SDL2 硬件渲染的奇怪行为 [英] SDL2 strange behaviour of hardware rendering
问题描述
我想创建我的第一个游戏.
没什么特别的，只是按下 WSAD 键时蓝色矩形移动.
I want to create my first game.
Nothing special, just blue rectangle moving when WSAD keys are pressed.
问题是当我运行我的游戏时，矩形有错误(见下图).错误仅在水平移动时出现，垂直时不会出现.
The problem is that when I run my game, there are bugs with rectangle(See image below). Bugs appears only during horizontal movement, and not vertical.
有趣的是，当我换行时:
Which is interesting, when I changed line:
renderer = SDL_CreateRenderer(display, -1, SDL_RENDERER_ACCELERATED)
到:
renderer = SDL_CreateRenderer(display, -1, SDL_RENDERER_SOFTWARE)
一切正常
我使用的是 Windows 10、MinGw 和 CMake(C++14) 和 SDL 2.0.8、英特尔酷睿 i5 第 7 代、Radeon M7 R465
I am using Windows 10, MinGw with CMake(C++14), and SDL 2.0.8, Intel core i5 7th gen, Radeon M7 R465
我的代码 OnRender 函数负责渲染，也许我做错了什么?(我的代码中的函数发布在问题末尾)
Im my code OnRender function is responsible for rendering, maybe I made something wrong in it?(Function in my code posted at end of question)
我也使用 SDL_WINDOW_OPENGL 标志来创建我的窗口，但将其更改为 SDL_WINDOW_SHOWN 不会改变任何内容.
I am also using SDL_WINDOW_OPENGL flag to create my window, but changing it to SDL_WINDOW_SHOWN doesn't change anything.
#include <SDL2/SDL.h>
class Game
{
private:
SDL_Surface *display_surf = nullptr;
SDL_Renderer *renderer = nullptr;
SDL_Window *display = nullptr;
private:
bool running, prW = false, prS = false, prD = false, prA = false;
int x, y;
int spd_y, spd_x;
int scr_w, scr_h;
public:
Game();
int OnExecute();
public:
bool OnInit();
void OnEvent( SDL_Event *event );
void OnLoop();
void OnRender();
void OnCleanup();
};
Game::Game()
{
running = false;
}
int Game::OnExecute()
{
if( !OnInit() )
{
return -1;
}
running = true;
SDL_Event event;
while( running )
{
while( SDL_PollEvent( &event ) )
{
OnEvent( &event );
}
OnLoop();
OnRender();
SDL_Delay( 1 );
}
OnCleanup();
return 0;
}
bool Game::OnInit()
{
if( SDL_Init( SDL_INIT_EVERYTHING ) < 0 )
{
return false;
}
SDL_DisplayMode dspm;
if( SDL_GetDesktopDisplayMode( 0, &dspm ) < 0 )
{
return false;
}
scr_h = dspm.h;
scr_w = dspm.w;
if( ( display = SDL_CreateWindow( "Game", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1920, 1080,
SDL_WINDOW_OPENGL ) ) == nullptr )
{
return false;
}
display_surf = SDL_GetWindowSurface( display );
if( ( renderer = SDL_CreateRenderer( display, -1, SDL_RENDERER_ACCELERATED ) ) == nullptr )
{
return false;
}
x = 0;
y = 0;
spd_x = 0;
spd_y = 0;
SDL_SetWindowFullscreen( display, SDL_WINDOW_FULLSCREEN );
return true;
}
void Game::OnEvent( SDL_Event *event )
{
if( event->type == SDL_QUIT )
{
running = false;
return;
}
switch( event->type )
{
case SDL_KEYDOWN:
switch( event->key.keysym.sym )
{
case SDLK_w:
if( prS )
{
spd_y = 0;
}
else
{
spd_y = -5;
}
prW = true;
break;
case SDLK_s:
if( prW )
{
spd_y = 0;
}
else
{
spd_y = 5;
}
prS = true;
break;
case SDLK_d:
if( prA )
{
spd_x = 0;
}
else
{
spd_x = 5;
}
prD = true;
break;
case SDLK_a:
if( prD )
{
spd_x = 0;
}
else
{
spd_x = -5;
}
prA = true;
break;
default:
return;
}
break;
case SDL_KEYUP:
switch( event->key.keysym.sym )
{
case SDLK_w:
if( !prS )
{
spd_y = 0;
}
else
{
spd_y = 5;
}
prW = false;
break;
case SDLK_s:
if( !prW )
{
spd_y = 0;
}
else
{
spd_y = -5;
}
prS = false;
break;
case SDLK_a:
if( !prD )
{
spd_x = 0;
}
else
{
spd_x = 5;
}
prA = false;
break;
case SDLK_d:
if( !prA )
{
spd_x = 0;
}
else
{
spd_x = -5;
}
prD = false;
break;
default:
return;
}
default:
return;
}
}
void Game::OnLoop()
{
x += spd_x;
y += spd_y;
if( x < 0 )
{
x = 0;
}
else if( x > scr_w - 100 )
{
x = scr_w - 100;
}
if( y < 0 )
{
y = 0;
}
else if( y > scr_h - 100 )
{
y = scr_h - 100;
}
}
void Game::OnRender()
{
SDL_SetRenderDrawColor( renderer, 0, 0, 0, 0x00 );
SDL_RenderClear( renderer );
SDL_Rect charc;
charc.x = x;
charc.y = y;
charc.w = 100;
charc.h = 100;
SDL_SetRenderDrawColor( renderer, 0, 0, 0xff, 0 );
SDL_RenderFillRect( renderer, &charc );
SDL_RenderPresent( renderer );
}
void Game::OnCleanup()
{
SDL_DestroyWindow( display );
SDL_Quit();
}
int main( int argc, char** argv )
{
Game game;
return game.OnExecute();
}
推荐答案
看起来很像 tearing 高帧率引起的 &缺乏垂直同步.
