diff --git a/app/src/main/java/de/trac/spherical/MainActivity.java b/app/src/main/java/de/trac/spherical/MainActivity.java
index 12e5425..d103db0 100644
--- a/app/src/main/java/de/trac/spherical/MainActivity.java
+++ b/app/src/main/java/de/trac/spherical/MainActivity.java
@@ -112,7 +112,7 @@ public class MainActivity extends AppCompatActivity {
             //App was launched via launcher icon
             //TODO: Remove later together with launcher intent filter
             default:
-                Toast.makeText(this, R.string.prompt_share_image, Toast.LENGTH_LONG).show();
+                Toast.makeText(this, R.string.toast_prompt_share_image, Toast.LENGTH_LONG).show();
         }
     }
 
@@ -139,9 +139,8 @@ public class MainActivity extends AppCompatActivity {
                         && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                     handleSentImageIntent(cachedIntent);
                 } else {
-                    Toast.makeText(this, R.string.missing_permission, Toast.LENGTH_LONG).show();
+                    Toast.makeText(this, R.string.toast_missing_permission, Toast.LENGTH_LONG).show();
                 }
-                return;
             }
         }
     }
@@ -173,7 +172,7 @@ public class MainActivity extends AppCompatActivity {
     public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()) {
             case R.id.menu_force_sphere:
-                Toast.makeText(this, R.string.not_yet_implemented, Toast.LENGTH_SHORT).show();
+                Toast.makeText(this, R.string.toast_not_yet_implemented, Toast.LENGTH_SHORT).show();
                 return true;
         }
 
@@ -191,7 +190,7 @@ public class MainActivity extends AppCompatActivity {
 
             Uri imageUri = intent.getParcelableExtra(Intent.EXTRA_STREAM);
             if (imageUri == null) {
-                Toast.makeText(this, R.string.file_not_found, Toast.LENGTH_SHORT).show();
+                Toast.makeText(this, R.string.toast_file_not_found, Toast.LENGTH_SHORT).show();
                 return;
             }
 
@@ -227,9 +226,11 @@ public class MainActivity extends AppCompatActivity {
             }
 
         } catch (FileNotFoundException e) {
-            e.printStackTrace();
+            Log.e(TAG, "File not found.", e);
+            Toast.makeText(this, R.string.toast_file_not_found, Toast.LENGTH_SHORT).show();
         } catch (IOException e) {
-            e.printStackTrace();
+            Log.e(TAG, "IOException: ", e);
+            Toast.makeText(this, R.string.toast_io_error, Toast.LENGTH_SHORT).show();
         }
     }
 
@@ -252,10 +253,10 @@ public class MainActivity extends AppCompatActivity {
 
         } catch (FileNotFoundException e) {
             Log.e(TAG, "File not found.", e);
-            Toast.makeText(this, R.string.file_not_found, Toast.LENGTH_SHORT).show();
+            Toast.makeText(this, R.string.toast_file_not_found, Toast.LENGTH_SHORT).show();
         } catch (IOException e) {
             Log.e(TAG, "IOException: ", e);
-            Toast.makeText(this, R.string.ioerror, Toast.LENGTH_SHORT).show();
+            Toast.makeText(this, R.string.toast_io_error, Toast.LENGTH_SHORT).show();
         }
     }
 
diff --git a/app/src/main/java/de/trac/spherical/rendering/Renderer.java b/app/src/main/java/de/trac/spherical/rendering/Renderer.java
index 7764237..23eaccb 100644
--- a/app/src/main/java/de/trac/spherical/rendering/Renderer.java
+++ b/app/src/main/java/de/trac/spherical/rendering/Renderer.java
@@ -10,8 +10,55 @@ import android.util.Log;
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
 
