//这是CUPCAKE中ui/EGLDisplaySurface raw代码
/*
**
** Copyright 2007 The Android Open Source Project
**
** Licensed under the Apache License Version 2.0(the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**
**
** Unless required by applicable law or agreed to in writing software
** distributed under the License is distributed on an "AS IS" BASIS
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#define LOG_TAG "EGLDisplaySurface"
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#if HAVE_ANDROID_OS
#include
#endif
#include
// ----------------------------------------------------------------------------
egl_native_window_t* android_createDisplaySurface()
{
egl_native_window_t* s = new android::EGLDisplaySurface();
s->memory_type = NATIVE_MEMORY_TYPE_GPU;
return s;
}
#define LIKELY( exp ) (__builtin_expect( (exp) != 0, true ))
#define UNLIKELY( exp ) (__builtin_expect( (exp) != 0, false ))
// ----------------------------------------------------------------------------
namespace android {
// ----------------------------------------------------------------------------
EGLDisplaySurface::EGLDisplaySurface() //构造函数
: EGLNativeSurface()
{
//填充基类成员
egl_native_window_t::version = sizeof(egl_native_window_t); //must be sizeof(egl_native_window_t)
egl_native_window_t::ident = 0; //ident is reserved for the Android platform
egl_native_window_t::incRef = &EGLDisplaySurface::hook_incRef;//Hook called by EGL to hold a reference on this structure
egl_native_window_t::decRef = &EGLDisplaySurface::hook_decRef;//Hook called by EGL to release a reference on this structure
/*
* Hook called by EGL to perform a page flip. This function
* may update the size attributes above, in which case it returns
* the EGL_NATIVES_FLAG_SIZE_CHANGED bit set.
*/
egl_native_window_t::swapBuffers = &EGLDisplaySurface::hook_swapBuffers;
/*
* Hook called by EGL when the native surface is associated to EGL
* (eglCreateWindowSurface). Can be NULL.
*/
egl_native_window_t::connect = 0;
/*
* Hook called by EGL when eglDestroySurface is called. Can be NULL.
*/
egl_native_window_t::disconnect = 0;
mFb[0].data = 0;//mFb是GGLSurface struct的对象
mFb[1].data = 0;
mBlitEngine = 0;//默认不使用硬件引擎
/*
* Heap the offset above is based from
*/
egl_native_window_t::fd = mapFrameBuffer();//fd是int型，应该是Framebuffer的句柄
if (egl_native_window_t::fd >= 0) {
hw_module_t const* module; //HAL 接口指针
//#define COPYBIT_HARDWARE_MODULE_ID "copybit"
//获取copybit的HAL stub
//libhardhare/hardware.c
if (hw_get_module(COPYBIT_HARDWARE_MODULE_ID, &module) == 0) {
copybit_open(module, &mBlitEngine);//copy_bit提供的API，mBlitEngine为copybit_device_t对象
}
const float in2mm = 25.4f;//英尺和毫米换算
float refreshRate = 1000000000000000LLU / (
float( mInfo.upper_margin + mInfo.lower_margin + mInfo.yres )
* ( mInfo.left_margin + mInfo.right_margin + mInfo.xres )
* mInfo.pixclock);
const GGLSurface& buffer = mFb[1 - mIndex];
/*
* width, height and stride of the window in pixels
* Any of these value can be nul in which case GL commands are
* accepted and processed as usual, but not rendering occurs.
