mirror of
https://github.com/storytold/effectcraft.git
synced 2026-11-02 08:40:44 +00:00
Brandon ThomasandClaude Opus 5.5
dec091e575
Advanced 3D comps render their 3D runs as one scene of world-space triangles: model and primitive layers (meshes, skinning, animation clips by layer time), extruded text/shape layers, and textured cards for every other layer with their Material Options. Shading is physically based in linear light: Cook-Torrance GGX + Lambert for parallel/spot/point lights (AE falloff and cone), ambient lights, image-based light from an Environment light's layer (equirectangular; cosine irradiance map + roughness mip chain + split-sum BRDF fit), and PCF shadow maps (spot/parallel/point cube faces). 2x2 SSAA, depth of field as a gather blur by circle of confusion, back to the working encoding. The software rasteriser (depth buffer, top-left rule, perspective-correct, opaque visibility then sorted transparent blending) is the reference and CI path; effectcraft-gpu implements Accelerator::raster_3d with a wgpu render pipeline (advanced3d.wgsl) and matches it within tolerance. Environment layers are hidden from both renderers. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
592 lines
22 KiB
Rust
592 lines
22 KiB
Rust
//! The Classic 3D compositor for a run of consecutive 3D layers.
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//!
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//! Each layer is a textured plane: its processed buffer (source → masks → effects, DOF-blurred)
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//! mapped through `projection · world`. Rendering is per output pixel (rows in parallel): every
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//! plane covering the pixel is inverse-mapped through its homography (exact perspective-correct
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//! texture coordinates, bilinear/bicubic sampling), its camera depth taken from the plane
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//! equation, and the fragment shaded by the comp's lights. The pixel's fragments are then sorted
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//! far→near (coplanar fragments keep layer-stack order) and blended with each layer's mode and
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//! opacity. Sorting per pixel handles intersecting layers exactly, and blend modes and partial
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//! transparency still compose in depth order, as in AE's Classic 3D renderer.
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//!
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//! Shadows are ray-cast against the shadow-casting planes (exact for planar layers, including
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//! alpha-shaped and coloured shadows through Light Transmission); Shadow Diffusion softens them
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//! with a penumbra that grows with the distance between caster and receiver.
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use std::sync::Arc;
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use effectcraft_color::{BlendMode, blend_pixel};
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use effectcraft_effects::Buf;
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use effectcraft_geom::{Mat3, Mat4, Vec3, vec3};
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use effectcraft_project::{Layer, LightKind, MatteKind};
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use effectcraft_raster::{Image, Px, hash_noise};
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use effectcraft_time::Tick;
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use rayon::prelude::*;
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use super::camera::{CameraState, NEAR, active_camera};
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use super::light::{LightState, Material, lights_at, shade};
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use crate::{EvalCtx, Renderer};
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/// One position of a plane (several with motion blur).
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#[derive(Clone, Copy, Debug)]
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pub(crate) struct Geo {
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/// Output pixel → homogeneous layer coordinates.
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hinv: Mat3,
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/// Camera-space depth as a function of layer (u, v): `d0·u + d1·v + d2`.
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depth: [f64; 3],
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world: Mat4,
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normal: Vec3,
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/// Output pixel bounds [x0, y0, x1, y1) covered by the plane.
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bbox: [i64; 4],
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cam: CameraState,
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}
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/// A prepared 3D layer.
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pub(crate) struct Item<'a> {
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pub layer: &'a Layer,
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/// Position in the layer stack (higher = above).
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order: usize,
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buf: Arc<Buf>,
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bicubic: bool,
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geos: Vec<Geo>,
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mat: Material,
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opacity: f32,
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/// Drawn (false for "Casts Shadows: Only" and shadow-only casters outside the run).
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draw: bool,
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/// Screen-space track matte factor (output size).
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matte: Option<Arc<Vec<f32>>>,
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preserve: bool,
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/// World → layer (for shadow rays) and the buffer's layer-space bounds.
