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Commit 78eb1224 authored by Jeff Brown's avatar Jeff Brown
Browse files

Dejank electron beam. 

On some devices it can take hundreds of milliseconds to get a
brand new EGL surface performing in tip-top shape.  To get it
ready make it do a few pushups before the show begins.

Bug: 7318962
Change-Id: I7ae92ce100c368327042a29ffa65faee9b567c8d
parent 9cf36b7a

services/java/com/android/server/power/ElectronBeam.java

+18 −0
Original line number Diff line number Diff line
@@ -63,6 +63,11 @@ final class ElectronBeam { 
    private static final float HSTRETCH_DURATION = 0.5f;

    private static final float VSTRETCH_DURATION = 1.0f - HSTRETCH_DURATION;



    // The number of frames to draw when preparing the animation so that it will

    // be ready to run smoothly.  We use 3 frames because we are triple-buffered.

    // See code for details.

    private static final int DEJANK_FRAMES = 3;



    // Set to true when the animation context has been fully prepared.

    private boolean mPrepared;

    private int mMode;
@@ -145,6 +150,19 @@ final class ElectronBeam { 


        // Done.

        mPrepared = true;



        // Dejanking optimization.

        // Some GL drivers can introduce a lot of lag in the first few frames as they

        // initialize their state and allocate graphics buffers for rendering.

        // Work around this problem by rendering the first frame of the animation a few

        // times.  The rest of the animation should run smoothly thereafter.

        // The frames we draw here aren't visible because we are essentially just

        // painting the screenshot as-is.

        if (mode == MODE_COOL_DOWN) {

            for (int i = 0; i < DEJANK_FRAMES; i++) {

                draw(1.0f);

            }

        }

        return true;

    }