The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...
/*
* Copyright (C) 2007 The Android开源工程
*
* 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 javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL;
import javax.microedition.khronos.opengles.GL10;
import javax.microedition.khronos.opengles.GL11ExtensionPack;
import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.opengl.GLU;
import android.os.Bundle;
import android.os.SystemClock;
/**
* Demonstrate the Frame Buffer Object OpenGL ES extension.
* <p>
* This sample renders a scene into an offscreen frame buffer, and then
* uses the resulting image as a texture to render an onscreen scene.
*/
public class FrameBufferObjectActivity extends Activity {
private GLSurfaceView mGLSurfaceView;
private class Renderer implements GLSurfaceView.Renderer {
private boolean mContextSupportsFrameBufferObject;
private int mTargetTexture;
private int mFramebuffer;
private int mFramebufferWidth = 256;
private int mFramebufferHeight = 256;
private int mSurfaceWidth;
private int mSurfaceHeight;
private Triangle mTriangle;
private Cube mCube;
private float mAngle;
/**
* Setting this to true will change the behavior of this sample. It
* will suppress the normally onscreen rendering, and it will cause the
* rendering that would normally be done to the offscreen FBO
* be rendered onscreen instead. This can be helpful in debugging the
* rendering algorithm.
*/
private static final boolean DEBUG_RENDER_OFFSCREEN_ONSCREEN = false;
public void onDrawFrame(GL10 gl) {
checkGLError(gl);
if (mContextSupportsFrameBufferObject) {
GL11ExtensionPack gl11ep = (GL11ExtensionPack) gl;
if (DEBUG_RENDER_OFFSCREEN_ONSCREEN) {
drawOffscreenImage(gl, mSurfaceWidth, mSurfaceHeight);
} else {
gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, mFramebuffer);
drawOffscreenImage(gl, mFramebufferWidth, mFramebufferHeight);
gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, 0);
drawOnscreen(gl, mSurfaceWidth, mSurfaceHeight);
}
} else {
// Current context doesn't support frame buffer objects.
// Indicate this by drawing a red background.
gl.glClearColor(1,0,0,0);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
}
}
public void onSurfaceChanged(GL10 gl, int width, int height) {
checkGLError(gl);
mSurfaceWidth = width;
mSurfaceHeight = height;
gl.glViewport(0, 0, width, height);
}
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
mContextSupportsFrameBufferObject = checkIfContextSupportsFrameBufferObject(gl);
if (mContextSupportsFrameBufferObject) {
mTargetTexture = createTargetTexture(gl, mFramebufferWidth, mFramebufferHeight);
mFramebuffer = createFrameBuffer(gl, mFramebufferWidth, mFramebufferHeight, mTargetTexture);
mCube = new Cube();
mTriangle = new Triangle();
}
}
private void drawOnscreen(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 3, 7);
gl.glClearColor(0,0,1,0);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glBindTexture(GL10.GL_TEXTURE_2D, mTargetTexture);
gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
GL10.GL_REPLACE);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
GLU.gluLookAt(gl, 0, 0, -5, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glActiveTexture(GL10.GL_TEXTURE0);
long time = SystemClock.uptimeMillis() % 4000L;
float angle = 0.090f * ((int) time);
gl.glRotatef(angle, 0, 0, 1.0f);
mTriangle.draw(gl);
// Restore default state so the other renderer is not affected.
gl.glBindTexture(GL10.GL_TEXTURE_2D, 0);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}
private void drawOffscreenImage(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
gl.glEnable(GL10.GL_CULL_FACE);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glClearColor(0,0.5f,1,0);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glTranslatef(0, 0, -3.0f);
gl.glRotatef(mAngle, 0, 1, 0);
gl.glRotatef(mAngle*0.25f, 1, 0, 0);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
mCube.draw(gl);
gl.glRotatef(mAngle*2.0f, 0, 1, 1);
gl.glTranslatef(0.5f, 0.5f, 0.5f);
mCube.draw(gl);
mAngle += 1.2f;
// Restore default state so the other renderer is not affected.