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winv: Mat4,
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bounds: [f64; 4],
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bbox: [i64; 4],
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}
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impl Item<'_> {
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#[inline]
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fn texel(&self, u: f64, v: f64) -> Px {
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let x = u * self.buf.scale + self.buf.offset[0];
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let y = v * self.buf.scale + self.buf.offset[1];
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if self.bicubic { self.buf.img.sample_bicubic(x, y) } else { self.buf.img.sample_bilinear(x, y) }
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}
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}
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/// Build the plane geometry of a layer for a camera.
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fn geo(cam: &CameraState, world: Mat4, buf: &Buf, comp: (f64, f64), scale: f64, out: (u32, u32)) -> Option<Geo> {
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let proj = Mat4::scale(vec3(scale, scale, 1.0)) * cam.projection(comp.0, comp.1);
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let full = proj * world;
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let h = full.plane_to_mat3();
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// Edge-on planes project to a line (singular homography): nothing to draw.
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let col = |j: usize| (h.0[0][j].powi(2) + h.0[1][j].powi(2) + h.0[2][j].powi(2)).sqrt();
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if h.determinant().abs() <= 1e-10 * col(0) * col(1) * col(2) {
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return None;
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}
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let hinv = h.inverse()?;
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let cv = cam.view * world;
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let depth = [cv.0[2][0], cv.0[2][1], cv.0[2][3]];
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let normal = world.apply_vec(vec3(1.0, 0.0, 0.0)).cross(world.apply_vec(vec3(0.0, 1.0, 0.0)));
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if normal.length() < 1e-12 {
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return None;
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}
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let normal = normal.normalize();
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let b = buf_bounds(buf);
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let corners = [(b[0], b[1]), (b[2], b[1]), (b[2], b[3]), (b[0], b[3])];
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let (mut x0, mut y0, mut x1, mut y1) = (f64::INFINITY, f64::INFINITY, f64::NEG_INFINITY, f64::NEG_INFINITY);
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let mut behind = 0;
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let mut full_frame = false;
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for (u, v) in corners {
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let z = depth[0] * u + depth[1] * v + depth[2];
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if !cam.ortho && z < NEAR {
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behind += 1;
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full_frame = true;
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continue;
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}
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let p = full.apply(vec3(u, v, 0.0));
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x0 = x0.min(p.x);
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y0 = y0.min(p.y);
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x1 = x1.max(p.x);
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y1 = y1.max(p.y);
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}
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if behind == 4 {
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return None;
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}
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let (ow, oh) = (out.0 as i64, out.1 as i64);
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let bbox = if full_frame {
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[0, 0, ow, oh]
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} else {
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[((x0.floor() as i64) - 2).max(0), ((y0.floor() as i64) - 2).max(0), ((x1.ceil() as i64) + 2).min(ow), ((y1.ceil() as i64) + 2).min(oh)]
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};
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if bbox[0] >= bbox[2] || bbox[1] >= bbox[3] {
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return None;
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}
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Some(Geo { hinv, depth, world, normal, bbox, cam: *cam })
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}
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/// Layer-space rectangle covered by a buffer.
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fn buf_bounds(buf: &Buf) -> [f64; 4] {
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let s = buf.scale.max(1e-9);
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[-buf.offset[0] / s, -buf.offset[1] / s, (buf.img.width as f64 - buf.offset[0]) / s, (buf.img.height as f64 - buf.offset[1]) / s]
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}
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/// Inverse-map an output pixel centre onto a plane: (u, v, camera depth).
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#[inline]
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fn unproject(g: &Geo, sx: f64, sy: f64) -> Option<(f64, f64, f64)> {
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let h = &g.hinv.0;
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let qz = h[2][0] * sx + h[2][1] * sy + h[2][2];
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if !g.cam.ortho && qz <= 0.0 {
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return None;
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}
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if qz.abs() < 1e-300 {
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return None;
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}
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let u = (h[0][0] * sx + h[0][1] * sy + h[0][2]) / qz;
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let v = (h[1][0] * sx + h[1][1] * sy + h[1][2]) / qz;
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let z = g.depth[0] * u + g.depth[1] * v + g.depth[2];
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if !g.cam.ortho && z < NEAR {
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return None;
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}
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Some((u, v, z))
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}
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/// The camera a renderer uses at a context time (view override only for the top-level comp).
