view docs/man3/SDL_BuildAudioCVT.3 @ 3333:b334b4f7dfa0

[SDL] Bad math in SDL_RenderCopy Mason Wheeler to sdl When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this: if (dstrect->w != real_dstrect.w) { int deltax = (dstrect->x - real_dstrect.x); int deltaw = (dstrect->w - real_dstrect.w); real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w; real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w; } if (dstrect->h != real_dstrect.h) { int deltay = (dstrect->y - real_dstrect.y); int deltah = (dstrect->h - real_dstrect.h); real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h; real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author Sam Lantinga <slouken@libsdl.org>
date Sat, 03 Oct 2009 16:23:16 +0000
parents 546f7c1eb755
children 1238da4a7112
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.TH "SDL_BuildAudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_BuildAudioCVT \- Initializes a SDL_AudioCVT structure for conversion
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_BuildAudioCVT\fP\fR(\fBSDL_AudioCVT *cvt, Uint16 src_format, Uint8 src_channels, int src_rate, Uint16 dst_format, Uint8 dst_channels, int dst_rate\fR);
.SH "DESCRIPTION"
.PP
Before an \fI\fBSDL_AudioCVT\fR\fR structure can be used to convert audio data it must be initialized with source and destination information\&. 
.PP
\fBsrc_format\fR and \fBdst_format\fR are the source and destination format of the conversion\&. (For information on audio formats see \fI\fB SDL_AudioSpec\fR\fR)\&. \fBsrc_channels\fR and \fBdst_channels\fR are the number of channels in the source and destination formats\&. Finally, \fBsrc_rate\fR and \fBdst_rate\fR are the frequency or samples-per-second of the source and destination formats\&. Once again, see \fI\fBSDL_AudioSpec\fR\fR\&.
.SH "RETURN VALUES"
.PP
Returns \fB-1\fR if the filter could not be built or 1 if it could\&.
.SH "EXAMPLES"
.PP
See \fI\fBSDL_ConvertAudio\fP\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioCVT\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58