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Commit 0309f009 authored by Steven Luo's avatar Steven Luo
Browse files

Forward-port surface dithering from CM10 

This allows the use of 16-bit color displays without excessive color
banding; behavior can be controlled by the persist.sys.use_dithering
property.

Incorporates http://review.cyanogenmod.org/19532 from CM10 as well as
code removed in upstream commit 1b03149f.

Change-Id: I290ca4ed4787dc81ac756d9af92cd6a690865a08
parent a84f5dca

services/surfaceflinger/Layer.cpp

+18 −0
Original line number Diff line number Diff line
@@ -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)

{
@@ -194,6 +195,23 @@ status_t Layer::setBuffers( uint32_t w, uint32_t h, 
    mSurfaceTexture->setDefaultBufferFormat(format);

    mSurfaceTexture->setConsumerUsageBits(getEffectiveUsage(0));



    int displayMinColorDepth;

    int layerRedsize;

    switch (mFlinger->getUseDithering()) {

    case 0:

        mNeedsDithering = false;

        break;

    case 1:

        displayMinColorDepth = mFlinger->getMinColorDepth();

        // we use the red index

        layerRedsize = info.getSize(PixelFormatInfo::INDEX_RED);

        mNeedsDithering = (layerRedsize > displayMinColorDepth);

        break;

    case 2:

        mNeedsDithering = true;

        break;

    }



    return NO_ERROR;

}

services/surfaceflinger/Layer.h

+2 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ public: 
    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 @@ private: 
    PixelFormat mFormat;

    const GLExtensions& mGLExtensions;

    bool mOpaqueLayer;

    bool mNeedsDithering;



    // page-flip thread (currently main thread)

    bool mSecure;         // no screenshots

services/surfaceflinger/LayerBase.cpp

+7 −0
Original line number Diff line number Diff line
@@ -354,6 +354,7 @@ 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);
@@ -428,6 +429,12 @@ 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());

services/surfaceflinger/SurfaceFlinger.cpp

+19 −2
Original line number Diff line number Diff line
@@ -104,7 +104,8 @@ SurfaceFlinger::SurfaceFlinger() 
        mLastSwapBufferTime(0),

        mDebugInTransaction(0),

        mLastTransactionTime(0),

        mBootFinished(false)

        mBootFinished(false),

        mUseDithering(0)

{

    ALOGI("SurfaceFlinger is starting");
@@ -122,8 +123,13 @@ 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");



#ifdef SAMSUNG_HDMI_SUPPORT

    ALOGD(">>> Run service");
@@ -429,7 +435,11 @@ void SurfaceFlinger::initializeGL(EGLDisplay display) { 
    glPixelStorei(GL_PACK_ALIGNMENT, 4);

    glEnableClientState(GL_VERTEX_ARRAY);

    glShadeModel(GL_FLAT);

    if (mUseDithering == 2) {

        glEnable(GL_DITHER);

    } else {

        glDisable(GL_DITHER);

    }

    glDisable(GL_CULL_FACE);



    struct pack565 {
@@ -467,6 +477,9 @@ void SurfaceFlinger::initializeGL(EGLDisplay display) { 
    ALOGI("extensions: %s", extensions.getExtension());

    ALOGI("GL_MAX_TEXTURE_SIZE = %d", mMaxTextureSize);

    ALOGI("GL_MAX_VIEWPORT_DIMS = %d x %d", mMaxViewportDims[0], mMaxViewportDims[1]);



    // XXX Assume bit depth for red is equal to minimum depth of all colors

    mMinColorDepth = r;

}



status_t SurfaceFlinger::readyToRun()
@@ -564,6 +577,10 @@ uint32_t SurfaceFlinger::getMaxTextureSize() const { 
    return mMaxTextureSize;

}



uint32_t SurfaceFlinger::getMinColorDepth() const {

    return mMinColorDepth;

}



uint32_t SurfaceFlinger::getMaxViewportDims() const {

    return mMaxViewportDims[0] < mMaxViewportDims[1] ?

            mMaxViewportDims[0] : mMaxViewportDims[1];

services/surfaceflinger/SurfaceFlinger.h

+6 −0
Original line number Diff line number Diff line
@@ -324,8 +324,12 @@ private: 
    static EGLContext createGLContext(EGLDisplay disp, EGLConfig config);

    void initializeGL(EGLDisplay display);

    uint32_t getMaxTextureSize() const;

    uint32_t getMinColorDepth() const;

    uint32_t getMaxViewportDims() const;



    // 0: surface doesn't need dithering, 1: use if necessary, 2: use permanently

    inline int getUseDithering() const { return mUseDithering; }



    /* ------------------------------------------------------------------------

     * Display and layer stack management

     */
@@ -423,6 +427,7 @@ private: 
    sp<EventThread> mEventThread;

    GLint mMaxViewportDims[2];

    GLint mMaxTextureSize;

    GLint mMinColorDepth;

    EGLContext mEGLContext;

    EGLConfig mEGLConfig;

    EGLDisplay mEGLDisplay;
@@ -448,6 +453,7 @@ private: 
    volatile nsecs_t mDebugInTransaction;

    nsecs_t mLastTransactionTime;

    bool mBootFinished;

    int mUseDithering;



    // these are thread safe

    mutable MessageQueue mEventQueue;