Mega Code Archive
Demonstrate the Frame Buffer Object OpenGL ES extension
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/*
* Copyright (C) 2007 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 app.test;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.nio.ShortBuffer;
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();
}
}
class Triangle {
public Triangle() {
// Buffers to be passed to gl*Pointer() functions
// must be direct, i.e., they must be placed on the
// native heap where the garbage collector cannot
// move them.
//
// Buffers with multi-byte datatypes (e.g., short, int, float)
// must have their byte order set to native order
ByteBuffer vbb = ByteBuffer.allocateDirect(VERTS * 3 * 4);
vbb.order(ByteOrder.nativeOrder());
mFVertexBuffer = vbb.asFloatBuffer();
ByteBuffer tbb = ByteBuffer.allocateDirect(VERTS * 2 * 4);
tbb.order(ByteOrder.nativeOrder());
mTexBuffer = tbb.asFloatBuffer();
ByteBuffer ibb = ByteBuffer.allocateDirect(VERTS * 2);
ibb.order(ByteOrder.nativeOrder());
mIndexBuffer = ibb.asShortBuffer();
// A unit-sided equalateral triangle centered on the origin.
float[] coords = {
// X, Y, Z
-0.5f, -0.25f, 0, 0.5f, -0.25f, 0, 0.0f, 0.559016994f, 0 };
for (int i = 0; i < VERTS; i++) {
for (int j = 0; j < 3; j++) {
mFVertexBuffer.put(coords[i * 3 + j] * 2.0f);
}
}
for (int i = 0; i < VERTS; i++) {
for (int j = 0; j < 2; j++) {
mTexBuffer.put(coords[i * 3 + j] * 2.0f + 0.5f);
}
}
for (int i = 0; i < VERTS; i++) {
mIndexBuffer.put((short) i);
}
mFVertexBuffer.position(0);
mTexBuffer.position(0);
mIndexBuffer.position(0);
}
public void draw(GL10 gl) {
gl.glFrontFace(GL10.GL_CCW);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mFVertexBuffer);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer);
gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, VERTS,
GL10.GL_UNSIGNED_SHORT, mIndexBuffer);
}
private final static int VERTS = 3;
private FloatBuffer mFVertexBuffer;
private FloatBuffer mTexBuffer;
private ShortBuffer mIndexBuffer;
}
/**
* A vertex shaded cube.
*/
class Cube {
public Cube() {
int one = 0x10000;
int vertices[] = { -one, -one, -one, one, -one, -one, one, one, -one,
-one, one, -one, -one, -one, one, one, -one, one, one, one,
one, -one, one, one, };
int colors[] = { 0, 0, 0, one, one, 0, 0, one, one, one, 0, one, 0,
one, 0, one, 0, 0, one, one, one, 0, one, one, one, one, one,
one, 0, one, one, one, };
byte indices[] = { 0, 4, 5, 0, 5, 1, 1, 5, 6, 1, 6, 2, 2, 6, 7, 2, 7,
3, 3, 7, 4, 3, 4, 0, 4, 7, 6, 4, 6, 5, 3, 0, 1, 3, 1, 2 };
// Buffers to be passed to gl*Pointer() functions
// must be direct, i.e., they must be placed on the
// native heap where the garbage collector cannot
// move them.
//
// Buffers with multi-byte datatypes (e.g., short, int, float)
// must have their byte order set to native order
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
vbb.order(ByteOrder.nativeOrder());
mVertexBuffer = vbb.asIntBuffer();
mVertexBuffer.put(vertices);
mVertexBuffer.position(0);
ByteBuffer cbb = ByteBuffer.allocateDirect(colors.length * 4);
cbb.order(ByteOrder.nativeOrder());
mColorBuffer = cbb.asIntBuffer();
mColorBuffer.put(colors);
mColorBuffer.position(0);
mIndexBuffer = ByteBuffer.allocateDirect(indices.length);
mIndexBuffer.put(indices);
mIndexBuffer.position(0);
}
public void draw(GL10 gl) {
gl.glFrontFace(GL10.GL_CW);
gl.glVertexPointer(3, GL10.GL_FIXED, 0, mVertexBuffer);
gl.glColorPointer(4, GL10.GL_FIXED, 0, mColorBuffer);
gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE,
mIndexBuffer);
}
private IntBuffer mVertexBuffer;
private IntBuffer mColorBuffer;
private ByteBuffer mIndexBuffer;
}
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