view test/testpalette.c @ 3566:07c8339c95c6

Fixed bug #905 Give the foreign window message proc more control over Windows events. This may need to be adjusted when we add the capability for the app to specify whether it wants SDL to handle input for the window or not.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 15 Dec 2009 09:20:10 +0000
parents 422452508c76
children 06f0768a904c
line wrap: on
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/*
 * testpalette.c
 *
 * A simple test of runtime palette modification for animation
 * (using the SDL_SetPalette() API). 
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

/* This isn't in the Windows headers */
#ifndef M_PI
#define M_PI	3.14159265358979323846
#endif

#include "SDL.h"

/* screen size */
#define SCRW 640
#define SCRH 480

#define NBOATS 5
#define SPEED 2

#ifndef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
#ifndef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#endif

/*
 * wave colours: Made by taking a narrow cross-section of a wave picture
 * in Gimp, saving in PPM ascii format and formatting with Emacs macros.
 */
static SDL_Color wavemap[] = {
    {0, 2, 103}, {0, 7, 110}, {0, 13, 117}, {0, 19, 125},
    {0, 25, 133}, {0, 31, 141}, {0, 37, 150}, {0, 43, 158},
    {0, 49, 166}, {0, 55, 174}, {0, 61, 182}, {0, 67, 190},
    {0, 73, 198}, {0, 79, 206}, {0, 86, 214}, {0, 96, 220},
    {5, 105, 224}, {12, 112, 226}, {19, 120, 227}, {26, 128, 229},
    {33, 135, 230}, {40, 143, 232}, {47, 150, 234}, {54, 158, 236},
    {61, 165, 238}, {68, 173, 239}, {75, 180, 241}, {82, 188, 242},
    {89, 195, 244}, {96, 203, 246}, {103, 210, 248}, {112, 218, 250},
    {124, 224, 250}, {135, 226, 251}, {146, 229, 251}, {156, 231, 252},
    {167, 233, 252}, {178, 236, 252}, {189, 238, 252}, {200, 240, 252},
    {211, 242, 252}, {222, 244, 252}, {233, 247, 252}, {242, 249, 252},
    {237, 250, 252}, {209, 251, 252}, {174, 251, 252}, {138, 252, 252},
    {102, 251, 252}, {63, 250, 252}, {24, 243, 252}, {7, 225, 252},
    {4, 203, 252}, {3, 181, 252}, {2, 158, 252}, {1, 136, 251},
    {0, 111, 248}, {0, 82, 234}, {0, 63, 213}, {0, 50, 192},
    {0, 39, 172}, {0, 28, 152}, {0, 17, 132}, {0, 7, 114}
};

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDL_Quit();
    exit(rc);
}

static void
sdlerr(char *when)
{
    fprintf(stderr, "SDL error: %s: %s\n", when, SDL_GetError());
    quit(1);
}

/* create a background surface */
static SDL_Surface *
make_bg(SDL_Surface * screen, int startcol)
{
    int i;
    SDL_Surface *bg =
        SDL_CreateRGBSurface(SDL_SWSURFACE, screen->w, screen->h,
                             8, 0, 0, 0, 0);
    if (!bg)
        sdlerr("creating background surface");

    /* set the palette to the logical screen palette so that blits
       won't be translated */
    SDL_SetSurfacePalette(bg, screen->format->palette);

    /* Make a wavy background pattern using colours 0-63 */
    if (SDL_LockSurface(bg) < 0)
        sdlerr("locking background");
    for (i = 0; i < SCRH; i++) {
        Uint8 *p = (Uint8 *) bg->pixels + i * bg->pitch;
        int j, d;
        d = 0;
        for (j = 0; j < SCRW; j++) {
            int v = MAX(d, -2);
            v = MIN(v, 2);
            if (i > 0)
                v += p[-bg->pitch] + 65 - startcol;
            p[j] = startcol + (v & 63);
            d += ((rand() >> 3) % 3) - 1;
        }
    }
    SDL_UnlockSurface(bg);
    return (bg);
}

