[androidkit] support GL surfaces in AndroidKit

Currently backed by sk_app, we need to move the Android window context files out of sk_app into its own module.

Vulkan is only supported by Android devices running SDK 24+, added guards to Create_VK and annotations for developers.

Change-Id: Ica64a1feef4a3daf50758df05df488da0346ed72
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/401796
Commit-Queue: Jorge Betancourt <jmbetancourt@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

modules/androidkit/src/Surface.cpp

@@ -171,7 +171,7 @@ private:
     SurfaceThread fThread;
 };
 
-// JNI methods
+// *** JNI methods ***
 
 static jlong Surface_CreateBitmap(JNIEnv* env, jobject, jobject bitmap) {
     return reinterpret_cast<jlong>(new BitmapSurface(env, bitmap));
@@ -182,6 +182,7 @@ static jlong Surface_CreateThreadedSurface(JNIEnv* env, jobject, jobject surface
 }
 
 static jlong Surface_CreateVK(JNIEnv* env, jobject, jobject jsurface) {
+#ifdef SK_VULKAN
     auto* win = ANativeWindow_fromSurface(env, jsurface);
     if (!win) {
         return 0;
@@ -195,6 +196,27 @@ static jlong Surface_CreateVK(JNIEnv* env, jobject, jobject jsurface) {
     }
 
     return reinterpret_cast<jlong>(sk_make_sp<WindowSurface>(win, std::move(winctx)).release());
+#endif // SK_VULKAN
+    return 0;
+}
+
+static jlong Surface_CreateGL(JNIEnv* env, jobject, jobject jsurface) {
+#ifdef SK_GL
+    auto* win = ANativeWindow_fromSurface(env, jsurface);
+    if (!win) {
+        return 0;
+    }
+
+    // TODO: match window params?
+    sk_app::DisplayParams params;
+    auto winctx = sk_app::window_context_factory::MakeGLForAndroid(win, params);
+    if (!winctx) {
+        return 0;
+    }
+
+    return reinterpret_cast<jlong>(sk_make_sp<WindowSurface>(win, std::move(winctx)).release());
+#endif // SK_GL
+    return 0;
 }
 
 static void Surface_Release(JNIEnv* env, jobject, jlong native_surface) {
@@ -227,6 +249,8 @@ static int Surface_GetHeight(JNIEnv* env, jobject, jlong native_surface) {
     return surface ? surface->height() : 0;
 }
 
+// *** End of JNI methods ***
+
 }  // namespace
 
 int register_androidkit_Surface(JNIEnv* env) {
@@ -237,6 +261,8 @@ int register_androidkit_Surface(JNIEnv* env) {
             reinterpret_cast<void*>(Surface_CreateThreadedSurface)                   },
         {"nCreateVKSurface", "(Landroid/view/Surface;)J",
             reinterpret_cast<void*>(Surface_CreateVK)                                },
+        {"nCreateGLSurface", "(Landroid/view/Surface;)J",
+            reinterpret_cast<void*>(Surface_CreateGL)                                },
         {"nRelease"        , "(J)V", reinterpret_cast<void*>(Surface_Release)        },
         {"nGetNativeCanvas", "(J)J", reinterpret_cast<void*>(Surface_GetNativeCanvas)},
         {"nFlushAndSubmit" , "(J)V", reinterpret_cast<void*>(Surface_FlushAndSubmit) },

platform_tools/android/apps/AndroidKit/src/main/java/org/skia/androidkit/Surface.java

@@ -8,6 +8,9 @@
 package org.skia.androidkit;
 
 import android.graphics.Bitmap;
+import android.os.Build;
+import android.support.annotation.RequiresApi;
+
 import org.skia.androidkit.Canvas;
 
 public class Surface {
@@ -22,10 +25,15 @@ public class Surface {
         this(CreateBitmapInstance(bitmap));
     }
 
+    @RequiresApi(Build.VERSION_CODES.N)
     static public Surface CreateVulkan(android.view.Surface surface) {
         return new Surface(nCreateVKSurface(surface));
     }
 
+    static public Surface CreateGL(android.view.Surface surface) {
+        return new Surface(nCreateGLSurface(surface));
+    }
+
     /**
      * Create a Surface backed by the provided Android Surface (android.view.Surface).
      * AndroidKit handles thread management. Assumes OpenGL backend.
@@ -89,6 +97,7 @@ public class Surface {
     private static native long nCreateBitmap(Bitmap bitmap);
     private static native long nCreateThreadedSurface(android.view.Surface surface);
     private static native long nCreateVKSurface(android.view.Surface surface);
+    private static native long nCreateGLSurface(android.view.Surface surface);
 
     private static native void nRelease(long nativeInstance);
     private static native long nGetNativeCanvas(long nativeInstance);

platform_tools/android/apps/androidkitdemo/src/main/java/org/skia/androidkitdemo1/RuntimeShaderActivity.java

@@ -80,7 +80,7 @@ class RuntimeShaderRenderThread extends Thread {
 
         long time_base = java.lang.System.currentTimeMillis();
 
-        Surface surface = Surface.CreateVulkan(mAndroidSurface);
+        Surface surface = Surface.CreateGL(mAndroidSurface);
 
         while (mRunning) {
             renderFrame(surface.getCanvas(),