android Gui系统之SurfaceFlinger(5)

bool SurfaceFlinger::handlePageFlip()
{
    Region dirtyRegion;

    bool visibleRegions = false;
    const LayerVector& layers(mDrawingState.layersSortedByZ);
    bool frameQueued = false;

    // Store the set of layers that need updates. This set must not change as
    // buffers are being latched, as this could result in a deadlock.
    // Example: Two producers share the same command stream and:
    // 1.) Layer 0 is latched
    // 2.) Layer 0 gets a new frame
    // 2.) Layer 1 gets a new frame
    // 3.) Layer 1 is latched.
    // Display is now waiting on Layer 1‘s frame, which is behind layer 0‘s
    // second frame. But layer 0‘s second frame could be waiting on display.
    Vector<Layer*> layersWithQueuedFrames;
    for (size_t i = 0, count = layers.size(); i<count ; i++) {
        const sp<Layer>& layer(layers[i]);
        if (layer->hasQueuedFrame()) {
            frameQueued = true;
            if (layer->shouldPresentNow(mPrimaryDispSync)) {
                layersWithQueuedFrames.push_back(layer.get());
            }
        }
    }
    for (size_t i = 0, count = layersWithQueuedFrames.size() ; i<count ; i++) {
        Layer* layer = layersWithQueuedFrames[i];
        const Region dirty(layer->latchBuffer(visibleRegions));
        const Layer::State& s(layer->getDrawingState());
        invalidateLayerStack(s.layerStack, dirty);
    }

    mVisibleRegionsDirty |= visibleRegions;

    // If we will need to wake up at some time in the future to deal with a
    // queued frame that shouldn‘t be displayed during this vsync period, wake
    // up during the next vsync period to check again.
    if (frameQueued && layersWithQueuedFrames.empty()) {
        signalLayerUpdate();
    }

    // Only continue with the refresh if there is actually new work to do
    return !layersWithQueuedFrames.empty();
}

void SurfaceFlinger::rebuildLayerStacks() {
#ifdef QCOM_BSP
    char prop[PROPERTY_VALUE_MAX];
    property_get("sys.extended_mode", prop, "0");
    sExtendedMode = atoi(prop) ? true : false;
#endif
    // rebuild the visible layer list per screen
    if (CC_UNLIKELY(mVisibleRegionsDirty)) {
        ATRACE_CALL();
        mVisibleRegionsDirty = false;
        invalidateHwcGeometry();

        const LayerVector& layers(mDrawingState.layersSortedByZ);
        for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
            Region opaqueRegion;
            Region dirtyRegion;
            Vector< sp<Layer> > layersSortedByZ;
            const sp<DisplayDevice>& hw(mDisplays[dpy]);
            const Transform& tr(hw->getTransform());
            const Rect bounds(hw->getBounds());
            int dpyId = hw->getHwcDisplayId();
            if (hw->isDisplayOn()) {
                SurfaceFlinger::computeVisibleRegions(dpyId, layers,
                        hw->getLayerStack(), dirtyRegion, opaqueRegion);

                const size_t count = layers.size();
                for (size_t i=0 ; i<count ; i++) {
                    const sp<Layer>& layer(layers[i]);
                    const Layer::State& s(layer->getDrawingState());
                    Region drawRegion(tr.transform(
                            layer->visibleNonTransparentRegion));
                    drawRegion.andSelf(bounds);
                    if (!drawRegion.isEmpty()) {
                        layersSortedByZ.add(layer);
                    }
                }
            }
            hw->setVisibleLayersSortedByZ(layersSortedByZ);
            hw->undefinedRegion.set(bounds);
            hw->undefinedRegion.subtractSelf(tr.transform(opaqueRegion));
            hw->dirtyRegion.orSelf(dirtyRegion);
        }
    }
}

void SurfaceFlinger::doDisplayComposition(const sp<const DisplayDevice>& hw,
        const Region& inDirtyRegion)
{
    // We only need to actually compose the display if:
    // 1) It is being handled by hardware composer, which may need this to
    //    keep its virtual display state machine in sync, or
    // 2) There is work to be done (the dirty region isn‘t empty)
    bool isHwcDisplay = hw->getHwcDisplayId() >= 0;
    if (!isHwcDisplay && inDirtyRegion.isEmpty()) {
        return;
    }

    Region dirtyRegion(inDirtyRegion);