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pub(crate) fn camera_for(r: &Renderer, ctx: &EvalCtx) -> CameraState {
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// Collapsed precomps see through the parent's camera.
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if let Some(c) = r.collapse3d {
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return c.cam;
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}
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match r.opts.view {
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Some(v) if r.depth == 0 => v,
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_ => active_camera(ctx),
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}
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}
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/// Number of motion-blur sub-samples for a layer.
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fn mb_samples(r: &Renderer, ctx: &EvalCtx, layer: &Layer) -> usize {
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if r.opts.motion_blur && ctx.comp.enable_motion_blur && layer.switches.motion_blur {
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if r.opts.draft { 4 } else { ctx.comp.motion_blur_samples.clamp(2, 64) as usize }
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} else {
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1
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}
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}
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/// Prepare a layer (buffer, geometry, material). `None` when it shows nothing.
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pub(crate) fn prepare<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Option<Item<'a>> {
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let buf = r.blend_layer_buf(ctx, layer)?;
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prepare_with(r, ctx, layer, order, out, in_run, buf, Mat4::IDENTITY)
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}
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/// Prepare a layer as planes: one per character for per-character 3D text, else one.
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pub(crate) fn prepare_all<'a>(r: &Renderer, ctx: &EvalCtx<'a>, layer: &'a Layer, order: usize, out: (u32, u32), in_run: bool) -> Vec<Item<'a>> {
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if crate::text::per_char_3d(ctx, layer) {
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return crate::text::per_char_planes(ctx, layer, r.opts.scale)
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.into_iter()
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.filter_map(|(buf, m)| prepare_with(r, ctx, layer, order, out, in_run, r.to_blend(Arc::new(buf), None), m))
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.collect();
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}
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prepare(r, ctx, layer, order, out, in_run).into_iter().collect()
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}
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/// Prepare a plane showing `buf`, whose space maps into the layer through `local`.
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#[allow(clippy::too_many_arguments)]
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fn prepare_with<'a>(
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r: &Renderer,
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ctx: &EvalCtx<'a>,
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layer: &'a Layer,
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order: usize,
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out: (u32, u32),
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in_run: bool,
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mut buf: Arc<Buf>,
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local: Mat4,
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) -> Option<Item<'a>> {
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if buf.img.is_empty() {
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return None;
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}
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let comp = (ctx.comp.width as f64, ctx.comp.height as f64);
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let s = r.opts.scale;
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let cam = camera_for(r, ctx);
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let outer = r.collapse3d.map_or(Mat4::IDENTITY, |c| c.world);
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let world = outer * ctx.world_matrix(layer) * local;
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// Depth of field: blur the layer by its circle of confusion at its centre.
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if let Some(dof) = cam.dof.filter(|_| !ctx.comp.draft_3d && !r.opts.draft) {
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let b = buf_bounds(&buf);
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let centre = world.apply(vec3((b[0] + b[2]) * 0.5, (b[1] + b[3]) * 0.5, 0.0));
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let z = cam.depth(centre);
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let coc = dof.coc(z);
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// Comp pixels on screen per layer pixel at that depth.
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let k = cam.zoom / z.max(NEAR) * world.apply_vec(vec3(1.0, 0.0, 0.0)).length().max(1e-9);
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let radius = coc * 0.5 / k * buf.scale;
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if radius > 0.3 {
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let sigma = radius / 1.5;
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let pad = (sigma * 3.0).ceil() as u32 + 1;
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let padded = buf.img.padded(pad);
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// The (cached, shared) layer buffer stays untouched; the blurred copy is per frame.
