Fix color matching function

ray-tracing-material-visualizer/src/bin/iridescent.rs

@@ -0,0 +1,102 @@
+use core::f32;
+
+use plotters::{prelude::*, style::full_palette::GREEN};
+use rand::{rngs::SmallRng, Rng, SeedableRng};
+use ray_tracing_material::iridescent::Iridescent;
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let root = BitMapBackend::new("iridescent_sweep.png", (800, 600)).into_drawing_area();
+
+    root.fill(&WHITE)?;
+    let mut chart = ChartBuilder::on(&root)
+        .margin(5)
+        .x_label_area_size(30)
+        .y_label_area_size(30)
+        .build_cartesian_2d(0f32..f32::consts::FRAC_PI_2, 0f32..1f32)?;
+
+    chart.configure_mesh().draw()?;
+
+    let (pixel_range_x, pixel_range_y) = chart.plotting_area().get_pixel_range();
+    let buckets = pixel_range_x.end - pixel_range_x.start;
+    let height_per_pixel = 1.0 / (pixel_range_y.end - pixel_range_y.start) as f32;
+    let samples = 10000;
+
+    let m = Iridescent::new(0.5 * 244.0, 0.5 * 244.0, 1.0, 1.5, 20);
+
+    let mut data = Vec::new();
+
+    let mut rng = SmallRng::seed_from_u64(0);
+
+    let plotting_area = chart.plotting_area();
+    for i in 0..buckets {
+        let mut s = ray_tracing_core::color::Color::black();
+        let mut s_wavelength = ray_tracing_core::color::Color::black();
+
+        for _ in 0..samples {
+            let theta1 = rng.gen_range(
+                (f32::consts::FRAC_PI_2 * (i as f32 / buckets as f32))
+                    ..=(f32::consts::FRAC_PI_2 * ((i + 1) as f32 / buckets as f32)),
+            );
+            s += m.monte_carlo_reflectance(theta1, &mut rng);
+            s_wavelength += ray_tracing_core::color::Color::new(
+                m.averaged_reflectance(595.0, theta1),
+                m.averaged_reflectance(556.0, theta1),
+                m.averaged_reflectance(442.0, theta1),
+            );
+        }
+
+        let c = s / samples as f32;
+
+        // data.push(c);
+        data.push(s_wavelength / samples as f32);
+        // dbg!(c);
+        for j in 0..10 {
+            plotting_area
+                .draw_pixel(
+                    (
+                        f32::consts::FRAC_PI_2 * (i as f32 / buckets as f32),
+                        1.0 - (height_per_pixel * (j as f32)),
+                    ),
+                    &RGBColor(
+                        (c.r() * 256.0) as u8,
+                        (c.g() * 256.0) as u8,
+                        (c.b() * 256.0) as u8,
+                    ),
+                )
+                .unwrap();
+        }
+    }
+
+    chart.draw_series(LineSeries::new(
+        data.iter().enumerate().map(|(i, c)| {
+            (
+                (f32::consts::FRAC_PI_2 * (i as f32 / buckets as f32)),
+                c.r(),
+            )
+        }),
+        &RED,
+    ))?;
+
+    chart.draw_series(LineSeries::new(
+        data.iter().enumerate().map(|(i, c)| {
+            (
+                (f32::consts::FRAC_PI_2 * (i as f32 / buckets as f32)),
+                c.g(),
+            )
+        }),
+        &GREEN,
+    ))?;
+
+    chart.draw_series(LineSeries::new(
+        data.iter().enumerate().map(|(i, c)| {
+            (
+                (f32::consts::FRAC_PI_2 * (i as f32 / buckets as f32)),
+                c.b(),
+            )
+        }),
+        &BLUE,
+    ))?;
+
+    root.present()?;
+
+    Ok(())
+}