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      1 /*
      2  * Copyright (C) 2009 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.android.gallery3d.ui;
     17 
     18 import android.opengl.GLSurfaceView.EGLConfigChooser;
     19 
     20 import javax.microedition.khronos.egl.EGL10;
     21 import javax.microedition.khronos.egl.EGLConfig;
     22 import javax.microedition.khronos.egl.EGLDisplay;
     23 
     24 /*
     25  * The code is copied/adapted from
     26  * <code>android.opengl.GLSurfaceView.BaseConfigChooser</code>. Here we try to
     27  * choose a configuration that support RGBA_8888 format and if possible,
     28  * with stencil buffer, but is not required.
     29  */
     30 class GalleryEGLConfigChooser implements EGLConfigChooser {
     31 
     32     private static final String TAG = "GalleryEGLConfigChooser";
     33 
     34     private final int mConfigSpec[] = new int[] {
     35             EGL10.EGL_RED_SIZE, 5,
     36             EGL10.EGL_GREEN_SIZE, 6,
     37             EGL10.EGL_BLUE_SIZE, 5,
     38             EGL10.EGL_ALPHA_SIZE, 0,
     39             EGL10.EGL_NONE
     40     };
     41 
     42     public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
     43         int[] numConfig = new int[1];
     44         if (!egl.eglChooseConfig(display, mConfigSpec, null, 0, numConfig)) {
     45             throw new RuntimeException("eglChooseConfig failed");
     46         }
     47 
     48         if (numConfig[0] <= 0) {
     49             throw new RuntimeException("No configs match configSpec");
     50         }
     51 
     52         EGLConfig[] configs = new EGLConfig[numConfig[0]];
     53         if (!egl.eglChooseConfig(display,
     54                 mConfigSpec, configs, configs.length, numConfig)) {
     55             throw new RuntimeException();
     56         }
     57 
     58         return chooseConfig(egl, display, configs);
     59     }
     60 
     61     private EGLConfig chooseConfig(
     62             EGL10 egl, EGLDisplay display, EGLConfig configs[]) {
     63 
     64         EGLConfig result = null;
     65         int minStencil = Integer.MAX_VALUE;
     66         int value[] = new int[1];
     67 
     68         // Because we need only one bit of stencil, try to choose a config that
     69         // has stencil support but with smallest number of stencil bits. If
     70         // none is found, choose any one.
     71         for (int i = 0, n = configs.length; i < n; ++i) {
     72             if (egl.eglGetConfigAttrib(
     73                 display, configs[i], EGL10.EGL_RED_SIZE, value)) {
     74                 // Filter out ARGB 8888 configs.
     75                 if (value[0] == 8) continue;
     76             }
     77             if (egl.eglGetConfigAttrib(
     78                     display, configs[i], EGL10.EGL_STENCIL_SIZE, value)) {
     79                 if (value[0] == 0) continue;
     80                 if (value[0] < minStencil) {
     81                     minStencil = value[0];
     82                     result = configs[i];
     83                 }
     84             } else {
     85                 throw new RuntimeException(
     86                         "eglGetConfigAttrib error: " + egl.eglGetError());
     87             }
     88         }
     89         if (result == null) result = configs[0];
     90         egl.eglGetConfigAttrib(
     91                 display, result, EGL10.EGL_STENCIL_SIZE, value);
     92         logConfig(egl, display, result);
     93         return result;
     94     }
     95 
     96     private static final int[] ATTR_ID = {
     97             EGL10.EGL_RED_SIZE,
     98             EGL10.EGL_GREEN_SIZE,
     99             EGL10.EGL_BLUE_SIZE,
    100             EGL10.EGL_ALPHA_SIZE,
    101             EGL10.EGL_DEPTH_SIZE,
    102             EGL10.EGL_STENCIL_SIZE,
    103             EGL10.EGL_CONFIG_ID,
    104             EGL10.EGL_CONFIG_CAVEAT
    105     };
    106 
    107     private static final String[] ATTR_NAME = {
    108         "R", "G", "B", "A", "D", "S", "ID", "CAVEAT"
    109     };
    110 
    111     private void logConfig(EGL10 egl, EGLDisplay display, EGLConfig config) {
    112         int value[] = new int[1];
    113         StringBuilder sb = new StringBuilder();
    114         for (int j = 0; j < ATTR_ID.length; j++) {
    115             egl.eglGetConfigAttrib(display, config, ATTR_ID[j], value);
    116             sb.append(ATTR_NAME[j] + value[0] + " ");
    117         }
    118         Log.i(TAG, "Config chosen: " + sb.toString());
    119     }
    120 }
    121