561 lines
16 KiB
Rust
561 lines
16 KiB
Rust
use crate::camera::{Camera, CameraTrait};
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use crate::core::bxdf::{BSDF, BxDFFlags};
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use crate::core::material::MaterialTrait;
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use crate::core::medium::{Medium, MediumInterface};
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use crate::core::pbrt::{Float, clamp_t};
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use crate::geometry::{
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Normal3f, Point2f, Point3f, Point3fi, Ray, RayDifferential, Vector3f, VectorLike,
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};
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use crate::lights::Light;
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use crate::shapes::Shape;
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use crate::utils::math::{difference_of_products, square};
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use std::any::Any;
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use std::sync::Arc;
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#[derive(Default, Clone, Debug)]
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pub struct InteractionData {
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pub pi: Point3fi,
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pub n: Normal3f,
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pub time: Float,
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pub wo: Vector3f,
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pub medium_interface: Option<Arc<MediumInterface>>,
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pub medium: Option<Arc<Medium>>,
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}
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pub trait Interaction: Send + Sync {
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fn get_common(&self) -> &InteractionData;
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fn get_common_mut(&mut self) -> &mut InteractionData;
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fn as_any(&self) -> &dyn Any;
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fn as_any_mut(&mut self) -> &mut dyn Any;
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fn into_any(self: Box<Self>) -> Box<dyn Any>;
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fn p(&self) -> Point3f {
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self.get_common().pi.into()
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}
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fn pi(&self) -> Point3fi {
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self.get_common().pi
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}
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fn time(&self) -> Float {
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self.get_common().time
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}
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fn wo(&self) -> Vector3f {
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self.get_common().wo
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}
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fn n(&self) -> Normal3f {
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self.get_common().n
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}
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fn is_surface_interaction(&self) -> bool {
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self.as_any().is::<SurfaceInteraction>()
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}
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fn is_medium_interaction(&self) -> bool {
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self.as_any().is::<MediumInteraction>()
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}
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fn get_medium(&self, w: Vector3f) -> Option<Arc<Medium>>;
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fn spawn_ray(&self, d: Vector3f) -> Ray;
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fn spawn_ray_to_point(&self, p2: Point3f) -> Ray {
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let origin = self.p();
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let direction = p2 - origin;
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Ray {
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o: origin,
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d: direction,
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time: self.time(),
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medium: self.get_medium(direction),
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differential: None,
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}
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}
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fn spawn_ray_to_interaction(&self, other: &dyn Interaction) -> Ray {
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self.spawn_ray_to_point(other.p())
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}
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fn offset_ray_vector(&self, w: Vector3f) -> Point3f {
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Ray::offset_origin(&self.pi(), &self.n(), &w)
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}
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fn offset_ray_point(&self, pt: Point3f) -> Point3f {
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self.offset_ray_vector(pt - self.p())
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}
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}
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#[derive(Default, Clone, Debug)]
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pub struct ShadingGeometry {
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pub n: Normal3f,
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pub dpdu: Vector3f,
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pub dpdv: Vector3f,
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pub dndu: Normal3f,
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pub dndv: Normal3f,
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}
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#[derive(Default, Debug, Clone)]
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pub struct SurfaceInteraction {
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pub common: InteractionData,
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pub uv: Point2f,
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pub dpdu: Vector3f,
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pub dpdv: Vector3f,
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pub dndu: Normal3f,
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pub dndv: Normal3f,
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pub shading: ShadingGeometry,
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pub medium_interface: Option<Arc<MediumInterface>>,
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pub face_index: usize,
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pub area_light: Option<Arc<Light>>,
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pub material: Option<Arc<dyn MaterialTrait>>,
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pub dpdx: Vector3f,
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pub dpdy: Vector3f,
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pub dudx: Float,
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pub dvdx: Float,
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pub dudy: Float,
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pub dvdy: Float,
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pub shape: Arc<Shape>,
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pub bsdf: Option<BSDF>,
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}
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impl SurfaceInteraction {
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pub fn compute_differentials(&mut self, r: &Ray, camera: Camera, samples_per_pixel: i32) {
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let computed = if let Some(diff) = &r.differential {
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let dot_rx = self.common.n.dot(diff.rx_direction.into());
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let dot_ry = self.common.n.dot(diff.ry_direction.into());
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if dot_rx != 0.0 && dot_ry != 0.0 {
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// Estimate screen-space change in p using ray differentials>
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let p_as_vec = Normal3f::new(self.p().x(), self.p().y(), self.p().z());
