status_t DisplayDevice::prepareFrame(const HWComposer& hwc) const {
DisplaySurface::CompositionType compositionType;
bool haveGles = hwc.hasGlesComposition(mHwcDisplayId);
bool haveHwc = hwc.hasHwcComposition(mHwcDisplayId);
if (haveGles && haveHwc) {
compositionType = DisplaySurface::COMPOSITION_MIXED;
} else if (haveGles) {
compositionType = DisplaySurface::COMPOSITION_GLES;
} else if (haveHwc) {
compositionType = DisplaySurface::COMPOSITION_HWC;
} else {
// Nothing to do -- when turning the screen off we get a frame like
// this. Call it a HWC frame since we won't be doing any GLES work but
// will do a prepare/set cycle.
compositionType = DisplaySurface::COMPOSITION_HWC;
}
return mDisplaySurface->prepareFrame(compositionType);
}
