Add GL demo app

Demonstrates rendering to a GLSurfaceView while applying a GL shader.

Issue: #6920
PiperOrigin-RevId: 293551724

RELEASENOTES.md

@@ -25,6 +25,7 @@
     ([#6753](https://github.com/google/ExoPlayer/issues/6753)).
   * Select multiple metadata tracks if multiple metadata renderers are available
     ([#6676](https://github.com/google/ExoPlayer/issues/6676)).
+  * Add support for ID3 genres added in Wimamp 5.6 (2010).
 * UI:
   * Show ad group markers in `DefaultTimeBar` even if they are after the end
     of the current window
@@ -54,7 +55,10 @@
   This issue caused FLAC streams with other bit depths to sound like white noise
   on earlier releases, but only when embedded in a non-FLAC container such as
   Matroska or MP4.
-* Add support for ID3 genres added in Wimamp 5.6 (2010).
+* Demo apps: Add
+  [GL demo app](https://github.com/google/ExoPlayer/tree/dev-v2/demos/gl) to
+  show how to render video to a `GLSurfaceView` while applying a GL shader.
+  ([#6920](https://github.com/google/ExoPlayer/issues/6920)).
 
 ### 2.11.1 (2019-12-20) ###
 

demos/gl/README.md

@@ -0,0 +1,11 @@
+# ExoPlayer GL demo
+
+This app demonstrates how to render video to a [GLSurfaceView][] while applying
+a GL shader.
+
+The shader shows an overlap bitmap on top of the video. The overlay bitmap is
+drawn using an Android canvas, and includes the current frame's presentation
+timestamp, to show how to get the timestamp of the frame currently in the
+off-screen surface texture.
+
+[GLSurfaceView]: https://developer.android.com/reference/android/opengl/GLSurfaceView

demos/gl/build.gradle

@@ -0,0 +1,53 @@
+// Copyright (C) 2020 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.
+apply from: '../../constants.gradle'
+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion project.ext.compileSdkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    defaultConfig {
+        versionName project.ext.releaseVersion
+        versionCode project.ext.releaseVersionCode
+        minSdkVersion project.ext.minSdkVersion
+        targetSdkVersion project.ext.appTargetSdkVersion
+    }
+
+    buildTypes {
+        release {
+            shrinkResources true
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt')
+        }
+    }
+
+    lintOptions {
+        // This demo app does not have translations.
+        disable 'MissingTranslation'
+    }
+}
+
+dependencies {
+    implementation project(modulePrefix + 'library-core')
+    implementation project(modulePrefix + 'library-ui')
+    implementation project(modulePrefix + 'library-dash')
+    implementation 'androidx.annotation:annotation:' + androidxAnnotationVersion
+    compileOnly 'org.checkerframework:checker-qual:' + checkerframeworkVersion
+    compileOnly 'org.checkerframework:checker-compat-qual:' + checkerframeworkVersion
+}

demos/gl/src/main/AndroidManifest.xml

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 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.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.google.android.exoplayer2.gldemo">
+
+  <uses-permission android:name="android.permission.INTERNET"/>
+  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+
+  <uses-sdk/>
+
+  <application
+      android:allowBackup="false"
+      android:icon="@mipmap/ic_launcher"
+      android:label="@string/application_name">
+
+    <activity
+        android:name=".MainActivity"
+        android:exported="true">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN"/>
+        <category android:name="android.intent.category.LAUNCHER"/>
+      </intent-filter>
+      <intent-filter>
+        <action android:name="com.google.android.exoplayer.gldemo.action.VIEW"/>
+        <category android:name="android.intent.category.DEFAULT"/>
+        <data android:scheme="http"/>
+        <data android:scheme="https"/>
+        <data android:scheme="content"/>
+        <data android:scheme="asset"/>
+        <data android:scheme="file"/>
+      </intent-filter>
+    </activity>
+
+  </application>
+
+</manifest>

demos/gl/src/main/assets/bitmap_overlay_video_processor_fragment.glsl

@@ -0,0 +1,35 @@
+// Copyright 2020 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.
+
+#extension GL_OES_EGL_image_external : require
+precision mediump float;
+// External texture containing video decoder output.
+uniform samplerExternalOES tex_sampler_0;
+// Texture containing the overlap bitmap.
+uniform sampler2D tex_sampler_1;
+// Horizontal scaling factor for the overlap bitmap.
+uniform float scaleX;
+// Vertical scaling factory for the overlap bitmap.
+uniform float scaleY;
+varying vec2 v_texcoord;
+void main() {
+  vec4 videoColor = texture2D(tex_sampler_0, v_texcoord);
+  vec4 overlayColor = texture2D(tex_sampler_1,
+                                vec2(v_texcoord.x * scaleX,
+                                     v_texcoord.y * scaleY));
+  // Blend the video decoder output and the overlay bitmap.
+  gl_FragColor = videoColor * (1.0 - overlayColor.a)
+      + overlayColor * overlayColor.a;
+}
+

demos/gl/src/main/assets/bitmap_overlay_video_processor_vertex.glsl

@@ -0,0 +1,21 @@
+// Copyright 2020 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.
+attribute vec4 a_position;
+attribute vec3 a_texcoord;
+varying vec2 v_texcoord;
+void main() {
+ gl_Position = a_position;
+ v_texcoord = a_texcoord.xy;
+}
+

demos/gl/src/main/java/com/google/android/exoplayer2/gldemo/BitmapOverlayVideoProcessor.java

