(svn r11433) -Fix: starting OpenTTD with DOS files made it look weird out of the box.

-Change: make extra sprites (the ones not in the TTD GRFs) replaceable using Action 5.
-Feature: make replacing contiguous subsets of sprites in for some types possible in Action 5.
Note to GRF authors: when you replaced OpenTTD sprites that are not from the TTD GRF files using Action A, your GRF will not have the intended result anymore as the sprite numbers have changed. You should replace the Action A with an Action 5 from now on.

1 files changed, 77 insertions, 27 deletions

diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 3be403a67..5a0d9098b 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -61,7 +61,6 @@
 
 static int _skip_sprites; // XXX
 static uint _file_index; // XXX
-SpriteID _signal_base;
 SpriteID _coast_base;
 
 static GRFFile *_cur_grffile;
@@ -3241,6 +3240,34 @@ static void FeatureNewName(byte *buf, int len)
 	}
 }
 
+/**
+ * Sanitize incoming sprite offsets for Action 5 graphics replacements.
+ * @param num         the number of sprites to load.
+ * @param offset      offset from the base.
+ * @param max_sprites the maximum number of sprites that can be loaded in this action 5.
+ * @param name        used for error warnings.
+ * @return the number of sprites that is going to be skipped
+ */
+static uint16 SanitizeSpriteOffset(uint16& num, uint16 offset, int max_sprites, const char *name)
+{
+
+	if (offset >= max_sprites) {
+		grfmsg(1, "GraphicsNew: %s sprite offset must be less than %i, skipping", name, max_sprites);
+		uint orig_num = num;
+		num = 0;
+		return orig_num;
+	}
+
+	if (offset + num > max_sprites) {
+		grfmsg(4, "GraphicsNew: %s sprite overflow, truncating...", name);
+		uint orig_num = num;
+		num = max(max_sprites - offset, 0);
+		return orig_num - num;
+	}
+
+	return 0;
+}
+
 /* Action 0x05 */
 static void GraphicsNew(byte *buf, int len)
 {
@@ -3252,50 +3279,52 @@ static void GraphicsNew(byte *buf, int len)
 	/* TODO */
 
 	SpriteID replace = 0;
-	const SpriteID *index_tbl = NULL;
 
 	if (!check_length(len, 2, "GraphicsNew")) return;
 	buf++;
 	uint8 type = grf_load_byte(&buf);
 	uint16 num = grf_load_extended(&buf);
+	uint16 skip_num = 0;
+	uint16 offset = HASBIT(type, 7) ? grf_load_extended(&buf) : 0;
+	CLRBIT(type, 7); // Clear the high bit as that only indicates whether there is an offset.
 
 	switch (type) {
 		case 0x04: // Signal graphics
-			if (num != 112 && num != 240) {
-				grfmsg(1, "GraphicsNew: Signal graphics sprite count must be 112 or 240, skipping");
+			if (num != PRESIGNAL_SPRITE_COUNT && num != PRESIGNAL_AND_SEMAPHORE_SPRITE_COUNT && num != PRESIGNAL_SEMAPHORE_AND_PBS_SPRITE_COUNT) {
+				grfmsg(1, "GraphicsNew: Signal graphics sprite count must be 48, 112 or 240, skipping");
 				return;
 			}
-			_signal_base = _cur_spriteid;
+			replace = SPR_SIGNALS_BASE;
 			break;
 
 		case 0x05: // Catenary graphics
-			if (num != 48) {
+			if (num != ELRAIL_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: Catenary graphics sprite count must be 48, skipping");
 				return;
 			}
-			replace = SPR_ELRAIL_BASE + 3;
+			replace = SPR_ELRAIL_BASE;
 			break;
 
 		case 0x06: // Foundations
-			switch (num) {
-				case 74: replace = SPR_SLOPES_BASE; break;
-				case 90: index_tbl = _slopes_action05_90; break;
-				default:
-					grfmsg(1, "GraphicsNew: Foundation graphics sprite count must be 74 or 90, skipping");
-					return;
+			if (num != NORMAL_FOUNDATION_SPRITE_COUNT && num != NORMAL_AND_HALFTILE_FOUNDATION_SPRITE_COUNT) {
+				grfmsg(1, "GraphicsNew: Foundation graphics sprite count must be 74 or 90, skipping");
+				return;
 			}
+			replace = SPR_SLOPES_BASE; break;
 			break;
 
