前言
上一篇主要讲解了BootAnimation是从何而来，如何启动，从开机，到SurfaceFlinger服务起来，然后到执行开机动画，如果要深入的看里面的代码，是需要花一定的时间的，我们旨在了解大致的流程，具体流程中的函数，变量意义，具体实现，读者请自研。
由来已知，执行待述~
###BootAnimation执行
1. 代码位置
frameworks/base/cmds/bootanimation
目录中包含如下文件
| 文件名 | 作用 |
|---|---|
| Android.mk | mk文件，编译模块使用 |
| AudioPlayer.cpp、AudioPlayer.h | 音频播放 |
| BootAnimation.cpp、BootAnimation.h | 开机动画的源文件和头文件 |
| bootanimation_main.cpp | 开机动画的入口 |
2. 源码分析
bootanimation_main.cpp
文件中定义main函数，也就是C语言中的执行文件的入口函数
int main(int argc, char** argv)
{
//宏定义判断是否设置进程的优先级
#if defined(HAVE_PTHREADS)
setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_DISPLAY);
#endif
char value[PROPERTY_VALUE_MAX];
//这个配置项决定是否存在开机动画
property_get("debug.sf.nobootanimation", value, "0");
int noBootAnimation = atoi(value);
ALOGI_IF(noBootAnimation, "boot animation disabled");
if (!noBootAnimation) {
//创建ProcessSate对象
// 这个过程会打开/dev/binder设备，形成和内核binder机制的交互的通道; 映射fd到内存
sp<ProcessState> proc(ProcessState::self());
//创建线程并加入到线程池
ProcessState::self()->startThreadPool();
// 创建开机动画对象
sp<BootAnimation> boot = new BootAnimation();
//把主线程加入到线程池
IPCThreadState::self()->joinThreadPool();
}
return 0;
}创建开机动画对象会执行到BootAnimation的构造方法，先看下BootAnimation的头文件
BootAnimation.h
......
namespace android {
class AudioPlayer;
class Surface;
class SurfaceComposerClient;
class SurfaceControl;
// ---------------------------------------------------------------------------
class BootAnimation : public Thread, public IBinder::DeathRecipient
{
public:
BootAnimation();
virtual ~BootAnimation();
sp<SurfaceComposerClient> session() const;
private:
virtual bool threadLoop();
virtual status_t readyToRun();
virtual void onFirstRef();
virtual void binderDied(const wp<IBinder>& who);
//Texture类定义
struct Texture {
GLint w; //宽度
GLint h; //高度
GLuint name; //名称
};
//动画内容结构体
struct Animation {
//动画帧
struct Frame {
String8 name;
FileMap* map;
mutable GLuint tid;
bool operator < (const Frame& rhs) const {
return name < rhs.name;
}
};
//动画部分，因为动画可能是由几个部分组成
struct Part {
int count;
int pause;
String8 path;
SortedVector<Frame> frames;
bool playUntilComplete;
float backgroundColor[3];
FileMap* audioFile;
};
int fps;
int width;
int height;
Vector<Part> parts;
};
status_t initTexture(Texture* texture, AssetManager& asset, const char* name);
status_t initTexture(const Animation::Frame& frame);
bool android();
bool readFile(const char* name, String8& outString);
bool movie();
void checkExit();
sp<SurfaceComposerClient> mSession;
sp<AudioPlayer> mAudioPlayer;
AssetManager mAssets;
Texture mAndroid[2];
int mWidth;
int mHeight;
EGLDisplay mDisplay;
EGLDisplay mContext;
EGLDisplay mSurface;
sp<SurfaceControl> mFlingerSurfaceControl;
sp<Surface> mFlingerSurface;
ZipFileRO *mZip;
};
// ---------------------------------------------------------------------------
}; // namespace android
#endif // ANDROID_BOOTANIMATION_H大致的定义和声明就是这么多，看下具体实现
BootAnimation.cpp
首先执行构造方法
BootAnimation::BootAnimation() : Thread(false), mZip(NULL)
{
//用于界面显示的mSession，与SurfaceFlinger交互的客户端
mSession = new SurfaceComposerClient();
