samples/ApiDemos/src/com/example/android/apis/graphics/kube/KubeRenderer.java

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics.kube;

import android.opengl.GLSurfaceView;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;


/**
 * Example of how to use OpenGL|ES in a custom view
 *
 */
class KubeRenderer implements GLSurfaceView.Renderer {
    public interface AnimationCallback {
        void animate();
    }

    public KubeRenderer(GLWorld world, AnimationCallback callback) {
        mWorld = world;
        mCallback = callback;
    }

    public void onDrawFrame(GL10 gl) {
         if (mCallback != null) {
             mCallback.animate();
         }

        /*
         * Usually, the first thing one might want to do is to clear
         * the screen. The most efficient way of doing this is to use
         * glClear(). However we must make sure to set the scissor
         * correctly first. The scissor is always specified in window
         * coordinates:
         */

        gl.glClearColor(0.5f,0.5f,0.5f,1);
        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

        /*
         * Now we're ready to draw some 3D object
         */

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();
        gl.glTranslatef(0, 0, -3.0f);
        gl.glScalef(0.5f, 0.5f, 0.5f);
        gl.glRotatef(mAngle,        0, 1, 0);
        gl.glRotatef(mAngle*0.25f,  1, 0, 0);

        gl.glColor4f(0.7f, 0.7f, 0.7f, 1.0f);
        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
        gl.glEnable(GL10.GL_CULL_FACE);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glEnable(GL10.GL_DEPTH_TEST);

        mWorld.draw(gl);
    }

    public void onSurfaceChanged(GL10 gl, int width, int height) {
        gl.glViewport(0, 0, width, height);

        /*
         * Set our projection matrix. This doesn't have to be done
         * each time we draw, but usually a new projection needs to be set
         * when the viewport is resized.
         */

        float ratio = (float)width / height;
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glFrustumf(-ratio, ratio, -1, 1, 2, 12);

        /*
         * By default, OpenGL enables features that improve quality
         * but reduce performance. One might want to tweak that
         * especially on software renderer.
         */
        gl.glDisable(GL10.GL_DITHER);
        gl.glActiveTexture(GL10.GL_TEXTURE0);
    }

    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        // Nothing special, don't have any textures we need to recreate.
    }

    public void setAngle(float angle) {
        mAngle = angle;
    }

    public float getAngle() {
        return mAngle;
    }

    private GLWorld mWorld;
    private AnimationCallback mCallback;
    private float mAngle;
}