color setzen



  • #include "SDL.h"
    int SDL_SetColors(SDL_Surface *surface, SDL_Color *colors, int firstcolor, int ncolors);

    wofür sind hier die variablen firstcolor und ncolors, was muss ich da eingeben?

    und ich hab noch ne frage:
    setzt SDL_SetColors den farbton des bildes(SDL_Surface) oder
    wird das bild komplett rot oder blau,grün....



  • SDL_SetColors
    Name
    SDL_SetColors -- Sets a portion of the colormap for the given 8-bit surface.
    Synopsis

    #include "SDL.h"

    int SDL_SetColors(SDL_Surface *surface, SDL_Color *colors, int firstcolor, int ncolors);

    Description

    Sets a portion of the colormap for the given 8-bit surface.

    When surface is the surface associated with the current display, the display colormap will be updated with the requested colors. If SDL_HWPALETTE was set in SDL_SetVideoMode flags, SDL_SetColors will always return 1, 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.

    The color components of a SDL_Color structure are 8-bits in size, giving you a total of 2563 =16777216 colors.

    Palettized (8-bit) screen surfaces with the SDL_HWPALETTE 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). SDL_SetColors modifies both palettes (if present), and is equivalent to calling SDL_SetPalette with the flags set to (SDL_LOGPAL | SDL_PHYSPAL).
    Return Value

    If surface is not a palettized surface, this function does nothing, returning 0. If all of the colors were set as passed to SDL_SetColors, it will return 1. If not all the color entries were set exactly as given, it will return 0, and you should look at the surface palette to determine the actual color palette.
    Example

    /* 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\n", SDL_GetError());
    exit(-1);
    }

    /* Set palette */
    SDL_SetColors(screen, colors, 0, 256);
    .
    .
    .



  • das hab ich mir schon angeguck verstehe es aber nich



  • mach dich mit dem konzept der farbpalette vertraut.


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