pbrt/shared/src/core/material.rs

896 lines
24 KiB
Rust

use bumpalo::Bump;
use enum_dispatch::enum_dispatch;
use std::ops::Deref;
use std::sync::Arc;
use crate::core::bssrdf::BSSRDF;
use crate::core::bxdf::{
BSDF, BxDF, CoatedConductorBxDF, CoatedDiffuseBxDF, ConductorBxDF, DielectricBxDF, DiffuseBxDF,
};
use crate::core::geometry::{Frame, Normal3f, Point2f, Point3f, Vector2f, Vector3f, VectorLike};
use crate::core::interaction::InteractionTrait;
use crate::core::interaction::{Interaction, Shadinggeom, SurfaceInteraction};
use crate::core::pbrt::Float;
use crate::core::scattering::TrowbridgeReitzDistribution;
use crate::core::texture::{
FloatTexture, FloatTextureTrait, SpectrumTexture, TextureEvalContext, TextureEvaluator,
};
use crate::image::{Image, WrapMode, WrapMode2D};
use crate::spectra::{SampledSpectrum, SampledWavelengths, Spectrum, SpectrumProvider};
use crate::utils::hash::hash_float;
use crate::utils::math::clamp;
#[derive(Clone, Debug)]
pub struct MaterialEvalContext {
pub texture: TextureEvalContext,
pub wo: Vector3f,
pub ns: Normal3f,
pub dpdus: Vector3f,
}
impl Deref for MaterialEvalContext {
type Target = TextureEvalContext;
fn deref(&self) -> &Self::Target {
&self.texture
}
}
impl From<&SurfaceInteraction> for MaterialEvalContext {
fn from(si: &SurfaceInteraction) -> Self {
Self {
texture: TextureEvalContext::from(si),
wo: si.common.wo,
ns: si.shading.n,
dpdus: si.shading.dpdu,
}
}
}
#[derive(Clone, Debug, Default)]
pub struct NormalBumpEvalContext {
p: Point3f,
uv: Point2f,
n: Normal3f,
shading: Shadinggeom,
dpdx: Vector3f,
dpdy: Vector3f,
// All 0
dudx: Float,
dudy: Float,
dvdx: Float,
dvdy: Float,
face_index: usize,
}
impl From<&SurfaceInteraction> for NormalBumpEvalContext {
fn from(si: &SurfaceInteraction) -> Self {
Self {
p: si.p(),
uv: si.uv,
n: si.n(),
shading: si.shading.clone(),
dudx: si.dudx,
dudy: si.dudy,
dvdx: si.dvdx,
dvdy: si.dvdy,
dpdx: si.dpdx,
dpdy: si.dpdy,
face_index: si.face_index,
}
}
}
impl From<&NormalBumpEvalContext> for TextureEvalContext {
fn from(ctx: &NormalBumpEvalContext) -> Self {
Self {
p: ctx.p,
uv: ctx.uv,
n: ctx.n,
dpdx: ctx.dpdx,
dpdy: ctx.dpdy,
dudx: ctx.dudx,
dudy: ctx.dudy,
dvdx: ctx.dvdx,
dvdy: ctx.dvdy,
face_index: ctx.face_index,
}
}
}
pub fn normal_map(normal_map: &Image, ctx: &NormalBumpEvalContext) -> (Vector3f, Vector3f) {
let wrap = WrapMode2D::from(WrapMode::Repeat);
let uv = Point2f::new(ctx.uv[0], 1. - ctx.uv[1]);
let r = normal_map.bilerp_channel_with_wrap(uv, 0, wrap);
let g = normal_map.bilerp_channel_with_wrap(uv, 1, wrap);
let b = normal_map.bilerp_channel_with_wrap(uv, 2, wrap);
let mut ns = Vector3f::new(2.0 * r - 1.0, 2.0 * g - 1.0, 2.0 * b - 1.0);
ns = ns.normalize();
let frame = Frame::from_xz(ctx.shading.dpdu.normalize(), Vector3f::from(ctx.shading.n));
ns = frame.from_local(ns);
let ulen = ctx.shading.dpdu.norm();
let vlen = ctx.shading.dpdv.norm();
let dpdu = ctx.shading.dpdu.gram_schmidt(ns).normalize() * ulen;
let dpdv = ctx.shading.dpdu.cross(dpdu).normalize() * vlen;
(dpdu, dpdv)
}
pub fn bump_map<T: TextureEvaluator>(
tex_eval: &T,
displacement: &FloatTexture,
ctx: &NormalBumpEvalContext,
) -> (Vector3f, Vector3f) {
debug_assert!(tex_eval.can_evaluate(&[displacement], &[]));
let mut du = 0.5 * (ctx.dudx.abs() + ctx.dudy.abs());
if du == 0.0 {
du = 0.0005;
}
let mut dv = 0.5 * (ctx.dvdx.abs() + ctx.dvdy.abs());
if dv == 0.0 {
dv = 0.0005;
}
