test/testpalette.c
author Ryan C. Gordon <icculus@icculus.org>
Wed, 28 Sep 2005 11:36:20 +0000
changeset 1151 be9c9c8f6d53
parent 0 74212992fb08
child 1429 aff0170f9f1b
permissions -rw-r--r--
Removed atexit() from most of the test programs; atexit(SDL_Quit) isn't safe
if SDL is built with a non-cdecl calling convention, and it's just generally
bad practice anyhow.

Now programs explicitly call SDL_Quit() where appropriate, wrap SDL_Quit() in
a cdecl function where it can't be avoided, and rely on the parachute where
a crash might have hit the atexit() before (these ARE test programs, after
all!).
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/*
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 * testpalette.c
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 *
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 * A simple test of runtime palette modification for animation
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 * (using the SDL_SetPalette() API). 
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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/* This isn't in the Windows headers */
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#ifndef M_PI
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#define M_PI	3.14159265358979323846
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#endif
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#include <SDL.h>
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/* screen size */
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#define SCRW 640
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#define SCRH 480
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#define NBOATS 5
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#define SPEED 2
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#ifndef MIN
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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#endif
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#ifndef MAX
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#define MAX(a, b) ((a) > (b) ? (a) : (b))
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#endif
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/*
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 * wave colours: Made by taking a narrow cross-section of a wave picture
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 * in Gimp, saving in PPM ascii format and formatting with Emacs macros.
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 */
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static SDL_Color wavemap[] = {
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    {0,2,103}, {0,7,110}, {0,13,117}, {0,19,125},
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    {0,25,133}, {0,31,141}, {0,37,150}, {0,43,158},
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    {0,49,166}, {0,55,174}, {0,61,182}, {0,67,190},
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    {0,73,198}, {0,79,206}, {0,86,214}, {0,96,220},
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    {5,105,224}, {12,112,226}, {19,120,227}, {26,128,229},
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    {33,135,230}, {40,143,232}, {47,150,234}, {54,158,236},
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    {61,165,238}, {68,173,239}, {75,180,241}, {82,188,242},
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    {89,195,244}, {96,203,246}, {103,210,248}, {112,218,250},
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    {124,224,250}, {135,226,251}, {146,229,251}, {156,231,252},
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    {167,233,252}, {178,236,252}, {189,238,252}, {200,240,252},
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    {211,242,252}, {222,244,252}, {233,247,252}, {242,249,252},
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    {237,250,252}, {209,251,252}, {174,251,252}, {138,252,252},
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    {102,251,252}, {63,250,252}, {24,243,252}, {7,225,252},
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    {4,203,252}, {3,181,252}, {2,158,252}, {1,136,251},
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    {0,111,248}, {0,82,234}, {0,63,213}, {0,50,192},
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    {0,39,172}, {0,28,152}, {0,17,132}, {0,7,114}
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};
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/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
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static void quit(int rc)
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{
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	SDL_Quit();
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	exit(rc);
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}
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static void sdlerr(char *when)
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{
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    fprintf(stderr, "SDL error: %s: %s\n", when, SDL_GetError());
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    quit(1);
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}
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/* create a background surface */
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static SDL_Surface *make_bg(SDL_Surface *screen, int startcol)
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{
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    int i;
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    SDL_Surface *bg = SDL_CreateRGBSurface(SDL_SWSURFACE, screen->w, screen->h,
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					   8, 0, 0, 0, 0);
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    if(!bg)
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	sdlerr("creating background surface");
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    /* set the palette to the logical screen palette so that blits
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       won't be translated */
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    SDL_SetColors(bg, screen->format->palette->colors, 0, 256);
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    /* Make a wavy background pattern using colours 0-63 */
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    if(SDL_LockSurface(bg) < 0)
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	sdlerr("locking background");
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    for(i = 0; i < SCRH; i++) {
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	Uint8 *p = (Uint8 *)bg->pixels + i * bg->pitch;
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	int j, d;
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	d = 0;
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	for(j = 0; j < SCRW; j++) {
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	    int v = MAX(d, -2);
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	    v = MIN(v, 2);
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	    if(i > 0)
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		v += p[-bg->pitch] + 65 - startcol;
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	    p[j] = startcol + (v & 63);
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	    d += ((rand() >> 3) % 3) - 1;
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	}
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    }
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    SDL_UnlockSurface(bg);
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    return(bg);
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}
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/*
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 * Return a surface flipped horisontally. Only works for 8bpp;
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 * extension to arbitrary bitness is left as an exercise for the reader.
