apps/CtsVerifier/src/com/android/cts/verifier/sensors/CtsMediaTextureRender.java - platform/cts - Git at Google

 /*
  * Copyright (C) 2013 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.cts.verifier.sensors;

 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;

 import android.graphics.Bitmap;
 import android.graphics.SurfaceTexture;
 import android.opengl.GLES11Ext;
 import android.opengl.GLES20;
 import android.opengl.Matrix;
 import android.util.Log;


 //
 // This file is copied from android.hardware.cts.media
 //

 /**
  * Code for rendering a texture onto a surface using OpenGL ES 2.0.
  */
 class CtsMediaTextureRender {
     private static final String TAG = "TextureRender";

     private static final int FLOAT_SIZE_BYTES = 4;
     private static final int TRIANGLE_VERTICES_DATA_STRIDE_BYTES = 5 * FLOAT_SIZE_BYTES;
     private static final int TRIANGLE_VERTICES_DATA_POS_OFFSET = 0;
     private static final int TRIANGLE_VERTICES_DATA_UV_OFFSET = 3;
     private final float[] mTriangleVerticesData = {
         // X, Y, Z, U, V
         -1.0f, -1.0f, 0, 0.f, 0.f,
          1.0f, -1.0f, 0, 1.f, 0.f,
         -1.0f,  1.0f, 0, 0.f, 1.f,
          1.0f,  1.0f, 0, 1.f, 1.f,
     };

     private FloatBuffer mTriangleVertices;

     private static final String VERTEX_SHADER =
             "uniform mat4 uMVPMatrix;\n" +
             "uniform mat4 uSTMatrix;\n" +
             "attribute vec4 aPosition;\n" +
             "attribute vec4 aTextureCoord;\n" +
             "varying vec2 vTextureCoord;\n" +
             "void main() {\n" +
             "  gl_Position = uMVPMatrix * aPosition;\n" +
             "  vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" +
             "}\n";

     private static final String FRAGMENT_SHADER =
             "#extension GL_OES_EGL_image_external : require\n" +
             "precision mediump float;\n" +      // highp here doesn't seem to matter
             "varying vec2 vTextureCoord;\n" +
             "uniform samplerExternalOES sTexture;\n" +
             "void main() {\n" +
             "  gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
             "}\n";

     private float[] mMVPMatrix = new float[16];
     private float[] mSTMatrix = new float[16];

     private int mProgram;
     private int mTextureID = -12345;
     private int muMVPMatrixHandle;
     private int muSTMatrixHandle;
     private int maPositionHandle;
     private int maTextureHandle;

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

         Matrix.setIdentityM(mSTMatrix, 0);
     }

     public int getTextureId() {
         return mTextureID;
     }

     public void drawFrame(SurfaceTexture st) {
         checkGlError("onDrawFrame start");
         st.getTransformMatrix(mSTMatrix);

         GLES20.glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
         GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);

         GLES20.glUseProgram(mProgram);
         checkGlError("glUseProgram");

         GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
         GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);

         mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
         GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
             TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
         checkGlError("glVertexAttribPointer maPosition");
         GLES20.glEnableVertexAttribArray(maPositionHandle);
         checkGlError("glEnableVertexAttribArray maPositionHandle");

         mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
         GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
             TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
         checkGlError("glVertexAttribPointer maTextureHandle");
         GLES20.glEnableVertexAttribArray(maTextureHandle);
         checkGlError("glEnableVertexAttribArray maTextureHandle");

         Matrix.setIdentityM(mMVPMatrix, 0);
         GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
         GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);

         GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
         checkGlError("glDrawArrays");
         GLES20.glFinish();
     }

