From b69ee811a0f3b49bef2eb26163f34e8430a24580 Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pjm@nac.net>
Date: Mon, 04 Mar 2013 20:41:33 -0500
Subject: Support palette cycling in area layers.

---
diff --git a/src/area.c b/src/area.c
index a41ff62..2e55fe9 100644
--- a/src/area.c
+++ b/src/area.c
@@ -5,12 +5,11 @@
 #include "logging.h"
 
 static void init_map_layers(struct area *);
-static void set_layers_palette(struct area *, struct viewport *);
 static void blit_map_layers(struct area *);
 static void blit_map_layer(struct area *, enum map_layer, enum area_layer);
 
 struct area *
-area_new(struct map *map, struct viewport *vp)
+area_new(struct map *map, SDL_Palette *pal)
 {
 	struct area *a;
 
@@ -25,12 +24,23 @@ area_new(struct map *map, struct viewport *vp)
 
 	a->map = map;
 	init_map_layers(a);
-	set_layers_palette(a, vp);
+	set_area_palette(a, pal);
 	blit_map_layers(a);
 
 	return a;
 }
 
+void
+set_area_palette(struct area *area, SDL_Palette *pal)
+{
+	enum area_layer l;
+
+	for (l = 0; l < AREA_LAYERS_MAX; ++l) {
+		SDL_SetPalette(area->map_layers[l], SDL_LOGPAL,
+				pal->colors, 0, pal->ncolors);
+	}
+}
+
 static void
 init_map_layers(struct area *area)
 {
@@ -59,20 +69,6 @@ init_map_layers(struct area *area)
 }
 
 static void
-set_layers_palette(struct area *area, struct viewport *vp)
-{
-	enum area_layer l;
-	SDL_Palette *pal;
-
-	pal = vp->screen->format->palette;
-
-	for (l = 0; l < AREA_LAYERS_MAX; ++l) {
-		SDL_SetColors(area->map_layers[l],
-				pal->colors, 0, pal->ncolors);
-	}
-}
-
-static void
 blit_map_layers(struct area *area)
 {
 	blit_map_layer(area, MAP_LAYER_GROUND, AREA_LAYER_BOT);
diff --git a/src/area.h b/src/area.h
index 3ab9aea..fae524d 100644
--- a/src/area.h
+++ b/src/area.h
@@ -16,7 +16,8 @@ struct area {
 	SDL_Surface *map_layers[AREA_LAYERS_MAX];
 };
 
-struct area *area_new(struct map *map, struct viewport *vp);
+struct area *area_new(struct map *map, SDL_Palette *pal);
+void set_area_palette(struct area *area, SDL_Palette *pal);
 void render_area_to_viewport(struct area *area, struct viewport *vp);
 void render_area_to_surface(struct area *area, SDL_Rect *arearect,
 		SDL_Surface *surface, SDL_Rect *surfacerect);
diff --git a/src/main.c b/src/main.c
index 0d75e4a..1dd376a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -11,24 +11,6 @@
 	do {                                                                   \
 		vp->x = x + map->tilewidth / 2 - vp->w / 2;                    \
 		vp->y = y + map->tileheight / 2 - vp->h / 2;                   \
-		/* This causes render_area_to_viewport() to use a lot more CPU \
-		 * time.                                                       \
-		 * Presumably, this is because SDL is mapping the area layers' \
-		 * color palettes onto the screen's palette.  (But they should \
-		 * be equal, so color mapping shouldn't happen…)               \
-		 * Oddly, the effect of this SDL_SetPalette() call is much     \
-		 * greater than is that of the other one.                      \
-		 * Hopefully, cycling the palettes of the area layers should   \
-		 * fix _everything_. */                                        \
-		if (!SDL_SetPalette(vp->screen, SDL_LOGPAL,                    \
-					map->palettes[MAP_PALETTE_DAY]         \
-						.palette->palette->colors,     \
-					0,                                     \
-					map->palettes[MAP_PALETTE_DAY]         \
-						.palette->palette->ncolors)) { \
-			warn("Failed to set palette");                         \
-		}                                                              \
-		render_area_to_viewport(a, vp);                                \
 		if (i % 720 < 180) {                                           \
 			pal_start = map->palettes[MAP_PALETTE_MORN]            \
 				.palette->palette;                             \
@@ -53,10 +35,12 @@
 		if (!cycle_palettes_cosine(i, 180, pal_start, pal_end, pal)) { \
 			warn("Failed to cycle palettes");                      \
 		}                                                              \
+		set_area_palette(a, pal);                                      \
 		if (!SDL_SetPalette(vp->screen, SDL_LOGPAL,                    \
 					pal->colors, 0, pal->ncolors)) {       \
 			warn("Failed to set palette");                         \
 		}                                                              \
+		render_area_to_viewport(a, vp);                                \
 		SDL_Flip(vp->screen);                                          \
 		SDL_Delay(10);                                                 \
 		++i;                                                           \
@@ -87,7 +71,7 @@ main(void)
 				0, pal->ncolors)) {
 		warn("Failed to set palette");
 	}
-	a = area_new(map, vp);
+	a = area_new(map, vp->screen->format->palette);
 
 	for (e = map->map_exits_head; e != NULL; e = e->next) {
 		debug("Map exit (size %dx%d) at (%d,%d) "
--
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