Added a critical difference to -1,1 and 0,1 dis

RayTracer/tools/Random.cpp

@@ -3,7 +3,7 @@
 namespace util {
 
 Vec3 rand_vec3() {
-	return Vec3(dis(gen), dis(gen), dis(gen));
+	return Vec3(dis0to1(gen), dis0to1(gen), dis0to1(gen));
 }
 
 bool in_circle(const Vec3& v) {

RayTracer/tools/Random.h

@@ -8,7 +8,8 @@ namespace util {
 
 static std::random_device rd;
 static std::mt19937 gen(rd());
-static std::uniform_real_distribution<> dis(-1.0, 1.0);
+static std::uniform_real_distribution<> dis0to1(0.0, 1.0);
+static std::uniform_real_distribution<> disMinus1To1(-1.0, 1.0);
 Vec3 rand_vec3();
 bool in_circle(const Vec3& v);
 Vec3 rand_vec3_in_circle(float r);