content: /*
   * Copyright (C) 2011-2014 GUIGUI Simon, fyhertz@gmail.com
   * 
   * This file is part of libstreaming (https://github.com/fyhertz/libstreaming)
   * 
   * Spydroid is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 3 of the License, or
   * (at your option) any later version.
   * 
   * This source code is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   * 
   * You should have received a copy of the GNU General Public License
   * along with this source code; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  /*
   * Based on the work of fadden
   * 
   * Copyright 2012 Google Inc. All Rights Reserved.
   *
   * 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 net.majorkernelpanic.streaming.gl;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.FloatBuffer;
  
  import android.annotation.SuppressLint;
  import android.graphics.SurfaceTexture;
  import android.opengl.GLES11Ext;
  import android.opengl.GLES20;
  import android.opengl.Matrix;
  import android.util.Log;
  
  /**
   * Code for rendering a texture onto a surface using OpenGL ES 2.0.
   */
  @SuppressLint("InlinedApi")
  public class TextureManager {
  	
  	public final static String TAG = "TextureManager";
  	
  	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;
  	
  	private SurfaceTexture mSurfaceTexture;
  
  	public TextureManager() {
  		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 SurfaceTexture getSurfaceTexture() {
  		return mSurfaceTexture;
  	}
  
  	public void updateFrame() {
  		mSurfaceTexture.updateTexImage();
  	}
  	
  	public void drawFrame() {	
  		checkGlError("onDrawFrame start");
  		mSurfaceTexture.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, 0);
  		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 SurfaceTexture createTexture() {
  		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");
  		
  		mSurfaceTexture = new SurfaceTexture(mTextureID);
  		return mSurfaceTexture;
  	}
  
  	public void release() {
  		mSurfaceTexture = null;
  	}
  	
  	/**
  	 * Replaces the fragment shader.  Pass in null to reset to default.
  	 */
  	public void changeFragmentShader(String fragmentShader) {
  		if (fragmentShader == null) {
  			fragmentShader = FRAGMENT_SHADER;
  		}
  		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);
  		}
  	}
  }
  