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      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 
     17 
     18 package android.media.effect;
     19 
     20 import android.filterfw.core.CachedFrameManager;
     21 import android.filterfw.core.FilterContext;
     22 import android.filterfw.core.GLEnvironment;
     23 import android.opengl.GLES20;
     24 
     25 /**
     26  * <p>An EffectContext keeps all necessary state information to run Effects within a Open GL ES 2.0
     27  * context.</p>
     28  *
     29  * <p>Every EffectContext is bound to one GL context. The application is responsible for creating
     30  * this EGL context, and making it current before applying any effect. If your EGL context is
     31  * destroyed, the EffectContext becomes invalid and any effects bound to this context can no longer
     32  * be used. If you switch to another EGL context, you must create a new EffectContext. Each Effect
     33  * is bound to a single EffectContext, and can only be executed in that context.</p>
     34  */
     35 public class EffectContext {
     36 
     37     private final int GL_STATE_FBO          = 0;
     38     private final int GL_STATE_PROGRAM      = 1;
     39     private final int GL_STATE_ARRAYBUFFER  = 2;
     40     private final int GL_STATE_COUNT        = 3;
     41 
     42     FilterContext mFilterContext;
     43 
     44     private EffectFactory mFactory;
     45 
     46     private int[] mOldState = new int[GL_STATE_COUNT];
     47 
     48     /**
     49      * Creates a context within the current GL context.
     50      *
     51      * <p>Binds the EffectContext to the current OpenGL context. All subsequent calls to the
     52      * EffectContext must be made in the GL context that was active during creation.
     53      * When you have finished using a context, you must call {@link #release()}. to dispose of all
     54      * resources associated with this context.</p>
     55      */
     56     public static EffectContext createWithCurrentGlContext() {
     57         EffectContext result = new EffectContext();
     58         result.initInCurrentGlContext();
     59         return result;
     60     }
     61 
     62     /**
     63      * Returns the EffectFactory for this context.
     64      *
     65      * <p>The EffectFactory returned from this method allows instantiating new effects within this
     66      * context.</p>
     67      *
     68      * @return The EffectFactory instance for this context.
     69      */
     70     public EffectFactory getFactory() {
     71         return mFactory;
     72     }
     73 
     74     /**
     75      * Releases the context.
     76      *
     77      * <p>Releases all the resources and effects associated with the EffectContext. This renders the
     78      * context and all the effects bound to this context invalid. You must no longer use the context
     79      * or any of its bound effects after calling release().</p>
     80      *
     81      * <p>Note that this method must be called with the proper EGL context made current, as the
     82      * EffectContext and its effects may release internal GL resources.</p>
     83      */
     84     public void release() {
     85         mFilterContext.tearDown();
     86         mFilterContext = null;
     87     }
     88 
     89     private EffectContext() {
     90         mFilterContext = new FilterContext();
     91         mFilterContext.setFrameManager(new CachedFrameManager());
     92         mFactory = new EffectFactory(this);
     93     }
     94 
     95     private void initInCurrentGlContext() {
     96         if (!GLEnvironment.isAnyContextActive()) {
     97             throw new RuntimeException("Attempting to initialize EffectContext with no active "
     98                 + "GL context!");
     99         }
    100         GLEnvironment glEnvironment = new GLEnvironment();
    101         glEnvironment.initWithCurrentContext();
    102         mFilterContext.initGLEnvironment(glEnvironment);
    103     }
    104 
    105     final void assertValidGLState() {
    106         GLEnvironment glEnv = mFilterContext.getGLEnvironment();
    107         if (glEnv == null || !glEnv.isContextActive()) {
    108             if (GLEnvironment.isAnyContextActive()) {
    109                 throw new RuntimeException("Applying effect in wrong GL context!");
    110             } else {
    111                 throw new RuntimeException("Attempting to apply effect without valid GL context!");
    112             }
    113         }
    114     }
    115 
    116     final void saveGLState() {
    117         GLES20.glGetIntegerv(GLES20.GL_FRAMEBUFFER_BINDING, mOldState, GL_STATE_FBO);
    118         GLES20.glGetIntegerv(GLES20.GL_CURRENT_PROGRAM, mOldState, GL_STATE_PROGRAM);
    119         GLES20.glGetIntegerv(GLES20.GL_ARRAY_BUFFER_BINDING, mOldState, GL_STATE_ARRAYBUFFER);
    120     }
    121 
    122     final void restoreGLState() {
    123         GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, mOldState[GL_STATE_FBO]);
    124         GLES20.glUseProgram(mOldState[GL_STATE_PROGRAM]);
    125         GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mOldState[GL_STATE_ARRAYBUFFER]);
    126     }
    127 }
    128 
    129