qzdoom/src/r_thread.h
2016-12-06 06:22:58 +01:00

227 lines
6.2 KiB
C++

/*
** Renderer multithreading framework
** Copyright (c) 2016 Magnus Norddahl
**
** This software is provided 'as-is', without any express or implied
** warranty. In no event will the authors be held liable for any damages
** arising from the use of this software.
**
** Permission is granted to anyone to use this software for any purpose,
** including commercial applications, and to alter it and redistribute it
** freely, subject to the following restrictions:
**
** 1. The origin of this software must not be misrepresented; you must not
** claim that you wrote the original software. If you use this software
** in a product, an acknowledgment in the product documentation would be
** appreciated but is not required.
** 2. Altered source versions must be plainly marked as such, and must not be
** misrepresented as being the original software.
** 3. This notice may not be removed or altered from any source distribution.
**
*/
#pragma once
#include "r_draw.h"
#include <vector>
#include <memory>
#include <thread>
#include <mutex>
#include <condition_variable>
// Use multiple threads when drawing
EXTERN_CVAR(Bool, r_multithreaded)
// Redirect drawer commands to worker threads
void R_BeginDrawerCommands();
// Wait until all drawers finished executing
void R_EndDrawerCommands();
// Worker data for each thread executing drawer commands
class DrawerThread
{
public:
std::thread thread;
// Thread line index of this thread
int core = 0;
// Number of active threads
int num_cores = 1;
// Range of rows processed this pass
int pass_start_y = 0;
int pass_end_y = MAXHEIGHT;
uint8_t dc_temp_buff[MAXHEIGHT * 4];
uint8_t *dc_temp = nullptr;
uint32_t dc_temp_rgbabuff_rgba[MAXHEIGHT * 4];
uint32_t *dc_temp_rgba = nullptr;
// Checks if a line is rendered by this thread
bool line_skipped_by_thread(int line)
{
return line < pass_start_y || line >= pass_end_y || line % num_cores != core;
}
// The number of lines to skip to reach the first line to be rendered by this thread
int skipped_by_thread(int first_line)
{
int pass_skip = MAX(pass_start_y - first_line, 0);
int core_skip = (num_cores - (first_line + pass_skip - core) % num_cores) % num_cores;
return pass_skip + core_skip;
}
// The number of lines to be rendered by this thread
int count_for_thread(int first_line, int count)
{
int lines_until_pass_end = MAX(pass_end_y - first_line, 0);
count = MIN(count, lines_until_pass_end);
int c = (count - skipped_by_thread(first_line) + num_cores - 1) / num_cores;
return MAX(c, 0);
}
// Calculate the dest address for the first line to be rendered by this thread
template<typename T>
T *dest_for_thread(int first_line, int pitch, T *dest)
{
return dest + skipped_by_thread(first_line) * pitch;
}
};
// Task to be executed by each worker thread
class DrawerCommand
{
protected:
int _dest_y;
void DetectRangeError(uint32_t *&dest, int &dest_y, int &count)
{
#if defined(_MSC_VER) && defined(_DEBUG)
if (dest_y < 0 || count < 0 || dest_y + count > swrenderer::drawerargs::dc_destheight)
__debugbreak(); // Buffer overrun detected!
#endif
if (dest_y < 0)
{
count += dest_y;
dest_y = 0;
dest = (uint32_t*)swrenderer::drawerargs::dc_destorg;
}
else if (dest_y >= swrenderer::drawerargs::dc_destheight)
{
dest_y = 0;
count = 0;
}
if (count < 0 || count > MAXHEIGHT) count = 0;
if (dest_y + count >= swrenderer::drawerargs::dc_destheight)
count = swrenderer::drawerargs::dc_destheight - dest_y;
}
public:
DrawerCommand()
{
if (swrenderer::r_swtruecolor)
_dest_y = static_cast<int>((swrenderer::drawerargs::dc_dest - swrenderer::drawerargs::dc_destorg) / (swrenderer::drawerargs::dc_pitch * 4));
else
_dest_y = static_cast<int>((swrenderer::drawerargs::dc_dest - swrenderer::drawerargs::dc_destorg) / (swrenderer::drawerargs::dc_pitch));
}
virtual ~DrawerCommand() { }
virtual void Execute(DrawerThread *thread) = 0;
virtual FString DebugInfo() = 0;
};
void VectoredTryCatch(void *data, void(*tryBlock)(void *data), void(*catchBlock)(void *data, const char *reason, bool fatal));
// Manages queueing up commands and executing them on worker threads
class DrawerCommandQueue
{
enum { memorypool_size = 16 * 1024 * 1024 };
char memorypool[memorypool_size];
size_t memorypool_pos = 0;
std::vector<DrawerCommand *> commands;
std::vector<DrawerThread> threads;
std::mutex start_mutex;
std::condition_variable start_condition;
std::vector<DrawerCommand *> active_commands;
bool shutdown_flag = false;
int run_id = 0;
std::mutex end_mutex;
std::condition_variable end_condition;
size_t finished_threads = 0;
FString thread_error;
bool thread_error_fatal = false;
int threaded_render = 0;
DrawerThread single_core_thread;
int num_passes = 1;
int rows_in_pass = MAXHEIGHT;
void StartThreads();
void StopThreads();
void Finish();
static DrawerCommandQueue *Instance();
static void ReportDrawerError(DrawerCommand *command, bool worker_thread, const char *reason, bool fatal);
DrawerCommandQueue();
~DrawerCommandQueue();
public:
// Allocate memory valid for the duration of a command execution
static void* AllocMemory(size_t size);
// Queue command to be executed by drawer worker threads
template<typename T, typename... Types>
static void QueueCommand(Types &&... args)
{
auto queue = Instance();
if (queue->threaded_render == 0 || !r_multithreaded)
{
T command(std::forward<Types>(args)...);
VectoredTryCatch(&command,
[](void *data)
{
T *c = (T*)data;
c->Execute(&Instance()->single_core_thread);
},
[](void *data, const char *reason, bool fatal)
{
T *c = (T*)data;
ReportDrawerError(c, false, reason, fatal);
});
}
else
{
void *ptr = AllocMemory(sizeof(T));
if (!ptr) // Out of memory - render what we got
{
queue->Finish();
ptr = AllocMemory(sizeof(T));
if (!ptr)
return;
}
T *command = new (ptr)T(std::forward<Types>(args)...);
queue->commands.push_back(command);
}
}
// Redirects all drawing commands to worker threads until End is called
// Begin/End blocks can be nested.
static void Begin();
// End redirection and wait until all worker threads finished executing
static void End();
// Waits until all worker threads finished executing
static void WaitForWorkers();
};