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Date: Sat, 14 Feb 2004 14:52:40 +0200 From: "Mike Gorchak" Subject: Batch of the QNX6 fixes for the SDL 1. Updated readme.QNX 2. Fixed crashes during intensive window updating under fast machines (got over 200 rectangles for update). 3. Fixed double-buffered fullscreen modes, now it works as needed. 4. Fixed Photon detection algorithm. 5. Fixed HWSURFACE update function. 6. Added SDL_PHOTON_FULLSCREEN_REFRESH environment variable support for control refresh rates under Photon. 7. Added 640x400 fullscreen mode emulation via 640x480 (if videodriver not supports original 640x400 mode of course) shifted by 40 vertical pixels from begin, to center it. It's needed for some old DOS games which ran in doubled 320x200 mode. 8. Added available video ram amount support. 8. Added hardware surface allocation/deallocation support if current videomode and videodriver supports it. 9. Added hardware filling support. 10. Added hardware blits support (simple and colorkeyed). And I've added to testvidinfo test color-keyed blits benchmark (maybe need to add alpha blits benchmark too ?). Currently Photon not supporting any alpha hardware blittings (all drivers lack of alpha blitting code support, only software alpha blitting exist in photon, which is hundreds times slowest than the SDL's one). So I've not added the alpha support. I suppose new QNX 6.3 will have the hardware alpha support, so when it will be done, I'll add alpha support.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 14 Feb 2004 20:22:21 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_AudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_AudioCVT\- Audio Conversion Structure
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  int needed;
  Uint16 src_format;
  Uint16 dest_format;
  double rate_incr;
  Uint8 *buf;
  int len;
  int len_cvt;
  int len_mult;
  double len_ratio;
  void (*filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);
  int filter_index;
} SDL_AudioCVT;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBneeded\fR
Set to one if the conversion is possible
.TP 20
\fBsrc_format\fR
Audio format of the source
.TP 20
\fBdest_format\fR
Audio format of the destination
.TP 20
\fBrate_incr\fR
Rate conversion increment
.TP 20
\fBbuf\fR
Audio buffer
.TP 20
\fBlen\fR
Length of the original audio buffer in bytes
.TP 20
\fBlen_cvt\fR
Length of converted audio buffer in bytes (calculated)
.TP 20
\fBlen_mult\fR
\fBbuf\fR must be \fBlen\fR*\fBlen_mult\fR bytes in size(calculated)
.TP 20
\fBlen_ratio\fR
Final audio size is \fBlen\fR*\fBlen_ratio\fR
.TP 20
\fBfilters[10](\&.\&.)\fR
Pointers to functions needed for this conversion
.TP 20
\fBfilter_index\fR
Current conversion function
.SH "DESCRIPTION"
.PP
The \fBSDL_AudioCVT\fR is used to convert audio data between different formats\&. A \fBSDL_AudioCVT\fR structure is created with the \fI\fBSDL_BuildAudioCVT\fP\fR function, while the actual conversion is done by the \fI\fBSDL_ConvertAudio\fP\fR function\&.
.PP
Many of the fields in the \fBSDL_AudioCVT\fR structure should be considered private and their function will not be discussed here\&.
.IP "\fBUint8 *\fP\fBbuf\fR" 10This points to the audio data that will be used in the conversion\&. It is both the source and the destination, which means the converted audio data overwrites the original data\&. It also means that the converted data may be larger than the original data (if you were converting from 8-bit to 16-bit, for instance), so you must ensure \fBbuf\fR is large enough\&. See below\&.
.IP "\fBint\fP \fBlen\fR" 10This is the length of the original audio data in bytes\&.
.IP "\fBint\fP \fBlen_mult\fR" 10As explained above, the audio buffer needs to be big enough to store the converted data, which may be bigger than the original audio data\&. The length of \fBbuf\fR should be \fBlen\fR*\fBlen_mult\fR\&.
.IP "\fBdouble\fP \fBlen_ratio\fR" 10When you have finished converting your audio data, you need to know how much of your audio buffer is valid\&. \fBlen\fR*\fBlen_ratio\fR is the size of the converted audio data in bytes\&. This is very similar to \fBlen_mult\fR, however when the convert audio data is shorter than the original \fBlen_mult\fR would be 1\&. \fBlen_ratio\fR, on the other hand, would be a fractional number between 0 and 1\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioSpec\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58