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let d = -self.common.n.dot(p_as_vec);
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// Compute t for x-auxiliary ray
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let rx_origin_vec =
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Normal3f::new(diff.rx_origin.x(), diff.rx_origin.y(), diff.rx_origin.z());
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let tx = (-self.common.n.dot(rx_origin_vec) - d) / dot_rx;
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// Compute intersection point px
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let px = diff.rx_origin + diff.rx_direction * tx;
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// Compute t for y-auxiliary ray
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let ry_origin_vec =
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Normal3f::new(diff.ry_origin.x(), diff.ry_origin.y(), diff.ry_origin.z());
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let ty = (-self.common.n.dot(ry_origin_vec) - d) / dot_ry;
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let py = diff.ry_origin + diff.ry_direction * ty;
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self.dpdx = px - self.p();
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self.dpdy = py - self.p();
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true
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} else {
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false
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}
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} else {
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false
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};
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if !computed {
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camera.approximate_dp_dxy(
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self.p(),
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self.n(),
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self.time(),
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samples_per_pixel,
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&mut self.dpdx,
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&mut self.dpdy,
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);
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}
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let ata00 = self.dpdu.dot(self.dpdu);
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let ata01 = self.dpdu.dot(self.dpdv);
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let ata11 = self.dpdv.dot(self.dpdv);
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let mut inv_det = 1. / difference_of_products(ata00, ata11, ata01, ata01);
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inv_det = if inv_det.is_finite() { inv_det } else { 0. };
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let atb0x = self.dpdu.dot(self.dpdx);
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let atb1x = self.dpdv.dot(self.dpdx);
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let atb0y = self.dpdu.dot(self.dpdy);
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let atb1y = self.dpdv.dot(self.dpdy);
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// Compute u and v derivatives in x and y
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self.dudx = difference_of_products(ata11, atb0x, ata01, atb1x) * inv_det;
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self.dvdx = difference_of_products(ata00, atb1x, ata01, atb0x) * inv_det;
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self.dudy = difference_of_products(ata11, atb0y, ata01, atb1y) * inv_det;
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self.dvdy = difference_of_products(ata00, atb1y, ata01, atb0y) * inv_det;
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// Clamp derivatives
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self.dudx = if self.dudx.is_finite() {
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clamp_t(self.dudx, -1e8, 1e8)
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} else {
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0.
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};
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self.dvdx = if self.dvdx.is_finite() {
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clamp_t(self.dvdx, -1e8, 1e8)
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} else {
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0.
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};
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self.dudy = if self.dudy.is_finite() {
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clamp_t(self.dudy, -1e8, 1e8)
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} else {
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0.
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};
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self.dvdy = if self.dvdy.is_finite() {
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clamp_t(self.dvdy, -1e8, 1e8)
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} else {
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0.
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};
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}
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pub fn skip_intersection(&self, ray: &mut Ray, t: Float) {
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let new_ray = Ray::spawn(&self.pi(), &self.n(), ray.time, ray.d);
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ray.o = new_ray.o;
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// Skipping other variables, since they should not change when passing through surface
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if let Some(diff) = &mut ray.differential {
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diff.rx_origin += diff.rx_direction * t;
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diff.ry_origin += diff.ry_direction * t;
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}
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}
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pub fn spawn_ray(&self, d: Vector3f) -> Ray {
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let mut ray = Ray::spawn(&self.pi(), &self.n(), self.time(), d);
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ray.medium = self.get_medium(d);
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ray
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}
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pub fn spawn_ray_to(&self, p2: Point3f) -> Ray {
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let mut ray = Ray::spawn_to_point(&self.pi(), &self.n(), self.time(), p2);
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ray.medium = self.get_medium(ray.d);
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ray
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}
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// fn get_medium(&self, w: &Vector3f) -> Option<Arc<Medium>> {
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// if w.dot(self.n().into()) > 0.0 {
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// self.medium_interface.outside.clone()
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// } else {
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// self.medium_interface.inside.clone()
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// }
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// }
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pub fn spawn_ray_with_differentials(
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&self,
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ray_i: &Ray,
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wi: Vector3f,
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flags: BxDFFlags,
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eta: Float,
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) -> Ray {
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let mut rd = self.spawn_ray(wi);
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if let Some(diff_i) = &ray_i.differential {
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let mut n = self.shading.n;
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let mut dndx = self.shading.dndu * self.dudx + self.shading.dndv * self.dvdx;
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let mut dndy = self.shading.dndu * self.dudy + self.shading.dndv * self.dvdy;
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let dwodx = -diff_i.rx_direction - self.wo();
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let dwody = -diff_i.ry_direction - self.wo();
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let new_diff_rx_origin = self.p() + self.dpdx;
