Add dielectric material. (glass ball)

1 files changed, 22 insertions, 0 deletions

diff --git a/material_dielectric.cpp b/material_dielectric.cpp
new file mode 100644
index 0000000..3aaf259
--- /dev/null
+++ b/material_dielectric.cpp
@@ -0,0 +1,22 @@
+//
+// Created by Keuin on 2022/4/15.
+//
+
+#include "material_dielectric.h"
+
+bool material_dielectric::scatter(ray3d &r, const object &hit_obj, double hit_t, random_uv_gen_3d &ruvg) const {
+    const auto hit_p = r.at(hit_t);
+    assert(hit_obj.is_on(hit_p));
+    auto n = hit_obj.normal_vector(hit_p);
+    auto ri_ = ri_inv;
+    if (dot(r.direction(), n) > 0) {
+        // the ray is started from the object's inner,
+        // use normal vector and ri on the surface's inner side
+        n = -n;
+        ri_ = 1.0 / ri_;
+    }
+    const auto r2 = n.refract<true>(r.direction(), ri_); // refracted vector
+    r.direction(r2.unit_vec());
+    r.source(hit_p);
+    return true;
+}