AndroidGLKit

AndroidGLKit provides OpenGL ES 2.0 boilerplate codes for Android. You can implement OpenGL 2.0 things easily by using AndroidGLKit.

Setup Gradle

dependencies {
	...
	implementation 'kr.pe.burt.android.lib:androidglkit:1.0.1'
}

How to Use

Extends Activity or Fragment

AndroidGLKit provides GLKActivity or GLKFragments. Also it has GLKAppCompatActivity and GLKSupportFragment. You can extends above activity or fragment like below.

public class TextureActivity extends GLKAppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    protected void onStart() {
        super.onStart();
        glkView.setGLKRenderer(new TextureRenderer(this));
    }
}

Notice that above code does not have set layout code setContentView(R.layout.texture_activity). Because AndroidGLKit provides default layout file as common_glk_view.xml like below:

<?xml version="1.0" encoding="utf-8"?>
<kr.pe.burt.android.lib.androidglkit.GLKView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/glkView"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</kr.pe.burt.android.lib.androidglkit.GLKView>

If you extends activity or fragment that GLKit provides, you don't need to have layout file.

Custom Layout file

Of course, You don't like the above approach. Therefore, You can use custom layout file like below:

public class SquareActivity extends GLKAppCompatActivity {

    @Override
    protected int getLayoutFileResourceId() {
        return R.layout.activity_square;
    }

    @Override
    protected void onStart() {
        super.onStart();
        glkView.setGLKRenderer(new SquareRenderer(this));
    }
}

Override getLayoutFileResourceId method and return resource id for your layout file. R.layout.activity_square looks like below:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:glk="http://schemas.android.com/apk/res-auto"
    tools:context="kr.pe.burt.android.lib.androidglkit.app.SquareActivity">


    <kr.pe.burt.android.lib.androidglkit.GLKView
        android:id="@+id/glkView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />


</RelativeLayout>

Important thing is GLKView must have android:id as glkView. It is rule for using AndroidGLKit.

Implement GLKRenderer

GLKRenderer takes responsibility for draw something on OpenGL ES Context. Maybe your opengl codes to be in here. The Simplest renderer is blank renderer like below:

public class BlankRenderer implements GLKRenderer {

    @Override
    public void init(GLKView view) {

    }

    @Override
    public void onSizeChanged(GLKView view, int width, int height) {
        GLES20.glViewport(0, 0, width, height);
    }

    @Override
    public void update(GLKView view, long dt) {
        GLES20.glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
    }
}

Set Renderer to GLKView

If you have implemented GLKRenderer, you should set it to GLKView like below:

@Override
public void onStart() {
    super.onStart();
    glkView.setGLKRenderer(new BlankRenderer());
}

It's all :) If you run the above code, You can see the result screen like below:

Examples

Square

Texture

Offscreen Rendering

You can get bitmap from OpenGL ES context easily like below:

@Override
protected void onStart() {
    super.onStart();

    GLKPixelBuffer pb = new GLKPixelBuffer(300, 300);
    Bitmap bitmap = pb.getBitmap(new SquareRenderer(this));
    imageView.setImageBitmap(bitmap);
    pb.destroy();
}

Enjoy OpenGL ES 2.0 with AndroidGLKit!

MIT License

The MIT License (MIT)

Copyright (c) 2016 Sungcheol Kim, https://github.com/skyfe79/AndroidGLKit

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.