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let new_diff_ry_origin = self.p() + self.dpdy;
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let mut new_diff_rx_dir = Vector3f::default();
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let mut new_diff_ry_dir = Vector3f::default();
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let mut valid_differentials = false;
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if flags.contains(BxDFFlags::SPECULAR_REFLECTION) {
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valid_differentials = true;
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let d_wo_dot_n_dx = dwodx.dot(n.into()) + self.wo().dot(dndx.into());
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let d_wo_dot_n_dy = dwody.dot(n.into()) + self.wo().dot(dndy.into());
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let wo_dot_n = self.wo().dot(n.into());
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new_diff_rx_dir = wi - dwodx
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+ (Vector3f::from(dndx) * wo_dot_n + Vector3f::from(n) * d_wo_dot_n_dx) * 2.0;
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new_diff_ry_dir = wi - dwody
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+ (Vector3f::from(dndy) * wo_dot_n + Vector3f::from(n) * d_wo_dot_n_dy) * 2.0;
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} else if flags.contains(BxDFFlags::SPECULAR_TRANSMISSION) {
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valid_differentials = true;
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if self.wo().dot(n.into()) < 0.0 {
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n = -n;
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dndx = -dndx;
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dndy = -dndy;
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}
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// Compute partial derivatives
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let d_wo_dot_n_dx = dwodx.dot(n.into()) + self.wo().dot(dndx.into());
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let d_wo_dot_n_dy = dwody.dot(n.into()) + self.wo().dot(dndy.into());
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let wo_dot_n = self.wo().dot(n.into());
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let wi_dot_n = wi.dot(Vector3f::from(n));
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let abs_wi_dot_n = wi.abs_dot(n.into());
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let mu = wo_dot_n / eta - abs_wi_dot_n;
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let f_eta = 1.0 / eta;
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let f_eta2 = 1.0 / square(eta);
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let term = f_eta + (f_eta2 * wo_dot_n / wi_dot_n);
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let dmudx = d_wo_dot_n_dx * term;
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let dmudy = d_wo_dot_n_dy * term;
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new_diff_rx_dir =
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wi - dwodx * eta + (Vector3f::from(dndx) * mu + Vector3f::from(n) * dmudx);
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new_diff_ry_dir =
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wi - dwody * eta + (Vector3f::from(dndy) * mu + Vector3f::from(n) * dmudy);
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}
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if valid_differentials {
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let threshold = 1e16;
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if new_diff_rx_dir.norm_squared() > threshold
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|| new_diff_ry_dir.norm_squared() > threshold
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|| Vector3f::from(new_diff_rx_origin).norm_squared() > threshold
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|| Vector3f::from(new_diff_ry_origin).norm_squared() > threshold
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{
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rd.differential = None;
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} else {
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rd.differential = Some(RayDifferential {
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rx_origin: new_diff_rx_origin,
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ry_origin: new_diff_ry_origin,
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rx_direction: new_diff_rx_dir,
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ry_direction: new_diff_ry_dir,
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});
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}
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}
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}
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rd
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}
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}
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#[derive(Default, Debug, Clone)]
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pub struct PhaseFunction;
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pub struct MediumInteraction {
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pub common: InteractionData,
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pub medium: Arc<Medium>,
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pub phase: PhaseFunction,
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}
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impl Interaction for SurfaceInteraction {
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fn as_any(&self) -> &dyn Any {
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self
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}
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fn as_any_mut(&mut self) -> &mut dyn Any {
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self
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}
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fn into_any(self: Box<Self>) -> Box<dyn Any> {
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self
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}
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fn get_common(&self) -> &InteractionData {
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&self.common
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}
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fn get_common_mut(&mut self) -> &mut InteractionData {
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&mut self.common
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}
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fn get_medium(&self, w: Vector3f) -> Option<Arc<Medium>> {
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self.medium_interface.as_ref().and_then(|interface| {
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if self.n().dot(w.into()) > 0.0 {
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interface.outside.clone()
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} else {
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interface.inside.clone()
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}
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})
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}
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fn spawn_ray(&self, d: Vector3f) -> Ray {
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let mut ray = Ray::spawn(&self.pi(), &self.n(), self.time(), d);
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ray.medium = self.get_medium(d);
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ray
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}
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fn spawn_ray_to_point(&self, p2: Point3f) -> Ray {
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let mut ray = Ray::spawn_to_point(&self.pi(), &self.n(), self.time(), p2);
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ray.medium = self.get_medium(ray.d);
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ray
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}
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fn spawn_ray_to_interaction(&self, other: &dyn Interaction) -> Ray {
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// Check if the other interaction is a surface to use the robust spawn method
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if let Some(si_to) = other.as_any().downcast_ref::<SurfaceInteraction>() {
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let mut ray = Ray::spawn_to_interaction(
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&self.pi(),
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&self.n(),