}然后执行
void BootAnimation::onFirstRef() {
status_t err = mSession->linkToComposerDeath(this);
ALOGE_IF(err, "linkToComposerDeath failed (%s) ", strerror(-err));
if (err == NO_ERROR) {
run("BootAnimation", PRIORITY_DISPLAY);
}
}由于BootAnimation继承Thread类，首先会调用readyToRun函数
status_t BootAnimation::readyToRun() {
mAssets.addDefaultAssets();
sp<IBinder> dtoken(SurfaceComposerClient::getBuiltInDisplay(
ISurfaceComposer::eDisplayIdMain));
DisplayInfo dinfo;
status_t status = SurfaceComposerClient::getDisplayInfo(dtoken, &dinfo);
if (status)
return -1;
// create the native surface
sp<SurfaceControl> control = session()->createSurface(String8("BootAnimation"),
dinfo.w, dinfo.h, PIXEL_FORMAT_RGB_565);
SurfaceComposerClient::openGlobalTransaction();
control->setLayer(0x40000000);
SurfaceComposerClient::closeGlobalTransaction();
sp<Surface> s = control->getSurface();
// initialize opengl and egl
const EGLint attribs[] = {
EGL_RED_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_BLUE_SIZE, 8,
EGL_DEPTH_SIZE, 0,
EGL_NONE
};
EGLint w, h, dummy;
EGLint numConfigs;
EGLConfig config;
EGLSurface surface;
EGLContext context;
EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
eglInitialize(display, 0, 0);
eglChooseConfig(display, attribs, &config, 1, &numConfigs);
surface = eglCreateWindowSurface(display, config, s.get(), NULL);
context = eglCreateContext(display, config, NULL, NULL);
eglQuerySurface(display, surface, EGL_WIDTH, &w);
eglQuerySurface(display, surface, EGL_HEIGHT, &h);
if (eglMakeCurrent(display, surface, surface, context) == EGL_FALSE)
return NO_INIT;
mDisplay = display;
mContext = context;
mSurface = surface;
mWidth = w;
mHeight = h;
mFlingerSurfaceControl = control;
mFlingerSurface = s;
// If the device has encryption turned on or is in process
// of being encrypted we show the encrypted boot animation.
char decrypt[PROPERTY_VALUE_MAX];
property_get("vold.decrypt", decrypt, "");
bool encryptedAnimation = atoi(decrypt) != 0 || !strcmp("trigger_restart_min_framework", decrypt);
ZipFileRO* zipFile = NULL;
if ((encryptedAnimation &&
(access(SYSTEM_ENCRYPTED_BOOTANIMATION_FILE, R_OK) == 0) &&
((zipFile = ZipFileRO::open(SYSTEM_ENCRYPTED_BOOTANIMATION_FILE)) != NULL)) ||
((access(OEM_BOOTANIMATION_FILE, R_OK) == 0) &&
((zipFile = ZipFileRO::open(OEM_BOOTANIMATION_FILE)) != NULL)) ||
((access(SYSTEM_BOOTANIMATION_FILE, R_OK) == 0) &&
((zipFile = ZipFileRO::open(SYSTEM_BOOTANIMATION_FILE)) != NULL))) {
mZip = zipFile;
}
return NO_ERROR;
}上面主要做两个操作：
1. 初始化显示界面用于播放开机动画，egl的一些内容；
2. 根据手机是否加密选择不同的开机动画文件，然后拿到入口zipFile
其中用到了一个文件路径在BootAnimation.cpp的开头有定义
#define OEM_BOOTANIMATION_FILE "/oem/media/bootanimation.zip" //这个应该是OEM厂商自己定制
#define SYSTEM_BOOTANIMATION_FILE "/system/media/bootanimation.zip" //正常情况下的Android原始开机动画
#define SYSTEM_ENCRYPTED_BOOTANIMATION_FILE "/system/media/bootanimation-encrypted.zip" //加密手机的开机动画readyToRun方法执行完之后，接着看threaLoop函数
bool BootAnimation::threadLoop()
{
bool r;
// We have no bootanimation file, so we use the stock android logo
// animation.