/*
 * Return a surface flipped horisontally. Only works for 8bpp;
 * extension to arbitrary bitness is left as an exercise for the reader.
 */
static SDL_Surface *
hflip(SDL_Surface * s)
{
    int i;
    SDL_Surface *z = SDL_CreateRGBSurface(SDL_SWSURFACE, s->w, s->h, 8,
                                          0, 0, 0, 0);
    /* copy palette */
    SDL_SetColors(z, s->format->palette->colors,
                  0, s->format->palette->ncolors);
    if (SDL_LockSurface(s) < 0 || SDL_LockSurface(z) < 0)
        sdlerr("locking flip images");

    for (i = 0; i < s->h; i++) {
        int j;
        Uint8 *from = (Uint8 *) s->pixels + i * s->pitch;
        Uint8 *to = (Uint8 *) z->pixels + i * z->pitch + s->w - 1;
        for (j = 0; j < s->w; j++)
            to[-j] = from[j];
    }

    SDL_UnlockSurface(z);
    SDL_UnlockSurface(s);
    return z;
}

int
main(int argc, char **argv)
{
    SDL_Color cmap[256];
    SDL_Surface *screen;
    SDL_Surface *bg;
    SDL_Surface *boat[2];
    unsigned vidflags = 0;
    unsigned start;
    int fade_max = 400;
    int fade_level, fade_dir;
    int boatcols, frames, i, red;
    int boatx[NBOATS], boaty[NBOATS], boatdir[NBOATS];
    int gamma_fade = 0;
    int gamma_ramp = 0;

    if (SDL_Init(SDL_INIT_VIDEO) < 0)
        sdlerr("initialising SDL");

    while (--argc) {
        ++argv;
        if (strcmp(*argv, "-hw") == 0)
            vidflags |= SDL_HWSURFACE;
        else if (strcmp(*argv, "-fullscreen") == 0)
            vidflags |= SDL_FULLSCREEN;
        else if (strcmp(*argv, "-nofade") == 0)
            fade_max = 1;
        else if (strcmp(*argv, "-gamma") == 0)
            gamma_fade = 1;
        else if (strcmp(*argv, "-gammaramp") == 0)
            gamma_ramp = 1;
        else {
            fprintf(stderr,
                    "usage: testpalette "
                    " [-hw] [-fullscreen] [-nofade] [-gamma] [-gammaramp]\n");
            quit(1);
        }
    }

    /* Ask explicitly for 8bpp and a hardware palette */
    if ((screen =
         SDL_SetVideoMode(SCRW, SCRH, 8, vidflags | SDL_HWPALETTE)) == NULL) {
        fprintf(stderr, "error setting %dx%d 8bpp indexed mode: %s\n",
                SCRW, SCRH, SDL_GetError());
        quit(1);
    }

    if (vidflags & SDL_FULLSCREEN)
        SDL_ShowCursor(SDL_FALSE);

    if ((boat[0] = SDL_LoadBMP("sail.bmp")) == NULL)
        sdlerr("loading sail.bmp");
    /* We've chosen magenta (#ff00ff) as colour key for the boat */
    SDL_SetColorKey(boat[0], SDL_SRCCOLORKEY | SDL_RLEACCEL,
                    SDL_MapRGB(boat[0]->format, 0xff, 0x00, 0xff));
    boatcols = boat[0]->format->palette->ncolors;
    if (boatcols >= 256)
        sdlerr("too many colors in sail.bmp");
    boat[1] = hflip(boat[0]);
    SDL_SetColorKey(boat[1], SDL_SRCCOLORKEY | SDL_RLEACCEL,
                    SDL_MapRGB(boat[1]->format, 0xff, 0x00, 0xff));

    /*
     * First set the physical screen palette to black, so the user won't
     * see our initial drawing on the screen.
     */
    memset(cmap, 0, sizeof(cmap));
    SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, 256);

    /*
     * Proper palette management is important when playing games with the
     * colormap. We have divided the palette as follows:
     *
     * index 0..(boatcols-1):           used for the boat
     * index boatcols..(boatcols+63):   used for the waves
     */
    SDL_SetPalette(screen, SDL_LOGPAL,
                   boat[0]->format->palette->colors, 0, boatcols);
    SDL_SetPalette(screen, SDL_LOGPAL, wavemap, boatcols, 64);

    /*
     * Now the logical screen palette is set, and will remain unchanged.
     * The boats already have the same palette so fast blits can be used.
     */
    memcpy(cmap, screen->format->palette->colors, 256 * sizeof(SDL_Color));

    /* save the index of the red colour for later */
    red = SDL_MapRGB(screen->format, 0xff, 0x00, 0x00);

    bg = make_bg(screen, boatcols);     /* make a nice wavy background surface */

    /* initial screen contents */
    if (SDL_BlitSurface(bg, NULL, screen, NULL) < 0)
        sdlerr("blitting background to screen");
    SDL_Flip(screen);           /* actually put the background on screen */

