(svn r2866) Move all functions and tables which aren't directly involved in managing the sprite heap to a new file gfxinit.c.

This doesn't ease the global variable mess, but makes the distinction between sprite heap and gfx loading routines easier.

10 files changed, 387 insertions, 330 deletions

diff --git a/Makefile b/Makefile
index f87fd497d..731330fd8 100644
--- a/Makefile
+++ b/Makefile
@@ -602,6 +602,7 @@ C_SOURCES += engine.c
 C_SOURCES += engine_gui.c
 C_SOURCES += fileio.c
 C_SOURCES += gfx.c
+C_SOURCES += gfxinit.c
 C_SOURCES += graph_gui.c
 C_SOURCES += newgrf.c
 C_SOURCES += industry_cmd.c
diff --git a/gfxinit.c b/gfxinit.c
new file mode 100644
index 000000000..c93a8b906
--- /dev/null
+++ b/gfxinit.c
@@ -0,0 +1,346 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "debug.h"
+#include "functions.h"
+#include "gfx.h"
+#include "gfxinit.h"
+#include "spritecache.h"
+#include "table/sprites.h"
+#include "fileio.h"
+#include "newgrf.h"
+#include "md5.h"
+#include "variables.h"
+#include <ctype.h>
+
+#define SPRITE_CACHE_SIZE 1024*1024
+
+#define WANT_NEW_LRU
+
+
+/* These are used in newgrf.c: */
+
+int _skip_sprites = 0; // XXX
+int _replace_sprites_count[16]; // XXX
+int _replace_sprites_offset[16]; // XXX
+
+const char* _cur_grffile; // XXX
+int _loading_stage; // XXX
+int _skip_specials; // XXX
+uint16 _custom_sprites_base; // XXX
+
+
+typedef struct MD5File {
+	const char * const filename;     // filename
+	const md5_byte_t hash[16]; // md5 sum of the file
+} MD5File;
+
+typedef struct FileList {
+	const MD5File basic[5];     // grf files that always have to be loaded
+	const MD5File landscape[3]; // landscape specific grf files
+} FileList;
+
+#include "table/files.h"
+#include "table/landscape_sprite.h"
+
+static const SpriteID * const _landscape_spriteindexes[] = {
+	_landscape_spriteindexes_1,
+	_landscape_spriteindexes_2,
+	_landscape_spriteindexes_3,
+};
+
+static const SpriteID * const _slopes_spriteindexes[] = {
+	_slopes_spriteindexes_0,
+	_slopes_spriteindexes_1,
+	_slopes_spriteindexes_2,
+	_slopes_spriteindexes_3,
+};
+
+
+static int LoadGrfFile(const char *filename, int load_index, int file_index)
+{
+	int load_index_org = load_index;
+
+	FioOpenFile(file_index, filename);
+
+	/* Thou shalt use LoadNewGrfFile() if thou loadeth a GRF file that
+	 * might contain some special sprites. */
+	_skip_specials = 1;
+	_skip_sprites = 0;
+
+	DEBUG(spritecache, 2) ("Reading grf-file ``%s''", filename);
+
+	while (LoadNextSprite(load_index, file_index)) {
+		load_index++;
+		if (load_index >= MAX_SPRITES) {
+			error("Too many sprites. Recompile with higher MAX_SPRITES value or remove some custom GRF files.");
+		}
+	}
+	DEBUG(spritecache, 2) ("Currently %i sprites are loaded", load_index);
+
+	return load_index - load_index_org;
+}
+
+static int LoadNewGrfFile(const char *filename, int load_index, int file_index)
+{
+	int i;
+
+	FioOpenFile(file_index, filename);
+	_cur_grffile = filename;
+	_skip_specials = 0;
+	_skip_sprites = 0;
+
+	DEBUG(spritecache, 2) ("Reading newgrf-file ``%s'' [offset: %u]",
+			filename, load_index);
+
+	/* Skip the first sprite; we don't care about how many sprites this
+	 * does contain; newest TTDPatches and George's longvehicles don't
+	 * neither, apparently. */
+	{
+		int length;
