surfaceflinger: Enable dithering if persist.sys.use_dithering=1|2

* Fixes color banding(1) and blur effect(2) 0 : surface doesn't need dithering 1 : enable dithering if necessary (default) 2 : enable dithering (always)
androidarmv6 · Dec 23, 2012 · db5cb80 · db5cb80
1 parent d8c7714
commit db5cb80
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Showing 5 changed files with 46 additions and 2 deletions.
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
@@ -63,6 +63,7 @@ Layer::Layer(SurfaceFlinger* flinger, const sp<Client>& client)
         mFormat(PIXEL_FORMAT_NONE),
         mGLExtensions(GLExtensions::getInstance()),
         mOpaqueLayer(true),
+        mNeedsDithering(false),
         mSecure(false),
         mProtectedByApp(false)
 {
@@ -182,6 +183,10 @@ status_t Layer::setBuffers( uint32_t w, uint32_t h,
         return BAD_VALUE;
     }
 
+    // the display's pixel format
+    //sp<const DisplayDevice> hw(mFlinger->getDefaultDisplayDevice());
+    //getPixelFormatInfo(PixelFormat(hw->getFormat()), &info->pixelFormatInfo);
+
     mFormat = format;
 
     mSecure = (flags & ISurfaceComposerClient::eSecure) ? true : false;
@@ -193,6 +198,21 @@ status_t Layer::setBuffers( uint32_t w, uint32_t h,
     mSurfaceTexture->setDefaultBufferFormat(format);
     mSurfaceTexture->setConsumerUsageBits(getEffectiveUsage(0));
 
+    int useDither = mFlinger->getUseDithering();
+    if (useDither) {
+        if (useDither == 2) {
+            mNeedsDithering = true;
+        }
+        else {
+            // we use the red index
+            //int displayRedSize = info->pixelFormatInfo->getSize(PixelFormatInfo::INDEX_RED);
+            //int layerRedsize = info->pixelFormatInfo->getSize(PixelFormatInfo::INDEX_RED);
+            mNeedsDithering = true; // (layerRedsize > displayRedSize);
+        }
+    } else {
+        mNeedsDithering = false;
+    }
+
     return NO_ERROR;
 }
 

diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
@@ -77,6 +77,7 @@ class Layer : public LayerBaseClient
     virtual uint32_t doTransaction(uint32_t transactionFlags);
     virtual Region latchBuffer(bool& recomputeVisibleRegions);
     virtual bool isOpaque() const;
+    virtual bool needsDithering() const     { return mNeedsDithering; }
     virtual bool isSecure() const           { return mSecure; }
     virtual bool isProtected() const;
     virtual void onRemoved();
@@ -142,6 +143,7 @@ class Layer : public LayerBaseClient
     PixelFormat mFormat;
     const GLExtensions& mGLExtensions;
     bool mOpaqueLayer;
+    bool mNeedsDithering;
 
     // page-flip thread (currently main thread)
     bool mSecure;         // no screenshots

diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
@@ -353,6 +353,7 @@ void LayerBase::clearWithOpenGL(const sp<const DisplayDevice>& hw, const Region&
     glDisable(GL_TEXTURE_EXTERNAL_OES);
     glDisable(GL_TEXTURE_2D);
     glDisable(GL_BLEND);
+    glDisable(GL_DITHER);
 
     LayerMesh mesh;
     computeGeometry(hw, &mesh);
@@ -427,6 +428,12 @@ void LayerBase::drawWithOpenGL(const sp<const DisplayDevice>& hw, const Region&
         texCoords[i].v = 1.0f - texCoords[i].v;
     }
 
+    if (needsDithering()) {
+        glEnable(GL_DITHER);
+    } else {
+        glDisable(GL_DITHER);
+    }
+
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
     glVertexPointer(2, GL_FLOAT, 0, mesh.getVertices());

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -101,7 +101,8 @@ SurfaceFlinger::SurfaceFlinger()
         mLastSwapBufferTime(0),
         mDebugInTransaction(0),
         mLastTransactionTime(0),
-        mBootFinished(false)
+        mBootFinished(false),
+        mUseDithering(0)
 {
     ALOGI("SurfaceFlinger is starting");
 
@@ -119,8 +120,13 @@ SurfaceFlinger::SurfaceFlinger()
             mDebugDDMS = 0;
         }
     }
+
+    property_get("persist.sys.use_dithering", value, "1");
+    mUseDithering = atoi(value);
+
     ALOGI_IF(mDebugRegion, "showupdates enabled");
     ALOGI_IF(mDebugDDMS, "DDMS debugging enabled");
+    ALOGI_IF(mUseDithering, "use dithering");
 }
 
 void SurfaceFlinger::onFirstRef()
@@ -417,7 +423,12 @@ void SurfaceFlinger::initializeGL(EGLDisplay display) {
     glPixelStorei(GL_PACK_ALIGNMENT, 4);
     glEnableClientState(GL_VERTEX_ARRAY);
     glShadeModel(GL_FLAT);
-    glDisable(GL_DITHER);
+    if (mUseDithering == 0 || mUseDithering == 1) {
+        glDisable(GL_DITHER);
+    }
+    else if (mUseDithering == 2) {
+        glEnable(GL_DITHER);
+    }
     glDisable(GL_CULL_FACE);
 
     struct pack565 {

diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
@@ -374,6 +374,9 @@ class SurfaceFlinger : public BinderService<SurfaceFlinger>,
         return mProtectedTexName;
     }
 
+    // 0: surface doesn't need dithering, 1: use if necessary, 2: use permanently
+    inline int  getUseDithering() const { return mUseDithering; }
+
     /* ------------------------------------------------------------------------
      * Display management
      */
@@ -444,6 +447,7 @@ class SurfaceFlinger : public BinderService<SurfaceFlinger>,
     volatile nsecs_t mDebugInTransaction;
     nsecs_t mLastTransactionTime;
     bool mBootFinished;
+    int mUseDithering;
 
     // these are thread safe
     mutable MessageQueue mEventQueue;