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self.time(),
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&si_to.pi(),
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&si_to.n(),
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);
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ray.medium = self.get_medium(ray.d);
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ray
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} else {
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// Fallback for non-surface interactions
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self.spawn_ray_to_point(other.p())
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}
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}
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}
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impl SurfaceInteraction {
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pub fn new(
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pi: Point3fi,
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uv: Point2f,
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wo: Vector3f,
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dpdu: Vector3f,
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dpdv: Vector3f,
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dndu: Normal3f,
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dndv: Normal3f,
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time: Float,
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flip: bool,
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) -> Self {
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let mut n = Normal3f::from(dpdu.cross(dpdv).normalize());
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let mut shading_n = n;
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if flip {
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n *= -1.0;
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shading_n *= -1.0;
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}
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Self {
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common: InteractionData {
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pi,
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n,
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time,
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wo,
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medium_interface: None,
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medium: None,
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},
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uv,
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dpdu,
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dpdv,
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dndu,
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dndv,
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shading: ShadingGeometry {
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n: shading_n,
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dpdu,
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dpdv,
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dndu,
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dndv,
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},
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medium_interface: None,
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material: None,
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face_index: 0,
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area_light: None,
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dpdx: Vector3f::zero(),
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dpdy: Vector3f::zero(),
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dudx: 0.0,
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dudy: 0.0,
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dvdx: 0.0,
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dvdy: 0.0,
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shape: Arc::new(Shape::default()),
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bsdf: None,
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}
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}
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pub fn new_with_face(
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pi: Point3fi,
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uv: Point2f,
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wo: Vector3f,
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dpdu: Vector3f,
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dpdv: Vector3f,
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dndu: Normal3f,
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dndv: Normal3f,
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time: Float,
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flip: bool,
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face_index: usize,
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) -> Self {
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let mut si = Self::new(pi, uv, wo, dpdu, dpdv, dndu, dndv, time, flip);
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si.face_index = face_index;
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si
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}
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pub fn set_shading_geometry(
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&mut self,
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ns: Normal3f,
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dpdus: Vector3f,
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dpdvs: Vector3f,
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dndus: Normal3f,
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dndvs: Normal3f,
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orientation: bool,
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) {
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self.shading.n = ns;
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if orientation {
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self.common.n = self.n().face_forward(self.shading.n.into());
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}
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self.shading.dpdu = dpdus;
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self.shading.dpdv = dpdvs;
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self.shading.dndu = dndus;
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self.shading.dndv = dndvs;
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}
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pub fn new_simple(pi: Point3fi, n: Normal3f, uv: Point2f) -> Self {
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Self {
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common: InteractionData {
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pi,
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n,
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time: 0.,
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wo: Vector3f::zero(),
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medium_interface: None,
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medium: None,
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},
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uv,
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..Default::default()
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}
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|
}
|
|
|
|
pub fn set_intersection_properties(
|
|
&mut self,
|
|
mtl: Arc<dyn MaterialTrait>,
|
|
area: Arc<Light>,
|
|
prim_medium_interface: Option<Arc<MediumInterface>>,
|
|
ray_medium: Arc<Medium>,
|
|
) {
|
|
self.material = Some(mtl);
|
|
self.area_light = Some(area);
|
|
if prim_medium_interface
|
|
.as_ref()
|
|
.is_some_and(|mi| mi.is_medium_transition())
|
|
{
|
|
self.common.medium_interface = prim_medium_interface;
|
|
} else {
|
|
self.common.medium = Some(ray_medium);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Interaction for MediumInteraction {
|
|
fn as_any(&self) -> &dyn Any {
|
|
self
|
|
}
|
|
|
|
fn as_any_mut(&mut self) -> &mut dyn Any {
|
|
self
|
|
}
|
|
|
|
fn into_any(self: Box<Self>) -> Box<dyn Any> {
|
|
self
|
|
}
|
|
|
|
fn get_common(&self) -> &InteractionData {
|
|
&self.common
|
|
}
|
|
|
|
fn get_common_mut(&mut self) -> &mut InteractionData {
|
|
&mut self.common
|
|
}
|
|
|
|
fn get_medium(&self, _w: Vector3f) -> Option<Arc<Medium>> {
|
|
Some(self.medium.clone())
|
|
}
|
|
|
|
fn spawn_ray(&self, d: Vector3f) -> Ray {
|
|
Ray {
|
|
o: self.p(),
|
|
d,
|
|
time: self.time(),
|
|
medium: Some(self.medium.clone()),
|
|
differential: None,
|
|
}
|
|
}
|
|
}
|