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 */
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static SDL_Surface *hflip(SDL_Surface *s)
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{
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    int i;
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    SDL_Surface *z = SDL_CreateRGBSurface(SDL_SWSURFACE, s->w, s->h, 8,
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					  0, 0, 0, 0);
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    /* copy palette */
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    SDL_SetColors(z, s->format->palette->colors,
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		  0, s->format->palette->ncolors);
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    if(SDL_LockSurface(s) < 0 || SDL_LockSurface(z) < 0)
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	sdlerr("locking flip images");
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    for(i = 0; i < s->h; i++) {
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	int j;
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	Uint8 *from = (Uint8 *)s->pixels + i * s->pitch;
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	Uint8 *to = (Uint8 *)z->pixels + i * z->pitch + s->w - 1;
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	for(j = 0; j < s->w; j++)
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	    to[-j] = from[j];
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    }
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    SDL_UnlockSurface(z);
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    SDL_UnlockSurface(s);
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    return z;
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}
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int main(int argc, char **argv)
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{
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    SDL_Color cmap[256];
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    SDL_Surface *screen;
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    SDL_Surface *bg;
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    SDL_Surface *boat[2];
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    unsigned vidflags = 0;
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    unsigned start;
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    int fade_max = 400;
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    int fade_level, fade_dir;
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    int boatcols, frames, i, red;
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    int boatx[NBOATS], boaty[NBOATS], boatdir[NBOATS];
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    int gamma_fade = 0;
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    int gamma_ramp = 0;
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    if(SDL_Init(SDL_INIT_VIDEO) < 0)
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	sdlerr("initialising SDL");
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    while(--argc) {
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	++argv;
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	if(strcmp(*argv, "-hw") == 0)
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	    vidflags |= SDL_HWSURFACE;
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	else if(strcmp(*argv, "-fullscreen") == 0)
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	    vidflags |= SDL_FULLSCREEN;
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	else if(strcmp(*argv, "-nofade") == 0)
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	    fade_max = 1;
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	else if(strcmp(*argv, "-gamma") == 0)
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	    gamma_fade = 1;
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	else if(strcmp(*argv, "-gammaramp") == 0)
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	    gamma_ramp = 1;
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	else {
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	    fprintf(stderr,
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		    "usage: testpalette "
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		    " [-hw] [-fullscreen] [-nofade] [-gamma] [-gammaramp]\n");
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	    quit(1);
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	}
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    }
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    /* Ask explicitly for 8bpp and a hardware palette */
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    if(!(screen = SDL_SetVideoMode(SCRW, SCRH, 8, vidflags | SDL_HWPALETTE))) {
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	fprintf(stderr, "error setting %dx%d 8bpp indexed mode: %s\n",
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		SCRW, SCRH, SDL_GetError());
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	quit(1);
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    }
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    if(!(boat[0] = SDL_LoadBMP("sail.bmp")))
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	sdlerr("loading sail.bmp");
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    /* We've chosen magenta (#ff00ff) as colour key for the boat */
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    SDL_SetColorKey(boat[0], SDL_SRCCOLORKEY | SDL_RLEACCEL,
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		    SDL_MapRGB(boat[0]->format, 0xff, 0x00, 0xff));
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    boatcols = boat[0]->format->palette->ncolors;
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    boat[1] = hflip(boat[0]);
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    SDL_SetColorKey(boat[1], SDL_SRCCOLORKEY | SDL_RLEACCEL,
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		    SDL_MapRGB(boat[1]->format, 0xff, 0x00, 0xff));
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    /*
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     * First set the physical screen palette to black, so the user won't
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     * see our initial drawing on the screen.
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     */
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    memset(cmap, 0, sizeof(cmap));
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    SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, 256);
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    /*
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     * Proper palette management is important when playing games with the
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     * colormap. We have divided the palette as follows:
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     *
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     * index 0..(boatcols-1):		used for the boat
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     * index boatcols..(boatcols+63):	used for the waves
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     */
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    SDL_SetPalette(screen, SDL_LOGPAL,
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		   boat[0]->format->palette->colors, 0, boatcols);
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    SDL_SetPalette(screen, SDL_LOGPAL, wavemap, boatcols, 64);
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    /*
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     * Now the logical screen palette is set, and will remain unchanged.
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     * The boats already have the same palette so fast blits can be used.