    /* determine initial boat placements */
    for (i = 0; i < NBOATS; i++) {
        boatx[i] = (rand() % (SCRW + boat[0]->w)) - boat[0]->w;
        boaty[i] = i * (SCRH - boat[0]->h) / (NBOATS - 1);
        boatdir[i] = ((rand() >> 5) & 1) * 2 - 1;
    }

    start = SDL_GetTicks();
    frames = 0;
    fade_dir = 1;
    fade_level = 0;
    do {
        SDL_Event e;
        SDL_Rect updates[NBOATS];
        SDL_Rect r;
        int redphase;

        /* A small event loop: just exit on any key or mouse button event */
        while (SDL_PollEvent(&e)) {
            if (e.type == SDL_KEYDOWN || e.type == SDL_QUIT
                || e.type == SDL_MOUSEBUTTONDOWN) {
                if (fade_dir < 0)
                    fade_level = 0;
                fade_dir = -1;
            }
        }

        /* move boats */
        for (i = 0; i < NBOATS; i++) {
            int old_x = boatx[i];
            /* update boat position */
            boatx[i] += boatdir[i] * SPEED;
            if (boatx[i] <= -boat[0]->w || boatx[i] >= SCRW)
                boatdir[i] = -boatdir[i];

            /* paint over the old boat position */
            r.x = old_x;
            r.y = boaty[i];
            r.w = boat[0]->w;
            r.h = boat[0]->h;
            if (SDL_BlitSurface(bg, &r, screen, &r) < 0)
                sdlerr("blitting background");

            /* construct update rectangle (bounding box of old and new pos) */
            updates[i].x = MIN(old_x, boatx[i]);
            updates[i].y = boaty[i];
            updates[i].w = boat[0]->w + SPEED;
            updates[i].h = boat[0]->h;
            /* clip update rectangle to screen */
            if (updates[i].x < 0) {
                updates[i].w += updates[i].x;
                updates[i].x = 0;
            }
            if (updates[i].x + updates[i].w > SCRW)
                updates[i].w = SCRW - updates[i].x;
        }

        for (i = 0; i < NBOATS; i++) {
            /* paint boat on new position */
            r.x = boatx[i];
            r.y = boaty[i];
            if (SDL_BlitSurface(boat[(boatdir[i] + 1) / 2], NULL,
                                screen, &r) < 0)
                sdlerr("blitting boat");
        }

        /* cycle wave palette */
        for (i = 0; i < 64; i++)
            cmap[boatcols + ((i + frames) & 63)] = wavemap[i];

        if (fade_dir) {
            /* Fade the entire palette in/out */
            fade_level += fade_dir;

            if (gamma_fade) {
                /* Fade linearly in gamma level (lousy) */
                float level = (float) fade_level / fade_max;
                if (SDL_SetGamma(level, level, level) < 0)
                    sdlerr("setting gamma");

            } else if (gamma_ramp) {
                /* Fade using gamma ramp (better) */
                Uint16 ramp[256];
                for (i = 0; i < 256; i++)
                    ramp[i] = (i * fade_level / fade_max) << 8;
                if (SDL_SetGammaRamp(ramp, ramp, ramp) < 0)
                    sdlerr("setting gamma ramp");

            } else {
                /* Fade using direct palette manipulation (best) */
                memcpy(cmap, screen->format->palette->colors,
                       boatcols * sizeof(SDL_Color));
                for (i = 0; i < boatcols + 64; i++) {
                    cmap[i].r = cmap[i].r * fade_level / fade_max;
                    cmap[i].g = cmap[i].g * fade_level / fade_max;
                    cmap[i].b = cmap[i].b * fade_level / fade_max;
                }
            }
            if (fade_level == fade_max)
                fade_dir = 0;
        }

        /* pulse the red colour (done after the fade, for a night effect) */
        redphase = frames % 64;
        cmap[red].r = (int) (255 * sin(redphase * M_PI / 63));

        SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, boatcols + 64);

        /* update changed areas of the screen */
        SDL_UpdateRects(screen, NBOATS, updates);
        frames++;
    } while (fade_level > 0);

    printf("%d frames, %.2f fps\n",
           frames, 1000.0 * frames / (SDL_GetTicks() - start));

    if (vidflags & SDL_FULLSCREEN)
        SDL_ShowCursor(SDL_TRUE);
    SDL_Quit();
    return 0;
}