@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2020 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.google.android.exoplayer2.gldemo;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.drawable.BitmapDrawable;
+import android.opengl.GLES20;
+import android.opengl.GLUtils;
+import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.GlUtil;
+import com.google.android.exoplayer2.util.Util;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Locale;
+import javax.microedition.khronos.opengles.GL10;
+
+/**
+ * Video processor that demonstrates how to overlay a bitmap on video output using a GL shader. The
+ * bitmap is drawn using an Android {@link Canvas}.
+ */
+/* package */ final class BitmapOverlayVideoProcessor
+    implements VideoProcessingGLSurfaceView.VideoProcessor {
+
+  private static final int OVERLAY_WIDTH = 512;
+  private static final int OVERLAY_HEIGHT = 256;
+
+  private final Context context;
+  private final Paint paint;
+  private final int[] textures;
+  private final Bitmap overlayBitmap;
+  private final Bitmap logoBitmap;
+  private final Canvas overlayCanvas;
+
+  private int program;
+  @Nullable private GlUtil.Attribute[] attributes;
+  @Nullable private GlUtil.Uniform[] uniforms;
+
+  private float bitmapScaleX;
+  private float bitmapScaleY;
+
+  public BitmapOverlayVideoProcessor(Context context) {
+    this.context = context.getApplicationContext();
+    paint = new Paint();
+    paint.setTextSize(64);
+    paint.setAntiAlias(true);
+    paint.setARGB(0xFF, 0xFF, 0xFF, 0xFF);
+    textures = new int[1];
+    overlayBitmap = Bitmap.createBitmap(OVERLAY_WIDTH, OVERLAY_HEIGHT, Bitmap.Config.ARGB_8888);
+    overlayCanvas = new Canvas(overlayBitmap);
+    try {
+      logoBitmap =
+          ((BitmapDrawable)
+                  context.getPackageManager().getApplicationIcon(context.getPackageName()))
+              .getBitmap();
+    } catch (PackageManager.NameNotFoundException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Override
+  public void initialize() {
+    String vertexShaderCode =
+        loadAssetAsString(context, "bitmap_overlay_video_processor_vertex.glsl");
+    String fragmentShaderCode =
+        loadAssetAsString(context, "bitmap_overlay_video_processor_fragment.glsl");
+    program = GlUtil.compileProgram(vertexShaderCode, fragmentShaderCode);
+    GlUtil.Attribute[] attributes = GlUtil.getAttributes(program);
+    GlUtil.Uniform[] uniforms = GlUtil.getUniforms(program);
+    for (GlUtil.Attribute attribute : attributes) {
+      if (attribute.name.equals("a_position")) {
+        attribute.setBuffer(
+            new float[] {
+              -1.0f, -1.0f, 0.0f, 1.0f, 1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 1.0f,
+              1.0f, 0.0f, 1.0f,
+            },
+            4);
+      } else if (attribute.name.equals("a_texcoord")) {
+        attribute.setBuffer(
+            new float[] {
+              0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,
+            },
+            3);
+      }
+    }
+    this.attributes = attributes;
+    this.uniforms = uniforms;
+    GLES20.glGenTextures(1, textures, 0);
+    GLES20.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
+    GLES20.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
+    GLES20.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
+    GLES20.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
+    GLES20.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);
+    GLUtils.texImage2D(GL10.GL_TEXTURE_2D, /* level= */ 0, overlayBitmap, /* border= */ 0);
+  }
+
+  @Override
+  public void setSurfaceSize(int width, int height) {
+    bitmapScaleX = (float) width / OVERLAY_WIDTH;
+    bitmapScaleY = (float) height / OVERLAY_HEIGHT;
+  }
+
+  @Override
+  public void draw(int frameTexture, long frameTimestampUs) {
+    // Draw to the canvas and store it in a texture.
+    String text = String.format(Locale.US, "%.02f", frameTimestampUs / (float) C.MICROS_PER_SECOND);
+    overlayBitmap.eraseColor(Color.TRANSPARENT);
+    overlayCanvas.drawBitmap(logoBitmap, /* left= */ 32, /* top= */ 32, paint);
+    overlayCanvas.drawText(text, /* x= */ 200, /* y= */ 130, paint);
+    GLES20.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
+    GLUtils.texSubImage2D(
+        GL10.GL_TEXTURE_2D, /* level= */ 0, /* xoffset= */ 0, /* yoffset= */ 0, overlayBitmap);
+    GlUtil.checkGlError();
+
+    // Run the shader program.
+    GlUtil.Uniform[] uniforms = Assertions.checkNotNull(this.uniforms);
+    GlUtil.Attribute[] attributes = Assertions.checkNotNull(this.attributes);
+    GLES20.glUseProgram(program);
+    for (GlUtil.Uniform uniform : uniforms) {
+      switch (uniform.name) {
+        case "tex_sampler_0":
+          uniform.setSamplerTexId(frameTexture, /* unit= */ 0);
+          break;
+        case "tex_sampler_1":
+          uniform.setSamplerTexId(textures[0], /* unit= */ 1);
+          break;
+        case "scaleX":
+          uniform.setFloat(bitmapScaleX);
+          break;
+        case "scaleY":
+          uniform.setFloat(bitmapScaleY);
+          break;
+      }
+    }
+    for (GlUtil.Attribute copyExternalAttribute : attributes) {
+      copyExternalAttribute.bind();
+    }
+    for (GlUtil.Uniform copyExternalUniform : uniforms) {
+      copyExternalUniform.bind();
+    }
+    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
+    GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, /* first= */ 0, /* count= */ 4);
+    GlUtil.checkGlError();
+  }
+
+  private static String loadAssetAsString(Context context, String assetFileName) {
+    @Nullable InputStream inputStream = null;
+    try {
+      inputStream = context.getAssets().open(assetFileName);
+      return Util.fromUtf8Bytes(Util.toByteArray(inputStream));
+    } catch (IOException e) {
+      throw new IllegalStateException(e);
+    } finally {
+      Util.closeQuietly(inputStream);
+    }
+  }
+}