let mut shifted_ctx = TextureEvalContext::from(ctx);
shifted_ctx.p = ctx.p + ctx.shading.dpdu * du;
shifted_ctx.uv = ctx.uv + Vector2f::new(du, 0.0);
let u_displace = tex_eval.evaluate_float(displacement, &shifted_ctx);
shifted_ctx.p = ctx.p + ctx.shading.dpdv * dv;
shifted_ctx.uv = ctx.uv + Vector2f::new(0.0, dv);
let v_displace = tex_eval.evaluate_float(displacement, &shifted_ctx);
let center_ctx = TextureEvalContext::from(ctx);
let displace = tex_eval.evaluate_float(displacement, &center_ctx);
let d_displace_du = (u_displace - displace) / du;
let d_displace_dv = (v_displace - displace) / dv;
let n_vec = Vector3f::from(ctx.shading.n);
let dndu_vec = Vector3f::from(ctx.shading.dndu);
let dndv_vec = Vector3f::from(ctx.shading.dndv);
let dpdu = ctx.shading.dpdu + n_vec * d_displace_du + dndu_vec * displace;
let dpdv = ctx.shading.dpdv + n_vec * d_displace_dv + dndv_vec * displace;
(dpdu, dpdv)
}
#[enum_dispatch]
pub trait MaterialTrait: Send + Sync + std::fmt::Debug {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF;
fn get_bssrdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> Option<BSSRDF>;
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool;
fn get_normal_map(&self) -> Option<Arc<Image>>;
fn get_displacement(&self) -> Option<FloatTexture>;
fn has_surface_scattering(&self) -> bool;
}
#[derive(Clone, Debug)]
#[enum_dispatch(MaterialTrait)]
pub enum Material {
CoatedDiffuse(CoatedDiffuseMaterial),
CoatedConductor(CoatedConductorMaterial),
Conductor(ConductorMaterial),
Dielectric(DielectricMaterial),
Diffuse(DiffuseMaterial),
DiffuseTransmission(DiffuseTransmissionMaterial),
Hair(HairMaterial),
Measured(MeasuredMaterial),
Subsurface(SubsurfaceMaterial),
ThinDielectric(ThinDielectricMaterial),
Mix(MixMaterial),
}
#[derive(Clone, Debug)]
pub struct CoatedDiffuseMaterial {
displacement: FloatTexture,
normal_map: Option<Arc<Image>>,
reflectance: SpectrumTexture,
albedo: SpectrumTexture,
u_roughness: FloatTexture,
v_roughness: FloatTexture,
thickness: FloatTexture,
g: FloatTexture,
eta: Spectrum,
remap_roughness: bool,
max_depth: usize,
n_samples: usize,
}
impl CoatedDiffuseMaterial {
#[allow(clippy::too_many_arguments)]
pub fn new(
reflectance: SpectrumTexture,
u_roughness: FloatTexture,
v_roughness: FloatTexture,
thickness: FloatTexture,
albedo: SpectrumTexture,
g: FloatTexture,
eta: Spectrum,
displacement: FloatTexture,
normal_map: Option<Arc<Image>>,
remap_roughness: bool,
max_depth: usize,
n_samples: usize,
) -> Self {
Self {
displacement,
normal_map,
reflectance,
albedo,
u_roughness,
v_roughness,
thickness,
g,
eta,
remap_roughness,
max_depth,
n_samples,
}
}
}
impl MaterialTrait for CoatedDiffuseMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF {
let r = SampledSpectrum::clamp(
&tex_eval.evaluate_spectrum(&self.reflectance, ctx, lambda),
0.,
1.,
);
let mut u_rough = tex_eval.evaluate_float(&self.u_roughness, ctx);
let mut v_rough = tex_eval.evaluate_float(&self.v_roughness, ctx);
if self.remap_roughness {
u_rough = TrowbridgeReitzDistribution::roughness_to_alpha(u_rough);
v_rough = TrowbridgeReitzDistribution::roughness_to_alpha(v_rough);
}
let distrib = TrowbridgeReitzDistribution::new(u_rough, v_rough);
let thick = tex_eval.evaluate_float(&self.thickness, ctx);
let mut sampled_eta = self.eta.evaluate(lambda[0]);
if self.eta.is_constant() {
let mut lambda = *lambda;
lambda.terminate_secondary_inplace();
}
if sampled_eta == 0. {
sampled_eta = 1.
