diff --git a/vtm-playground/src/org/oscim/test/renderer/CustomRenderer.java b/vtm-playground/src/org/oscim/test/renderer/CustomRenderer.java
index f9e0c915..f1e96c94 100644
--- a/vtm-playground/src/org/oscim/test/renderer/CustomRenderer.java
+++ b/vtm-playground/src/org/oscim/test/renderer/CustomRenderer.java
@@ -120,7 +120,7 @@ public class CustomRenderer extends LayerRenderer {
         // Draw the triangle
         gl.drawArrays(GL.TRIANGLE_STRIP, 0, 4);
 
-        GLUtils.checkGlError("...");
+        GLUtils.checkGlError(getClass().getName() + ": render() end");
     }
 
     private boolean init() {
diff --git a/vtm-playground/src/org/oscim/test/renderer/HexagonRenderTest.java b/vtm-playground/src/org/oscim/test/renderer/HexagonRenderTest.java
index 2791db65..d7661c96 100644
--- a/vtm-playground/src/org/oscim/test/renderer/HexagonRenderTest.java
+++ b/vtm-playground/src/org/oscim/test/renderer/HexagonRenderTest.java
@@ -175,7 +175,7 @@ public class HexagonRenderTest extends GdxMapApp {
                 }
             }
 
-            GLUtils.checkGlError("...");
+            GLUtils.checkGlError(getClass().getName() + ": render() end");
         }
 
         private boolean init() {
diff --git a/vtm/src/org/oscim/backend/GL.java b/vtm/src/org/oscim/backend/GL.java
index 9766d767..60d36753 100644
--- a/vtm/src/org/oscim/backend/GL.java
+++ b/vtm/src/org/oscim/backend/GL.java
@@ -106,7 +106,7 @@ public interface GL {
     public static final int POLYGON_OFFSET_FILL = 0x8037;
     public static final int SAMPLE_ALPHA_TO_COVERAGE = 0x809E;
     public static final int SAMPLE_COVERAGE = 0x80A0;
-    //public static final int NO_ERROR = 0;
+    public static final int NO_ERROR = 0;
     public static final int INVALID_ENUM = 0x0500;
     public static final int INVALID_VALUE = 0x0501;
     public static final int INVALID_OPERATION = 0x0502;
diff --git a/vtm/src/org/oscim/renderer/GLShader.java b/vtm/src/org/oscim/renderer/GLShader.java
index cb76fd05..83c73cf3 100644
--- a/vtm/src/org/oscim/renderer/GLShader.java
+++ b/vtm/src/org/oscim/renderer/GLShader.java
@@ -139,11 +139,11 @@ public abstract class GLShader {
 
         int program = gl.createProgram();
         if (program != 0) {
-            GLUtils.checkGlError("glCreateProgram");
+            GLUtils.checkGlError(GLShader.class.getName() + ": glCreateProgram");
             gl.attachShader(program, vertexShader);
-            GLUtils.checkGlError("glAttachShader");
+            GLUtils.checkGlError(GLShader.class.getName() + ": glAttachShader");
             gl.attachShader(program, pixelShader);
-            GLUtils.checkGlError("glAttachShader");
+            GLUtils.checkGlError(GLShader.class.getName() + ": glAttachShader");
             gl.linkProgram(program);
             IntBuffer linkStatus = MapRenderer.getIntBuffer(1);
             gl.getProgramiv(program, GL.LINK_STATUS, linkStatus);
diff --git a/vtm/src/org/oscim/renderer/GLUtils.java b/vtm/src/org/oscim/renderer/GLUtils.java
index 4527692c..5eb0c2bc 100644
--- a/vtm/src/org/oscim/renderer/GLUtils.java
+++ b/vtm/src/org/oscim/renderer/GLUtils.java
@@ -1,6 +1,7 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016 devemux86
+ * Copyright 2016-2019 devemux86
+ * Copyright 2019 Gustl22
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -27,6 +28,8 @@ import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.oscim.backend.GLAdapter.gl;
 
@@ -107,26 +110,102 @@ public class GLUtils {
         return textureIds[0];
     }
 
