Dosbox vsync opengl how to#
Dosbox vsync opengl windows#

To enable vync you can call wglSwapIntervalEXT(1), to disable it you call wglSwapIntervalEXT(0). Then you can use these pointers as any other pointer to function. WglGetSwapIntervalEXT = (PFNWGLGETSWAPINTERVALEXTPROC) wglGetProcAddress('wglGetSwapIntervalEXT') this is another function from WGL_EXT_swap_control extension WglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC) wglGetProcAddress('wglSwapIntervalEXT')

Extension is supported, init pointers. If (WGLExtensionSupported('WGL_EXT_swap_control')) PFNWGLGETSWAPINTERVALEXTPROC wglGetSwapIntervalEXT = NULL To initialize your function pointers you need to: PFNWGLSWAPINTERVALEXTPROC wglSwapIntervalEXT = NULL If (strstr(_wglGetExtensionsStringEXT(), extension_name) = NULL) _wglGetExtensionsStringEXT = (PFNWGLGETEXTENSIONSSTRINGEXTPROC) wglGetProcAddress('wglGetExtensionsStringEXT') determine pointer to wglGetExtensionsStringEXT function PFNWGLGETEXTENSIONSSTRINGEXTPROC _wglGetExtensionsStringEXT = NULL

this is pointer to function which returns pointer to string with list of all wgl extensions To test for support of given extension you can use function like this: #include īool WGLExtensionSupported(const char *extension_name) Itīefore using this function you need query whether you card has WglSwapIntervalEXT is from WGL_EXT_swap_control extension. To get more info about all published extensions you can look into

Dosbox vsync opengl windows#

In wglext file all entry points for Windows specific extensions are If you are working on Windows you have to use extensions to useĭefined in wglext.h. Loop Until MultiKey(FB.SC_Q) Or MultiKey(FB.On Windows there is OpenGL extension method wglSwapIntervalEXT. If Timer - PrevT < dT Then Sleep dT*1000, 1 ' Test For intersection with the obsticle If MultiKey(FB.SC_UP) Then circley -= circlespeed * dT If MultiKey(FB.SC_DOWN) Then circley += circlespeed * dT If MultiKey(FB.SC_LEFT) Then circlex -= circlespeed * dT If MultiKey(FB.SC_RIGHT) Then circlex += circlespeed * dT ' According to pushed key we change the circle's coordinates. Sleep 250, 1 'Emulate Really Slow computer Image you need to run the code: (save as BMP)ĭim Shared As Single PrevX, PrevY, circlex, circley, circlespeedĬirclespeed = 200 ' Circle's speed => 200 pixels per secĬircle (circlex, circley), 10, RGB(255, 0, 0),F Test it for different FPS (SLEEP command). Screenunlock ' Unlock the page to display what has been drawn.ĭim as double timer_elapsed = (timer - start_time) PRINT 'time-based factor:' tb_movement_factor PUT (guybrush_x ,140), Frame(frame1), PSET Screenset workpage, workpage xor 1 ' Swap work pages. Screenlock ' Lock our screen (nothing will be Guybrush_x = guybrush_x + 2 * tb_movement_factor ' (if your program runs 60 FPS, tb_movement_factor will be 1)įrame1 = frame1 + 0.09 * tb_movement_factor Tb_movement_factor = loop_time * 60 ' adjust your movement factor to 60 FPS

If loop_time > 1.6 then loop_time = 1.6 ' initial loop cap max If loop_time = 0 then loop_time = 1 ' initial loop cap min

Dosbox vsync opengl how to#

So that brings me a question - how to time game so it'll have constant framerate, not depended on CPU speed (and therefore player won't be able to cheat it using CPU slower and it'll run on uber 500 GHz quantum computers in future ) Example BASIC codes would be welcomed.ĭIM SHARED AS Double frame1=1, guybrush_x = -120ĭim Shared As Double loop_time=1, this_time, tb_movement_factor=1 If you will put Win98 (last Windows with real dos, me doesn't count) on one of modern computers (like Pentium 4 or Core2Duo, not sure if 98 will go on really modern computers )) it'll run as fast as it did when it came out, it won't glitch and can't be cheated with cpu slower (it has slow down option in pause menu anyway, so it is not needed for people who can't go through game otherwise). Well, there are some titles that doesn't have such issues, for example first Jazz Jackrabbit. There are some games, especially very old ones that on newest computers runs like hell and they glitched up, because programmer didn't think that computers will get faster eventually and only solution for that is program that will slow down your CPU, while some others which run fine on modern equipment can be cheated using cpu slower. Sorry for title but couldn't think of another.