为什么glFlush()很慢很慢?
Cline 2011-07-11 01:13:18 OS: Win7 64Bit.
显卡:NVIDIA GeForce 9800GT
1.如果把驱动禁掉:Control Panel >Appearance Personalization>Display>Screen resolution>Advance Settings>Adapter>Adapter Type>Properties>Driver>Disable.
glFlush()很慢很慢!
Vendor = Microsoft Corporation
Extensions = GL_WIN_swap_hint
GL_EXT_bgra
GL_EXT_paletted_texture
2.如果驱动正常
glFlush()不慢!
Vendor = NVIDIA Corporation
Extensions = GL_ARB_blend_func_extended
GL_ARB_color_buffer_float
GL_ARB_compatibility
GL_ARB_copy_buffer
GL_ARB_depth_buffer_float
GL_ARB_depth_clamp
GL_ARB_depth_texture
GL_ARB_draw_buffers
GL_ARB_draw_elements_base_vertex
GL_ARB_draw_instanced
GL_ARB_ES2_compatibility
GL_ARB_explicit_attrib_location
GL_ARB_fragment_coord_conventions
GL_ARB_fragment_program
GL_ARB_fragment_program_shadow
GL_ARB_
请问为什么会慢呢?可以通过什么标志能判断一定会慢?谢谢!
代码:
//
// GLSAMPLE.CPP
// by Blaine Hodge
//
// Includes
#include <windows.h>
#include <gl/gl.h>
// Function Declarations
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
void EnableOpenGL(HWND hWnd, HDC * hDC, HGLRC * hRC);
void DisableOpenGL(HWND hWnd, HDC hDC, HGLRC hRC);
// WinMain
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int iCmdShow)
{
WNDCLASS wc;
HWND hWnd;
HDC hDC;
HGLRC hRC;
MSG msg;
BOOL quit = FALSE;
float theta = 0.0f;
// register window class
wc.style = CS_OWNDC;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon( NULL, IDI_APPLICATION );
wc.hCursor = LoadCursor( NULL, IDC_ARROW );
wc.hbrBackground = (HBRUSH)GetStockObject( BLACK_BRUSH );
wc.lpszMenuName = NULL;
wc.lpszClassName = "GLSample";
RegisterClass( &wc );
// create main window
hWnd = CreateWindow(
"GLSample", "OpenGL Sample",
WS_CAPTION | WS_POPUPWINDOW | WS_VISIBLE,
0, 0, 856, 856,
NULL, NULL, hInstance, NULL );
// enable OpenGL for the window
EnableOpenGL( hWnd, &hDC, &hRC );
// program main loop
while ( !quit )
{
// check for messages
if ( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
{
// handle or dispatch messages
if ( msg.message == WM_QUIT )
{
quit = TRUE;
}
else
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
}
else
{
const char* vendor = (const char*)::glGetString(GL_VENDOR);
const char* ext = (const char*)::glGetString(GL_EXTENSIONS);
// OpenGL animation code goes here
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();
glRotatef( theta, 0.0f, 0.0f, 1.0f );
glBegin( GL_TRIANGLES );
glColor3f( 1.0f, 0.0f, 0.0f ); glVertex2f( 0.0f, 1.0f );
glColor3f( 0.0f, 1.0f, 0.0f ); glVertex2f( 0.87f, -0.5f );
glColor3f( 0.0f, 0.0f, 1.0f ); glVertex2f( -0.87f, -0.5f );
glEnd();
glPopMatrix();
glFlush();
glDrawBuffer(GL_FRONT);
glReadBuffer(GL_BACK);
glCopyPixels(0, 0, 856, 856, GL_COLOR);
glFlush();
glDrawBuffer(GL_BACK);
theta += 1.0f;
}
}
// shutdown OpenGL
DisableOpenGL( hWnd, hDC, hRC );
// destroy the window explicitly
DestroyWindow( hWnd );
return msg.wParam;
}
// Window Procedure
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
return 0;
case WM_CLOSE:
PostQuitMessage( 0 );
return 0;
case WM_DESTROY:
return 0;
case WM_KEYDOWN:
switch ( wParam )
{
case VK_ESCAPE:
PostQuitMessage(0);
return 0;
}
return 0;
default:
return DefWindowProc( hWnd, message, wParam, lParam );
}
}
// Enable OpenGL
void EnableOpenGL(HWND hWnd, HDC * hDC, HGLRC * hRC)
{
// get the device context (DC)
*hDC = GetDC( hWnd );
PIXELFORMATDESCRIPTOR pfd, *ppfd = &pfd;
ppfd->nSize = sizeof(PIXELFORMATDESCRIPTOR);
ppfd->nVersion = 1;
ppfd->dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER ;
ppfd->dwLayerMask = PFD_MAIN_PLANE;
ppfd->iPixelType = PFD_TYPE_RGBA;
ppfd->cColorBits = 8;
ppfd->cDepthBits = 24;
ppfd->cAccumBits = 0;
ppfd->cStencilBits = 0;
int pixelformat = ChoosePixelFormat(*hDC, ppfd);
if ((pixelformat = ChoosePixelFormat(*hDC, ppfd)) == 0) {
return ;
}
if (SetPixelFormat(*hDC, pixelformat, ppfd) == FALSE) {
return ;
}
// create and enable the render context (RC)
*hRC = wglCreateContext( *hDC );
wglMakeCurrent( *hDC, *hRC );
}
// Disable OpenGL
void DisableOpenGL(HWND hWnd, HDC hDC, HGLRC hRC)
{
wglMakeCurrent( NULL, NULL );
wglDeleteContext( hRC );
ReleaseDC( hWnd, hDC );
}