*/
egl_native_window_t::width = buffer.width;
egl_native_window_t::height = buffer.height;
egl_native_window_t::stride = buffer.stride;
egl_native_window_t::format = buffer.format;//* format of the native window (see ui/PixelFormat.h)
egl_native_window_t::base = intptr_t(mFb[0].data);//Base memory virtual address of the surface in the CPU side
egl_native_window_t::offset =
intptr_t(buffer.data) - egl_native_window_t::base;//Offset of the bits in the VRAM
/*
* flags describing some attributes of this surface
* EGL_NATIVES_FLAG_DESTROY_BACKBUFFER: backbuffer not preserved after
* eglSwapBuffers 这个标志位比较重要，关系到是否打开page_flip功能
*/
egl_native_window_t::flags = 0;
/*
* horizontal and vertical resolution in DPI
*/
egl_native_window_t::xdpi = (mInfo.xres * in2mm) / mInfo.width;
egl_native_window_t::ydpi = (mInfo.yres * in2mm) / mInfo.height;
egl_native_window_t::fps = refreshRate;//refresh rate in frames per second (Hz)
egl_native_window_t::memory_type = NATIVE_MEMORY_TYPE_FB;//Memory type the surface resides into
// no error, set the magic word
egl_native_window_t::magic = 0x600913;
}
mSwapCount = -1;
mPageFlipCount = 0;
}
//析构函数
EGLDisplaySurface::~EGLDisplaySurface()
{
magic = 0;
copybit_close(mBlitEngine);//关闭copybit
mBlitEngine = 0;
close(egl_native_window_t::fd);//关闭句柄
munmap(mFb[0].data, mSize);//unmap空间
if (!(mFlags & PAGE_FLIP))
free((void*)mFb[1].data);
}
//three hook
void EGLDisplaySurface::hook_incRef(NativeWindowType window) {
EGLDisplaySurface* that = static_cast(window);
that->incStrong(that);
}
void EGLDisplaySurface::hook_decRef(NativeWindowType window) {
EGLDisplaySurface* that = static_cast(window);
that->decStrong(that);
}
uint32_t EGLDisplaySurface::hook_swapBuffers(NativeWindowType window) {
EGLDisplaySurface* that = static_cast(window);
return that->swapBuffers();
}
void EGLDisplaySurface::setSwapRectangle(int l, int t, int w, int h)
{
mInfo.reserved[0] = 0x54445055; // "UPDT";
mInfo.reserved[1] = (uint16_t)l | ((uint32_t)t << 16);
mInfo.reserved[2] = (uint16_t)(l+w) | ((uint32_t)(t+h) << 16);
}
//重要函数swapBuffers()
uint32_t EGLDisplaySurface::swapBuffers()
{
#define SHOW_FPS 0
#if SHOW_FPS //计算FPS部分代码
nsecs_t now = systemTime();
if (mSwapCount == -1) {
mTime = now;
mSwapCount = 0;
mSleep = 0;
} else {
nsecs_t d = now-mTime;
if (d >= seconds(1)) {
double fps = (mSwapCount * double(seconds(1))) / double(d);
LOGD("%f fps, sleep=%d / frame",
fps, (int)ns2us(mSleep / mSwapCount));
mSwapCount = 0;
mTime = now;
mSleep = 0;
} else {
mSwapCount++;
}
}
#endif
/* If we can't do the page_flip, just copy the back buffer to the front */
//如果无法利用page_flip功能，显示时仅仅是从back向front拷贝
if (!(mFlags & PAGE_FLIP)) {
memcpy(mFb[0].data, mFb[1].data, mInfo.xres*mInfo.yres*2);
return 0;
}
// do the actual flip 硬件PAGE_FLIP
mIndex = 1 - mIndex;//reflesh mindex number
mInfo.activate = FB_ACTIVATE_VBL;
mInfo.yoffset = mIndex ? mInfo.yres : 0;//根据mindex判断y轴的offset
//通过FBIOPUT_VSCREENINFO获取fb参数
if (ioctl(egl_native_window_t::fd, FBIOPUT_VSCREENINFO, &mInfo) == -1) {
LOGE("FBIOPUT_VSCREENINFO failed");
return 0;
}
/*
* this is a monstrous hack: Because the h/w accelerator is not able
* to render directly into the framebuffer, we need to copy its
* internal framebuffer out to the fb.
这是一个古怪的hack，由于硬件加速单元无法直接作用在framebuffer上，因此需要拷贝到fb上。
* oem[0] is used to access the fd of internal fb.//oem用于访问internal fb
* All this is needed only in standalone mode, in SurfaceFlinger mode
* we control where the GPU renders.
* We do this only if we have copybit, since this hack is needed only
* with msm7k.
有copybit时才这样做，只有msm7k才需要这个hack。
*/
if (egl_native_window_t::memory_type == NATIVE_MEMORY_TYPE_GPU && oem[0] && mBlitEngine) {
copybit_device_t *copybit = mBlitEngine;
/*fill Rectangle */
copybit_rect_t sdrect = { 0, 0,
egl_native_window_t::width, egl_native_window_t::height };
/*fill dst Image structure */
copybit_image_t dst = {
egl_native_window_t::width,
egl_native_window_t::height,
egl_native_window_t::format,
egl_native_window_t::offset,
(void*)egl_native_window_t::base,
egl_native_window_t::fd
};
/*fill src Image structure */
copybit_image_t src = {
egl_native_window_t::width,
egl_native_window_t::height,
egl_native_window_t::format, // XXX: use proper format
egl_native_window_t::offset,
(void*)egl_native_window_t::base, // XXX: use proper base
egl_native_window_t::oem[0]//内部fb句柄
};
//实例一个region_iterator 的it对象
region_iterator it(Region(Rect( egl_native_window_t::width, egl_native_window_t::height)));
/**
* Set a copybit parameter.
*
* @param dev from open
* @param name one for the COPYBIT_NAME_xxx
* @param value one of the COPYBIT_VALUE_xxx
*
* @return 0 if successful
*/
copybit->set_parameter(copybit, COPYBIT_TRANSFORM, 0);
copybit->set_parameter(copybit, COPYBIT_PLANE_ALPHA, 0xFF);
copybit->set_parameter(copybit, COPYBIT_DITHER, COPYBIT_DISABLE);
/**
* Execute the stretch bit blit copy operation 通过这个函数真正拷贝
*
* @param dev from open
* @param dst is the destination image
* @param src is the source image
* @param dst_rect is the destination rectangle
* @param src_rect is the source rectangle
* @param region the clip region
*
* @return 0 if successful
*/
copybit->stretch(copybit, &dst, &src, &sdrect, &sdrect, &it);
}
// update the address of the buffer to draw to next
const GGLSurface& buffer = mFb[1 - mIndex];//更新next to draw address
egl_native_window_t::offset =
intptr_t(buffer.data) - egl_native_window_t::base;
#if SHOW_FPS
mSleep += systemTime()-now;
#endif
mPageFlipCount++;//增加计数器
// We don't support screen-size changes for now 目前不支持屏幕改变屏幕尺寸
return 0;
}
int32_t EGLDisplaySurface::getPageFlipCount() const
{
return mPageFlipCount;
}
void EGLDisplaySurface::copyFrontToBack(const Region& copyback) //从front 拷贝到 back
{
#if HAVE_ANDROID_OS
if (mBlitEngine) {
copybit_image_t dst = {
w: egl_native_window_t::stride,
h: egl_native_window_t::height,
format: egl_native_window_t::format,
offset: mFb[1-mIndex].data - mFb[0].data,
base: (void*)egl_native_window_t::base,
fd: egl_native_window_t::fd
};
copybit_image_t src = {
w: egl_native_window_t::stride,
h: egl_native_window_t::height,
format: egl_native_window_t::format,
offset: mFb[mIndex].data - mFb[0].data,
base: (void*)egl_native_window_t::base,
fd: egl_native_window_t::fd
};
region_iterator it(copyback);
/**调用blit函数
* Execute the bit blit copy operation
*
* @param dev from open
* @param dst is the destination image
* @param src is the source image
* @param region the clip region
*
* @return 0 if successful
*/
mBlitEngine->blit(mBlitEngine, &dst, &src, &it);
} else
#endif
{
/* no extra copy needed since we copied back to front instead of
* flipping 如果使用copy代替flip的方法，则不需要额外拷贝*/
if (!(mFlags & PAGE_FLIP)) {
return;
}
//软件方法copy
Region::iterator iterator(copyback);//Region的子类iterator 对象
if (iterator) {
Rect r;
uint8_t* const screen_src = mFb[ mIndex].data;
uint8_t* const screen_dst = mFb[1-mIndex].data;
const size_t bpp = bytesPerPixel(egl_native_window_t::format);
const size_t bpr = egl_native_window_t::stride * bpp;
while (iterator.iterate(&r)) {
ssize_t h = r.bottom - r.top;
if (h) {
size_t size = (r.right - r.left) * bpp;
size_t o = (r.left + egl_native_window_t::stride * r.top) * bpp;
uint8_t* s = screen_src + o;
uint8_t* d = screen_dst + o;
if (size == bpr) {
size *= h;
h = 1;
}
do {
memcpy(d, s, size);
d += bpr;
s += bpr;
} while (--h > 0);
}
}
}
}
}
void EGLDisplaySurface::copyFrontToImage(const copybit_image_t& dst)//copy front to image image是什么？
{
#if HAVE_ANDROID_OS
if (mBlitEngine) {//copybit方法
copybit_image_t src = {
w: egl_native_window_t::stride,
h: egl_native_window_t::height,
format: egl_native_window_t::format,
offset: mFb[mIndex].data - mFb[0].data,
base: (void*)egl_native_window_t::base,
fd: egl_native_window_t::fd
};
region_iterator it(Region(Rect(
egl_native_window_t::width, egl_native_window_t::height)));
//copybit->blit 操作
mBlitEngine->blit(mBlitEngine, &dst, &src, &it);
} else
#endif
{ //软件方法src to des
uint8_t* const screen_src = mFb[ mIndex].data;
const size_t bpp = bytesPerPixel(egl_native_window_t::format);
const size_t bpr = egl_native_window_t::stride * bpp;
memcpy((char*)dst.base + dst.offset, screen_src, bpr*egl_native_window_t::height);
}
}
void EGLDisplaySurface::copyBackToImage(const copybit_image_t& dst) //back to image，和上个函数的区别在于mFb不同
{
#if HAVE_ANDROID_OS
if (mBlitEngine) {//硬件方法
copybit_image_t src = {
w: egl_native_window_t::stride,
h: egl_native_window_t::height,
format: egl_native_window_t::format,
offset: mFb[1-mIndex].data - mFb[0].data,
base: (void*)egl_native_window_t::base,
fd: egl_native_window_t::fd
};
region_iterator it(Region(Rect(
egl_native_window_t::width, egl_native_window_t::height)));
//copybit->blit 操作
mBlitEngine->blit(mBlitEngine, &dst, &src, &it);
} else
#endif
{ //软件方法src to des
uint8_t* const screen_src = mFb[1-mIndex].data;
const size_t bpp = bytesPerPixel(egl_native_window_t::format);
const size_t bpr = egl_native_window_t::stride * bpp;
memcpy((char*)dst.base + dst.offset, screen_src, bpr*egl_native_window_t::height);
}
}
//初始化调用的map函数
status_t EGLDisplaySurface::mapFrameBuffer()
{
char const * const device_template[] = {
"/dev/graphics/fb%u",
"/dev/fb%u",
0 };
int fd = -1;
int i=0;
char name[64];
while ((fd==-1) && device_template[i]) {
snprintf(name, 64, device_template[i], 0);
fd = open(name, O_RDWR, 0);//打开fb
i++;
}
if (fd < 0)
return -errno;
struct fb_fix_screeninfo finfo;//获取fb_fix_screeninfo信息
if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
return -errno;
struct fb_var_screeninfo info;//获取fb_var_screeninfo信息
if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
return -errno;
//填充默认数据
info.reserved[0] = 0;
info.reserved[1] = 0;
info.reserved[2] = 0;
info.xoffset = 0;
info.yoffset = 0;
info.yres_virtual = info.yres * 2;//双buffer是实际值的2倍
info.bits_per_pixel = 16;
/* Explicitly request 5/6/5 */
info.red.offset = 11;
info.red.length = 5;
info.green.offset = 5;
info.green.length = 6;
info.blue.offset = 0;
info.blue.length = 5;
info.transp.offset = 0;
info.transp.length = 0;
info.activate = FB_ACTIVATE_NOW;
uint32_t flags = PAGE_FLIP;
//默认支持PAGE_FLIP，然后判断是否支持双buffer
if (ioctl(fd, FBIOPUT_VSCREENINFO, &info) == -1) {
info.yres_virtual = info.yres;
flags &= ~PAGE_FLIP;
LOGW("FBIOPUT_VSCREENINFO failed, page flipping not supported");
}
//如果info.yres_virtual < info.yres * 2，同上
if (info.yres_virtual < info.yres * 2) {
info.yres_virtual = info.yres;
flags &= ~PAGE_FLIP;
LOGW("page flipping not supported (yres_virtual=%d, requested=%d)",
info.yres_virtual, info.yres*2);
}
if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
return -errno;
//计算刷新率，貌似三星的总是算不对
int refreshRate = 1000000000000000LLU /
(
uint64_t( info.upper_margin + info.lower_margin + info.yres )
* ( info.left_margin + info.right_margin + info.xres )
* info.pixclock
);
if (refreshRate == 0) {
// bleagh, bad info from the driver
refreshRate = 60*1000; // 60 Hz
}
//如果驱动没有返回，使用默认值
if (int(info.width) <= 0 || int(info.height) <= 0) {
// the driver doesn't return that information
// default to 160 dpi
info.width = ((info.xres * 25.4f)/160.0f + 0.5f);
info.height = ((info.yres * 25.4f)/160.0f + 0.5f);
}
float xdpi = (info.xres * 25.4f) / info.width;
float ydpi = (info.yres * 25.4f) / info.height;
float fps = refreshRate / 1000.0f;
//启动时的输出
LOGI( "using (fd=%d)\n"
"id = %s\n"
"xres = %d px\n"
"yres = %d px\n"
"xres_virtual = %d px\n"
"yres_virtual = %d px\n"
"bpp = %d\n"
"r = %2u:%u\n"
"g = %2u:%u\n"
"b = %2u:%u\n",
fd,
finfo.id,
info.xres,
info.yres,
info.xres_virtual,
info.yres_virtual,
info.bits_per_pixel,
info.red.offset, info.red.length,
info.green.offset, info.green.length,
info.blue.offset, info.blue.length
);
LOGI( "width = %d mm (%f dpi)\n"
"height = %d mm (%f dpi)\n"
"refresh rate = %.2f Hz\n",
info.width, xdpi,
info.height, ydpi,
fps
);
//检查参数
if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
return -errno;
if (finfo.smem_len <= 0)
return -errno;
/*
* Open and map the display.
*/
//通过mmap将fd映射到用户空间
void* buffer = (uint16_t*) mmap(
0, finfo.smem_len,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, 0);
if (buffer == MAP_FAILED)
return -errno;
//清空buffer
// at least for now, always clear the fb
memset(buffer, 0, finfo.smem_len);
uint8_t* offscreen[2];
offscreen[0] = (uint8_t*)buffer;
if (flags & PAGE_FLIP) {
offscreen[1] = (uint8_t*)buffer + finfo.line_length*info.yres;
} else {
offscreen[1] = (uint8_t*)malloc(finfo.smem_len);
if (offscreen[1] == 0) {
munmap(buffer, finfo.smem_len);
return NO_MEMORY;
}
}
//填充class EGLDisplaySurface成员，private成员可随意使用
mFlags = flags;
mInfo = info;
mFinfo = finfo;
mSize = finfo.smem_len;
mIndex = 0;
//填充mFb[0]和mFb[1]
for (int i=0 ; i<2 ; i++) {
mFb[i].version = sizeof(GGLSurface);
mFb[i].width = info.xres;
mFb[i].height = info.yres;
mFb[i].stride = finfo.line_length / (info.bits_per_pixel >> 3);
mFb[i].data = (GGLubyte*)(offscreen[i]);
mFb[i].format = GGL_PIXEL_FORMAT_RGB_565;
}
return fd;
}
// ----------------------------------------------------------------------------
}; // namespace android
// ----------------------------------------------------------------------------