gl.glDisable(GL10.GL_CULL_FACE);
gl.glDisable(GL10.GL_DEPTH_TEST);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
}
private int createTargetTexture(GL10 gl, int width, int height) {
int texture;
int[] textures = new int[1];
gl.glGenTextures(1, textures, 0);
texture = textures[0];
gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);
gl.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_RGBA, width, height, 0,
GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, null);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,
GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
GL10.GL_REPEAT);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
GL10.GL_REPEAT);
; return texture;
}
private int createFrameBuffer(GL10 gl, int width, int height, int targetTextureId) {
GL11ExtensionPack gl11ep = (GL11ExtensionPack) gl;
int framebuffer;
int[] framebuffers = new int[1];
gl11ep.glGenFramebuffersOES(1, framebuffers, 0);
framebuffer = framebuffers[0];
gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, framebuffer);
int depthbuffer;
int[] renderbuffers = new int[1];
gl11ep.glGenRenderbuffersOES(1, renderbuffers, 0);
depthbuffer = renderbuffers[0];
gl11ep.glBindRenderbufferOES(GL11ExtensionPack.GL_RENDERBUFFER_OES, depthbuffer);
gl11ep.glRenderbufferStorageOES(GL11ExtensionPack.GL_RENDERBUFFER_OES,
GL11ExtensionPack.GL_DEPTH_COMPONENT16, width, height);
gl11ep.glFramebufferRenderbufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES,
GL11ExtensionPack.GL_DEPTH_ATTACHMENT_OES,
GL11ExtensionPack.GL_RENDERBUFFER_OES, depthbuffer);
gl11ep.glFramebufferTexture2DOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES,
GL11ExtensionPack.GL_COLOR_ATTACHMENT0_OES, GL10.GL_TEXTURE_2D,
targetTextureId, 0);
int status = gl11ep.glCheckFramebufferStatusOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES);
if (status != GL11ExtensionPack.GL_FRAMEBUFFER_COMPLETE_OES) {
throw new RuntimeException("Framebuffer is not complete: " +
Integer.toHexString(status));
}
gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, 0);
return framebuffer;
}
private boolean checkIfContextSupportsFrameBufferObject(GL10 gl) {
return checkIfContextSupportsExtension(gl, "GL_OES_framebuffer_object");
}
/**
* This is not the fastest way to check for an extension, but fine if
* we are only checking for a few extensions each time a context is created.
* @param gl
* @param extension
* @return true if the extension is present in the current context.
*/
private boolean checkIfContextSupportsExtension(GL10 gl, String extension) {
String extensions = " " + gl.glGetString(GL10.GL_EXTENSIONS) + " ";
// The extensions string is padded with spaces between extensions, but not
// necessarily at the beginning or end. For simplicity, add spaces at the
// beginning and end of the extensions string and the extension string.
// This means we can avoid special-case checks for the first or last
// extension, as well as avoid special-case checks when an extension name
// is the same as the first part of another extension name.
return extensions.indexOf(" " + extension + " ") >= 0;
}
}
static void checkGLError(GL gl) {
int error = ((GL10) gl).glGetError();
if (error != GL10.GL_NO_ERROR) {
throw new RuntimeException("GLError 0x" + Integer.toHexString(error));
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create our surface view and set it as the content of our
// Activity
mGLSurfaceView = new GLSurfaceView(this);
mGLSurfaceView.setRenderer(new Renderer());
setContentView(mGLSurfaceView);
}
@Override
protected void onResume() {
// Ideally a game should implement onResume() and onPause()
// to take appropriate action when the activity looses focus
super.onResume();
mGLSurfaceView.onResume();
}
@Override
protected void onPause() {
// Ideally a game should implement onResume() and onPause()
// to take appropriate action when the activity looses focus
super.onPause();
mGLSurfaceView.onPause();
}
}