+		/* case 0x07: // TTDP GUI sprites. Not used by OTTD. */
+
 		case 0x08: // Canal graphics
-			if (num != 65) {
+			if (num != CANALS_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: Canal graphics sprite count must be 65, skipping");
 				return;
 			}
-			replace = SPR_CANALS_BASE + 5;
+			replace = SPR_CANALS_BASE;
 			break;
 
 		case 0x09: // One way graphics
-			if (num != 6) {
+			if (num != ONEWAY_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: One way road graphics sprite count must be 6, skipping");
 				return;
 			}
@@ -3303,7 +3332,7 @@ static void GraphicsNew(byte *buf, int len)
 			break;
 
 		case 0x0A: // 2CC colour maps
-			if (num != 256) {
+			if (num != TWOCCMAP_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: 2CC colour maps sprite count must be 256, skipping");
 				return;
 			}
@@ -3311,13 +3340,15 @@ static void GraphicsNew(byte *buf, int len)
 			break;
 
 		case 0x0B: // tramways
-			if (num != 113) {
+			if (num != TRAMWAY_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: Tramway graphics sprite count must be 113, skipping");
 				return;
 			}
 			replace = SPR_TRAMWAY_BASE;
 			break;
 
+		/* case 0x0C: // Snowy temperate trees. Not yet used by OTTD. */
+
 		case 0x0D: // Coast graphics
 			if (num != 16) {
 				grfmsg(1, "GraphicsNew: Coast graphics sprite count must be 16, skipping");
@@ -3327,8 +3358,12 @@ static void GraphicsNew(byte *buf, int len)
 			_loaded_newgrf_features.has_newwater = true;
 			break;
 
+		/* case 0x0E: // New Signals. Not yet used by OTTD. */
+
+		/* case 0x0F: // Tracks for marking sloped rail. Not yet used by OTTD. */
+
 		case 0x10: // New airport sprites
-			if (num != 15) {
+			if (num != AIRPORTX_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: Airport graphics sprite count must be 15, skipping");
 				return;
 			}
@@ -3336,13 +3371,33 @@ static void GraphicsNew(byte *buf, int len)
 			break;
 
 		case 0x11: // Road stop sprites
-			if (num != 8) {
+			if (num != ROADSTOP_SPRITE_COUNT) {
 				grfmsg(1, "GraphicsNew: Road stop graphics sprite count must be 8, skipping");
 				return;
 			}
 			replace = SPR_ROADSTOP_BASE;
 			break;
 
+		/* case 0x12: // Aqueduct sprites. Not yet used by OTTD. */
+
+		case 0x13: // Autorail sprites
+			if (num != AUTORAIL_SPRITE_COUNT) {
+				grfmsg(1, "GraphicsNew: Autorail graphics sprite count must be 55, skipping");
+				return;
+			}
+			replace = SPR_AUTORAIL_BASE;
+			break;
+
+		case 0x14: // Flag sprites
+			skip_num = SanitizeSpriteOffset(num, offset, FLAGS_SPRITE_COUNT, "Flag graphics");
+			replace = SPR_FLAGS_BASE + offset;
+			break;
+
+		case 0x15: // OpenTTD GUI sprites
+			skip_num = SanitizeSpriteOffset(num, offset, OPENTTD_SPRITE_COUNT, "OpenTTD graphics");
+			replace = SPR_OPENTTD_BASE + offset;
+			break;
+
 		default:
 			grfmsg(2, "GraphicsNew: Custom graphics (type 0x%02X) sprite block of length %u (unimplemented, ignoring)",
 					type, num);
@@ -3350,12 +3405,6 @@ static void GraphicsNew(byte *buf, int len)
 			return;
 	}
 
-	if (index_tbl != NULL) {
-		grfmsg(2, "GraphicsNew: Loading %u sprites of type 0x%02X at indexed SpriteIDs", num, type);
-		LoadSpritesIndexed(_file_index, &_nfo_line, index_tbl);
-		return;
-	}
-
 	if (replace == 0) {
 		grfmsg(2, "GraphicsNew: Loading %u sprites of type 0x%02X at SpriteID 0x%04X", num, type, _cur_spriteid);
 	} else {
@@ -3366,6 +3415,8 @@ static void GraphicsNew(byte *buf, int len)
 		LoadNextSprite(replace == 0 ? _cur_spriteid++ : replace++, _file_index, _nfo_line);
 		_nfo_line++;
 	}
+
+	_skip_sprites = skip_num;
 }
 
 /* Action 0x05 (SKIP) */
@@ -5028,7 +5079,6 @@ static void ResetNewGRFData()
 	_loaded_newgrf_features.has_newhouses     = false;
 	_loaded_newgrf_features.has_newindustries = false;
 	_loaded_newgrf_features.has_newwater      = false;
-	_signal_base = 0;
 	_coast_base = 0;
 
 	InitializeSoundPool();