Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_SetColors.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 |
| rev | line source |
|---|---|
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_SetColors" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_SetColors\- Sets a portion of the colormap for the given 8-bit surface\&. | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 .sp | |
| 8 \fBint \fBSDL_SetColors\fP\fR(\fBSDL_Surface *surface, SDL_Color *colors, int firstcolor, int ncolors\fR); | |
| 9 .SH "DESCRIPTION" | |
| 10 .PP | |
| 11 Sets a portion of the colormap for the given 8-bit surface\&. | |
| 12 .PP | |
| 13 When \fBsurface\fR is the surface associated with the current display, the display colormap will be updated with the requested colors\&. If \fBSDL_HWPALETTE\fP was set in \fISDL_SetVideoMode\fR flags, \fBSDL_SetColors\fP will always return \fB1\fR, and the palette is guaranteed to be set the way you desire, even if the window colormap has to be warped or run under emulation\&. | |
| 14 .PP | |
| 15 The color components of a \fI\fBSDL_Color\fR\fR structure are 8-bits in size, giving you a total of 256^3 =16777216 colors\&. | |
| 16 .PP | |
| 17 Palettized (8-bit) screen surfaces with the \fBSDL_HWPALETTE\fP flag have two palettes, a logical palette that is used for mapping blits to/from the surface and a physical palette (that determines how the hardware will map the colors to the display)\&. \fBSDL_SetColors\fP modifies both palettes (if present), and is equivalent to calling \fISDL_SetPalette\fR with the \fBflags\fR set to \fB(SDL_LOGPAL | SDL_PHYSPAL)\fP\&. | |
| 18 .SH "RETURN VALUE" | |
| 19 .PP | |
| 20 If \fBsurface\fR is not a palettized surface, this function does nothing, returning \fB0\fR\&. If all of the colors were set as passed to \fBSDL_SetColors\fP, it will return \fB1\fR\&. If not all the color entries were set exactly as given, it will return \fB0\fR, and you should look at the surface palette to determine the actual color palette\&. | |
| 21 .SH "EXAMPLE" | |
| 22 .PP | |
| 23 .nf | |
| 24 \f(CW/* Create a display surface with a grayscale palette */ | |
| 25 SDL_Surface *screen; | |
| 26 SDL_Color colors[256]; | |
| 27 int i; | |
| 28 \&. | |
| 29 \&. | |
| 30 \&. | |
| 31 /* Fill colors with color information */ | |
| 32 for(i=0;i<256;i++){ | |
| 33 colors[i]\&.r=i; | |
| 34 colors[i]\&.g=i; | |
| 35 colors[i]\&.b=i; | |
| 36 } | |
| 37 | |
| 38 /* Create display */ | |
| 39 screen=SDL_SetVideoMode(640, 480, 8, SDL_HWPALETTE); | |
| 40 if(!screen){ | |
| 41 printf("Couldn\&'t set video mode: %s | |
| 42 ", SDL_GetError()); | |
| 43 exit(-1); | |
| 44 } | |
| 45 | |
| 46 /* Set palette */ | |
| 47 SDL_SetColors(screen, colors, 0, 256); | |
| 48 \&. | |
| 49 \&. | |
| 50 \&. | |
| 51 \&.\fR | |
| 52 .fi | |
| 53 .PP | |
| 54 .SH "SEE ALSO" | |
| 55 .PP | |
| 56 \fI\fBSDL_Color\fR\fR \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_SetPalette\fP\fR, \fI\fBSDL_SetVideoMode\fP\fR | |
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
57 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |