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Surface closures and light sampling now take both shading and geometric normals.

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This will allow them to appropriately handle weirdness that comes
from the shading normal and geometric normal being different.
This commit is contained in:
Nathan Vegdahl 2017-07-30 19:17:32 -07:00
parent 05578a1240
commit 0481d931b9
6 changed files with 125 additions and 58 deletions
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3
src/accel/light_array.rs
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@ -45,11 +45,12 @@ impl<'a> LightAccel for LightArray<'a> {
inc: Vector,
pos: Point,
nor: Normal,
nor_g: Normal,
sc: &SurfaceClosure,
time: f32,
n: f32,
) -> Option<(usize, f32, f32)> {
let _ = (inc, pos, nor, sc, time); // Not using these, silence warnings
let _ = (inc, pos, nor, nor_g, sc, time); // Not using these, silence warnings
assert!(n >= 0.0 && n <= 1.0);

3
src/accel/light_tree.rs
View File

@ -134,6 +134,7 @@ impl<'a> LightAccel for LightTree<'a> {
inc: Vector,
pos: Point,
nor: Normal,
nor_g: Normal,
sc: &SurfaceClosure,
time: f32,
n: f32,
@ -160,7 +161,7 @@ impl<'a> LightAccel for LightTree<'a> {
let sin_theta_max2 = (r2 / dist2).min(1.0);
(1.0 - sin_theta_max2).sqrt()
};
sc.estimate_eval_over_solid_angle(inc, d, nor, cos_theta_max)
sc.estimate_eval_over_solid_angle(inc, d, nor, nor_g, cos_theta_max)
};
node_ref.energy() * inv_surface_area * approx_contrib

1
src/accel/mod.rs
View File

@ -28,6 +28,7 @@ pub trait LightAccel {
inc: Vector,
pos: Point,
nor: Normal,
nor_g: Normal,
sc: &SurfaceClosure,
time: f32,
n: f32,

67
src/renderer.rs
View File

@ -467,36 +467,41 @@ impl LightPath {
{
// Check if pdf is zero, to avoid NaN's.
if light_pdf > 0.0 {
// Calculate and store the light that will be contributed
// to the film plane if the light is not in shadow.
self.pending_color_addition = {
let material = closure.as_surface_closure();
let la = material.evaluate(
ray.dir,
shadow_vec,
idata.nor,
self.wavelength,
);
light_color.e * la.e * self.light_attenuation /
(light_pdf * light_sel_pdf)
};
// Calculate the shadow ray for testing if the light is
// in shadow or not.
let offset_pos = robust_ray_origin(
idata.pos,
idata.pos_err,
idata.nor_g.normalized(),
let material = closure.as_surface_closure();
let attenuation = material.evaluate(
ray.dir,
shadow_vec,
idata.nor,
idata.nor_g,
self.wavelength,
);
*ray = Ray::new(offset_pos, shadow_vec, self.time, true);
// For distant lights
if is_infinite {
ray.max_t = std::f32::INFINITY;
if attenuation.e.h_max() > 0.0 {
// Calculate and store the light that will be contributed
// to the film plane if the light is not in shadow.
self.pending_color_addition = light_color.e * attenuation.e *
self.light_attenuation /
(light_pdf * light_sel_pdf);
// Calculate the shadow ray for testing if the light is
// in shadow or not.
let offset_pos = robust_ray_origin(
idata.pos,
idata.pos_err,
idata.nor_g.normalized(),
shadow_vec,
);
*ray = Ray::new(offset_pos, shadow_vec, self.time, true);
// For distant lights
if is_infinite {
ray.max_t = std::f32::INFINITY;
}
true
} else {
false
}
true
} else {
false
}
@ -513,11 +518,17 @@ impl LightPath {
let material = closure.as_surface_closure();
let u = self.next_lds_samp();
let v = self.next_lds_samp();
material.sample(idata.incoming, idata.nor, (u, v), self.wavelength)
material.sample(
idata.incoming,
idata.nor,
idata.nor_g,
(u, v),
self.wavelength,
)
};
// Check if pdf is zero, to avoid NaN's.
if pdf > 0.0 {
if (pdf > 0.0) && (filter.e.h_max() > 0.0) {
// Account for the additional light attenuation from
// this bounce
self.next_attentuation_fac = filter.e / pdf;

1
src/scene/assembly.rs
View File

@ -60,6 +60,7 @@ impl<'a> Assembly<'a> {
idata.incoming * sel_xform,
idata.pos * sel_xform,
idata.nor * sel_xform,
idata.nor_g * sel_xform,
closure.as_surface_closure(),
time,
n,