}
let a = SampledSpectrum::clamp(
&tex_eval.evaluate_spectrum(&self.albedo, ctx, lambda),
0.,
1.,
);
let gg = clamp(tex_eval.evaluate_float(&self.g, ctx), -1., 1.);
let bxdf = BxDF::CoatedDiffuse(CoatedDiffuseBxDF::new(
DielectricBxDF::new(sampled_eta, distrib),
DiffuseBxDF::new(r),
thick,
a,
gg,
self.max_depth,
self.n_samples,
));
BSDF::new(ctx.ns, ctx.dpdus, Some(bxdf))
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
None
}
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool {
tex_eval.can_evaluate(
&[
&self.u_roughness,
&self.v_roughness,
&self.thickness,
&self.g,
],
&[&self.reflectance, &self.albedo],
)
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
self.normal_map.clone()
}
fn get_displacement(&self) -> Option<FloatTexture> {
Some(self.displacement.clone())
}
fn has_surface_scattering(&self) -> bool {
false
}
}
#[derive(Clone, Debug)]
pub struct CoatedConductorMaterial {
displacement: FloatTexture,
normal_map: Option<Arc<Image>>,
interface_uroughness: FloatTexture,
interface_vroughness: FloatTexture,
thickness: FloatTexture,
interface_eta: Spectrum,
g: FloatTexture,
albedo: SpectrumTexture,
conductor_uroughness: FloatTexture,
conductor_vroughness: FloatTexture,
conductor_eta: Option<SpectrumTexture>,
k: Option<SpectrumTexture>,
reflectance: SpectrumTexture,
remap_roughness: bool,
max_depth: usize,
n_samples: usize,
}
impl CoatedConductorMaterial {
#[allow(clippy::too_many_arguments)]
pub fn new(
displacement: FloatTexture,
normal_map: Option<Arc<Image>>,
interface_uroughness: FloatTexture,
interface_vroughness: FloatTexture,
thickness: FloatTexture,
interface_eta: Spectrum,
g: FloatTexture,
albedo: SpectrumTexture,
conductor_uroughness: FloatTexture,
conductor_vroughness: FloatTexture,
conductor_eta: Option<SpectrumTexture>,
k: Option<SpectrumTexture>,
reflectance: SpectrumTexture,
remap_roughness: bool,
max_depth: usize,
n_samples: usize,
) -> Self {
Self {
displacement,
normal_map,
interface_uroughness,
interface_vroughness,
thickness,
interface_eta,
g,
albedo,
conductor_uroughness,
conductor_vroughness,
conductor_eta,
k,
reflectance,
remap_roughness,
max_depth,
n_samples,
}
}
}
impl MaterialTrait for CoatedConductorMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF {
let mut iurough = tex_eval.evaluate_float(&self.interface_uroughness, ctx);
let mut ivrough = tex_eval.evaluate_float(&self.interface_vroughness, ctx);
if self.remap_roughness {
iurough = TrowbridgeReitzDistribution::roughness_to_alpha(iurough);
ivrough = TrowbridgeReitzDistribution::roughness_to_alpha(ivrough);
}
let interface_distrib = TrowbridgeReitzDistribution::new(iurough, ivrough);
let thick = tex_eval.evaluate_float(&self.thickness, ctx);
let mut ieta = self.interface_eta.evaluate(lambda[0]);
if self.interface_eta.is_constant() {
let mut lambda = *lambda;
lambda.terminate_secondary_inplace();
}
if ieta == 0. {
ieta = 1.;
}
let (mut ce, mut ck) = if let Some(eta_tex) = &self.conductor_eta {
let k_tex = self
.k
.as_ref()
.expect("CoatedConductor: 'k' must be provided if 'conductor_eta' is present");
let ce = tex_eval.evaluate_spectrum(eta_tex, ctx, lambda);
let ck = tex_eval.evaluate_spectrum(k_tex, ctx, lambda);
(ce, ck)
