From a3d78debd21a173383183bacf55836fa9b87da1b Mon Sep 17 00:00:00 2001
From: Teng-Hui Zhu <ztenghui@google.com>
Date: Thu, 29 Sep 2011 17:51:13 -0700
Subject: Make the Gpu Upload path faster

Basically, move unnecessary function calls out from the loop.
And move the clear related code into DEBUG only.
This is saving us some CPU overhead.

bug:5347539
Change-Id: I237162fd6a502e93ea32c9856f907c5a9ddb2e78
---
 .../platform/graphics/android/TransferQueue.cpp    | 26 +++++++++++++++-------
 1 file changed, 18 insertions(+), 8 deletions(-)

(limited to 'Source/WebCore/platform/graphics/android/TransferQueue.cpp')

diff --git a/Source/WebCore/platform/graphics/android/TransferQueue.cpp b/Source/WebCore/platform/graphics/android/TransferQueue.cpp
index fa7f5b6..a857adb 100644
--- a/Source/WebCore/platform/graphics/android/TransferQueue.cpp
+++ b/Source/WebCore/platform/graphics/android/TransferQueue.cpp
@@ -173,9 +173,6 @@ void TransferQueue::blitTileFromQueue(GLuint fboID, BaseTileTexture* destTex,
                                                             0);
     }
     GLUtils::checkEglError("CreateSyncKHR");
-    // Clean up FBO setup.
-    glBindFramebuffer(GL_FRAMEBUFFER, 0); // rebind the standard FBO
-
     GLUtils::checkGlError("copy the surface texture into the normal one");
 }
 
@@ -260,8 +257,6 @@ void TransferQueue::discardQueue()
 // Call on UI thread to copy from the shared Surface Texture to the BaseTile's texture.
 void TransferQueue::updateDirtyBaseTiles()
 {
-    if (m_currentUploadType == GpuUpload)
-        saveGLState();
     android::Mutex::Autolock lock(m_transferQueueItemLocks);
 
     cleanupTransportQueue();
@@ -272,6 +267,7 @@ void TransferQueue::updateDirtyBaseTiles()
     // the texture and blit that into each BaseTile's texture.
     const int nextItemIndex = getNextTransferQueueIndex();
     int index = nextItemIndex;
+    bool usedFboForUpload = false;
     for (int k = 0; k < ST_BUFFER_NUMBER ; k++) {
         if (m_transferQueue[index].status == pendingBlit) {
             bool obsoleteBaseTile = checkObsolete(index);
@@ -298,6 +294,10 @@ void TransferQueue::updateDirtyBaseTiles()
                 GLUtils::updateTextureWithBitmap(destTexture->m_ownTextureId, 0, 0,
                                                  *m_transferQueue[index].bitmap);
             } else {
+                if (!usedFboForUpload) {
+                    saveGLState();
+                    usedFboForUpload = true;
+                }
                 blitTileFromQueue(m_fboID, destTexture,
                                   m_sharedSurfaceTextureId,
                                   m_sharedSurfaceTexture->getCurrentTextureTarget(),
@@ -320,8 +320,13 @@ void TransferQueue::updateDirtyBaseTiles()
         index = (index + 1) % ST_BUFFER_NUMBER;
     }
 
-    if (m_currentUploadType == GpuUpload)
+    // Clean up FBO setup. Doing this for both CPU/GPU upload can make the
+    // dynamic switch possible. Moving this out from the loop can save some
+    // milli-seconds.
+    if (usedFboForUpload) {
+        glBindFramebuffer(GL_FRAMEBUFFER, 0); // rebind the standard FBO
         restoreGLState();
+    }
 
     m_emptyItemCount = ST_BUFFER_NUMBER;
     m_transferQueueItemCond.signal();
@@ -461,7 +466,9 @@ void TransferQueue::saveGLState()
     glGetIntegerv(GL_VIEWPORT, m_GLStateBeforeBlit.viewport);
     glGetBooleanv(GL_SCISSOR_TEST, m_GLStateBeforeBlit.scissor);
     glGetBooleanv(GL_DEPTH_TEST, m_GLStateBeforeBlit.depth);
+#if DEBUG
     glGetFloatv(GL_COLOR_CLEAR_VALUE, m_GLStateBeforeBlit.clearColor);
+#endif
 }
 
 void TransferQueue::setGLStateForCopy(int width, int height)
@@ -470,9 +477,11 @@ void TransferQueue::setGLStateForCopy(int width, int height)
     glViewport(0, 0, width, height);
     glDisable(GL_SCISSOR_TEST);
     glDisable(GL_DEPTH_TEST);
-
+    // Clear the content is only for debug purpose.
+#if DEBUG
     glClearColor(0, 0, 0, 0);
     glClear(GL_COLOR_BUFFER_BIT);
+#endif
 }
 
 void TransferQueue::restoreGLState()
@@ -487,11 +496,12 @@ void TransferQueue::restoreGLState()
 
     if (m_GLStateBeforeBlit.depth[0])
         glEnable(GL_DEPTH_TEST);
-
+#if DEBUG
     glClearColor(m_GLStateBeforeBlit.clearColor[0],
                  m_GLStateBeforeBlit.clearColor[1],
                  m_GLStateBeforeBlit.clearColor[2],
                  m_GLStateBeforeBlit.clearColor[3]);
+#endif
 }
 
 int TransferQueue::getNextTransferQueueIndex()
-- 
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