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buf = Arc::new(Buf {
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img: effectcraft_raster::gaussian_blur(&padded, sigma, sigma, false),
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offset: [buf.offset[0] + pad as f64, buf.offset[1] + pad as f64],
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scale: buf.scale,
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});
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}
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}
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let n = if in_run { mb_samples(r, ctx, layer) } else { 1 };
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let geos: Vec<Geo> = if n <= 1 {
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geo(&cam, world, &buf, comp, s, out).into_iter().collect()
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} else {
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let fd = ctx.comp.frame_duration().seconds();
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let angle = ctx.comp.shutter_angle / 360.0;
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let phase = ctx.comp.shutter_phase / 360.0;
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(0..n)
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.filter_map(|i| {
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let f = phase + angle * i as f64 / (n - 1) as f64;
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let sub = ctx.at(ctx.time + Tick::from_seconds_f64(f * fd));
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let c = camera_for(r, &sub);
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geo(&c, outer * sub.world_matrix(layer) * local, &buf, comp, s, out)
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})
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.collect()
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};
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if geos.is_empty() && in_run {
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return None;
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}
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let mut bbox = [i64::MAX, i64::MAX, i64::MIN, i64::MIN];
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for g in &geos {
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bbox = [bbox[0].min(g.bbox[0]), bbox[1].min(g.bbox[1]), bbox[2].max(g.bbox[2]), bbox[3].max(g.bbox[3])];
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}
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let mat = Material::of(ctx, layer);
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let bounds = buf_bounds(&buf);
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Some(Item {
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layer,
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order,
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bicubic: matches!(r.sampling(layer), effectcraft_raster::Sampling::Bicubic),
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buf,
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geos,
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opacity: ctx.opacity(layer) as f32 * r.opacity_mul(),
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draw: in_run && mat.casts_shadows != 2,
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mat,
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matte: None,
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preserve: layer.preserve_transparency,
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winv: world.inverse().unwrap_or(Mat4::IDENTITY),
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bounds,
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bbox,
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})
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}
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/// Screen-space track matte factor for a layer, or None.
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fn matte_for(r: &Renderer, ctx: &EvalCtx, layer: &Layer, out: (u32, u32)) -> Option<Arc<Vec<f32>>> {
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let tm = layer.track_matte?;
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let m = ctx.comp.layer(tm.layer).filter(|m| m.id != layer.id)?;
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let mut img = Image::new(out.0, out.1);
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if m.is_active_at(ctx.time) {
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if m.is_3d() {
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// Render the matte plane alone (its own matte is ignored).
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let mut solo = m.clone();
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solo.track_matte = None;
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solo.preserve_transparency = false;
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solo.blend_mode = BlendMode::Normal;
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let its = prepare_all(r, ctx, &solo, 0, out, true);
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if !its.is_empty() {
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let lights = scene_lights(ctx);
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composite(&mut img, &its, &lights, &[], m.id.0 as u32);
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}
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} else if let Some(mb) = r.layer_buf(ctx, m) {
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r.place(ctx, m, &mb, &mut img, BlendMode::Normal, ctx.opacity(m) as f32);
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}
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}
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Some(Arc::new(
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img.data
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.par_iter()
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.map(|q| {
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match tm.kind {
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MatteKind::Alpha => q[3],
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MatteKind::AlphaInverted => 1.0 - q[3],
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MatteKind::Luma => effectcraft_color::luminance(q[0], q[1], q[2]),
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MatteKind::LumaInverted => 1.0 - effectcraft_color::luminance(q[0], q[1], q[2]),
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}
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.clamp(0.0, 1.0)
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})
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.collect(),
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))
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}
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/// Lights used for shading: none in Draft 3D (which also turns off shadows and depth of field).
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fn scene_lights(ctx: &EvalCtx) -> Vec<LightState> {
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if ctx.comp.draft_3d { vec![] } else { lights_at(ctx) }
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}
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/// Draw a run of consecutive 3D layers (bottom-to-top order) into `canvas`.
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pub(crate) fn draw_run(r: &Renderer, ctx: &EvalCtx, run: &[&Layer], canvas: &mut Image) {
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// 3D adjustment layers act on everything below them in the stack (like 2D ones): split.
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if let Some(k) = run.iter().position(|l| l.switches.adjustment) {
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draw_run(r, ctx, &run[..k], canvas);
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r.draw_layer(ctx, run[k], canvas, false);
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draw_run(r, ctx, &run[k + 1..], canvas);
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return;
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}
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if run.is_empty() {
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return;
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}
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// Advanced 3D comps: meshes, physically based lights, shadow maps (collapsed precomps keep
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// the parent's Classic 3D planes).
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if ctx.comp.renderer == effectcraft_project::Renderer::Advanced3D && r.collapse3d.is_none() {
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super::adv::draw_run(r, ctx, run, canvas);
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return;
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}
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let out = (canvas.width, canvas.height);
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// A collapsed precomp's 3D layers are lit by the outer comp's lights.
