Android example source code file (CompressedTextureActivity.java)

This example Android source code file (CompressedTextureActivity.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, buffer, bytearrayinputstream, bytearrayoutputstream, compressedtextureactivity, could, etc1, glsurfaceview, graphics, io, ioexception, nio, opengl, os, override, statictrianglerenderer, syntheticcompressedtextureloader, tag, test_create_texture, use_stream_io

The CompressedTextureActivity.java Android example source code

/*
 * 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;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

import javax.microedition.khronos.opengles.GL10;

import android.app.Activity;
import android.opengl.ETC1Util;
import android.opengl.GLES10;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.util.Log;

import com.example.android.apis.R;

/**
 * Demonstrate how to use ETC1 format compressed textures.
 * This sample can be recompiled to use either resource-based
 * textures (compressed offline using the etc1tool), or
 * textures created on the fly by compressing images.
 *
 */
public class CompressedTextureActivity extends Activity {
    private final static String TAG = "CompressedTextureActivity";
    /**
     * Choose between creating a compressed texture on the fly or
     * loading a compressed texture from a resource.
     */
    private final static boolean TEST_CREATE_TEXTURE = false;
    /**
     * When creating a compressed texture on the fly, choose
     * whether or not to use the i/o stream APIs.
     */
    private final static boolean USE_STREAM_IO = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mGLView = new GLSurfaceView(this);
        mGLView.setEGLConfigChooser(false);
        StaticTriangleRenderer.TextureLoader loader;
        if (TEST_CREATE_TEXTURE) {
            loader = new SyntheticCompressedTextureLoader();
        } else {
            loader = new CompressedTextureLoader();
        }
        mGLView.setRenderer(new StaticTriangleRenderer(this, loader));
        setContentView(mGLView);
    }

    @Override
    protected void onPause() {
        super.onPause();
        mGLView.onPause();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mGLView.onResume();
    }

    /**
     * Demonstrate how to load a compressed texture from an APK resource.
     *
     */
    private class CompressedTextureLoader implements StaticTriangleRenderer.TextureLoader {
        public void load(GL10 gl) {
            Log.w(TAG, "ETC1 texture support: " + ETC1Util.isETC1Supported());
            InputStream input = getResources().openRawResource(R.raw.androids);
            try {
                ETC1Util.loadTexture(GLES10.GL_TEXTURE_2D, 0, 0,
                        GLES10.GL_RGB, GLES10.GL_UNSIGNED_SHORT_5_6_5, input);
            } catch (IOException e) {
                Log.w(TAG, "Could not load texture: " + e);
            } finally {
                try {
                    input.close();
                } catch (IOException e) {
                    // ignore exception thrown from close.
                }
            }
        }
    }

    /**
     * Demonstrate how to create a compressed texture on the fly.
     */
    private class SyntheticCompressedTextureLoader implements StaticTriangleRenderer.TextureLoader {
        public void load(GL10 gl) {
            int width = 128;
            int height = 128;
            Buffer image = createImage(width, height);
            ETC1Util.ETC1Texture etc1Texture = ETC1Util.compressTexture(image, width, height, 3, 3 * width);
            if (USE_STREAM_IO) {
                // Test the ETC1Util APIs for reading and writing compressed textures to I/O streams.
                try {
                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
                    ETC1Util.writeTexture(etc1Texture, bos);
                    ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
                    ETC1Util.loadTexture(GLES10.GL_TEXTURE_2D, 0, 0,
                            GLES10.GL_RGB, GLES10.GL_UNSIGNED_SHORT_5_6_5, bis);
                } catch (IOException e) {
                    Log.w(TAG, "Could not load texture: " + e);
                }
            } else {
                ETC1Util.loadTexture(GLES10.GL_TEXTURE_2D, 0, 0,
                        GLES10.GL_RGB, GLES10.GL_UNSIGNED_SHORT_5_6_5, etc1Texture);
            }
        }

        private Buffer createImage(int width, int height) {
            int stride = 3 * width;
            ByteBuffer image = ByteBuffer.allocateDirect(height * stride)
                .order(ByteOrder.nativeOrder());

            // Fill with a pretty "munching squares" pattern:
            for (int t = 0; t < height; t++) {
                byte red = (byte)(255-2*t);
                byte green = (byte)(2*t);
                byte blue = 0;
                for (int x = 0; x < width; x++) {
                    int y = x ^ t;
                    image.position(stride*y+x*3);
                    image.put(red);
                    image.put(green);
                    image.put(blue);
                }
            }
            image.position(0);
            return image;
        }
    }
    private GLSurfaceView mGLView;
}