Sync changes in cross product computation to all vec3.h src files

Addresses: #69

Author: ronaldfw

src/TheNextWeek/vec3.h

@@ -98,9 +98,9 @@ inline float dot(const vec3 &v1, const vec3 &v2) {
 }
 
 inline vec3 cross(const vec3 &v1, const vec3 &v2) {
-    return vec3( (v1.e[1]*v2.e[2] - v1.e[2]*v2.e[1]),
-                (-(v1.e[0]*v2.e[2] - v1.e[2]*v2.e[0])),
-                (v1.e[0]*v2.e[1] - v1.e[1]*v2.e[0]));
+    return vec3(v1.e[1]*v2.e[2] - v1.e[2]*v2.e[1],
+                v1.e[2]*v2.e[0] - v1.e[0]*v2.e[2],
+                v1.e[0]*v2.e[1] - v1.e[1]*v2.e[0]);
 }
 
 

src/TheRestOfYourLife/vec3.h

@@ -99,12 +99,11 @@ inline float dot(const vec3 &v1, const vec3 &v2) {
 }
 
 inline vec3 cross(const vec3 &v1, const vec3 &v2) {
-    return vec3( (v1.e[1]*v2.e[2] - v1.e[2]*v2.e[1]),
-                (-(v1.e[0]*v2.e[2] - v1.e[2]*v2.e[0])),
-                (v1.e[0]*v2.e[1] - v1.e[1]*v2.e[0]));
+    return vec3(v1.e[1]*v2.e[2] - v1.e[2]*v2.e[1],
+                v1.e[2]*v2.e[0] - v1.e[0]*v2.e[2],
+                v1.e[0]*v2.e[1] - v1.e[1]*v2.e[0]);
 }
 
-
 inline vec3& vec3::operator+=(const vec3 &v){
     e[0]  += v.e[0];
     e[1]  += v.e[1];