Looks a lot like tearing caused by a high frame-rate & lack of vsync.
我可以通过传递SDL_RENDERER_ACCELERATED | 获得无撕裂的绘图SDL_RENDERER_PRESENTVSYNC 到 SDL_CreateRenderer() 上的 flags:
I can get tear-less drawing by passing SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC to flags on SDL_CreateRenderer():
#include <SDL2/SDL.h>
#include <iostream>
class Game
{
private:
SDL_Renderer *renderer = nullptr;
SDL_Window *display = nullptr;
private:
bool running, prW = false, prS = false, prD = false, prA = false;
int x, y;
int spd_y, spd_x;
int scr_w, scr_h;
public:
Game();
int OnExecute();
public:
bool OnInit();
void OnEvent( SDL_Event *event );
void OnLoop();
void OnRender();
void OnCleanup();
};
Game::Game()
{
running = false;
}
int Game::OnExecute()
{
if( !OnInit() )
{
return -1;
}
running = true;
SDL_Event event;
Uint32 beg = SDL_GetTicks();
size_t frames = 0;
while( running )
{
while( SDL_PollEvent( &event ) )
{
OnEvent( &event );
}
OnLoop();
OnRender();
frames++;
Uint32 end = SDL_GetTicks();
if( end - beg > 1000 )
{
std::cout << "Frame time: " << ( end - beg ) / frames << " ms" << std::endl;
beg = end;
frames = 0;
}
}
OnCleanup();
return 0;
}
bool Game::OnInit()
{
if( SDL_Init( SDL_INIT_EVERYTHING ) < 0 )
{
return false;
}
if( ( display = SDL_CreateWindow( "Game", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, 0 ) ) == nullptr )
{
return false;
}
scr_w = 1280;
scr_h = 720;
Uint32 rflags = SDL_RENDERER_ACCELERATED;
rflags |= SDL_RENDERER_PRESENTVSYNC;
if( ( renderer = SDL_CreateRenderer( display, -1, rflags ) ) == nullptr )
{
return false;
}
x = 0;
y = 0;
spd_x = 0;
spd_y = 0;
return true;
}
void Game::OnEvent( SDL_Event *event )
{
if( event->type == SDL_QUIT )
{
running = false;
return;
}
switch( event->type )
{
case SDL_KEYDOWN:
switch( event->key.keysym.sym )
{
case SDLK_w:
if( prS )
{
spd_y = 0;
}
else
{
spd_y = -5;
}
prW = true;
break;
case SDLK_s:
if( prW )
{
spd_y = 0;
}
else
{
spd_y = 5;
}
prS = true;
break;
case SDLK_d:
if( prA )
{
spd_x = 0;
}
else
{
spd_x = 5;
}
prD = true;
break;
case SDLK_a:
if( prD )
{
spd_x = 0;
}
else
{
spd_x = -5;
}
prA = true;
break;
default:
return;
}
break;
case SDL_KEYUP:
switch( event->key.keysym.sym )
{
case SDLK_w:
if( !prS )
{
spd_y = 0;
}
else
{
spd_y = 5;
}
prW = false;
break;
case SDLK_s:
if( !prW )
{
spd_y = 0;
}
else
{
spd_y = -5;
}
prS = false;
break;
case SDLK_a:
if( !prD )
{
spd_x = 0;
}
else
{
spd_x = 5;
}
prA = false;
break;
case SDLK_d:
if( !prA )
{
spd_x = 0;
}
else
{
spd_x = -5;
}
prD = false;
break;
default:
return;
}
default:
return;
}
}
void Game::OnLoop()
{
x += spd_x;
y += spd_y;
if( x < 0 )
{
x = 0;
}
else if( x > scr_w - 100 )
{
x = scr_w - 100;
}
if( y < 0 )
{
y = 0;
}
else if( y > scr_h - 100 )
{
y = scr_h - 100;
}
}
void Game::OnRender()
{
SDL_SetRenderDrawColor( renderer, 0, 0, 0, 0x00 );
SDL_RenderClear( renderer );
SDL_Rect charc;
charc.x = x;
charc.y = y;
charc.w = 100;
charc.h = 100;
SDL_SetRenderDrawColor( renderer, 0, 0, 0xff, 0 );
SDL_RenderFillRect( renderer, &charc );
SDL_Delay( 1 );
SDL_RenderPresent( renderer );
}
void Game::OnCleanup()
{
SDL_DestroyWindow( display );
SDL_Quit();
}
int main( int argc, char** argv )
{
Game game;
return game.OnExecute();
}
如果我只是通过了SDL_RENDERER_ACCELERATED，我会撕裂并且大大更高的帧速率.
If I just pass SDL_RENDERER_ACCELERATED I get tearing and a vastly higher frame-rate.
确保您的操作系统未配置为默认禁用 vsync.
Make sure your OS isn't configured to disable vsync by default.
这篇关于SDL2 硬件渲染的奇怪行为的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