-    public static void checkGlError(String op) {
-        //GL = GLAdapter.get();
+    /**
+     * Check the status of current framebuffer.
+     * See: https://www.khronos.org/registry/OpenGL-Refpages/es2.0/xhtml/glCheckFramebufferStatus.xml
+     *
+     * @param op the operation which should be debugged
+     * @return the status code
+     */
+    public static int checkFramebufferStatus(String op) {
+        int status = gl.checkFramebufferStatus(GL.FRAMEBUFFER);
+        if (status != GL.FRAMEBUFFER_COMPLETE)
+            log.error(op + ": \tglFramebuffer " + getFramebufferStatusString(status) + " (" + status + ")");
+        return status;
+    }
 
-        int error;
-        while ((error = gl.getError()) != 0) { // GL20.NO_ERROR) {
-            log.error(op + ": glError " + error);
+    /**
+     * @param status the status code of a framebuffer
+     * @return the status code as string
+     */
+    public static String getFramebufferStatusString(int status) {
+        switch (status) {
+            case GL.FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
+                return "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT";
+            case GL.FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
+                return "GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS";
+            case GL.FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
+                return "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT";
+            case GL.FRAMEBUFFER_UNSUPPORTED:
+                return "GL_FRAMEBUFFER_UNSUPPORTED";
+            case GL.FRAMEBUFFER_COMPLETE:
+                return "GL_FRAMEBUFFER_COMPLETE";
+            default:
+                return String.valueOf(status);
+        }
+    }
+
+    /**
+     * Check GL error.
+     * See: https://www.khronos.org/opengl/wiki/OpenGL_Error
+     *
+     * @param op the operation which should be debugged
+     */
+    public static void checkGlError(String op) {
+        int error; // GL.NO_ERROR
+        while ((error = gl.getError()) != GL.NO_ERROR) {
+            log.error(op + ": \tglError " + getGlErrorString(error) + " (" + error + ")");
             // throw new RuntimeException(op + ": glError " + error);
         }
     }
 
-    public static boolean checkGlOutOfMemory(String op) {
-        int error;
-        boolean oom = false;
-        while ((error = gl.getError()) != 0) {// GL20.NO_ERROR) {
-            log.error(op + ": glError " + error);
+    /**
+     * Check GL errors.
+     * See: https://www.khronos.org/opengl/wiki/OpenGL_Error
+     *
+     * @param op the operation which should be debugged
+     * @return the OpenGL error codes
+     */
+    public static List<Integer> checkGlErrors(String op) {
+        int error; // GL.NO_ERROR
+        List<Integer> errors = new ArrayList<>();
+        while ((error = gl.getError()) != GL.NO_ERROR) {
+            log.error(op + ": \tglError " + getGlErrorString(error) + " (" + error + ")");
+            errors.add(error);
             // throw new RuntimeException(op + ": glError " + error);
-            if (error == 1285)
-                oom = true;
         }
-        return oom;
+        return errors;
+    }
+
+    /**
+     * @param error the error code of OpenGL
+     * @return the error code as string
+     */
+    public static String getGlErrorString(int error) {
+        switch (error) {
+            case GL.INVALID_ENUM:
+                return "GL_INVALID_ENUM";
+            case GL.INVALID_VALUE:
+                return "GL_INVALID_VALUE";
+            case GL.INVALID_OPERATION:
+                return "GL_INVALID_OPERATION";
+            case 0x0503: // GL.STACK_OVERFLOW
+                return "GL_STACK_OVERFLOW";
+            case 0x0504: // GL.STACK_UNDERFLOW
+                return "GL_STACK_UNDERFLOW";
+            case GL.OUT_OF_MEMORY:
+                return "GL_OUT_OF_MEMORY";
+            case GL.INVALID_FRAMEBUFFER_OPERATION:
+                return "GL_INVALID_FRAMEBUFFER_OPERATION";
+            case 0x0507: // GL.CONTEXT_LOST (with OpenGL 4.5)
+                return "GL_CONTEXT_LOST";
+            case 0x8031: // GL.TABLE_TOO_LARGE (deprecated in OpenGL 3.0)
+                return "GL_TABLE_TOO_LARGE";
+            case GL.NO_ERROR:
+                return "GL_NO_ERROR";
+            default:
+                return String.valueOf(error);
+        }
     }
 
