Mercurial > sdl-ios-xcode
view docs/man3/SDL_Surface.3 @ 3880:74e828c64315 SDL-1.2
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 24 Sep 2006 15:45:37 +0000 |
parents | e5bc29de3f0a |
children | 546f7c1eb755 |
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.TH "SDL_Surface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_Surface\- Graphical Surface Structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct SDL_Surface { Uint32 flags; /* Read-only */ SDL_PixelFormat *format; /* Read-only */ int w, h; /* Read-only */ Uint16 pitch; /* Read-only */ void *pixels; /* Read-write */ /* clipping information */ SDL_Rect clip_rect; /* Read-only */ /* Reference count -- used when freeing surface */ int refcount; /* Read-mostly */ /* This structure also contains private fields not shown here */ } SDL_Surface;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBflags\fR Surface flags .TP 20 \fBformat\fR Pixel \fIformat\fR .TP 20 \fBw, h\fR Width and height of the surface .TP 20 \fBpitch\fR Length of a surface scanline in bytes .TP 20 \fBpixels\fR Pointer to the actual pixel data .TP 20 \fBclip_rect\fR surface clip \fIrectangle\fR .SH "DESCRIPTION" .PP \fBSDL_Surface\fR\&'s represent areas of "graphical" memory, memory that can be drawn to\&. The video framebuffer is returned as a \fBSDL_Surface\fR by \fI\fBSDL_SetVideoMode\fP\fR and \fI\fBSDL_GetVideoSurface\fP\fR\&. Most of the fields should be pretty obvious\&. \fBw\fR and \fBh\fR are the width and height of the surface in pixels\&. \fBpixels\fR is a pointer to the actual pixel data, the surface should be \fIlocked\fR before accessing this field\&. The \fBclip_rect\fR field is the clipping rectangle as set by \fI\fBSDL_SetClipRect\fP\fR\&. .PP The following are supported in the \fBflags\fR field\&. .TP 20 \fBSDL_SWSURFACE\fP Surface is stored in system memory .TP 20 \fBSDL_HWSURFACE\fP Surface is stored in video memory .TP 20 \fBSDL_ASYNCBLIT\fP Surface uses asynchronous blits if possible .TP 20 \fBSDL_ANYFORMAT\fP Allows any pixel-format (Display surface) .TP 20 \fBSDL_HWPALETTE\fP Surface has exclusive palette .TP 20 \fBSDL_DOUBLEBUF\fP Surface is double buffered (Display surface) .TP 20 \fBSDL_FULLSCREEN\fP Surface is full screen (Display Surface) .TP 20 \fBSDL_OPENGL\fP Surface has an OpenGL context (Display Surface) .TP 20 \fBSDL_OPENGLBLIT\fP Surface supports OpenGL blitting (Display Surface) .TP 20 \fBSDL_RESIZABLE\fP Surface is resizable (Display Surface) .TP 20 \fBSDL_HWACCEL\fP Surface blit uses hardware acceleration .TP 20 \fBSDL_SRCCOLORKEY\fP Surface use colorkey blitting .TP 20 \fBSDL_RLEACCEL\fP Colorkey blitting is accelerated with RLE .TP 20 \fBSDL_SRCALPHA\fP Surface blit uses alpha blending .TP 20 \fBSDL_PREALLOC\fP Surface uses preallocated memory .SH "SEE ALSO" .PP \fI\fBSDL_PixelFormat\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01