    // compute the invalid region
    hw->swapRegion.orSelf(dirtyRegion);

    uint32_t flags = hw->getFlags();
    if (flags & DisplayDevice::SWAP_RECTANGLE) {
        // we can redraw only what‘s dirty, but since SWAP_RECTANGLE only
        // takes a rectangle, we must make sure to update that whole
        // rectangle in that case
        dirtyRegion.set(hw->swapRegion.bounds());
    } else {
        if (flags & DisplayDevice::PARTIAL_UPDATES) {
            // We need to redraw the rectangle that will be updated
            // (pushed to the framebuffer).
            // This is needed because PARTIAL_UPDATES only takes one
            // rectangle instead of a region (see DisplayDevice::flip())
            dirtyRegion.set(hw->swapRegion.bounds());
        } else {
            // we need to redraw everything (the whole screen)
            dirtyRegion.set(hw->bounds());
            hw->swapRegion = dirtyRegion;
        }
    }

    if (CC_LIKELY(!mDaltonize && !mHasColorMatrix)) {
        if (!doComposeSurfaces(hw, dirtyRegion)) return;
    } else {
        RenderEngine& engine(getRenderEngine());
        mat4 colorMatrix = mColorMatrix;
        if (mDaltonize) {
            colorMatrix = colorMatrix * mDaltonizer();
        }
        mat4 oldMatrix = engine.setupColorTransform(colorMatrix);
        doComposeSurfaces(hw, dirtyRegion);
        engine.setupColorTransform(oldMatrix);
    }

    // update the swap region and clear the dirty region
    hw->swapRegion.orSelf(dirtyRegion);

    // swap buffers (presentation)
    hw->swapBuffers(getHwComposer());
}

bool SurfaceFlinger::doComposeSurfaces(const sp<const DisplayDevice>& hw, const Region& dirty)
{
    RenderEngine& engine(getRenderEngine());
    const int32_t id = hw->getHwcDisplayId();
    HWComposer& hwc(getHwComposer());
    HWComposer::LayerListIterator cur = hwc.begin(id);
    const HWComposer::LayerListIterator end = hwc.end(id);

    Region clearRegion;
    bool hasGlesComposition = hwc.hasGlesComposition(id);
    const bool hasHwcComposition = hwc.hasHwcComposition(id);
    if (hasGlesComposition) {
        if (!hw->makeCurrent(mEGLDisplay, mEGLContext)) {
            ALOGW("DisplayDevice::makeCurrent failed. Aborting surface composition for display %s",
                  hw->getDisplayName().string());
            eglMakeCurrent(mEGLDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
            if(!getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext)) {
              ALOGE("DisplayDevice::makeCurrent on default display failed. Aborting.");
            }
            return false;
        }

        // Never touch the framebuffer if we don‘t have any framebuffer layers
        if (hasHwcComposition) {
            // when using overlays, we assume a fully transparent framebuffer
            // NOTE: we could reduce how much we need to clear, for instance
            // remove where there are opaque FB layers. however, on some
            // GPUs doing a "clean slate" clear might be more efficient.
            // We‘ll revisit later if needed.
            if(!(mGpuTileRenderEnable && (mDisplays.size()==1)))
                engine.clearWithColor(0, 0, 0, 0);
        } else {
            // we start with the whole screen area
            const Region bounds(hw->getBounds());

            // we remove the scissor part
            // we‘re left with the letterbox region
            // (common case is that letterbox ends-up being empty)
            const Region letterbox(bounds.subtract(hw->getScissor()));

            // compute the area to clear
            Region region(hw->undefinedRegion.merge(letterbox));

            // but limit it to the dirty region
            region.andSelf(dirty);


            // screen is already cleared here
#ifdef QCOM_BSP
            clearRegion.clear();
            if(mGpuTileRenderEnable && (mDisplays.size()==1)) {
                clearRegion = region;
                if (cur == end) {
                    drawWormhole(hw, region);
                } else if(mCanUseGpuTileRender) {
                   /* If GPUTileRect DR optimization on clear only the UnionDR
                    * (computed by computeTiledDr) which is the actual region
                    * that will be drawn on FB in this cycle.. */
                    clearRegion = clearRegion.andSelf(Region(mUnionDirtyRect));
                }
            } else
#endif
            {
                if (!region.isEmpty()) {
                    if (cur != end) {
                        if (cur->getCompositionType() != HWC_BLIT)
                            // can happen with SurfaceView
                            drawWormhole(hw, region);
                    } else
                        drawWormhole(hw, region);
                }
            }
        }

        if (hw->getDisplayType() != DisplayDevice::DISPLAY_PRIMARY) {
            // just to be on the safe side, we don‘t set the
            // scissor on the main display. It should never be needed
            // anyways (though in theory it could since the API allows it).
            const Rect& bounds(hw->getBounds());
            const Rect& scissor(hw->getScissor());
            if (scissor != bounds) {
                // scissor doesn‘t match the screen‘s dimensions, so we
                // need to clear everything outside of it and enable
                // the GL scissor so we don‘t draw anything where we shouldn‘t

