diff --git a/shader/materialshader.cpp b/shader/materialshader.cpp
index 5f6550a..d3907c0 100644
--- a/shader/materialshader.cpp
+++ b/shader/materialshader.cpp
@@ -6,20 +6,24 @@
 
 Vector3d
 tangentToWorldSpace(const Vector3d &surfaceNormal, const Vector3d &surfaceTangent, const Vector3d &surfaceBitangent,
-                    const Vector3d &textureNormal) {
+                    const Vector3d &textureNormal)
+{
     return textureNormal.x * surfaceTangent + textureNormal.y * surfaceBitangent + textureNormal.z * surfaceNormal;
 }
 
 MaterialShader::MaterialShader() : opacity(1.0f), normalCoefficient(1.0f), diffuseCoefficient(0.5f), reflectance(0.0f),
-                                   specularCoefficient(0.5f), shininessExponent(8) {}
+                                   specularCoefficient(0.5f), shininessExponent(8)
+{}
 
-Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
+Color MaterialShader::shade(Scene const &scene, Ray const &ray) const
+{
     Color fragmentColor;
     // IMPLEMENT ME
 
     // (Normal Map) Calculate the new normal vector
     Vector3d surfaceNormal = ray.normal;
-    if (this->normalMap != nullptr) {
+    if (this->normalMap != nullptr)
+    {
         auto surfaceNormalMapColor = this->normalMap->color(ray.surface, true);
         Vector3d textureNormal = {surfaceNormalMapColor.r, surfaceNormalMapColor.g, surfaceNormalMapColor.b};
         textureNormal = textureNormal * 2.0f - Vector3d{1, 1, 1};
@@ -30,12 +34,14 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
 
     // (Diffuse-/Specular Map) Accumulate the light over all light sources
     Color surfaceDiffuseColor(0, 0, 0);
-    if (this->diffuseMap != nullptr) {
+    if (this->diffuseMap != nullptr)
+    {
         surfaceDiffuseColor = this->diffuseMap->color(ray.surface, true);
     }
 
     Color surfaceSpecularColor(0, 0, 0);
-    if (this->specularMap != nullptr) {
+    if (this->specularMap != nullptr)
+    {
         surfaceSpecularColor = this->specularMap->color(ray.surface, true);
     }
 
@@ -43,7 +49,8 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
     // (Reflection Map) Calculate the reflectance, create a reflection ray
     Vector3d const reflection = ray.direction - 2 * dotProduct(surfaceNormal, ray.direction) * ray.normal;
     float surfaceReflectanceCoefficient = this->reflectance;
-    if (this->reflectionMap != nullptr) {
+    if (this->reflectionMap != nullptr)
+    {
         auto surfaceReflectiveMapColor = this->reflectionMap->color(ray.surface, true);
         surfaceReflectanceCoefficient = surfaceReflectiveMapColor.r;
     }
@@ -55,7 +62,8 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
 
     // (Alpha Map) Calculate the opacity, create a background ray
     float surfaceAlphaCoefficient(1);
-    if (this->alphaMap != nullptr) {
+    if (this->alphaMap != nullptr)
+    {
         auto surfaceAlphaMapColor = this->alphaMap->color(ray.surface, true);
         surfaceAlphaCoefficient = surfaceAlphaMapColor.r;
     }
@@ -66,7 +74,8 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
     propagatedRay.primitive = nullptr;
 
     // Iterate over light sources
-    for (const auto &light: scene.lights()) {
+    for (const auto &light: scene.lights())
+    {
         Light::Illumination const illum = light->illuminate(scene, ray);
 
         // Diffuse term (lambertian)
@@ -76,7 +85,8 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
 
         // Specular term (phong)
         float const cosine = dotProduct(-illum.direction, reflection);
-        if (cosine > 0) {
+        if (cosine > 0)
+        {
             Color const specular = this->specularCoefficient * surfaceSpecularColor // highlight
                                    * powf(cosine, this->shininessExponent);        // shininess factor
             fragmentColor += specular * illum.color;
@@ -85,10 +95,21 @@ Color MaterialShader::shade(Scene const &scene, Ray const &ray) const {
 
     }
     // Reflected ray
-    fragmentColor += scene.traceRay(reflectionRay) * surfaceReflectanceCoefficient * reflectance;
+    if (surfaceReflectanceCoefficient > 0)
+    {
+        Color const reflectionColor = scene.traceRay(reflectionRay);
+        fragmentColor += surfaceReflectanceCoefficient * reflectionColor * reflectance;
+    }
 
     // Opacity
-    return  fragmentColor * surfaceAlphaCoefficient + scene.traceRay(propagatedRay) * (1 - surfaceAlphaCoefficient);
+    if (surfaceAlphaCoefficient < 1)
+    {
+        Color const background = scene.traceRay(propagatedRay);
+        fragmentColor = (1 - surfaceAlphaCoefficient) * background + surfaceAlphaCoefficient * fragmentColor;
+    }
+
+    return fragmentColor;
 }
 
-bool MaterialShader::isTransparent() const { return this->opacity < 1.0f || this->alphaMap; }
+bool MaterialShader::isTransparent() const
+{ return this->opacity < 1.0f || this->alphaMap; }