1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.example.android.opengl; 17 18 import android.content.Context; 19 import android.opengl.GLSurfaceView; 20 import android.view.MotionEvent; 21 22 /** 23 * A view container where OpenGL ES graphics can be drawn on screen. 24 * This view can also be used to capture touch events, such as a user 25 * interacting with drawn objects. 26 */ 27 public class MyGLSurfaceView extends GLSurfaceView { 28 29 private final MyGLRenderer mRenderer; 30 31 public MyGLSurfaceView(Context context) { 32 super(context); 33 34 // Create an OpenGL ES 2.0 context. 35 setEGLContextClientVersion(2); 36 37 // Set the Renderer for drawing on the GLSurfaceView 38 mRenderer = new MyGLRenderer(); 39 setRenderer(mRenderer); 40 41 // Render the view only when there is a change in the drawing data 42 setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY); 43 } 44 45 private final float TOUCH_SCALE_FACTOR = 180.0f / 320; 46 private float mPreviousX; 47 private float mPreviousY; 48 49 @Override 50 public boolean onTouchEvent(MotionEvent e) { 51 // MotionEvent reports input details from the touch screen 52 // and other input controls. In this case, you are only 53 // interested in events where the touch position changed. 54 55 float x = e.getX(); 56 float y = e.getY(); 57 58 switch (e.getAction()) { 59 case MotionEvent.ACTION_MOVE: 60 61 float dx = x - mPreviousX; 62 float dy = y - mPreviousY; 63 64 // reverse direction of rotation above the mid-line 65 if (y > getHeight() / 2) { 66 dx = dx * -1 ; 67 } 68 69 // reverse direction of rotation to left of the mid-line 70 if (x < getWidth() / 2) { 71 dy = dy * -1 ; 72 } 73 74 mRenderer.setAngle( 75 mRenderer.getAngle() + 76 ((dx + dy) * TOUCH_SCALE_FACTOR)); // = 180.0f / 320 77 requestRender(); 78 } 79 80 mPreviousX = x; 81 mPreviousY = y; 82 return true; 83 } 84 85 } 86
