Make ray3::decay_ distinguishable between different color channels.

1 files changed, 13 insertions, 0 deletions

diff --git a/vec.h b/vec.h
index 5050065..99004d6 100644
--- a/vec.h
+++ b/vec.h
@@ -36,12 +36,20 @@ struct vec3 {
         return vec3{0, 0, 0};
     }
 
+    static vec3 one() {
+        return vec3{1, 1, 1};
+    }
+
     bool is_zero() const {
 #define EPS (1e-8)
         return x >= -EPS && y >= -EPS && z >= -EPS && x <= EPS && y <= EPS && z <= EPS;
 #undef EPS
     }
 
+    bool is_one() const {
+        return (*this - vec3::one()).is_zero();
+    }
+
     vec3 operator+(const vec3 &b) const {
         return vec3{.x=x + b.x, .y=y + b.y, .z=z + b.z};
     }
@@ -68,6 +76,11 @@ struct vec3 {
         return vec3{.x=y * b.z - z * b.y, .y=x * b.z - z * b.x, .z=x * b.y - y * b.x};
     }
 
+    // Multiply with b on every dimension.
+    vec3 scale(const vec3 &b) const {
+        return vec3{.x=x * b.x, .y=y * b.y, .z=z * b.z};
+    }
+
     // norm value
     double norm(const int level = 2) const {
         if (level == 2) {