Mark vec3.h free functions inline

Author: JankoDedic

src/common/vec3.h

@@ -119,42 +119,42 @@ inline vec3 unit_vector(vec3 v) {
     return v / v.length();
 }
 
-vec3 random_unit_vector() {
+inline vec3 random_unit_vector() {
     auto a = random_double(0, 2*pi);
     auto z = random_double(-1, 1);
     auto r = sqrt(1 - z*z);
     return vec3(r*cos(a), r*sin(a), z);
 }
 
-vec3 random_in_unit_disk() {
+inline vec3 random_in_unit_disk() {
     while (true) {
         auto p = vec3(random_double(-1,1), random_double(-1,1), 0);
         if (p.length_squared() >= 1) continue;
         return p;
     }
 }
 
-vec3 random_in_unit_sphere() {
+inline vec3 random_in_unit_sphere() {
     while (true) {
         auto p = vec3::random(-1,1);
         if (p.length_squared() >= 1) continue;
         return p;
     }
 }
 
-vec3 random_in_hemisphere(const vec3& normal) {
+inline vec3 random_in_hemisphere(const vec3& normal) {
     vec3 in_unit_sphere = random_in_unit_sphere();
     if (dot(in_unit_sphere, normal) > 0.0) // In the same hemisphere as the normal
         return in_unit_sphere;
     else
         return -in_unit_sphere;
 }
 
-vec3 reflect(const vec3& v, const vec3& n) {
+inline vec3 reflect(const vec3& v, const vec3& n) {
     return v - 2*dot(v,n)*n;
 }
 
-vec3 refract(const vec3& uv, const vec3& n, double etai_over_etat) {
+inline vec3 refract(const vec3& uv, const vec3& n, double etai_over_etat) {
     auto cos_theta = fmin(dot(-uv, n), 1.0);
     vec3 r_out_perp =  etai_over_etat * (uv + cos_theta*n);
     vec3 r_out_parallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;