} else {
let r = SampledSpectrum::clamp(
&tex_eval.evaluate_spectrum(&self.reflectance, ctx, lambda),
0.,
0.9999,
);
let ce = SampledSpectrum::new(1.0);
let one_minus_r = SampledSpectrum::new(1.) - r;
let ck = 2. * r.sqrt() / SampledSpectrum::clamp_zero(&one_minus_r).sqrt();
(ce, ck)
};
ce /= ieta;
ck /= ieta;
let mut curough = tex_eval.evaluate_float(&self.conductor_uroughness, ctx);
let mut cvrough = tex_eval.evaluate_float(&self.conductor_vroughness, ctx);
if self.remap_roughness {
curough = TrowbridgeReitzDistribution::roughness_to_alpha(curough);
cvrough = TrowbridgeReitzDistribution::roughness_to_alpha(cvrough);
}
let conductor_distrib = TrowbridgeReitzDistribution::new(curough, cvrough);
let a = SampledSpectrum::clamp(
&tex_eval.evaluate_spectrum(&self.albedo, ctx, lambda),
0.,
1.,
);
let gg = clamp(tex_eval.evaluate_float(&self.g, ctx), -1., 1.);
let bxdf = BxDF::CoatedConductor(CoatedConductorBxDF::new(
DielectricBxDF::new(ieta, interface_distrib),
ConductorBxDF::new(&conductor_distrib, ce, ck),
thick,
a,
gg,
self.max_depth,
self.n_samples,
));
BSDF::new(ctx.ns, ctx.dpdus, Some(bxdf))
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
None
}
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool {
let float_textures = [
&self.interface_uroughness,
&self.interface_vroughness,
&self.thickness,
&self.g,
&self.conductor_uroughness,
&self.conductor_vroughness,
];
let mut spectrum_textures = Vec::with_capacity(4);
spectrum_textures.push(&self.albedo);
if let Some(eta) = &self.conductor_eta {
spectrum_textures.push(eta);
}
if let Some(k) = &self.k {
spectrum_textures.push(k);
}
if self.conductor_eta.is_none() {
spectrum_textures.push(&self.reflectance);
}
tex_eval.can_evaluate(&float_textures, &spectrum_textures)
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
self.normal_map.clone()
}
fn get_displacement(&self) -> Option<FloatTexture> {
Some(self.displacement.clone())
}
fn has_surface_scattering(&self) -> bool {
false
}
}
#[derive(Clone, Debug)]
pub struct ConductorMaterial;
impl MaterialTrait for ConductorMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct DielectricMaterial {
normal_map: Option<Arc<Image>>,
displacement: FloatTexture,
u_roughness: FloatTexture,
v_roughness: FloatTexture,
remap_roughness: bool,
eta: Spectrum,
}
impl MaterialTrait for DielectricMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF {
let mut sampled_eta = self.eta.evaluate(lambda[0]);
if !self.eta.is_constant() {
lambda.terminate_secondary();
}
if sampled_eta == 0.0 {
sampled_eta = 1.0;
}
let mut u_rough = tex_eval.evaluate_float(&self.u_roughness, ctx);
let mut v_rough = tex_eval.evaluate_float(&self.v_roughness, ctx);
if self.remap_roughness {
u_rough = TrowbridgeReitzDistribution::roughness_to_alpha(u_rough);
v_rough = TrowbridgeReitzDistribution::roughness_to_alpha(v_rough);
}
let distrib = TrowbridgeReitzDistribution::new(u_rough, v_rough);
let bxdf = BxDF::Dielectric(DielectricBxDF::new(sampled_eta, distrib));
BSDF::new(ctx.ns, ctx.dpdus, Some(bxdf))
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
None
}
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool {
tex_eval.can_evaluate(&[&self.u_roughness, &self.v_roughness], &[])