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let lights = scene_lights(&r.collapse3d.map_or(*ctx, |c| c.parent));
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let mut items: Vec<Item> = run
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.par_iter()
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.enumerate()
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.filter(|(_, l)| ctx.opacity(l) > 0.0 && l.switches.quality != effectcraft_project::Quality::Wireframe)
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.flat_map_iter(|(i, l)| {
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// Stack order with room for a collapsed precomp's layers in between.
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let i = i * 1024;
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if let Some(item) = r.collapsed(ctx, l) {
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return collapsed_items(r, ctx, l, item, i, out);
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}
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let mut its = prepare_all(r, ctx, l, i, out, true);
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if !its.is_empty() {
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let m = matte_for(r, ctx, l, out);
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for it in &mut its {
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it.matte = m.clone();
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}
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}
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its
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})
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.collect();
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// Shadow casters outside this run (other 3D layers of the comp).
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let mut extra: Vec<Item> = vec![];
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if lights.iter().any(|l| l.casts_shadows && l.kind != LightKind::Ambient) {
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let in_run: Vec<_> = run.iter().map(|l| l.id).collect();
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extra = ctx
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.comp
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.layers
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.par_iter()
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.filter(|l| l.switches.three_d && l.has_video() && l.is_active_at(ctx.time) && !in_run.contains(&l.id) && !l.switches.adjustment)
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.filter(|l| Material::of(ctx, l).casts_shadows != 0)
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.flat_map_iter(|l| prepare_all(r, ctx, l, 0, out, false))
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.collect();
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}
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items.sort_by_key(|i| i.order);
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let casters: Vec<&Item> = items.iter().chain(extra.iter()).filter(|i| i.mat.casts_shadows != 0 && !i.geos.is_empty()).collect();
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composite(canvas, &items, &lights, &casters, run[0].id.0 as u32);
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for l in run.iter().filter(|l| l.switches.quality == effectcraft_project::Quality::Wireframe) {
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r.draw_layer(ctx, l, canvas, false);
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}
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}
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/// A collapsed 3D precomp layer inside a 3D run: its nested layers become planes in this comp's
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/// 3D space (world = precomp layer's world × nested world), depth-sorted with the run, so they
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/// intersect the parent's 3D layers; nested 2D layers lie on the precomp layer's plane in stack
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/// order. (Nested adjustment layers are skipped here.)
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fn collapsed_items<'a>(
|
||
r: &Renderer<'a>,
|
||
ctx: &EvalCtx<'a>,
|
||
layer: &'a Layer,
|
||
item: effectcraft_project::ItemId,
|
||
order: usize,
|
||
out: (u32, u32),
|
||
) -> Vec<Item<'a>> {
|
||
let op = ctx.opacity(layer) as f32 * r.opacity_mul();
|
||
let Some((sub, nctx)) = r.collapse_into(ctx, layer, item, op) else { return vec![] };
|
||
let t = nctx.time;
|
||
let any_solo = nctx.comp.layers.iter().any(|l| l.switches.solo && l.source.is_av() && l.is_active_at(t));
|
||
let nested: Vec<&'a Layer> = nctx
|
||
.comp
|
||
.layers
|
||
.iter()
|
||
.rev()
|
||
.filter(|l| l.is_active_at(t) && l.has_video() && !l.switches.adjustment && (!any_solo || l.switches.solo) && (r.opts.guides || !l.switches.guide))
|
||
.collect();
|
||
let mut items = Vec::new();
|
||
for (k, l) in nested.into_iter().enumerate() {
|
||
if nctx.opacity(l) <= 0.0 {
|
||
continue;
|
||
}
|
||
let mut its = prepare_all(&sub, &nctx, l, order + 1 + k.min(1022), out, true);
|
||
if !its.is_empty() {
|
||
let m = matte_for(&sub, &nctx, l, out);
|
||
for it in &mut its {
|
||
it.matte = m.clone();
|
||
}
|
||
}
|
||
items.extend(its);
|
||
}
|
||
items
|
||
}
|
||
|
||
/// Per-pixel depth-sorted compositing of prepared planes.
