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Fixed bug #611 From Tim Angus 2008-08-12 11:18:06 I'm one of the maintainers of ioquake3.org, an updated version of the Quake 3 engine. Relatively recently, we moved ioq3 to use SDL as a replacement for 95% of the platform specific code that was there. On the whole it's doing a great job but unfortunately since the move we've been getting complaints about the quality of the mouse input on the Windows platform to the point where for many the game is unplayable. Put in other terms, the current stable SDL 1.2 is basically not fit for purpose if you need high quality mouse input as you do in a first person shooter. Over the weekend I decided to pull my finger out and actually figure out what's going on. There are basically two major problems. Firstly, when using the "windib" driver, mouse input is gathered via the WM_MOUSEMOVE message. Googling for this indicates that often this is known to result in "spurious" and/or "missing" mouse movement events; this is the primary cause of the poor mouse input. The second problem is that the "directx" driver does not work at all in combination with OpenGL meaning that you can't use DirectInput if your application also uses OpenGL. In other words you're locked into using the "windib" driver and its poor mouse input. In order to address these problems I've done the following: * Remove WM_MOUSEMOVE based motion event generation and replace with calls to GetCursorPos which seems much more reliable. In order to achieve this I've moved mouse motion out into a separate function that is called once per DIB_PumpEvents. * Remove the restriction on the "directx" driver being inoperable in combination with OpenGL. There is a bug for this issues that I've hijacked to a certain extent (http://bugzilla.libsdl.org/show_bug.cgi?id=265). I'm the first to admit I don't really understand why this restriction is there in the first place. The commit message for the bug fix that introduced this restriction (r581) isn't very elaborate and I couldn't see any other bug tracking the issue. If anyone has more information on the bug that was avoided by r581 it would be helpful as I/someone could then look into addressing the problem without disabling the "directx" driver. * I've also removed the restriction on not being allowed to use DirectInput in windowed mode. I couldn't see any reason for this, at least not from our perspective. I have my suspicions that it'll be something like matching up the cursor with the mouse coordinates... * I bumped up the DirectInput API used to version 7 in order to get access to mouse buttons 4-7. I've had to inject a little bit of the DX7 headers into SDL there as the MinGW ones aren't up to date in this respect.
author Sam Lantinga <slouken@libsdl.org>
date Thu, 02 Apr 2009 04:43:36 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>Video</TITLE
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><DIV
CLASS="CHAPTER"
><H1
><A
NAME="VIDEO"
></A
>Chapter 6. Video</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlgetvideosurface.html"
>SDL_GetVideoSurface</A
>&nbsp;--&nbsp;returns a pointer to the current display surface</DT
><DT
><A
HREF="sdlgetvideoinfo.html"
>SDL_GetVideoInfo</A
>&nbsp;--&nbsp;returns a pointer to information about the video hardware</DT
><DT
><A
HREF="sdlvideodrivername.html"
>SDL_VideoDriverName</A
>&nbsp;--&nbsp;Obtain the name of the video driver</DT
><DT
><A
HREF="sdllistmodes.html"
>SDL_ListModes</A
>&nbsp;--&nbsp;Returns a pointer to an array of available screen dimensions for 
the given format and video flags</DT
><DT
><A
HREF="sdlvideomodeok.html"
>SDL_VideoModeOK</A
>&nbsp;--&nbsp;Check to see if a particular video mode is supported.</DT
><DT
><A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>&nbsp;--&nbsp;Set up a video mode with the specified width, height and bits-per-pixel.</DT
><DT
><A
HREF="sdlupdaterect.html"
>SDL_UpdateRect</A
>&nbsp;--&nbsp;Makes sure the given area is updated on the given screen.</DT
><DT
><A