108
src/shading/surface_closure.rs
View File

@ -36,9 +36,10 @@ pub trait SurfaceClosure {
/// Given an incoming ray and sample values, generates an outgoing ray and
/// color filter.
///
/// inc: Incoming light direction.
/// nor: The surface normal at the surface point.
/// uv: The sampling values.
/// inc: Incoming light direction.
/// nor: The shading surface normal at the surface point.
/// nor_g: The geometric surface normal at the surface point.
/// uv: The sampling values.
/// wavelength: The wavelength of light to sample at.
///
/// Returns a tuple with the generated outgoing light direction, color filter, and pdf.
@ -46,27 +47,37 @@ pub trait SurfaceClosure {
&self,
inc: Vector,
nor: Normal,
nor_g: Normal,
uv: (f32, f32),
wavelength: f32,
) -> (Vector, SpectralSample, f32);
/// Evaluates the closure for the given incoming and outgoing rays.
///
/// inc: The incoming light direction.
/// out: The outgoing light direction.
/// nor: The surface normal of the reflecting/transmitting surface point.
/// inc: The incoming light direction.
/// out: The outgoing light direction.
/// nor: The shading surface normal at the surface point.
/// nor_g: The geometric surface normal at the surface point.
/// wavelength: The wavelength of light to evaluate for.
///
/// Returns the resulting filter color.
fn evaluate(&self, inc: Vector, out: Vector, nor: Normal, wavelength: f32) -> SpectralSample;
fn evaluate(
&self,
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
wavelength: f32,
) -> SpectralSample;
/// Returns the pdf for the given 'in' direction producing the given 'out'
/// direction with the given differential geometry.
///
/// inc: The incoming light direction.
/// out: The outgoing light direction.
/// nor: The surface normal of the reflecting/transmitting surface point.
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal) -> f32;
/// nor: The shading surface normal at the surface point.
/// nor_g: The geometric surface normal at the surface point.
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal, nor_g: Normal) -> f32;
/// Returns an estimate of the sum total energy that evaluate() would return
/// when 'out' is evaluated over a circular solid angle.
@ -78,6 +89,7 @@ pub trait SurfaceClosure {
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
cos_theta: f32,
) -> f32;
}
@ -180,10 +192,11 @@ impl SurfaceClosure for EmitClosure {
&self,
inc: Vector,
nor: Normal,
nor_g: Normal,
uv: (f32, f32),
wavelength: f32,
) -> (Vector, SpectralSample, f32) {
let _ = (inc, nor, uv); // Not using these, silence warning
let _ = (inc, nor, nor_g, uv); // Not using these, silence warning
(
Vector::new(0.0, 0.0, 0.0),
@ -192,14 +205,21 @@ impl SurfaceClosure for EmitClosure {
)
}
fn evaluate(&self, inc: Vector, out: Vector, nor: Normal, wavelength: f32) -> SpectralSample {
let _ = (inc, out, nor); // Not using these, silence warning
fn evaluate(
&self,
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
wavelength: f32,
) -> SpectralSample {
let _ = (inc, out, nor, nor_g); // Not using these, silence warning
SpectralSample::new(wavelength)
}
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal) -> f32 {
let _ = (inc, out, nor); // Not using these, silence warning
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal, nor_g: Normal) -> f32 {
let _ = (inc, out, nor, nor_g); // Not using these, silence warning
1.0
}
@ -209,9 +229,10 @@ impl SurfaceClosure for EmitClosure {
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
cos_theta: f32,
) -> f32 {
let _ = (inc, out, nor, cos_theta); // Not using these, silence warning
let _ = (inc, out, nor, nor_g, cos_theta); // Not using these, silence warning
// TODO: what to do here?
unimplemented!()
@ -240,10 +261,11 @@ impl SurfaceClosure for LambertClosure {
&self,
inc: Vector,
nor: Normal,
nor_g: Normal,
uv: (f32, f32),
wavelength: f32,
) -> (Vector, SpectralSample, f32) {
let nn = if dot(nor.into_vector(), inc) <= 0.0 {
let nn = if dot(nor_g.into_vector(), inc) <= 0.0 {
nor.normalized()
} else {
-nor.normalized()
@ -254,14 +276,21 @@ impl SurfaceClosure for LambertClosure {
