Add: Support alternative sprites for RTL languages. (#46)

Author: frosch123

docs/grf.txt

@@ -121,6 +121,7 @@ Normal sprites
     1   2  Pixel format contains alpha component.
     2   4  Pixel format contains mask/palette component.
     3   8  Has transparency (i.e. is a tile), see below.
+    4  10h Alternative sprite for right-to-left languages.
     6  40h The exact size of this sprite is significant. If not set,
              grfcodec may attempt to remove extraneous transparent pixels.
     others Undefined.

src/info.cpp

@@ -223,6 +223,7 @@ void infowriter::flush()
 							zoom_levels[s->info.zoom]);
 					if (HASTRANSPARENCY(s->info.info)) fputs(" chunked", info);
 					if (DONOTCROP(s->info.info)) fputs(" nocrop", info);
+					if (ISRTL(s->info.info)) fputs(" rtl", info);
 				}
 			} else {
 				fprintf(info, "%s %d %d %02X %d %d %d %d",

src/nforenum.cpp

@@ -76,11 +76,14 @@ nfe_map nfo_escapes;
 #endif
 
 struct RealSpriteFormat{
+	bool rtl;
 	bool bpp32;
 	int zoom;
 
 	bool operator<(const RealSpriteFormat&other)const{
-		return bpp32==other.bpp32?zoom<other.zoom:other.bpp32;
+		if (rtl != other.rtl) return other.rtl;
+		if (bpp32 != other.bpp32) return other.bpp32;
+		return zoom < other.zoom;
 	}
 };
 
@@ -670,14 +673,16 @@ bool verify_real(std::string&data,RealSpriteState&formats){
 			else { IssueMessage(0,REAL_MISSING_DATA,"zoom"); return COMMENTOFF(); }
 
 			std::string flag;
-			bool chunked = false, nocrop=false;
+			bool chunked = false, nocrop = false, rtl = false;
 			while (!extract_string(meta,flag,processed,anyprocessing)) {
 				if (!chunked&&flag=="chunked") chunked = true;
 				else if (!nocrop&&flag=="nocrop") nocrop = true;
+				else if (!rtl&&flag=="rtl") rtl = true;
 				else { IssueMessage(0,REAL_UNKNOWN_FLAG,flag.c_str()); return COMMENTOFF(); }
 			}
 
 			RealSpriteFormat format;
+			format.rtl = rtl;
 			format.bpp32 = depth=="32bpp";
 			format.zoom = zoom;
 

src/readinfo.cpp

@@ -200,8 +200,8 @@ void Real::AddSprite(size_t sprite,int infover,const std::string&data){
 		inf.yrel = S16(ry);
 	}else{
 		int sx,sy,rx,ry;
-		char depth[8],zoom[8],flags[2][8];
-		int read = sscanf(meta,"%7s %d %d %d %d %d %d %7s %7s %7s",depth,&inf.xpos,&inf.ypos,&sx,&sy,&rx,&ry,zoom,flags[0],flags[1]);
+		char depth[8],zoom[8],flags[3][8];
+		int read = sscanf(meta,"%7s %d %d %d %d %d %d %7s %7s %7s %7s",depth,&inf.xpos,&inf.ypos,&sx,&sy,&rx,&ry,zoom,flags[0],flags[1],flags[2]);
 		if(strcmp(depth,"mask")==0?read!=3:read < 8){
 			throw Sprite::unparseable("Insufficient meta-data",sprite);
 		}
@@ -236,6 +236,7 @@ void Real::AddSprite(size_t sprite,int infover,const std::string&data){
 				/* Comment. */
 				if (*flag == '#' || *flag == '/' || *flag == ';') break;
 				if (strcmp(flag,"chunked")==0)inf.info|=8;
+				else if (strcmp(flag,"rtl")==0)inf.info|=16;
 				else if (strcmp(flag,"nocrop")==0)inf.info|=64;
 				else throw Sprite::unparseable("invalid flag",sprite);
 			}

src/sprites.cpp

@@ -177,14 +177,14 @@ void SpriteInfo::writetobuffer(U8 *buffer, int grfcontversion)
 {
 	int i = 0;
 	if (grfcontversion == 2) {
-		/* Copy bits 3 and 6 of the nfo and make it, for now, an 8bpp normal GRF. */
+		/* Copy bits 3, 4, 6 of the nfo and make it, for now, an 8bpp normal GRF. */
 		U8 img=0;
 		switch(this->depth){
 			case DEPTH_8BPP:  img=0x04; break;
 			case DEPTH_32BPP: img=0x03; break;
 			case DEPTH_MASK:  img=0x07; break;
 		}
-		buffer[i++] = img | (this->info & (1 << 3 | 1 << 6));
+		buffer[i++] = img | (this->info & (1 << 3 | 1 << 4 | 1 << 6));
 		buffer[i++] = this->zoom;
 		buffer[i++] = this->ydim & 0xFF;
 		buffer[i++] = this->ydim >> 8;
@@ -204,8 +204,8 @@ void SpriteInfo::readfromfile(const char *action, int grfcontversion, FILE *grf,
 {
 	if (grfcontversion == 2) {
 		U8 data = fgetc(grf);
-		/* According to the documentation bit 0 must always be set, and bits 3 and 6 are the same as in the nfo. */
-		this->info = (1 << 0) | (data & (1 << 3 | 1 << 6));
+		/* According to the documentation bit 0 must always be set, and bits 3, 4, 6 are the same as in the nfo. */
+		this->info = (1 << 0) | (data & (1 << 3 | 1 << 4 | 1 << 6));
 		switch(data&0x7){
 			case 0x03: this->depth=DEPTH_32BPP; break;
 			case 0x04: this->depth=DEPTH_8BPP; break;

src/sprites.h

@@ -39,6 +39,7 @@ static const int DEPTH_MASK  = 2;
 
 // Define some of the bits in SpriteInfo::info
 #define DONOTCROP(info) (info & 64)
+#define ISRTL(info) (info & 16)
 #define HASTRANSPARENCY(info) (info & 8)
 #define SIZEISCOMPRESSED(info) (info & 2)