HREF="sdlupdaterects.html"
>SDL_UpdateRects</A
>&nbsp;--&nbsp;Makes sure the given list of rectangles is updated on the given screen.</DT
><DT
><A
HREF="sdlflip.html"
>SDL_Flip</A
>&nbsp;--&nbsp;Swaps screen buffers</DT
><DT
><A
HREF="sdlsetcolors.html"
>SDL_SetColors</A
>&nbsp;--&nbsp;Sets a portion of the colormap for the given 8-bit surface.</DT
><DT
><A
HREF="sdlsetpalette.html"
>SDL_SetPalette</A
>&nbsp;--&nbsp;Sets the colors in the palette of an 8-bit surface.</DT
><DT
><A
HREF="sdlsetgamma.html"
>SDL_SetGamma</A
>&nbsp;--&nbsp;Sets the color gamma function for the display</DT
><DT
><A
HREF="sdlgetgammaramp.html"
>SDL_GetGammaRamp</A
>&nbsp;--&nbsp;Gets the color gamma lookup tables for the display</DT
><DT
><A
HREF="sdlsetgammaramp.html"
>SDL_SetGammaRamp</A
>&nbsp;--&nbsp;Sets the color gamma lookup tables for the display</DT
><DT
><A
HREF="sdlmaprgb.html"
>SDL_MapRGB</A
>&nbsp;--&nbsp;Map a RGB color value to a pixel format.</DT
><DT
><A
HREF="sdlmaprgba.html"
>SDL_MapRGBA</A
>&nbsp;--&nbsp;Map a RGBA color value to a pixel format.</DT
><DT
><A
HREF="sdlgetrgb.html"
>SDL_GetRGB</A
>&nbsp;--&nbsp;Get RGB values from a pixel in the specified pixel format.</DT
><DT
><A
HREF="sdlgetrgba.html"
>SDL_GetRGBA</A
>&nbsp;--&nbsp;Get RGBA values from a pixel in the specified pixel format.</DT
><DT
><A
HREF="sdlcreatergbsurface.html"
>SDL_CreateRGBSurface</A
>&nbsp;--&nbsp;Create an empty SDL_Surface</DT
><DT
><A
HREF="sdlcreatergbsurfacefrom.html"
>SDL_CreateRGBSurfaceFrom</A
>&nbsp;--&nbsp;Create an SDL_Surface from pixel data</DT
><DT
><A
HREF="sdlfreesurface.html"
>SDL_FreeSurface</A
>&nbsp;--&nbsp;Frees (deletes) a SDL_Surface</DT
><DT
><A
HREF="sdllocksurface.html"
>SDL_LockSurface</A
>&nbsp;--&nbsp;Lock a surface for directly access.</DT
><DT
><A
HREF="sdlunlocksurface.html"
>SDL_UnlockSurface</A
>&nbsp;--&nbsp;Unlocks a previously locked surface.</DT
><DT
><A
HREF="sdlloadbmp.html"
>SDL_LoadBMP</A
>&nbsp;--&nbsp;Load a Windows BMP file into an SDL_Surface.</DT
><DT
><A
HREF="sdlsavebmp.html"
>SDL_SaveBMP</A
>&nbsp;--&nbsp;Save an SDL_Surface as a Windows BMP file.</DT
><DT
><A
HREF="sdlsetcolorkey.html"
>SDL_SetColorKey</A
>&nbsp;--&nbsp;Sets the color key (transparent pixel) in a blittable surface and
RLE acceleration.</DT
><DT
><A
HREF="sdlsetalpha.html"
>SDL_SetAlpha</A
>&nbsp;--&nbsp;Adjust the alpha properties of a surface</DT
><DT
><A
HREF="sdlsetcliprect.html"
>SDL_SetClipRect</A
>&nbsp;--&nbsp;Sets the clipping rectangle for a surface.</DT
><DT
><A
HREF="sdlgetcliprect.html"
>SDL_GetClipRect</A
>&nbsp;--&nbsp;Gets the clipping rectangle for a surface.</DT
><DT
><A
HREF="sdlconvertsurface.html"
>SDL_ConvertSurface</A
>&nbsp;--&nbsp;Converts a surface to the same format as another surface.</DT
><DT
><A
HREF="sdlblitsurface.html"
>SDL_BlitSurface</A
>&nbsp;--&nbsp;This performs a fast blit from the source surface to the destination surface.</DT
><DT
><A
HREF="sdlfillrect.html"
>SDL_FillRect</A
>&nbsp;--&nbsp;This function performs a fast fill of the given rectangle with some color</DT
><DT
><A
HREF="sdldisplayformat.html"
>SDL_DisplayFormat</A
>&nbsp;--&nbsp;Convert a surface to the display format</DT
><DT
><A
HREF="sdldisplayformatalpha.html"
>SDL_DisplayFormatAlpha</A
>&nbsp;--&nbsp;Convert a surface to the display format</DT
><DT
><A
HREF="sdlwarpmouse.html"
>SDL_WarpMouse</A
>&nbsp;--&nbsp;Set the position of the mouse cursor.</DT
><DT
><A
HREF="sdlcreatecursor.html"
>SDL_CreateCursor</A
>&nbsp;--&nbsp;Creates a new mouse cursor.</DT
><DT
><A
HREF="sdlfreecursor.html"
>SDL_FreeCursor</A
>&nbsp;--&nbsp;Frees a cursor created with SDL_CreateCursor.</DT
><DT
><A
HREF="sdlsetcursor.html"
>SDL_SetCursor</A
>&nbsp;--&nbsp;Set the currently active mouse cursor.</DT
><DT
><A
HREF="sdlgetcursor.html"
>SDL_GetCursor</A
>&nbsp;--&nbsp;Get the currently active mouse cursor.</DT
><DT
><A
HREF="sdlshowcursor.html"
>SDL_ShowCursor</A
>&nbsp;--&nbsp;Toggle whether or not the cursor is shown on the screen.</DT
><DT
><A
HREF="sdlglloadlibrary.html"
>SDL_GL_LoadLibrary</A
