SurfaceFlinger代码笔记

drawLayers是做client合成，合成完以后的buffer会放在RenderSurface里

FrameBufferSurface里的buffer是通过setClientTarget给到HWC的（HWC应该给client合成的buffer留了一个slot)

Output.cpp这个文件非常关键，代表着具体一个Display的操作

drawLayers第三个参数是个

renderengine::ExternalTexture，是

dequeueRenderBuffer的时候从

mRenderSurface->dequeueBuffer中获取到的，drawLayers就是把最终的东西放到这个buffer里

 

 

具体代码都在Output.cpp里

 

而

setClientTarget就是被

FramebufferSurface::advanceFrame调用的

以下函数是重头戏：

void Output::present(const compositionengine::CompositionRefreshArgs& refreshArgs) {ATRACE_FORMAT("%s for %s", __func__, mNamePlusId.c_str());ALOGV(__FUNCTION__);updateColorProfile(refreshArgs);updateCompositionState(refreshArgs);planComposition();writeCompositionState(refreshArgs);setColorTransform(refreshArgs);beginFrame();GpuCompositionResult result;const bool predictCompositionStrategy = canPredictCompositionStrategy(refreshArgs);if (predictCompositionStrategy) {result = prepareFrameAsync();} else {prepareFrame();}devOptRepaintFlash(refreshArgs);finishFrame(std::move(result));postFramebuffer();renderCachedSets(refreshArgs);
}