From ff190847a14253aff7fda04ef78388bc3430f44f Mon Sep 17 00:00:00 2001
From: Mathias Agopian <mathias@google.com>
Date: Thu, 14 Oct 2021 20:46:10 -0700
Subject: [PATCH] ExternalStreamManagerAndroid actually depends on GLES

Since ExternalStreamManagerAndroid depends on GLES, move it to the
opengl directory.
---
 filament/backend/CMakeLists.txt                       |  2 +-
 .../src/android/ExternalTextureManagerAndroid.h       | 11 ++++++++++-
 .../ExternalStreamManagerAndroid.cpp                  |  0
 .../ExternalStreamManagerAndroid.h                    | 11 +++++++++++
 filament/backend/src/opengl/PlatformEGLAndroid.cpp    |  2 +-
 5 files changed, 23 insertions(+), 3 deletions(-)
 rename filament/backend/src/{android => opengl}/ExternalStreamManagerAndroid.cpp (100%)
 rename filament/backend/src/{android => opengl}/ExternalStreamManagerAndroid.h (88%)

diff --git a/filament/backend/CMakeLists.txt b/filament/backend/CMakeLists.txt
index ba9070805c..6b503f9aa5 100644
--- a/filament/backend/CMakeLists.txt
+++ b/filament/backend/CMakeLists.txt
@@ -87,7 +87,7 @@ if (FILAMENT_SUPPORTS_OPENGL AND NOT FILAMENT_USE_EXTERNAL_GLES3 AND NOT FILAMEN
         list(APPEND SRCS src/VirtualMachineEnv.cpp)
     endif ()
     if (ANDROID)
-        list(APPEND SRCS src/android/ExternalStreamManagerAndroid.cpp)
+        list(APPEND SRCS src/opengl/ExternalStreamManagerAndroid.cpp)
         list(APPEND SRCS src/android/ExternalTextureManagerAndroid.cpp)
         list(APPEND SRCS src/opengl/PlatformEGLAndroid.cpp)
     elseif (IOS)
diff --git a/filament/backend/src/android/ExternalTextureManagerAndroid.h b/filament/backend/src/android/ExternalTextureManagerAndroid.h
index faa04b9efb..69d9ffb56a 100644
--- a/filament/backend/src/android/ExternalTextureManagerAndroid.h
+++ b/filament/backend/src/android/ExternalTextureManagerAndroid.h
@@ -31,6 +31,15 @@
 
 namespace filament {
 
+/*
+ * ExternalTextureManagerAndroid::ExternalTexture is basically a wrapper for AHardwareBuffer.
+ *
+ * This class doesn't rely on GL or EGL, and could be used for other Android platform if needed
+ * (e.g. Vulkan).
+ *
+ * ExternalTextureManagerAndroid handle allocation/destruction using either Java or the NDK,
+ * whichever is available.
+ */
 class ExternalTextureManagerAndroid {
 public:
 
@@ -47,7 +56,7 @@ public:
     // not quite sure on which thread this is going to be called
     ~ExternalTextureManagerAndroid() noexcept;
 
-    // called on gl thread
+    // called on backend thread
     backend::Platform::ExternalTexture* create() noexcept;
 
     // called on app thread
diff --git a/filament/backend/src/android/ExternalStreamManagerAndroid.cpp b/filament/backend/src/opengl/ExternalStreamManagerAndroid.cpp
similarity index 100%
rename from filament/backend/src/android/ExternalStreamManagerAndroid.cpp
rename to filament/backend/src/opengl/ExternalStreamManagerAndroid.cpp
diff --git a/filament/backend/src/android/ExternalStreamManagerAndroid.h b/filament/backend/src/opengl/ExternalStreamManagerAndroid.h
similarity index 88%
rename from filament/backend/src/android/ExternalStreamManagerAndroid.h
rename to filament/backend/src/opengl/ExternalStreamManagerAndroid.h
index addf4b7a0f..c38bf2c6e6 100644
--- a/filament/backend/src/android/ExternalStreamManagerAndroid.h
+++ b/filament/backend/src/opengl/ExternalStreamManagerAndroid.h
@@ -31,6 +31,11 @@ typedef struct ASurfaceTexture ASurfaceTexture;
 
 namespace filament {
 
+/*
+ * ExternalStreamManagerAndroid::Stream is basically a wrapper for SurfaceTexture.
+ *
+ * This class DOES DEPEND on having a GLES context, because that's how SurfaceTexture works.
+ */
 class ExternalStreamManagerAndroid {
 public:
     using Stream = backend::Platform::Stream;
@@ -40,8 +45,14 @@ public:
 
     Stream* acquire(jobject surfaceTexture) noexcept;
     void release(Stream* stream) noexcept;
+
+    // attach Stream to current GLES context
     void attach(Stream* stream, intptr_t tname) noexcept;
+
+    // detach Stream to current GLES context
     void detach(Stream* stream) noexcept;
+
+    // must be called on GLES context thread, updates the stream content
     void updateTexImage(Stream* stream, int64_t* timestamp) noexcept;
 
 private:
diff --git a/filament/backend/src/opengl/PlatformEGLAndroid.cpp b/filament/backend/src/opengl/PlatformEGLAndroid.cpp
index 28ba47a477..cdc4dbb8e1 100644
--- a/filament/backend/src/opengl/PlatformEGLAndroid.cpp
+++ b/filament/backend/src/opengl/PlatformEGLAndroid.cpp
@@ -20,7 +20,7 @@
 #include "OpenGLContext.h"
 
 #include "android/ExternalTextureManagerAndroid.h"
-#include "android/ExternalStreamManagerAndroid.h"
+#include "ExternalStreamManagerAndroid.h"
 #include "private/backend/VirtualMachineEnv.h"
 
 #include <android/api-level.h>