--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/testpalette.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,332 @@
+/*
+ * 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}
+};
+
+static void sdlerr(char *when)
+{
+    fprintf(stderr, "SDL error: %s: %s\n", when, SDL_GetError());
+    exit(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_SetColors(bg, screen->format->palette->colors, 0, 256);
+
+    /* 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");
+
+    atexit(SDL_Quit);
+
+    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");
+	    return 1;
+	}
+    }
+
+    /* Ask explicitly for 8bpp and a hardware palette */
+    if(!(screen = SDL_SetVideoMode(SCRW, SCRH, 8, vidflags | SDL_HWPALETTE))) {
+	fprintf(stderr, "error setting %dx%d 8bpp indexed mode: %s\n",
+		SCRW, SCRH, SDL_GetError());
+	return 1;
+    }
+
+    if(!(boat[0] = SDL_LoadBMP("sail.bmp")))
+	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;
+    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));
+    return 0;
+}
+