>&nbsp;--&nbsp;Specify an OpenGL library</DT
><DT
><A
HREF="sdlglgetprocaddress.html"
>SDL_GL_GetProcAddress</A
>&nbsp;--&nbsp;Get the address of a GL function</DT
><DT
><A
HREF="sdlglgetattribute.html"
>SDL_GL_GetAttribute</A
>&nbsp;--&nbsp;Get the value of a special SDL/OpenGL attribute</DT
><DT
><A
HREF="sdlglsetattribute.html"
>SDL_GL_SetAttribute</A
>&nbsp;--&nbsp;Set a special SDL/OpenGL attribute</DT
><DT
><A
HREF="sdlglswapbuffers.html"
>SDL_GL_SwapBuffers</A
>&nbsp;--&nbsp;Swap OpenGL framebuffers/Update Display</DT
><DT
><A
HREF="sdlcreateyuvoverlay.html"
>SDL_CreateYUVOverlay</A
>&nbsp;--&nbsp;Create a YUV video overlay</DT
><DT
><A
HREF="sdllockyuvoverlay.html"
>SDL_LockYUVOverlay</A
>&nbsp;--&nbsp;Lock an overlay</DT
><DT
><A
HREF="sdlunlockyuvoverlay.html"
>SDL_UnlockYUVOverlay</A
>&nbsp;--&nbsp;Unlock an overlay</DT
><DT
><A
HREF="sdldisplayyuvoverlay.html"
>SDL_DisplayYUVOverlay</A
>&nbsp;--&nbsp;Blit the overlay to the display</DT
><DT
><A
HREF="sdlfreeyuvoverlay.html"
>SDL_FreeYUVOverlay</A
>&nbsp;--&nbsp;Free a YUV video overlay</DT
><DT
><A
HREF="sdlglattr.html"
>SDL_GLattr</A
>&nbsp;--&nbsp;SDL GL Attributes</DT
><DT
><A
HREF="sdlrect.html"
>SDL_Rect</A
>&nbsp;--&nbsp;Defines a rectangular area</DT
><DT
><A
HREF="sdlcolor.html"
>SDL_Color</A
>&nbsp;--&nbsp;Format independent color description</DT
><DT
><A
HREF="sdlpalette.html"
>SDL_Palette</A
>&nbsp;--&nbsp;Color palette for 8-bit pixel formats</DT
><DT
><A
HREF="sdlpixelformat.html"
>SDL_PixelFormat</A
>&nbsp;--&nbsp;Stores surface format information</DT
><DT
><A
HREF="sdlsurface.html"
>SDL_Surface</A
>&nbsp;--&nbsp;Graphical Surface Structure</DT
><DT
><A
HREF="sdlvideoinfo.html"
>SDL_VideoInfo</A
>&nbsp;--&nbsp;Video Target information</DT
><DT
><A
HREF="sdloverlay.html"
>SDL_Overlay</A
>&nbsp;--&nbsp;YUV video overlay</DT
></DL
></DIV
><P
>SDL presents a very simple interface to the display framebuffer.  The
framebuffer is represented as an offscreen surface to which you can write
directly.  If you want the screen to show what you have written, call the <A
HREF="sdlupdaterects.html"
>update</A
> function which will
guarantee that the desired portion of the screen is updated.</P
><P
>Before you call any of the SDL video functions, you must first call
<SPAN
CLASS="TOKEN"
>SDL_Init(SDL_INIT_VIDEO)</SPAN
>, which initializes the video
and events in the SDL library.  Check the return code, which should be
<SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, to see if there were any errors in starting up.</P
><P
>If you use both sound and video in your application, you need to call
<SPAN
CLASS="TOKEN"
>SDL_Init(SDL_INIT_AUDIO | SDL_INIT_VIDEO)</SPAN
> before opening the
sound device, otherwise under Win32 DirectX, you won't be able to set
full-screen display modes.</P
><P
>After you have initialized the library, you can start up the video display in a
number of ways.  The easiest way is to pick a common screen resolution and
depth and just initialize the video, checking for errors.  You will probably
get what you want, but SDL may be emulating your requested mode and converting
the display on update.  The best way is to
<A
HREF="sdlgetvideoinfo.html"
>query</A
>, for the best
video mode closest to the desired one, and then
<A
HREF="sdldisplayformat.html"
>convert</A
>
your images to that pixel format.</P
><P
>SDL currently supports any bit depth &gt;= 8 bits per pixel.  8 bpp formats are
considered 8-bit palettized modes, while 12, 15, 16, 24, and 32 bits per pixel
are considered "packed pixel" modes, meaning each pixel contains the RGB color
components packed in the bits of the pixel.</P
><P
>After you have initialized your video mode, you can take the surface that was
returned, and write to it like any other framebuffer, calling the update
routine as you go.</P
><P
>When you have finished your video access and are ready to quit your
application, you should call "<SPAN
CLASS="TOKEN"
>SDL_Quit()</SPAN
>" to shutdown the
video and events.</P
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