|
||
fn composite(canvas: &mut Image, items: &[Item], lights: &[LightState], casters: &[&Item], seed: u32) {
|
||
let w = canvas.width as usize;
|
||
canvas.rows_mut().for_each(|(y, row)| {
|
||
let yi = y as i64;
|
||
let active: Vec<&Item> = items.iter().filter(|it| it.draw && yi >= it.bbox[1] && yi < it.bbox[3]).collect();
|
||
if active.is_empty() {
|
||
return;
|
||
}
|
||
let mut frags: Vec<(f64, usize, Px, usize)> = Vec::with_capacity(active.len());
|
||
for x in 0..w {
|
||
let xi = x as i64;
|
||
frags.clear();
|
||
for (k, it) in active.iter().enumerate() {
|
||
if xi < it.bbox[0] || xi >= it.bbox[2] {
|
||
continue;
|
||
}
|
||
if let Some((z, px)) = fragment(it, x as f64 + 0.5, y as f64 + 0.5, lights, casters) {
|
||
let px = match &it.matte {
|
||
Some(m) => {
|
||
let f = m[y * w + x];
|
||
[px[0] * f, px[1] * f, px[2] * f, px[3] * f]
|
||
}
|
||
None => px,
|
||
};
|
||
if px[3] > 0.0 || px[0] != 0.0 || px[1] != 0.0 || px[2] != 0.0 {
|
||
frags.push((z, it.order, px, k));
|
||
}
|
||
}
|
||
}
|
||
if frags.is_empty() {
|
||
continue;
|
||
}
|
||
// Far → near; (near-)coplanar fragments in stack order (lower layer first).
|
||
for i in 1..frags.len() {
|
||
let mut j = i;
|
||
while j > 0 && before(&frags[j], &frags[j - 1]) {
|
||
frags.swap(j, j - 1);
|
||
j -= 1;
|
||
}
|
||
}
|
||
let mut d = row[x];
|
||
for (_, _, px, k) in &frags {
|
||
let it = active[*k];
|
||
let mut s = *px;
|
||
let op = it.opacity * if it.preserve { d[3] } else { 1.0 };
|
||
for c in s.iter_mut() {
|
||
*c *= op;
|
||
}
|
||
let mode = it.layer.blend_mode;
|
||
let n = if matches!(mode, BlendMode::Dissolve | BlendMode::DancingDissolve) {
|
||
hash_noise(x as u32, y as u32, seed ^ it.layer.id.0 as u32)
|
||
} else {
|
||
0.5
|
||
};
|
||
d = blend_pixel(mode, d, s, n);
|
||
}
|
||
row[x] = d;
|
||
}
|
||
});
|
||
}
|
||
|
||
#[inline]
|
||
fn before(a: &(f64, usize, Px, usize), b: &(f64, usize, Px, usize)) -> bool {
|
||
let tol = 1e-6 * a.0.abs().max(b.0.abs()).max(1.0);
|
||
if (a.0 - b.0).abs() <= tol { a.1 < b.1 } else { a.0 > b.0 }
|
||
}
|
||
|
||
/// Shaded premultiplied fragment of a plane at an output pixel centre, with its depth.
