looks like the ones
// still on the tree, season included. The prepass does the same in `falling_prepass.wesl`.
import bevy_pbr::render::{
mesh_functions,
forward_io::{Vertex, VertexOutput, decompress_vertex},
view_transformations::position_world_to_clip,
mesh_view_bindings::globals,
};
import package::shading::common::{leaf_season_tint, FALLEN_LEAF_CLIP};
import package::shading::falling_common::falling_leaf;
@vertex
fn vertex(
vertex_no_morph: Vertex,
@location(11) sway: vec4<f32>,
@location(12) anchor: vec4<f32>,
@location(13) path: vec4<f32>,
@location(14) face: vec4<f32>,
) -> VertexOutput {
var out: VertexOutput;
let vertex = decompress_vertex(vertex_no_morph, vertex_no_morph.instance_index);
let world_from_local = mesh_functions::get_world_from_local(vertex_no_morph.instance_index);
var normal = vec3<f32>(0.0, 1.0, 0.0);
@if(VERTEX_NORMALS)
normal = vertex.normal;
let leaf = falling_leaf(world_from_local, vertex.position, normal, anchor, path, face, globals.time);
if !leaf.shown {
out.position = FALLEN_LEAF_CLIP;
return out;
}
out.world_position = vec4<f32>(leaf.position, 1.0);
out.position = position_world_to_clip(leaf.position);
@if(VERTEX_NORMALS)
out.world_normal = leaf.normal;
@if(VERTEX_UVS_A)
out.uv = vertex.uv;
// Out of the crown it is no longer in its tree's shade (`uv1.y`, how much sky it sees).
@if(VERTEX_UVS_B)
out.uv_b = vec2<f32>(vertex.uv_b.x, mix(vertex.uv_b.y, 1.0, leaf.open));
@if(VERTEX_COLORS)
out.color = vec4<f32>(vertex.color.rgb * leaf_season_tint(sway, vertex.color), vertex.color.a);
@if(VERTEX_OUTPUT_INSTANCE_INDEX)
out.instance_index = vertex_no_morph.instance_index;
@if(VISIBILITY_RANGE_DITHER)
out.visibility_range_dither = mesh_functions::get_visibility_range_dither_level(
vertex_no_morph.instance_index, world_from_local[3]);
return out;
}