-import static android.opengl.GLES20.*;
-import static android.opengl.GLUtils.getEGLErrorString;
+import static android.opengl.GLES20.GL_COLOR_BUFFER_BIT;
+import static android.opengl.GLES20.GL_COMPILE_STATUS;
+import static android.opengl.GLES20.GL_CULL_FACE;
+import static android.opengl.GLES20.GL_CW;
+import static android.opengl.GLES20.GL_DEPTH_BUFFER_BIT;
+import static android.opengl.GLES20.GL_DEPTH_TEST;
+import static android.opengl.GLES20.GL_FLOAT;
+import static android.opengl.GLES20.GL_FRAGMENT_SHADER;
+import static android.opengl.GLES20.GL_LINEAR;
+import static android.opengl.GLES20.GL_LINK_STATUS;
+import static android.opengl.GLES20.GL_NEAREST;
+import static android.opengl.GLES20.GL_TEXTURE0;
+import static android.opengl.GLES20.GL_TEXTURE_2D;
+import static android.opengl.GLES20.GL_TEXTURE_MAG_FILTER;
+import static android.opengl.GLES20.GL_TEXTURE_MIN_FILTER;
+import static android.opengl.GLES20.GL_TRIANGLES;
+import static android.opengl.GLES20.GL_TRUE;
+import static android.opengl.GLES20.GL_UNSIGNED_SHORT;
+import static android.opengl.GLES20.GL_VERTEX_SHADER;
+import static android.opengl.GLES20.glActiveTexture;
+import static android.opengl.GLES20.glAttachShader;
+import static android.opengl.GLES20.glBindTexture;
+import static android.opengl.GLES20.glClear;
+import static android.opengl.GLES20.glClearColor;
+import static android.opengl.GLES20.glCompileShader;
+import static android.opengl.GLES20.glCreateProgram;
+import static android.opengl.GLES20.glCreateShader;
+import static android.opengl.GLES20.glDeleteProgram;
+import static android.opengl.GLES20.glDeleteShader;
+import static android.opengl.GLES20.glDisableVertexAttribArray;
+import static android.opengl.GLES20.glDrawElements;
+import static android.opengl.GLES20.glEnable;
+import static android.opengl.GLES20.glEnableVertexAttribArray;
+import static android.opengl.GLES20.glFrontFace;
+import static android.opengl.GLES20.glGenTextures;
+import static android.opengl.GLES20.glGetAttribLocation;
+import static android.opengl.GLES20.glGetProgramInfoLog;
+import static android.opengl.GLES20.glGetProgramiv;
+import static android.opengl.GLES20.glGetShaderInfoLog;
+import static android.opengl.GLES20.glGetShaderiv;
+import static android.opengl.GLES20.glGetUniformLocation;
+import static android.opengl.GLES20.glLinkProgram;
+import static android.opengl.GLES20.glShaderSource;
+import static android.opengl.GLES20.glTexParameteri;
+import static android.opengl.GLES20.glUniform1i;
+import static android.opengl.GLES20.glUniformMatrix4fv;
+import static android.opengl.GLES20.glUseProgram;
+import static android.opengl.GLES20.glVertexAttribPointer;
+import static android.opengl.GLES20.glViewport;
 
 public class Renderer implements GLSurfaceView.Renderer {
 
diff --git a/app/src/main/res/values-de/strings.xml b/app/src/main/res/values-de/strings.xml
index a6b3dae..0755aec 100644
--- a/app/src/main/res/values-de/strings.xml
+++ b/app/src/main/res/values-de/strings.xml
@@ -1,2 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
-<resources></resources>
\ No newline at end of file
+<resources>
+    <string name="menu_force_sphere">Erzwinge Kugelansicht</string>
+    <string name="toast_file_not_found">Datei nicht gefunden.</string>
+    <string name="toast_io_error">Ein Fehler ist aufgetreten: IO-Error.</string>
+    <string name="toast_missing_permission">Foto kann nicht angezeigt werden: Fehlende Berechtigung für externen Speicher.</string>
+    <string name="toast_not_yet_implemented">Noch nicht implementiert!</string>
+    <string name="toast_prompt_share_image">Teile ein Bild mit der App!</string>
+</resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index a384a13..3f60415 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1,10 +1,9 @@
 <resources>
-    <string name="app_name">Spherical</string>
-    <string name="prompt_share_image">Share an image with the app!</string>
-    <string name="file_not_found">File not found.</string>
-    <string name="ioerror">An Error has occurred: IOError.</string>
-    <string name="wow">WOW! SUCH 3D!!!</string>
+    <string name="app_name" translatable="false">Spherical</string>
+    <string name="toast_prompt_share_image">Share an image with the app!</string>
+    <string name="toast_file_not_found">File not found.</string>
+    <string name="toast_io_error">An Error has occurred: IO-Error.</string>
     <string name="menu_force_sphere">Show as Sphere</string>
-    <string name="not_yet_implemented">Not yet implemented!</string>
-    <string name="missing_permission">Cannot display photo: Missing permissions to access external storage.</string>
+    <string name="toast_not_yet_implemented">Not yet implemented!</string>
+    <string name="toast_missing_permission">Cannot display photo: Missing permissions to access external storage.</string>
 </resources>