view docs/html/sdlsetpalette.html @ 914:bbf8dcc8aed6

Date: Wed, 23 Jun 2004 17:05:33 -0400 From: Chris Nelson Subject: [SDL] [Patch] WiseGroup MP-8800 / MP-8866 (PS2 Joystick) In the current cvs version, SDL doesn't handle these Playstation2 controller => USB adapters correctly, in linux. It will always assume that the maximum number of joysticks (2 in the case of the MP-8866, 4 in the case of the 8800) are plugged in. This is bad not only because it allows SDL to exaggerate the number of logical joysticks, but primarily because the joystick axes are mapped incorrectly, all over the place, such that the devices are effectively unusable unless you have the maximum number of joysticks plugged in. My changes to src/joystick/linux/SDL_sysjoystick.c build on another's previous work (which was a special case for this very joystick, actually), and fix both of these problems, as well as making the current code a little more general, to allow for others to more easily drop in code for quirky joysticks such as these. I've tested this code under 2.6.7 as well as 2.4.24... Both work as advertised (provided you load the JOYDEV linux code as a module, otherwise they won't work at all, new code or old, but that's another issue entirely). Though this sounds horribly formal, you have my permission to distribute all of my work on this issue under the LGPL. So there.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 25 Jul 2004 18:31:50 +0000
parents 355632dca928
children
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>SDL_SetPalette</TITLE
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><H1
><A
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>SDL_SetPalette</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1517"
></A
><H2
>Name</H2
>SDL_SetPalette&nbsp;--&nbsp;Sets the colors in the palette of an 8-bit surface.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1520"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1521"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SetPalette</B
></CODE
>(SDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1527"
></A
><H2
>Description</H2
><P
>Sets a portion of the palette for the given 8-bit surface.</P
><P
>Palettized (8-bit) screen surfaces with the
<TT
CLASS="LITERAL"
>SDL_HWPALETTE</TT
> 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). <A
HREF="sdlblitsurface.html"
>SDL_BlitSurface</A
>
always uses the logical palette when blitting surfaces (if it has to
convert between surface pixel formats). Because of this, it is often
useful to modify only one or the other palette to achieve various
special color effects (e.g., screen fading, color flashes, screen dimming).</P
><P
>This function can modify either the logical or physical palette by
specifing <TT
CLASS="LITERAL"
>SDL_LOGPAL</TT
> or
<TT
CLASS="LITERAL"
>SDL_PHYSPAL</TT
>the in the <TT
CLASS="PARAMETER"
><I
>flags</I
></TT
>
parameter.</P
><P
>When <TT
CLASS="PARAMETER"
><I
>surface</I
></TT
> is the surface associated with the current
display, the display colormap will be updated with the requested colors.  If
<TT
CLASS="LITERAL"
>SDL_HWPALETTE</TT
> was set in <A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
> flags,
<TT
CLASS="FUNCTION"
>SDL_SetPalette</TT
> will always return <SPAN
CLASS="RETURNVALUE"
>1</SPAN
>,
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.</P
><P
>The color components of a
<A
HREF="sdlcolor.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Color</SPAN
></A
> structure
are 8-bits in size, giving you a total of
256<SUP
>3</SUP
>=16777216 colors.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1547"
></A
><H2
>Return Value</H2
><P
>If <TT
CLASS="PARAMETER"
><I
>surface</I
></TT
> is not a palettized surface, this function
does nothing, returning <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>.  If all of the colors were set
as passed to <TT
CLASS="FUNCTION"
>SDL_SetPalette</TT
>, it will return
<SPAN
CLASS="RETURNVALUE"
>1</SPAN
>.  If not all the color entries were set exactly as
given, it will return <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, and you should look at the
surface palette to determine the actual color palette.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1555"
></A
><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>        /* Create a display surface with a grayscale palette */
        SDL_Surface *screen;
        SDL_Color colors[256];
        int i;
        .
        .
        .
        /* Fill colors with color information */
        for(i=0;i&#60;256;i++){
          colors[i].r=i;
          colors[i].g=i;
          colors[i].b=i;
        }

        /* Create display */
        screen=SDL_SetVideoMode(640, 480, 8, SDL_HWPALETTE);
        if(!screen){
          printf("Couldn't set video mode: %s\n", SDL_GetError());
          exit(-1);
        }

        /* Set palette */
        SDL_SetPalette(screen, SDL_LOGPAL|SDL_PHYSPAL, colors, 0, 256);
        .
        .
        .
        .</PRE
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><H2
>See Also</H2
><P
><A
HREF="sdlsetcolors.html"
>SDL_SetColors</A
>,
<A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>,
<A
HREF="sdlsurface.html"
>SDL_Surface</A
>,
<A
HREF="sdlcolor.html"
>SDL_Color</A
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