泉港报名网站建设需要,长沙市建设厅网站,wordpress 锚,wordpress主题格式化1. 前言
Filament中使用了FrameGraph来管理渲染管线#xff0c;需要准备两点#xff1a;
设备接口抽象#xff1a;设备API抽象为Command资源抽象#xff1a;使用虚拟资源#xff0c;在实际用到时再创建#xff0c;方便剔除无用资源
下面就围绕Filament中设备API抽象为…1. 前言
Filament中使用了FrameGraph来管理渲染管线需要准备两点
设备接口抽象设备API抽象为Command资源抽象使用虚拟资源在实际用到时再创建方便剔除无用资源
下面就围绕Filament中设备API抽象为Command代码部分做一个解读
2. 代码分析
先贴一段创建顶点缓冲的接口调用堆栈
[Inlined] filament::backend::CommandBase::CommandBase(void (*)(filament::backend::Driver , filament::backend::CommandBase *, int *)) CommandStream.h:63
[Inlined] filament::backend::CommandTypevoid (filament::backend::Driver::*)(filament::backend::Handlefilament::backend::HwVertexBuffer, unsigned char, unsigned char, unsigned int, std::__ndk1::arrayfilament::backend::Attribute, 16u)::Commandfilament::backend::Driver::createVertexBufferR(filament::backend::Handlefilament::backend::HwVertexBuffer, unsigned char, unsigned char, unsigned int, std::__ndk1::arrayfilament::backend::Attribute, 16u)::Commandfilament::backend::Handlefilament::backend::HwVertexBuffer, unsigned char, unsigned char, unsigned int, std::__ndk1::arrayfilament::backend::Attribute, 16u(void (*)(filament::backend::Driver, filament::backend::CommandBase*, int*), filament::backend::Handlefilament::backend::HwVertexBuffer, unsigned char, unsigned char, unsigned int, std::__ndk1::arrayfilament::backend::Attribute, 16u) CommandStream.h:154
[Inlined] filament::backend::CommandStream::createVertexBuffer(unsigned char, unsigned char, unsigned int, std::__ndk1::array…) DriverAPI.inc:169
filament::FVertexBuffer::FVertexBuffer(filament::FEngine , const filament::VertexBuffer::Builder ) VertexBuffer.cpp:185
[Inlined] utils::Arena::make…(filament::FEngine , const filament::VertexBuffer::Builder ) Allocator.h:647
[Inlined] filament::FEngine::create…(filament::ResourceList… , const filament::FVertexBuffer::Builder ) Engine.cpp:680
filament::FEngine::createVertexBuffer(const filament::VertexBuffer::Builder ) Engine.cpp:690
filament::FEngine::init() Engine.cpp:277
filament::FEngine::create(filament::backend::Backend, filament::backend::Platform *, void *, const filament::Engine::Config *) Engine.cpp:110
[Inlined] FilamentTest::setupFilament() FilamentTest.cpp:98
FilamentTest::init() FilamentTest.cpp:68
boxing::xr::composer::StartBase::instance(ANativeWindow *, int, int) StartBase.h:263
[Inlined] native_OnDrawFrame::$_0::operator()() const JniImpl.cpp:100
[Inlined] std::__ndk1::__invoke…(native_OnDrawFrame::$_0 ) type_traits:3874
[Inlined] std::__ndk1::__apply_functor…(native_OnDrawFrame::$_0 , std::__ndk1::tuple… , std::__ndk1::__tuple_indices…, std::__ndk1::tuple… ) functional:2853
[Inlined] std::__ndk1::__bind::operator()…() functional:2886
[Inlined] std::__ndk1::__invoke…(std::__ndk1::__bind… ) type_traits:3874
std::__ndk1::__packaged_task_func::operator()() future:1817
[Inlined] std::__ndk1::__packaged_task_function::operator()() const future:1994
std::__ndk1::packaged_task::operator()() future:2214
[Inlined] std::__ndk1::__function::__value_func::operator()() const functional:1884
[Inlined] std::__ndk1::function::operator()() const functional:2556
lambda::operator()() const ThreadPool.h:71
[Inlined] decltype(std::__ndk1::forwardboxing::core::ThreadPool::ThreadPool(unsigned int)::lambda()(fp)()) std::__ndk1::__invokeboxing::core::ThreadPool::ThreadPool(unsigned int)::lambda()(boxing::core::ThreadPool::ThreadPool(unsigned int)::lambda()) type_traits:3874
[Inlined] std::__ndk1::__thread_execute…(std::__ndk1::tuple… , std::__ndk1::__tuple_indices…) thread:273
std::__ndk1::__thread_proxy…(void *) thread:284
__pthread_start(void*) 0x00000000eab36828
__start_thread 0x00000000eaaed5ce渲染设备API定义
filament\filament\backend\include\private\backend\DriverAPI.incDriverAPI.inc中使用大量的宏替换操作将设备接口进行封装或打包这部分代码可读性极差不过可从其调用逻辑来进行拆解和理解 先来分析其中一个接口: createVertexBuffer 创建一个顶点缓冲