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     */
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    memcpy(cmap, screen->format->palette->colors, 256 * sizeof(SDL_Color));
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    /* save the index of the red colour for later */
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    red = SDL_MapRGB(screen->format, 0xff, 0x00, 0x00);
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    bg = make_bg(screen, boatcols); /* make a nice wavy background surface */
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    /* initial screen contents */
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    if(SDL_BlitSurface(bg, NULL, screen, NULL) < 0)
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	sdlerr("blitting background to screen");
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    SDL_Flip(screen);		/* actually put the background on screen */
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    /* determine initial boat placements */
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    for(i = 0; i < NBOATS; i++) {
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	boatx[i] = (rand() % (SCRW + boat[0]->w)) - boat[0]->w;
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	boaty[i] = i * (SCRH - boat[0]->h) / (NBOATS - 1);
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	boatdir[i] = ((rand() >> 5) & 1) * 2 - 1;
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    }
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    start = SDL_GetTicks();
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    frames = 0;
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    fade_dir = 1;
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    fade_level = 0;
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    do {
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	SDL_Event e;
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	SDL_Rect updates[NBOATS];
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	SDL_Rect r;
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	int redphase;
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	/* A small event loop: just exit on any key or mouse button event */
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	while(SDL_PollEvent(&e)) {
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	    if(e.type == SDL_KEYDOWN || e.type == SDL_QUIT
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	       || e.type == SDL_MOUSEBUTTONDOWN) {
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		if(fade_dir < 0)
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		    fade_level = 0;
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		fade_dir = -1;
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	    }
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	}
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	/* move boats */
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	for(i = 0; i < NBOATS; i++) {
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	    int old_x = boatx[i];
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	    /* update boat position */
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	    boatx[i] += boatdir[i] * SPEED;
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	    if(boatx[i] <= -boat[0]->w || boatx[i] >= SCRW)
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		boatdir[i] = -boatdir[i];
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	    /* paint over the old boat position */
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	    r.x = old_x;
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	    r.y = boaty[i];
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	    r.w = boat[0]->w;
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	    r.h = boat[0]->h;
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	    if(SDL_BlitSurface(bg, &r, screen, &r) < 0)
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		sdlerr("blitting background");
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	    /* construct update rectangle (bounding box of old and new pos) */
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	    updates[i].x = MIN(old_x, boatx[i]);
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	    updates[i].y = boaty[i];
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	    updates[i].w = boat[0]->w + SPEED;
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	    updates[i].h = boat[0]->h;
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	    /* clip update rectangle to screen */
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	    if(updates[i].x < 0) {
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		updates[i].w += updates[i].x;
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		updates[i].x = 0;
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	    }
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	    if(updates[i].x + updates[i].w > SCRW)
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		updates[i].w = SCRW - updates[i].x;
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	}
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	for(i = 0; i < NBOATS; i++) {
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	    /* paint boat on new position */
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	    r.x = boatx[i];
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	    r.y = boaty[i];
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	    if(SDL_BlitSurface(boat[(boatdir[i] + 1) / 2], NULL,
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			       screen, &r) < 0)
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		sdlerr("blitting boat");
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	}
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	/* cycle wave palette */
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	for(i = 0; i < 64; i++)
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	    cmap[boatcols + ((i + frames) & 63)] = wavemap[i];
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	if(fade_dir) {
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	    /* Fade the entire palette in/out */
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	    fade_level += fade_dir;
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	    if(gamma_fade) {
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		/* Fade linearly in gamma level (lousy) */
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		float level = (float)fade_level / fade_max;
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		if(SDL_SetGamma(level, level, level) < 0)
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		    sdlerr("setting gamma");
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	    } else if(gamma_ramp) {
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		/* Fade using gamma ramp (better) */
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		Uint16 ramp[256];
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		for(i = 0; i < 256; i++)
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		    ramp[i] = (i * fade_level / fade_max) << 8;
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		if(SDL_SetGammaRamp(ramp, ramp, ramp) < 0)
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		    sdlerr("setting gamma ramp");
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	    } else {
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		/* Fade using direct palette manipulation (best) */
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		memcpy(cmap, screen->format->palette->colors,
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		       boatcols * sizeof(SDL_Color));
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		for(i = 0; i < boatcols + 64; i++) {
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		    cmap[i].r = cmap[i].r * fade_level / fade_max;
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		    cmap[i].g = cmap[i].g * fade_level / fade_max;
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		    cmap[i].b = cmap[i].b * fade_level / fade_max;
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		}
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	    }
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	    if(fade_level == fade_max)
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		fade_dir = 0;
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	}
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	/* pulse the red colour (done after the fade, for a night effect) */
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	redphase = frames % 64;
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	cmap[red].r = (int)(255 * sin(redphase * M_PI / 63));
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	SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, boatcols + 64);
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	/* update changed areas of the screen */
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	SDL_UpdateRects(screen, NBOATS, updates);
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	frames++;
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    } while(fade_level > 0);
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    printf("%d frames, %.2f fps\n",
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	   frames, 1000.0 * frames / (SDL_GetTicks() - start));
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    SDL_Quit();
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    return 0;
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}
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