Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetPalette.3 @ 1555:780fd5b61df1
Fixed bug #89
Date: Sun, 23 Oct 2005 16:39:03 +0200
From: "A. Schmid" <sahib@phreaker.net>
Subject: [SDL] no software surfaces with svgalib driver?
Hi,
I noticed that the SDL (1.2.9) svgalib driver only makes use of linear
addressable (framebuffer) video modes. On older systems (like one of
mine), linear addressable modes are often not available.
Especially for cards with VESA VBE < 2.0 the svgalib vesa driver is
unusable, since VESA only supports framebuffering for VBE 2.0 and later.
The changes necessary to add support for software surfaces seem to be
relatively small. I only had to hack src/video/svga/SDL_svgavideo.c (see
attached patch). The code worked fine for me, but it is no more than a
proof of concept and should be reviewed (probably has a memory leak when
switching modes). It also uses the vgagl library (included in the
svgalib package) and needs to be linked against it.
-Alex
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 19 Mar 2006 12:05:16 +0000 |
parents | e5bc29de3f0a |
children | 546f7c1eb755 |
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.TH "SDL_SetPalette" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetPalette\- Sets the colors in the palette of an 8-bit surface\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetPalette\fP\fR(\fBSDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors\fR); .SH "DESCRIPTION" .PP Sets a portion of the palette for the given 8-bit surface\&. .PP 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)\&. \fISDL_BlitSurface\fR 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)\&. .PP This function can modify either the logical or physical palette by specifing \fBSDL_LOGPAL\fP or \fBSDL_PHYSPAL\fPthe in the \fBflags\fR parameter\&. .PP 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_SetPalette\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\&. .PP 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\&. .SH "RETURN VALUE" .PP 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_SetPalette\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\&. .SH "EXAMPLE" .PP .nf \f(CW /* 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<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 ", SDL_GetError()); exit(-1); } /* Set palette */ SDL_SetPalette(screen, SDL_LOGPAL|SDL_PHYSPAL, colors, 0, 256); \&. \&. \&. \&.\fR .fi .PP .SH "SEE ALSO" .PP \fISDL_SetColors\fR, \fISDL_SetVideoMode\fR, \fISDL_Surface\fR, \fISDL_Color\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01