Fix vec3::reflect. Add tests for vec3::reflect and vec3::is_zero.

2 files changed, 28 insertions, 4 deletions

diff --git a/test_vec.cpp b/test_vec.cpp
index 1b765aa..143d5b3 100644
--- a/test_vec.cpp
+++ b/test_vec.cpp
@@ -74,4 +74,28 @@ TEST(Vec, Mod2) {
     vec3d b{2.5, 3, 1.2};
     ASSERT_EQ(a.mod2(), 14);
     ASSERT_LE(abs(b.mod2() - (2.5 * 2.5 + 3 * 3 + 1.2 * 1.2)), 1e-10);
+}
+
+TEST(Vec, IsZero) {
+    vec3i a{1,0,0}, b{0,-1,0}, c{1,2,3};
+    ASSERT_FALSE(a.is_zero());
+    ASSERT_FALSE(b.is_zero());
+    ASSERT_FALSE(c.is_zero());
+
+    vec3d d{0.1,0,0}, e{0,-0.1,0},f{0.1,0.1,0.1};
+    ASSERT_FALSE(d.is_zero());
+    ASSERT_FALSE(e.is_zero());
+    ASSERT_FALSE(f.is_zero());
+
+    vec3i g{0,0,0};
+    vec3d h{0,0,0}, i{1e-10,0,0}, j{1e-10,1e-10,1e-10};
+    ASSERT_TRUE(g.is_zero());
+    ASSERT_TRUE(h.is_zero());
+    ASSERT_TRUE(i.is_zero());
+    ASSERT_TRUE(j.is_zero());
+}
+
+TEST(Vec, Reflect) {
+    vec3d n{1,0,0}, u{-1,1.1,0}, v{1,1.1,0};
+    ASSERT_EQ(v, n.reflect(u));
 }
\ No newline at end of file
diff --git a/vec.h b/vec.h
index c7669bf..5050065 100644
--- a/vec.h
+++ b/vec.h
@@ -88,10 +88,10 @@ struct vec3 {
         return *this * (1.0 / norm());
     }
 
-    // Get the reflected vector. Current vector is the incoming vector, n is the normal vector (length should be 1).
-    vec3 reflect(const vec3 &n) const {
-        assert(fabs(n.mod2() - 1.0) < 1e-8);
-        return *this - 2.0 * dot(*this, n) * n;
+    // Get the reflected vector. Current vector is the normal vector (length should be 1), v is the incoming vector.
+    vec3 reflect(const vec3 &v) const {
+        assert(fabs(mod2() - 1.0) < 1e-8);
+        return v - (2.0 * dot(v)) * (*this);
     }
 };