if (mZip == NULL) {
r = android(); //没有开机动画文件，执行android logo
} else {
r = movie(); //存在开机动画文件，则执行对应的开机动画文件解析出来的内容
}
eglMakeCurrent(mDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
eglDestroyContext(mDisplay, mContext);
eglDestroySurface(mDisplay, mSurface);
mFlingerSurface.clear();
mFlingerSurfaceControl.clear();
eglTerminate(mDisplay);
IPCThreadState::self()->stopProcess();
return r;
}——————————————>android()
bool BootAnimation::android()
{
//初始化两个纹理用于显示logo
initTexture(&mAndroid[0], mAssets, "images/android-logo-mask.png");
initTexture(&mAndroid[1], mAssets, "images/android-logo-shine.png");
// clear screen 清屏
glShadeModel(GL_FLAT);
glDisable(GL_DITHER);
glDisable(GL_SCISSOR_TEST);
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT);
eglSwapBuffers(mDisplay, mSurface);
glEnable(GL_TEXTURE_2D);
glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
const GLint xc = (mWidth - mAndroid[0].w) / 2;
const GLint yc = (mHeight - mAndroid[0].h) / 2;
const Rect updateRect(xc, yc, xc + mAndroid[0].w, yc + mAndroid[0].h);
glScissor(updateRect.left, mHeight - updateRect.bottom, updateRect.width(),
updateRect.height());
// Blend state
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
const nsecs_t startTime = systemTime();
//不停的显示知道exitPending()返回true
do {
......
EGLBoolean res = eglSwapBuffers(mDisplay, mSurface);
......
checkExit();
} while (!exitPending());
glDeleteTextures(1, &mAndroid[0].name);
glDeleteTextures(1, &mAndroid[1].name);
return false;
}主要工作，初始化显示的logo纹理，不断刷新界面直到exitPending()返回true，exitPenging()是Thread类中定义的函数，在checkExit()函数中通过requestExit()来执行退出
void BootAnimation::checkExit() {
// Allow surface flinger to gracefully request shutdown
char value[PROPERTY_VALUE_MAX];
//EXIT_PROP_NAME "service.bootanim.exit" 这个配置项在SurfaceFlinger的bootFinished函数中设置为1，然后这里才能退出开机动画，这个过程设计到开机启动到launcher的整个过程，这里不赘述
property_get(EXIT_PROP_NAME, value, "0");
int exitnow = atoi(value);
if (exitnow) {
requestExit();
if (mAudioPlayer != NULL) {
mAudioPlayer->requestExit();
}
}
}——————————————>movie()
movie()这个函数有点长，我们截断一点一点的看
1. 读取bootanimation.zip中的配置文件
if (!readFile("desc.txt", desString)) {
return false;
}
char const* s = desString.string();
//读取desc.txt文件
// Create and initialize an AudioPlayer if we have an audio_conf.txt file
String8 audioConf;
//判断是否需要创建AudioPlayer,这部分我们暂时不关注
if (readFile("audio_conf.txt", audioConf)) {
mAudioPlayer = new AudioPlayer;
if (!mAudioPlayer->init(audioConf.string())) {
ALOGE("mAudioPlayer.init failed");
mAudioPlayer = NULL;
}
}- 解析desc.txt文件，就是上面拿到的那个char const *s
for (;;) {
//一行一行的截取
const char* endl = strstr(s, "
");
if (!endl) break;
String8 line(s, endl - s);
const char* l = line.string();
//几个需要捕获的参数,帧率 宽高，次数
int fps, width, height, count, pause;
char path[ANIM_ENTRY_NAME_MAX];
char color[7] = "000000"; // default to black if unspecified
char pathType;
//读取帧率和宽高
if (sscanf(l, "%d %d %d", &width, &height, &fps) == 3) {
// ALOGD("> w=%d, h=%d, fps=%d", width, height, fps);
animation.width = width;
animation.height = height;
animation.fps = fps;
}
//或者读取part内容
else if (sscanf(l, " %c %d %d %s #%6s", &pathType, &count, &pause, path, color) >= 4) {
// ALOGD("> type=%c, count=%d, pause=%d, path=%s, color=%s", pathType, count, pause, path, color);
Animation::Part part;
part.playUntilComplete = pathType == 'c';
part.count = count;
part.pause = pause;
part.path = path;
part.audioFile = NULL;
if (!parseColor(color, part.backgroundColor)) {
ALOGE("> invalid color '#%s'", color);
part.backgroundColor[0] = 0.0f;
part.backgroundColor[1] = 0.0f;
part.backgroundColor[2] = 0.0f;
}
animation.parts.add(part);
}
s = ++endl;
}- 读取所有的数据
// read all the data structures
const size_t pcount = animation.parts.size();
void *cookie = NULL;
if (!mZip->startIteration(&cookie)) {
return false;
}
ZipEntryRO entry;