     /**
      * Initializes GL state.  Call this after the EGL surface has been created and made current.
      */
     public void surfaceCreated() {
         mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER);
         if (mProgram == 0) {
             throw new RuntimeException("failed creating program");
         }
         maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
         checkGlError("glGetAttribLocation aPosition");
         if (maPositionHandle == -1) {
             throw new RuntimeException("Could not get attrib location for aPosition");
         }
         maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
         checkGlError("glGetAttribLocation aTextureCoord");
         if (maTextureHandle == -1) {
             throw new RuntimeException("Could not get attrib location for aTextureCoord");
         }

         muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
         checkGlError("glGetUniformLocation uMVPMatrix");
         if (muMVPMatrixHandle == -1) {
             throw new RuntimeException("Could not get attrib location for uMVPMatrix");
         }

         muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
         checkGlError("glGetUniformLocation uSTMatrix");
         if (muSTMatrixHandle == -1) {
             throw new RuntimeException("Could not get attrib location for uSTMatrix");
         }


         int[] textures = new int[1];
         GLES20.glGenTextures(1, textures, 0);

         mTextureID = textures[0];
         GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);
         checkGlError("glBindTexture mTextureID");

         GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
                 GLES20.GL_NEAREST);
         GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
                 GLES20.GL_LINEAR);
         GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S,
                 GLES20.GL_CLAMP_TO_EDGE);
         GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T,
                 GLES20.GL_CLAMP_TO_EDGE);
         checkGlError("glTexParameter");
     }

     /**
      * Replaces the fragment shader.
      */
     public void changeFragmentShader(String fragmentShader) {
         GLES20.glDeleteProgram(mProgram);
         mProgram = createProgram(VERTEX_SHADER, fragmentShader);
         if (mProgram == 0) {
             throw new RuntimeException("failed creating program");
         }
     }

     private int loadShader(int shaderType, String source) {
         int shader = GLES20.glCreateShader(shaderType);
         checkGlError("glCreateShader type=" + shaderType);
         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();
         checkGlError("glCreateProgram");
         if (program == 0) {
             Log.e(TAG, "Could not create program");
         }
         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;
     }

     public 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);
         }
     }

     /**
      * Saves the current frame to disk as a PNG image.  Frame starts from (0,0).
      * <p>
      * Useful for debugging.
      */
     public static void saveFrame(String filename, int width, int height) {
         // glReadPixels gives us a ByteBuffer filled with what is essentially big-endian RGBA
         // data (i.e. a byte of red, followed by a byte of green...).  We need an int[] filled
         // with native-order ARGB data to feed to Bitmap.
         //
         // If we implement this as a series of buf.get() calls, we can spend 2.5 seconds just
         // copying data around for a 720p frame.  It's better to do a bulk get() and then
         // rearrange the data in memory.  (For comparison, the PNG compress takes about 500ms
         // for a trivial frame.)
         //
         // So... we set the ByteBuffer to little-endian, which should turn the bulk IntBuffer
         // get() into a straight memcpy on most Android devices.  Our ints will hold ABGR data.
         // Swapping B and R gives us ARGB.  We need about 30ms for the bulk get(), and another
         // 270ms for the color swap.
         //
         // Making this even more interesting is the upside-down nature of GL, which means we
         // may want to flip the image vertically here.

         ByteBuffer buf = ByteBuffer.allocateDirect(width * height * 4);
         buf.order(ByteOrder.LITTLE_ENDIAN);
         GLES20.glReadPixels(0, 0, width, height, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, buf);
         buf.rewind();

         int pixelCount = width * height;
         int[] colors = new int[pixelCount];
         buf.asIntBuffer().get(colors);
         for (int i = 0; i < pixelCount; i++) {
             int c = colors[i];
             colors[i] = (c & 0xff00ff00) | ((c & 0x00ff0000) >> 16) | ((c & 0x000000ff) << 16);
         }

         FileOutputStream fos = null;
         try {
             fos = new FileOutputStream(filename);
             Bitmap bmp = Bitmap.createBitmap(colors, width, height, Bitmap.Config.ARGB_8888);
             bmp.compress(Bitmap.CompressFormat.PNG, 90, fos);
             bmp.recycle();
         } catch (IOException ioe) {
             throw new RuntimeException("Failed to write file " + filename, ioe);
         } finally {
             try {
                 if (fos != null) fos.close();
             } catch (IOException ioe2) {
                 throw new RuntimeException("Failed to close file " + filename, ioe2);
             }
         }
         Log.d(TAG, "Saved " + width + "x" + height + " frame as '" + filename + "'");
     }
 }
	/*
	* Copyright (C) 2013 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.cts.verifier.sensors;

	import java.io.File;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.nio.ByteBuffer;
	import java.nio.ByteOrder;
	import java.nio.FloatBuffer;

	import android.graphics.Bitmap;
	import android.graphics.SurfaceTexture;
	import android.opengl.GLES11Ext;
	import android.opengl.GLES20;
	import android.opengl.Matrix;
	import android.util.Log;


