From 5db8e20db77bf86eba25ec713c76da783dd98b19 Mon Sep 17 00:00:00 2001
From: Alan Newberger <alann@google.com>
Date: Tue, 30 Sep 2014 14:59:32 -0700
Subject: [PATCH] Only allow one draw call pending at a time

If modules call draw aggressively, there should only be one pending
at a time. If we get another, just drop it, there will be a draw
momentarily.

Bug: 17703978
Change-Id: I60b3b9e257ae4e064287a97973b1de878ce66de1
---
 src/com/android/camera/SurfaceTextureRenderer.java | 42 +++++++---------------
 1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/src/com/android/camera/SurfaceTextureRenderer.java b/src/com/android/camera/SurfaceTextureRenderer.java
index 69897cad8..ee557f88b 100644
--- a/src/com/android/camera/SurfaceTextureRenderer.java
+++ b/src/com/android/camera/SurfaceTextureRenderer.java
@@ -44,6 +44,8 @@ public class SurfaceTextureRenderer {
     private EGL10 mEgl;
     private GL10 mGl;
 
+    private volatile boolean mDrawPending = false;
+
     private final Handler mEglHandler;
     private final FrameDrawer mFrameDrawer;
 
@@ -55,32 +57,13 @@ public class SurfaceTextureRenderer {
                 if (mEglDisplay != null && mEglSurface != null) {
                     mFrameDrawer.onDrawFrame(mGl);
                     mEgl.eglSwapBuffers(mEglDisplay, mEglSurface);
+                    mDrawPending = false;
                 }
                 mRenderLock.notifyAll();
             }
         }
     };
 
-    public class RenderThread extends Thread {
-        private Boolean mRenderStopped = false;
-
-        @Override
-        public void run() {
-            while (true) {
-                synchronized (mRenderStopped) {
-                    if (mRenderStopped) return;
-                }
-                draw(true);
-            }
-        }
-
-        public void stopRender() {
-            synchronized (mRenderStopped) {
-                mRenderStopped = true;
-            }
-        }
-    }
-
     public SurfaceTextureRenderer(SurfaceTexture tex,
             Handler handler, FrameDrawer renderer) {
         mEglHandler = handler;
@@ -89,10 +72,6 @@ public class SurfaceTextureRenderer {
         initialize(tex);
     }
 
-    public RenderThread createRenderThread() {
-        return new RenderThread();
-    }
-
     public void release() {
         mEglHandler.post(new Runnable() {
             @Override
@@ -116,12 +95,15 @@ public class SurfaceTextureRenderer {
      */
     public void draw(boolean sync) {
         synchronized (mRenderLock) {
-            mEglHandler.post(mRenderTask);
-            if (sync) {
-                try {
-                    mRenderLock.wait();
-                } catch (InterruptedException ex) {
-                    Log.v(TAG, "RenderLock.wait() interrupted");
+            if (!mDrawPending) {
+                mEglHandler.post(mRenderTask);
+                mDrawPending = true;
+                if (sync) {
+                    try {
+                        mRenderLock.wait();
+                    } catch (InterruptedException ex) {
+                        Log.v(TAG, "RenderLock.wait() interrupted");
+                    }
                 }
             }
         }
-- 
2.11.0