Android example source code file (GL2JavaView.java)

This example Android source code file (GL2JavaView.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, could, eglconfig, floatbuffer, gl2javaview, glsurfaceview, graphics, io, nio, opengl, renderer, runtimeexception, string, tag, view

The GL2JavaView.java Android example source code

/*
 * Copyright (C) 2009 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.android.gl2java;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLES20;

/**
 * An implementation of SurfaceView that uses the dedicated surface for
 * displaying an OpenGL animation.  This allows the animation to run in a
 * separate thread, without requiring that it be driven by the update mechanism
 * of the view hierarchy.
 *
 * The application-specific rendering code is delegated to a GLView.Renderer
 * instance.
 */
class GL2JavaView extends GLSurfaceView {
    private static String TAG = "GL2JavaView";

    public GL2JavaView(Context context) {
        super(context);
        setEGLContextClientVersion(2);
        setRenderer(new Renderer());
    }

    private static class Renderer implements GLSurfaceView.Renderer {

        public Renderer() {
            mTriangleVertices = ByteBuffer.allocateDirect(mTriangleVerticesData.length * 4)
                .order(ByteOrder.nativeOrder()).asFloatBuffer();
            mTriangleVertices.put(mTriangleVerticesData).position(0);
        }

        public void onDrawFrame(GL10 gl) {
            GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
            GLES20.glClear( GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
            GLES20.glUseProgram(mProgram);
            checkGlError("glUseProgram");

            GLES20.glVertexAttribPointer(mvPositionHandle, 2, GLES20.GL_FLOAT, false, 0, mTriangleVertices);
            checkGlError("glVertexAttribPointer");
            GLES20.glEnableVertexAttribArray(mvPositionHandle);
            checkGlError("glEnableVertexAttribArray");
            GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 3);
            checkGlError("glDrawArrays");

        }

        public void onSurfaceChanged(GL10 gl, int width, int height) {
            GLES20.glViewport(0, 0, width, height);
        }

        public void onSurfaceCreated(GL10 gl, EGLConfig config) {
            mProgram = createProgram(mVertexShader, mFragmentShader);
            if (mProgram == 0) {
                return;
            }
            mvPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
            checkGlError("glGetAttribLocation");
            if (mvPositionHandle == -1) {
                throw new RuntimeException("Could not get attrib location for vPosition");
            }
        }

        private int loadShader(int shaderType, String source) {
            int shader = GLES20.glCreateShader(shaderType);
            if (shader != 0) {
                GLES20.glShaderSource(shader, source);
                GLES20.glCompileShader(shader);
                int[] compiled = new int[1];
                GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
                if (compiled[0] == 0) {
                    Log.e(TAG, "Could not compile shader " + shaderType + ":");
                    Log.e(TAG, GLES20.glGetShaderInfoLog(shader));
                    GLES20.glDeleteShader(shader);
                    shader = 0;
                }
            }
            return shader;
        }

        private int createProgram(String vertexSource, String fragmentSource) {
            int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
            if (vertexShader == 0) {
                return 0;
            }

            int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
            if (pixelShader == 0) {
                return 0;
            }

            int program = GLES20.glCreateProgram();
            if (program != 0) {
                GLES20.glAttachShader(program, vertexShader);
                checkGlError("glAttachShader");
                GLES20.glAttachShader(program, pixelShader);
                checkGlError("glAttachShader");
                GLES20.glLinkProgram(program);
                int[] linkStatus = new int[1];
                GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus, 0);
                if (linkStatus[0] != GLES20.GL_TRUE) {
                    Log.e(TAG, "Could not link program: ");
                    Log.e(TAG, GLES20.glGetProgramInfoLog(program));
                    GLES20.glDeleteProgram(program);
                    program = 0;
                }
            }
            return program;
        }

        private void checkGlError(String op) {
            int error;
            while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
                Log.e(TAG, op + ": glError " + error);
                throw new RuntimeException(op + ": glError " + error);
            }
        }

        private final float[] mTriangleVerticesData = { 0.0f, 0.5f, -0.5f, -0.5f,
                0.5f, -0.5f };

        private FloatBuffer mTriangleVertices;

        private final String mVertexShader = "attribute vec4 vPosition;\n"
            + "void main() {\n"
            + "  gl_Position = vPosition;\n"
            + "}\n";

        private final String mFragmentShader = "precision mediump float;\n"
            + "void main() {\n"
            + "  gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
            + "}\n";

        private int mProgram;
        private int mvPositionHandle;

    }
}