char name[ANIM_ENTRY_NAME_MAX];
while ((entry = mZip->nextEntry(cookie)) != NULL) {
const int foundEntryName = mZip->getEntryFileName(entry, name, ANIM_ENTRY_NAME_MAX);
if (foundEntryName > ANIM_ENTRY_NAME_MAX || foundEntryName == -1) {
ALOGE("Error fetching entry file name");
continue;
}
const String8 entryName(name);
const String8 path(entryName.getPathDir());
const String8 leaf(entryName.getPathLeaf());
if (leaf.size() > 0) {
for (size_t j=0 ; j<pcount ; j++) {
if (path == animation.parts[j].path) {
int method;
// supports only stored png files
if (mZip->getEntryInfo(entry, &method, NULL, NULL, NULL, NULL, NULL)) {
if (method == ZipFileRO::kCompressStored) {
FileMap* map = mZip->createEntryFileMap(entry);
if (map) {
Animation::Part& part(animation.parts.editItemAt(j));
if (leaf == "audio.wav") {
// a part may have at most one audio file
part.audioFile = map;
} else {
Animation::Frame frame;
frame.name = leaf;
frame.map = map;
part.frames.add(frame);
}
}
}
}
}
}
}
}
mZip->endIteration(cookie);- 显示动画
// clear screen
glShadeModel(GL_FLAT);
glDisable(GL_DITHER);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_BLEND);
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT);
eglSwapBuffers(mDisplay, mSurface);
glBindTexture(GL_TEXTURE_2D, 0);
glEnable(GL_TEXTURE_2D);
glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
const int xc = (mWidth - animation.width) / 2;
const int yc = ((mHeight - animation.height) / 2);
nsecs_t lastFrame = systemTime();
nsecs_t frameDuration = s2ns(1) / animation.fps;
Region clearReg(Rect(mWidth, mHeight));
clearReg.subtractSelf(Rect(xc, yc, xc+animation.width, yc+animation.height));
for (size_t i=0 ; i<pcount ; i++) {
const Animation::Part& part(animation.parts[i]);
const size_t fcount = part.frames.size();
glBindTexture(GL_TEXTURE_2D, 0);
for (int r=0 ; !part.count || r<part.count ; r++) {
// Exit any non playuntil complete parts immediately
if(exitPending() && !part.playUntilComplete)
break;
// only play audio file the first time we animate the part
if (r == 0 && mAudioPlayer != NULL && part.audioFile) {
mAudioPlayer->playFile(part.audioFile);
}
glClearColor(
part.backgroundColor[0],
part.backgroundColor[1],
part.backgroundColor[2],
1.0f);
for (size_t j=0 ; j<fcount && (!exitPending() || part.playUntilComplete) ; j++) {
const Animation::Frame& frame(part.frames[j]);
nsecs_t lastFrame = systemTime();
if (r > 0) {
glBindTexture(GL_TEXTURE_2D, frame.tid);
} else {
if (part.count != 1) {
glGenTextures(1, &frame.tid);
glBindTexture(GL_TEXTURE_2D, frame.tid);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}
initTexture(frame);
}
if (!clearReg.isEmpty()) {
Region::const_iterator head(clearReg.begin());
Region::const_iterator tail(clearReg.end());
glEnable(GL_SCISSOR_TEST);
while (head != tail) {
const Rect& r(*head++);
glScissor(r.left, mHeight - r.bottom,
r.width(), r.height());
glClear(GL_COLOR_BUFFER_BIT);
}
glDisable(GL_SCISSOR_TEST);
}
glDrawTexiOES(xc, yc, 0, animation.width, animation.height);
eglSwapBuffers(mDisplay, mSurface);
nsecs_t now = systemTime();
nsecs_t delay = frameDuration - (now - lastFrame);
//ALOGD("%lld, %lld", ns2ms(now - lastFrame), ns2ms(delay));
lastFrame = now;
if (delay > 0) {
struct timespec spec;
spec.tv_sec = (now + delay) / 1000000000;
spec.tv_nsec = (now + delay) % 1000000000;
int err;
do {
err = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &spec, NULL);
} while (err<0 && errno == EINTR);
}
checkExit();
}
usleep(part.pause * ns2us(frameDuration));
// For infinite parts, we've now played them at least once, so perhaps exit
if(exitPending() && !part.count)
break;
}
// free the textures for this part
if (part.count != 1) {
for (size_t j=0 ; j<fcount ; j++) {
const Animation::Frame& frame(part.frames[j]);
glDeleteTextures(1, &frame.tid);
}
}
}备注
主要工作，贴代码，加自己的理解，有问题留言。