DECL_DRIVER_API_R_N(backend::VertexBufferHandle, createVertexBuffer,uint8_t, bufferCount,uint8_t, attributeCount,uint32_t, vertexCount,backend::AttributeArray, attributes)这里不是真的创建而要看这个宏接口在哪里使用我们主要看看这两个地方 CommandStream.h //命令流Driver.h //设备接口这两个文件中都对DriverAPI.inc进行了include但是意义完全不一样先看DECL_DRIVER_API_R_N
#define DECL_DRIVER_API_R_N(R, N, ...) \DECL_DRIVER_API_RETURN(R, N, PAIR_ARGS_N(ARG, ##__VA_ARGS__), PAIR_ARGS_N(PARAM, ##__VA_ARGS__))关键在DECL_DRIVER_API_RETURN这个宏在CommandStream.h和Driver.h头文件中include文件DriverAPI.inc 之前分别定义了自己的DECL_DRIVER_API_RETURN宏看看CommandStream.h中
#define DECL_DRIVER_API(methodName, paramsDecl, params) \inline void methodName(paramsDecl) { \DEBUG_COMMAND_BEGIN(methodName, false, params); \using Cmd COMMAND_TYPE(methodName); \void* const p allocateCommand(CommandBase::align(sizeof(Cmd))); \new(p) Cmd(mDispatcher.methodName##_, APPLY(std::move, params)); \DEBUG_COMMAND_END(methodName, false); \}#define DECL_DRIVER_API_SYNCHRONOUS(RetType, methodName, paramsDecl, params) \inline RetType methodName(paramsDecl) { \DEBUG_COMMAND_BEGIN(methodName, true, params); \AutoExecute callOnExit([](){ \DEBUG_COMMAND_END(methodName, true); \}); \return apply(Driver::methodName, mDriver, std::forward_as_tuple(params)); \}#define DECL_DRIVER_API_RETURN(RetType, methodName, paramsDecl, params) \inline RetType methodName(paramsDecl) { \DEBUG_COMMAND_BEGIN(methodName, false, params); \RetType result mDriver.methodName##S(); \using Cmd COMMAND_TYPE(methodName##R); \void* const p allocateCommand(CommandBase::align(sizeof(Cmd))); \new(p) Cmd(mDispatcher.methodName##_, RetType(result), APPLY(std::move, params)); \DEBUG_COMMAND_END(methodName, false); \return result; \}上面三个宏的作用基本是一样的都将要调用的函数和参数封装为了Command不同之处在于DECL_DRIVER_API是command无返回值的DECL_DRIVER_API_SYNCHRONOUS是封装为command后同步执行的DECL_DRIVER_API_RETURN是需要返回值的 主要看看DECL_DRIVER_API_RETURN
RetType result mDriver.methodName##S(); 将方法名后面拼接了S调用拿到返回类型 看看拼接S后的实现
HandleHwVertexBuffer OpenGLDriver::createVertexBufferS() noexcept {return initHandleGLVertexBuffer();
}initHandle()这句在filament内存池HandleArena上创建了一个GLVertexBuffer对象然后根据内存地址创建了对象的唯一handeID 再看下面这句 using Cmd COMMAND_TYPE(methodName##R); 方法名后面拼接了R然后获取了command的类型没有执行方法看看拼接R后的实现
void OpenGLDriver::createVertexBufferR(HandleHwVertexBuffer vbh,uint8_t bufferCount,uint8_t attributeCount,uint32_t elementCount,AttributeArray attributes) {DEBUG_MARKER()constructGLVertexBuffer(vbh, bufferCount, attributeCount, elementCount, attributes);
}内存池HandleArena上创建了一个GLVertexBuffer对象 再看下面一句
void* const p allocateCommand(CommandBase::align(sizeof(Cmd)));
new(p) Cmd(mDispatcher.methodName##_, RetType(result), APPLY(std::move, params)); 在CommandStream内部的环形缓冲上申请了一块Command对象的内存p然后在内存p上new了对象Command 看看CommandBase* execute执行函数的实现
inline CommandBase* execute(Driver driver) {// returning the next command by output parameter allows the compiler to perform the// tail-call optimization in the function called by mExecute, however that comes at// a cost here (writing and reading the stack at each iteration), in the end its// probably better to pay the cost at just one location.intptr_t next;mExecute(driver, this, next);return reinterpret_castCommandBase*(reinterpret_castintptr_t(this) next);
}mExecute就是上面new(p) Cmd(mDispatcher.methodName##_, RetType(result), APPLY(std::move, params)); 后的函数和参数的封装体然后拿到了下一个圆形缓冲中下一个command的地址偏移量next返回下一个command地址 CommandStream中执行command执行完然后获取下一个执行。。。
mDriver.execute([this, buffer]() {Driver UTILS_RESTRICT driver mDriver;CommandBase* UTILS_RESTRICT base static_castCommandBase*(buffer);while (UTILS_LIKELY(base)) {base base-execute(driver);}
});
