Nathan Vegdahl
d504ca5e6a
This involved fixing a bug in PsychoBlend. It was including translation in how it was transforming the sun lights' direction vector.
81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
use std::f64::consts::PI as PI_64;
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use color::{XYZ, SpectralSample, Color};
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use lerp::lerp_slice;
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use math::{Vector, coordinate_system_from_vector};
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use sampling::{uniform_sample_cone, uniform_sample_cone_pdf};
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use super::WorldLightSource;
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// TODO: handle case where radius = 0.0.
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#[derive(Debug)]
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pub struct DistantDiskLight {
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radii: Vec<f32>,
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directions: Vec<Vector>,
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colors: Vec<XYZ>,
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}
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impl DistantDiskLight {
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pub fn new(radii: Vec<f32>, directions: Vec<Vector>, colors: Vec<XYZ>) -> DistantDiskLight {
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DistantDiskLight {
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radii: radii,
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directions: directions,
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colors: colors,
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}
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}
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}
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impl WorldLightSource for DistantDiskLight {
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fn sample(&self, u: f32, v: f32, wavelength: f32, time: f32) -> (SpectralSample, Vector, f32) {
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// Calculate time interpolated values
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let radius: f64 = lerp_slice(&self.radii, time) as f64;
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let direction = lerp_slice(&self.directions, time);
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let col = lerp_slice(&self.colors, time);
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let solid_angle_inv = 1.0 / (2.0 * PI_64 * (1.0 - radius.cos()));
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// Create a coordinate system from the vector pointing at the center of
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// of the light.
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let (z, x, y) = coordinate_system_from_vector(-direction.normalized());
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// Sample the cone subtended by the light.
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let cos_theta_max: f64 = radius.cos();
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let sample = uniform_sample_cone(u, v, cos_theta_max).normalized();
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// Calculate the final values and return everything.
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let spectral_sample = (col * solid_angle_inv as f32).to_spectral_sample(wavelength);
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let shadow_vec = (x * sample.x()) + (y * sample.y()) + (z * sample.z());
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let pdf = uniform_sample_cone_pdf(cos_theta_max);
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return (spectral_sample, shadow_vec, pdf as f32);
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}
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fn sample_pdf(&self, sample_dir: Vector, wavelength: f32, time: f32) -> f32 {
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// We're not using these, silence warnings
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let _ = (sample_dir, wavelength);
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let radius: f64 = lerp_slice(&self.radii, time) as f64;
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return uniform_sample_cone_pdf(radius.cos()) as f32;
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}
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fn outgoing(&self, dir: Vector, wavelength: f32, time: f32) -> SpectralSample {
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// We're not using this, silence warning
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let _ = dir;
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let radius = lerp_slice(&self.radii, time) as f64;
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let col = lerp_slice(&self.colors, time);
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let solid_angle = 2.0 * PI_64 * (1.0 - radius.cos());
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(col / solid_angle as f32).to_spectral_sample(wavelength)
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}
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fn is_delta(&self) -> bool {
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false
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}
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fn approximate_energy(&self) -> f32 {
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let color: XYZ = self.colors.iter().fold(XYZ::new(0.0, 0.0, 0.0), |a, &b| a + b) /
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self.colors.len() as f32;
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color.y
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}
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}
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