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
self.normal_map.clone()
}
fn get_displacement(&self) -> Option<FloatTexture> {
Some(self.displacement.clone())
}
fn has_surface_scattering(&self) -> bool {
false
}
}
#[derive(Clone, Debug)]
pub struct DiffuseMaterial {
normal_map: Option<Arc<Image>>,
displacement: FloatTexture,
reflectance: SpectrumTexture,
}
impl MaterialTrait for DiffuseMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF {
let r = tex_eval.evaluate_spectrum(&self.reflectance, ctx, lambda);
let bxdf = BxDF::Diffuse(DiffuseBxDF::new(r));
BSDF::new(ctx.ns, ctx.dpdus, Some(bxdf))
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool {
tex_eval.can_evaluate(&[], &[&self.reflectance])
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
self.normal_map.clone()
}
fn get_displacement(&self) -> Option<FloatTexture> {
Some(self.displacement.clone())
}
fn has_surface_scattering(&self) -> bool {
false
}
}
#[derive(Clone, Debug)]
pub struct DiffuseTransmissionMaterial;
impl MaterialTrait for DiffuseTransmissionMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct HairMaterial;
impl MaterialTrait for HairMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct MeasuredMaterial;
impl MaterialTrait for MeasuredMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct SubsurfaceMaterial;
impl MaterialTrait for SubsurfaceMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct ThinDielectricMaterial;
impl MaterialTrait for ThinDielectricMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> BSDF {
todo!()
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
todo!()
}
fn can_evaluate_textures(&self, _tex_eval: &dyn TextureEvaluator) -> bool {
todo!()
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
todo!()
}
fn get_displacement(&self) -> Option<FloatTexture> {
todo!()
}
fn has_surface_scattering(&self) -> bool {
todo!()
}
}
#[derive(Clone, Debug)]
pub struct MixMaterial {
pub amount: FloatTexture,
pub materials: [Box<Material>; 2],
}
impl MixMaterial {
pub fn choose_material<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
) -> &Material {
let amt = tex_eval.evaluate_float(&self.amount, ctx);
if amt <= 0.0 {
return &self.materials[0];
}
if amt >= 1.0 {
return &self.materials[1];
}
let u = hash_float(&(ctx.p, ctx.wo));
if amt < u {
&self.materials[0]
} else {
&self.materials[1]
}
}
}
impl MaterialTrait for MixMaterial {
fn get_bsdf<T: TextureEvaluator>(
&self,
tex_eval: &T,
ctx: &MaterialEvalContext,
lambda: &SampledWavelengths,
) -> BSDF {
let chosen_mat = self.choose_material(tex_eval, ctx);
chosen_mat.get_bsdf(tex_eval, ctx, lambda)
}
fn get_bssrdf<T>(
&self,
_tex_eval: &T,
_ctx: &MaterialEvalContext,
_lambda: &SampledWavelengths,
) -> Option<BSSRDF> {
None
}
fn can_evaluate_textures(&self, tex_eval: &dyn TextureEvaluator) -> bool {
tex_eval.can_evaluate(&[&self.amount], &[])
}
fn get_normal_map(&self) -> Option<Arc<Image>> {
None
}
fn get_displacement(&self) -> Option<FloatTexture> {
panic!(
"MixMaterial::get_displacement() shouldn't be called. \
Displacement is not supported on Mix materials directly."
);
}
fn has_surface_scattering(&self) -> bool {
false
}
}