	//
	// This file is copied from android.hardware.cts.media
	//

	/**
	* Code for rendering a texture onto a surface using OpenGL ES 2.0.
	*/
	class CtsMediaTextureRender {
	private static final String TAG = "TextureRender";

	private static final int FLOAT_SIZE_BYTES = 4;
	private static final int TRIANGLE_VERTICES_DATA_STRIDE_BYTES = 5 * FLOAT_SIZE_BYTES;
	private static final int TRIANGLE_VERTICES_DATA_POS_OFFSET = 0;
	private static final int TRIANGLE_VERTICES_DATA_UV_OFFSET = 3;
	private final float[] mTriangleVerticesData = {
	// X, Y, Z, U, V
	-1.0f, -1.0f, 0, 0.f, 0.f,
	1.0f, -1.0f, 0, 1.f, 0.f,
	-1.0f, 1.0f, 0, 0.f, 1.f,
	1.0f, 1.0f, 0, 1.f, 1.f,
	};

	private FloatBuffer mTriangleVertices;

	private static final String VERTEX_SHADER =
	"uniform mat4 uMVPMatrix;\n" +
	"uniform mat4 uSTMatrix;\n" +
	"attribute vec4 aPosition;\n" +
	"attribute vec4 aTextureCoord;\n" +
	"varying vec2 vTextureCoord;\n" +
	"void main() {\n" +
	" gl_Position = uMVPMatrix * aPosition;\n" +
	" vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" +
	"}\n";

	private static final String FRAGMENT_SHADER =
	"#extension GL_OES_EGL_image_external : require\n" +
	"precision mediump float;\n" + // highp here doesn't seem to matter
	"varying vec2 vTextureCoord;\n" +
	"uniform samplerExternalOES sTexture;\n" +
	"void main() {\n" +
	" gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
	"}\n";

	private float[] mMVPMatrix = new float[16];
	private float[] mSTMatrix = new float[16];

	private int mProgram;
	private int mTextureID = -12345;
	private int muMVPMatrixHandle;
	private int muSTMatrixHandle;
	private int maPositionHandle;
	private int maTextureHandle;

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

	Matrix.setIdentityM(mSTMatrix, 0);
	}

	public int getTextureId() {
	return mTextureID;
	}

	public void drawFrame(SurfaceTexture st) {
	checkGlError("onDrawFrame start");
	st.getTransformMatrix(mSTMatrix);

	GLES20.glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
	GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT \| GLES20.GL_COLOR_BUFFER_BIT);

	GLES20.glUseProgram(mProgram);
	checkGlError("glUseProgram");

	GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
	GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);

	mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
	GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
	TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
	checkGlError("glVertexAttribPointer maPosition");
	GLES20.glEnableVertexAttribArray(maPositionHandle);
	checkGlError("glEnableVertexAttribArray maPositionHandle");

	mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
	GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
	TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
	checkGlError("glVertexAttribPointer maTextureHandle");
	GLES20.glEnableVertexAttribArray(maTextureHandle);
	checkGlError("glEnableVertexAttribArray maTextureHandle");

	Matrix.setIdentityM(mMVPMatrix, 0);
	GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
	GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);

	GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
	checkGlError("glDrawArrays");
	GLES20.glFinish();
	}