let dir = cosine_sample_hemisphere(uv.0, uv.1);
let pdf = dir.z() * INV_PI;
let out = zup_to_vec(dir, nn);
let filter = self.evaluate(inc, out, nor, wavelength);
let filter = self.evaluate(inc, out, nor, nor_g, wavelength);
(out, filter, pdf)
}
fn evaluate(&self, inc: Vector, out: Vector, nor: Normal, wavelength: f32) -> SpectralSample {
fn evaluate(
&self,
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
wavelength: f32,
) -> SpectralSample {
let v = out.normalized();
let nn = if dot(nor.into_vector(), inc) <= 0.0 {
let nn = if dot(nor_g.into_vector(), inc) <= 0.0 {
nor.normalized()
} else {
-nor.normalized()
@ -271,9 +300,9 @@ impl SurfaceClosure for LambertClosure {
self.col.to_spectral_sample(wavelength) * fac
}
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal) -> f32 {
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal, nor_g: Normal) -> f32 {
let v = out.normalized();
let nn = if dot(nor.into_vector(), inc) <= 0.0 {
let nn = if dot(nor_g.into_vector(), inc) <= 0.0 {
nor.normalized()
} else {
-nor.normalized()
@ -287,8 +316,11 @@ impl SurfaceClosure for LambertClosure {
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
cos_theta: f32,
) -> f32 {
let _ = nor_g; // Not using this, silence warning
assert!(cos_theta >= -1.0 && cos_theta <= 1.0);
// Analytically calculates lambert shading from a uniform light source
@ -449,11 +481,12 @@ impl SurfaceClosure for GTRClosure {
&self,
inc: Vector,
nor: Normal,
nor_g: Normal,
uv: (f32, f32),
wavelength: f32,
) -> (Vector, SpectralSample, f32) {
// Get normalized surface normal
let nn = if dot(nor.into_vector(), inc) < 0.0 {
let nn = if dot(nor_g.into_vector(), inc) < 0.0 {
nor.normalized()
} else {
-nor.normalized() // If back-facing, flip normal
@ -468,26 +501,37 @@ impl SurfaceClosure for GTRClosure {
half_dir = zup_to_vec(half_dir, nn).normalized();
let out = inc - (half_dir * 2.0 * dot(inc, half_dir));
let filter = self.evaluate(inc, out, nor, wavelength);
let pdf = self.sample_pdf(inc, out, nor);
let filter = self.evaluate(inc, out, nor, nor_g, wavelength);
let pdf = self.sample_pdf(inc, out, nor, nor_g);
(out, filter, pdf)
}
fn evaluate(&self, inc: Vector, out: Vector, nor: Normal, wavelength: f32) -> SpectralSample {
fn evaluate(
&self,
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
wavelength: f32,
) -> SpectralSample {
// Calculate needed vectors, normalized
let aa = -inc.normalized(); // Vector pointing to where "in" came from
let bb = out.normalized(); // Out
let hh = (aa + bb).normalized(); // Half-way between aa and bb
// Surface normal
let nn = if dot(nor.into_vector(), hh) < 0.0 {
let nn = if dot(nor_g.into_vector(), hh) < 0.0 {
-nor.normalized() // If back-facing, flip normal
} else {
nor.normalized()
}.into_vector();
if dot(nn, aa) < 0.0 {
return SpectralSample::from_value(0.0, 0.0);
}
// Calculate needed dot products
let na = clamp(dot(nn, aa), -1.0, 1.0);
let nb = clamp(dot(nn, bb), -1.0, 1.0);
@ -571,19 +615,23 @@ impl SurfaceClosure for GTRClosure {
}
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal) -> f32 {
fn sample_pdf(&self, inc: Vector, out: Vector, nor: Normal, nor_g: Normal) -> f32 {
// Calculate needed vectors, normalized
let aa = -inc.normalized(); // Vector pointing to where "in" came from
let bb = out.normalized(); // Out
let hh = (aa + bb).normalized(); // Half-way between aa and bb
// Surface normal
let nn = if dot(nor.into_vector(), hh) < 0.0 {
let nn = if dot(nor_g.into_vector(), hh) < 0.0 {
-nor.normalized() // If back-facing, flip normal
} else {
nor.normalized()
}.into_vector();
if dot(nn, aa) < 0.0 {
return 0.0;
}
// Calculate needed dot products
let nh = clamp(dot(nn, hh), -1.0, 1.0);
@ -596,11 +644,15 @@ impl SurfaceClosure for GTRClosure {
inc: Vector,
out: Vector,
nor: Normal,
nor_g: Normal,
cos_theta: f32,
) -> f32 {
// TODO: all of the stuff in this function is horribly hacky.
// Find a proper way to approximate the light contribution from a
// solid angle.
let _ = nor_g; // Not using this, silence warning
assert!(cos_theta >= -1.0);
assert!(cos_theta <= 1.0);