|
||
fn fragment(it: &Item, sx: f64, sy: f64, lights: &[LightState], casters: &[&Item]) -> Option<(f64, Px)> {
|
||
let n = it.geos.len();
|
||
let mut acc = [0.0f32; 4];
|
||
let mut depth = None;
|
||
for g in &it.geos {
|
||
let Some((u, v, z)) = unproject(g, sx, sy) else { continue };
|
||
let t = it.texel(u, v);
|
||
if t[3] <= 1e-6 {
|
||
continue;
|
||
}
|
||
depth.get_or_insert(z);
|
||
let px = shade_texel(it, g, u, v, t, lights, casters);
|
||
for c in 0..4 {
|
||
acc[c] += px[c];
|
||
}
|
||
}
|
||
let depth = depth?;
|
||
if n > 1 {
|
||
let k = 1.0 / n as f32;
|
||
for c in acc.iter_mut() {
|
||
*c *= k;
|
||
}
|
||
}
|
||
Some((depth, acc))
|
||
}
|
||
|
||
fn shade_texel(it: &Item, g: &Geo, u: f64, v: f64, t: Px, lights: &[LightState], casters: &[&Item]) -> Px {
|
||
if lights.is_empty() || !it.mat.accepts_lights {
|
||
if it.mat.accepts_shadows == 2 {
|
||
return [0.0; 4];
|
||
}
|
||
return t;
|
||
}
|
||
let a = t[3];
|
||
let rgb = [t[0] / a, t[1] / a, t[2] / a];
|
||
let p = g.world.apply(vec3(u, v, 0.0));
|
||
let shadow = |li: usize, p: Vec3| -> [f32; 3] {
|
||
let l = &lights[li];
|
||
let mut tr = [1.0f32; 3];
|
||
for c in casters {
|
||
if std::ptr::eq(*c, it) || c.layer.id == it.layer.id {
|
||
continue;
|
||
}
|
||
let o = occlusion(c, p, l);
|
||
for k in 0..3 {
|
||
tr[k] *= o[k];
|
||
}
|
||
}
|
||
tr
|
||
};
|
||
let (lit, shadow_amt) = shade(rgb, p, g.normal, g.cam.to_viewer(p), &it.mat, lights, &shadow);
|
||
if it.mat.accepts_shadows == 2 {
|
||
return [0.0, 0.0, 0.0, a * shadow_amt];
|
||
}
|
||
[lit[0] * a, lit[1] * a, lit[2] * a, a]
|
||
}
|
||
|
||
/// RGB transmittance of light `l` reaching `p` past caster `c` (1 = unoccluded).
|
||
fn occlusion(c: &Item, p: Vec3, l: &LightState) -> [f32; 3] {
|
||
const FAR: f64 = 1.0e6;
|
||
let a = c.winv.apply(p);
|
||
let target = if l.kind == LightKind::Parallel { p - l.dir * FAR } else { l.pos };
|
||
let b = c.winv.apply(target);
|
||
if a.z == b.z || a.z.signum() == b.z.signum() {
|
||
return [1.0; 3];
|
||
}
|
||
let t = a.z / (a.z - b.z);
|
||
if t <= 1e-6 || t >= 1.0 - 1e-9 {
|
||
return [1.0; 3];
|
||
}
|
||
let hit = a + (b - a) * t;
|
||
// Penumbra radius (layer pixels) from Shadow Diffusion: grows with receiver–caster distance.
|
||
let seg = (target - p).length();
|
||
let d_pc = seg * t;
|
||
let d_cl = if l.kind == LightKind::Parallel { 1000.0 } else { (seg * (1.0 - t)).max(1.0) };
|
||
let r = l.shadow_diffusion * (d_pc / d_cl).min(4.0);
|
||
let bd = &c.bounds;
|
||
if hit.x < bd[0] - r || hit.y < bd[1] - r || hit.x > bd[2] + r || hit.y > bd[3] + r {
|
||
return [1.0; 3];
|
||
}
|
||
let mut px = [0.0f32; 4];
|
||
if r * c.buf.scale < 0.5 {
|
||
px = c.texel(hit.x, hit.y);
|
||
} else {
|
||
for j in -1..=1 {
|
||
for i in -1..=1 {
|
||
let q = c.texel(hit.x + i as f64 * r * 0.66, hit.y + j as f64 * r * 0.66);
|
||
for k in 0..4 {
|
||
px[k] += q[k] / 9.0;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
let alpha = (px[3] * c.opacity).clamp(0.0, 1.0);
|
||
if alpha <= 0.0 {
|
||
return [1.0; 3];
|
||
}
|
||
let tr = c.mat.light_transmission;
|
||
let dark = l.shadow_darkness as f32;
|
||
let mut out = [1.0f32; 3];
|
||
for k in 0..3 {
|
||
let straight = if px[3] > 0.0 { (px[k] / px[3]).clamp(0.0, 1.0) } else { 0.0 };
|
||
let pass = (1.0 - alpha) + alpha * tr * straight;
|
||
out[k] = 1.0 - dark * (1.0 - pass);
|
||
}
|
||
out
|
||
}
|