hi everybody,

got an problem on testing my app on device (htc desire), but works on emulator

10-15 14:34:05.629: ERROR/AndroidRuntime(25714): FATAL EXCEPTION: GLThread 9
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): java.lang.NullPointerException
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): at com.google.android.gles_jni.GLImpl.glVertexPointer(GLImpl.java:1121)
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): at de.mydrawing.Main.mainLoopIteration(Main.java:72)
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): at de.mydrawing.GameActivity.onDrawFrame(GameActivity.java:180)
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1341)
10-15 14:34:05.629: ERROR/AndroidRuntime(25714): at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1118)


when i comment these lines out it starts but then its black screen

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gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertices);
gl.glColorPointer( 4, GL10.GL_FLOAT, 0, colors );

anybody an idea what the problem can be?

Did you enable GlVectexPointer and glColorPointer?

hi Jug6ernaut,

i think so,like that

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gl.glEnableClientState(GL10.GL_VERTEX_ARRAY );
gl.glEnableClientState(GL10.GL_COLOR_ARRAY );

am i wrong?

Is vertices a float array or FloatBuffer? If it is a float array, it will compile, but will not work. The last argument in the glVertexPointer(...) and glColorPointer(...) methods is required to be a Buffer type object.

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        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
        vbb.order(ByteOrder.nativeOrder());
        FloatBuffer vBuffer= vbb.asFloatBuffer();
        vBuffer.put(vertices);
        vBuffer.position(0);


Then, after enabling the GL_VERTEX_ARRAY client state (like you did above), you would make a call like so:
gl.glVertexPointer(3, gl.GL_FLOAT, 0, vBuffer);

That should make it run. Whether or not it displays what you wish, however, depends on your array of vertices...

hi jonbonazza,

won't work at all,vertices is a float buffer

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private FloatBuffer vertices;
            ByteBuffer buffer = ByteBuffer.allocateDirect( 3 * 4 * 3 );
            buffer.order(ByteOrder.nativeOrder());
            vertices = buffer.asFloatBuffer();
           
            vertices.put( -0.5f );
            vertices.put( -0.5f );
            vertices.put( 0 );
           
            vertices.put( 0.5f );
            vertices.put( -0.5f );
            vertices.put( 0 );
           
            vertices.put( 0 );
            vertices.put( 0.5f );
            vertices.put( 0 );
           
            vertices.rewind();
           
            buffer = ByteBuffer.allocateDirect( 3 * 4 * 4 );
            buffer.order(ByteOrder.nativeOrder());
            colors = buffer.asFloatBuffer();
           
            colors.put( 1 );
            colors.put( 0 );
            colors.put( 0 );
            colors.put( 1 );
           
            colors.put( 0 );
            colors.put( 1 );
            colors.put( 0 );
            colors.put( 1 );
           
            colors.put( 0 );
            colors.put( 0 );
            colors.put( 1 );
            colors.put( 1 );
           
            colors.rewind();




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gl.glEnableClientState(GL10.GL_COLOR_ARRAY );
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY );
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertices);
gl.glViewport( 0, 0, activity.getViewportWidth(), activity.getViewportHeight() );           
gl.glColorPointer( 4, GL10.GL_FLOAT, 0, colors );
gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);


could maybe post some code which draws some circle or so, to see if it works?

Remove the vertices.rewind(); and colors.rewind(); lines and use vertices.position(0); and colors.position(0);

Also, put all of your float values into a single array and then use a single .put() statement to add the entire array. The way you have it now, you are putting multiple "arrays" the each contain only one value. This is likely a problem.

thanks for help, it works