     public static void setColor(int handle, float[] c, float alpha) {
diff --git a/vtm/src/org/oscim/renderer/MapRenderer.java b/vtm/src/org/oscim/renderer/MapRenderer.java
index 749af542..eea59fb9 100644
--- a/vtm/src/org/oscim/renderer/MapRenderer.java
+++ b/vtm/src/org/oscim/renderer/MapRenderer.java
@@ -160,7 +160,7 @@ public class MapRenderer {
                 GLUtils.checkGlError(renderer.getClass().getName());
         }
 
-        if (GLUtils.checkGlOutOfMemory("finish")) {
+        if (GLUtils.checkGlErrors(getClass().getName() + ": finish").contains(GL.OUT_OF_MEMORY)) {
             BufferObject.checkBufferUsage(true);
             // FIXME also throw out some textures etc
         }
diff --git a/vtm/src/org/oscim/renderer/OffscreenRenderer.java b/vtm/src/org/oscim/renderer/OffscreenRenderer.java
index dd3f4a0f..069bea55 100644
--- a/vtm/src/org/oscim/renderer/OffscreenRenderer.java
+++ b/vtm/src/org/oscim/renderer/OffscreenRenderer.java
@@ -66,7 +66,7 @@ public class OffscreenRenderer extends LayerRenderer {
         gl.genTextures(1, buf);
         renderTex = buf.get(0);
 
-        GLUtils.checkGlError("0");
+        GLUtils.checkGlError(getClass().getName() + ": 0");
 
         gl.bindFramebuffer(GL.FRAMEBUFFER, fb);
 
@@ -89,7 +89,7 @@ public class OffscreenRenderer extends LayerRenderer {
                 GL.COLOR_ATTACHMENT0,
                 GL.TEXTURE_2D,
                 renderTex, 0);
-        GLUtils.checkGlError("1");
+        GLUtils.checkGlError(getClass().getName() + ": 1");
 
         if (useDepthTexture) {
             buf.clear();
@@ -128,17 +128,13 @@ public class OffscreenRenderer extends LayerRenderer {
                     depthRenderbuffer);
         }
 
-        GLUtils.checkGlError("2");
+        GLUtils.checkGlError(getClass().getName() + ": 2");
 
-        int status = gl.checkFramebufferStatus(GL.FRAMEBUFFER);
+        int status = GLUtils.checkFramebufferStatus(getClass().getName());
         gl.bindFramebuffer(GL.FRAMEBUFFER, 0);
         gl.bindTexture(GL.TEXTURE_2D, 0);
 
-        if (status != GL.FRAMEBUFFER_COMPLETE) {
-            log.debug("invalid framebuffer! " + status);
-            return false;
-        }
-        return true;
+        return status == GL.FRAMEBUFFER_COMPLETE;
     }
 
     public void enable(boolean on) {
@@ -223,6 +219,6 @@ public class OffscreenRenderer extends LayerRenderer {
         GLState.test(false, false);
         GLState.blend(true);
         gl.drawArrays(GL.TRIANGLE_STRIP, 0, 4);
-        GLUtils.checkGlError("....");
+        GLUtils.checkGlError(getClass().getName() + ": render() end");
     }
 }
diff --git a/vtm/src/org/oscim/renderer/bucket/TextureItem.java b/vtm/src/org/oscim/renderer/bucket/TextureItem.java
index 55d43966..0a3bd8dd 100755
--- a/vtm/src/org/oscim/renderer/bucket/TextureItem.java
+++ b/vtm/src/org/oscim/renderer/bucket/TextureItem.java
@@ -305,7 +305,7 @@ public class TextureItem extends Inlist<TextureItem> {
                 gl.generateMipmap(GL.TEXTURE_2D);
 
             if (dbg)
-                GLUtils.checkGlError(TextureItem.class.getName());
+                GLUtils.checkGlError(getClass().getName());
 
             if (mUseBitmapPool)
                 releaseBitmap(t);