	/**
	* Initializes GL state. Call this after the EGL surface has been created and made current.
	*/
	public void surfaceCreated() {
	mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER);
	if (mProgram == 0) {
	throw new RuntimeException("failed creating program");
	}
	maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
	checkGlError("glGetAttribLocation aPosition");
	if (maPositionHandle == -1) {
	throw new RuntimeException("Could not get attrib location for aPosition");
	}
	maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
	checkGlError("glGetAttribLocation aTextureCoord");
	if (maTextureHandle == -1) {
	throw new RuntimeException("Could not get attrib location for aTextureCoord");
	}

	muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
	checkGlError("glGetUniformLocation uMVPMatrix");
	if (muMVPMatrixHandle == -1) {
	throw new RuntimeException("Could not get attrib location for uMVPMatrix");
	}

	muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
	checkGlError("glGetUniformLocation uSTMatrix");
	if (muSTMatrixHandle == -1) {
	throw new RuntimeException("Could not get attrib location for uSTMatrix");
	}


	int[] textures = new int[1];
	GLES20.glGenTextures(1, textures, 0);

	mTextureID = textures[0];
	GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);
	checkGlError("glBindTexture mTextureID");

	GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
	GLES20.GL_NEAREST);
	GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
	GLES20.GL_LINEAR);
	GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S,
	GLES20.GL_CLAMP_TO_EDGE);
	GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T,
	GLES20.GL_CLAMP_TO_EDGE);
	checkGlError("glTexParameter");
	}

	/**
	* Replaces the fragment shader.
	*/
	public void changeFragmentShader(String fragmentShader) {
	GLES20.glDeleteProgram(mProgram);
	mProgram = createProgram(VERTEX_SHADER, fragmentShader);
	if (mProgram == 0) {
	throw new RuntimeException("failed creating program");
	}
	}

	private int loadShader(int shaderType, String source) {
	int shader = GLES20.glCreateShader(shaderType);
	checkGlError("glCreateShader type=" + shaderType);
	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();
	checkGlError("glCreateProgram");
	if (program == 0) {
	Log.e(TAG, "Could not create program");
	}
	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;
	}

	public 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);
	}
	}

	/**
	* Saves the current frame to disk as a PNG image. Frame starts from (0,0).
	* <p>
	* Useful for debugging.
	*/
	public static void saveFrame(String filename, int width, int height) {
	// glReadPixels gives us a ByteBuffer filled with what is essentially big-endian RGBA
	// data (i.e. a byte of red, followed by a byte of green...). We need an int[] filled
	// with native-order ARGB data to feed to Bitmap.
	//
	// If we implement this as a series of buf.get() calls, we can spend 2.5 seconds just
	// copying data around for a 720p frame. It's better to do a bulk get() and then
	// rearrange the data in memory. (For comparison, the PNG compress takes about 500ms
	// for a trivial frame.)
	//
	// So... we set the ByteBuffer to little-endian, which should turn the bulk IntBuffer
	// get() into a straight memcpy on most Android devices. Our ints will hold ABGR data.
	// Swapping B and R gives us ARGB. We need about 30ms for the bulk get(), and another
	// 270ms for the color swap.
	//
	// Making this even more interesting is the upside-down nature of GL, which means we
	// may want to flip the image vertically here.

	ByteBuffer buf = ByteBuffer.allocateDirect(width * height * 4);
	buf.order(ByteOrder.LITTLE_ENDIAN);
	GLES20.glReadPixels(0, 0, width, height, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, buf);
	buf.rewind();

	int pixelCount = width * height;
	int[] colors = new int[pixelCount];
	buf.asIntBuffer().get(colors);
	for (int i = 0; i < pixelCount; i++) {
	int c = colors[i];
	colors[i] = (c & 0xff00ff00) \| ((c & 0x00ff0000) >> 16) \| ((c & 0x000000ff) << 16);
	}

	FileOutputStream fos = null;
	try {
	fos = new FileOutputStream(filename);
	Bitmap bmp = Bitmap.createBitmap(colors, width, height, Bitmap.Config.ARGB_8888);
	bmp.compress(Bitmap.CompressFormat.PNG, 90, fos);
	bmp.recycle();
	} catch (IOException ioe) {
	throw new RuntimeException("Failed to write file " + filename, ioe);
	} finally {
	try {
	if (fos != null) fos.close();
	} catch (IOException ioe2) {
	throw new RuntimeException("Failed to close file " + filename, ioe2);
	}
	}
	Log.d(TAG, "Saved " + width + "x" + height + " frame as '" + filename + "'");
	}
	}