Mercurial > sdl-ios-xcode
view docs/man3/SDL_DisplayFormatAlpha.3 @ 2661:d38309be5178 gsoc2008_audio_resampling
The windowed sinc filter generation code seems to be working fine. The FIR filtering code is also now working reasonably well. Occasionally the FIR filter will pop, but setting the normalization factor lower seems to help this. I suspect the problem is in the fixed point multiply/add. I also have a hunch the zero stuffing/sample discarding code is not correct, and I'll look at that soon to get it sorted out.
| author | Aaron Wishnick <schnarf@gmail.com> |
|---|---|
| date | Wed, 02 Jul 2008 08:04:50 +0000 |
| parents | 546f7c1eb755 |
| children | 1238da4a7112 |
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.TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_DisplayFormatAlpha \- Convert a surface to the display format .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR); .SH "DESCRIPTION" .PP This function takes a surface and copies it to a new surface of the pixel format and colors of the video framebuffer plus an alpha channel, suitable for fast blitting onto the display surface\&. It calls \fISDL_ConvertSurface\fR .PP If you want to take advantage of hardware colorkey or alpha blit acceleration, you should set the colorkey and alpha value before calling this function\&. .PP This function can be used to convert a colourkey to an alpha channel, if the \fBSDL_SRCCOLORKEY\fP flag is set on the surface\&. The generated surface will then be transparent (alpha=0) where the pixels match the colourkey, and opaque (alpha=255) elsewhere\&. .SH "RETURN VALUE" .PP If the conversion fails or runs out of memory, it returns \fBNULL\fR .SH "SEE ALSO" .PP \fISDL_ConvertSurface\fR, \fISDL_SetAlpha\fR, \fISDL_SetColorKey\fR, \fISDL_DisplayFormat\fR, \fISDL_Surface\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01