                // enable scissor for this frame
                const uint32_t height = hw->getHeight();
                engine.setScissor(scissor.left, height - scissor.bottom,
                        scissor.getWidth(), scissor.getHeight());
            }
        }
    }

    /*
     * and then, render the layers targeted at the framebuffer
     */

    const Vector< sp<Layer> >& layers(hw->getVisibleLayersSortedByZ());
    const size_t count = layers.size();
    const Transform& tr = hw->getTransform();
    if (cur != end) {
        // we‘re using h/w composer
#ifdef QCOM_BSP
        int fbWidth= hw->getWidth();
        int fbHeight= hw->getHeight();
        /* if GPUTileRender optimization property is on & can be used
         * i) Enable EGL_SWAP_PRESERVED flag
         * ii) do startTile with union DirtyRect
         * else , Disable EGL_SWAP_PRESERVED */
        if(mGpuTileRenderEnable && (mDisplays.size()==1)) {
            if(mCanUseGpuTileRender && !mUnionDirtyRect.isEmpty()) {
                hw->eglSwapPreserved(true);
                Rect dr = mUnionDirtyRect;
                engine.startTileComposition(dr.left, (fbHeight-dr.bottom),
                      (dr.right-dr.left),
                      (dr.bottom-dr.top), 0);
            } else {
                // Un Set EGL_SWAP_PRESERVED flag, if no tiling required.
                hw->eglSwapPreserved(false);
            }
            // DrawWormHole/Any Draw has to be within startTile & EndTile
            if (hasGlesComposition) {
                if (hasHwcComposition) {
                    if(mCanUseGpuTileRender && !mUnionDirtyRect.isEmpty()) {
                        const Rect& scissor(mUnionDirtyRect);
                        engine.setScissor(scissor.left,
                              hw->getHeight()- scissor.bottom,
                              scissor.getWidth(), scissor.getHeight());
                        engine.clearWithColor(0, 0, 0, 0);
                        engine.disableScissor();
                    } else {
                        engine.clearWithColor(0, 0, 0, 0);
                    }
                } else {
                    if (cur->getCompositionType() != HWC_BLIT &&
                          !clearRegion.isEmpty()) {
                        drawWormhole(hw, clearRegion);
                    }
                }
            }
        }
#endif

        for (size_t i=0 ; i<count && cur!=end ; ++i, ++cur) {
            const sp<Layer>& layer(layers[i]);
            const Region clip(dirty.intersect(tr.transform(layer->visibleRegion)));
            if (!clip.isEmpty()) {
                switch (cur->getCompositionType()) {
                    case HWC_CURSOR_OVERLAY:
                    case HWC_OVERLAY: {
                        const Layer::State& state(layer->getDrawingState());
                        if ((cur->getHints() & HWC_HINT_CLEAR_FB)
                                && i
                                && layer->isOpaque(state) && (state.alpha == 0xFF)
                                && hasGlesComposition) {
                            // never clear the very first layer since we‘re
                            // guaranteed the FB is already cleared
                            layer->clearWithOpenGL(hw, clip);
                        }
                        break;
                    }
                    case HWC_FRAMEBUFFER: {
                        layer->draw(hw, clip);
                        break;
                    }
                    case HWC_BLIT:
                        //Do nothing
                        break;
                    case HWC_FRAMEBUFFER_TARGET: {
                        // this should not happen as the iterator shouldn‘t
                        // let us get there.
                        ALOGW("HWC_FRAMEBUFFER_TARGET found in hwc list (index=%zu)", i);
                        break;
                    }
                }
            }
            layer->setAcquireFence(hw, *cur);
        }

#ifdef QCOM_BSP
        // call EndTile, if starTile has been called in this cycle.
        if(mGpuTileRenderEnable && (mDisplays.size()==1)) {
            if(mCanUseGpuTileRender && !mUnionDirtyRect.isEmpty()) {
                engine.endTileComposition(GL_PRESERVE);
            }
        }
#endif
    } else {
        // we‘re not using h/w composer
        for (size_t i=0 ; i<count ; ++i) {
            const sp<Layer>& layer(layers[i]);
            const Region clip(dirty.intersect(
                    tr.transform(layer->visibleRegion)));
            if (!clip.isEmpty()) {
                layer->draw(hw, clip);
            }
        }
    }

    // disable scissor at the end of the frame
    engine.disableScissor();
    return true;
}