+		byte type;
+
+		length = FioReadWord();
+		type = FioReadByte();
+
+		if (length == 4 && type == 0xFF) {
+			FioReadDword();
+		} else {
+			error("Custom .grf has invalid format.");
+		}
+	}
+
+	for (i = 0; LoadNextSprite(load_index + i, file_index); i++) {
+		if (load_index + i >= MAX_SPRITES)
+			error("Too many sprites (0x%X). Recompile with higher MAX_SPRITES value or remove some custom GRF files.",
+			      load_index + i);
+	}
+
+	/* Clean up. */
+	_skip_sprites = 0;
+	memset(_replace_sprites_count, 0, sizeof(_replace_sprites_count));
+	memset(_replace_sprites_offset, 0, sizeof(_replace_sprites_offset));
+
+	return i;
+}
+
+static void LoadGrfIndexed(const char *filename, const SpriteID *index_tbl, int file_index)
+{
+	int start;
+
+	FioOpenFile(file_index, filename);
+	_skip_specials = 1;
+	_skip_sprites = 0;
+
+	DEBUG(spritecache, 2) ("Reading indexed grf-file ``%s''", filename);
+
+	for (; (start = *index_tbl++) != 0xffff;) {
+		int end = *index_tbl++;
+		if(start == 0xfffe) { // skip sprites (amount in second var)
+			SkipSprites(end);
+		} else { // load sprites and use indexes from start to end
+			do {
+			#ifdef NDEBUG
+				LoadNextSprite(start, file_index);
+			#else
+				bool b = LoadNextSprite(start, file_index);
+				assert(b);
+			#endif
+			} while (++start <= end);
+		}
+	}
+}
+
+
+static byte _sprite_page_to_load = 0xFF;
+
+#define OPENTTD_SPRITES_COUNT 100
+static const SpriteID _openttd_grf_indexes[] = {
+	SPR_OPENTTD_BASE + 0, SPR_OPENTTD_BASE + 7, // icons etc
+	134, 134,  // euro symbol medium size
+	582, 582,  // euro symbol large size
+	358, 358,  // euro symbol tiny
+	SPR_OPENTTD_BASE+11, SPR_OPENTTD_BASE+57, // more icons
+	648, 648, // nordic char: æ
+	616, 616, // nordic char: Æ
+	666, 666, // nordic char: ø
+	634, 634, // nordic char: Ø
+	SPR_OPENTTD_BASE+62, SPR_OPENTTD_BASE + OPENTTD_SPRITES_COUNT, // more icons
+	0xffff,
+};
+
+/* FUNCTIONS FOR CHECKING MD5 SUMS OF GRF FILES */
+
+/* Check that the supplied MD5 hash matches that stored for the supplied filename */
+static bool CheckMD5Digest(const MD5File file, md5_byte_t *digest, bool warn)
+{
+	uint i;
+
+	/* Loop through each byte of the file MD5 and the stored MD5... */
+	for (i = 0; i < 16; i++) if (file.hash[i] != digest[i]) break;
+
+		/* If all bytes of the MD5's match (i.e. the MD5's match)... */
+	if (i == 16) {
+		return true;
+	} else {
+		if (warn) fprintf(stderr, "MD5 of %s is ****INCORRECT**** - File Corrupt.\n", file.filename);
+		return false;
+	};
+}
+
+/* Calculate and check the MD5 hash of the supplied filename.
+ * returns true if the checksum is correct */
+static bool FileMD5(const MD5File file, bool warn)
+{
+	FILE *f;
+	char buf[MAX_PATH];
+
+	// open file
+	sprintf(buf, "%s%s", _path.data_dir, file.filename);
+	f = fopen(buf, "rb");
+
+#if !defined(WIN32)
+	if (f == NULL) {
+		char *s;
+	// make lower case and check again
+		for (s = buf + strlen(_path.data_dir) - 1; *s != '\0'; s++)
+			*s = tolower(*s);
+		f = fopen(buf, "rb");
+	}
+#endif
+
+	if (f != NULL) {
+		md5_state_t filemd5state;
+		md5_byte_t buffer[1024];
+		md5_byte_t digest[16];
+		size_t len;
+
+		md5_init(&filemd5state);
+		while ((len = fread(buffer, 1, sizeof(buffer), f)) != 0)
+			md5_append(&filemd5state, buffer, len);
+
+		if (ferror(f) && warn) fprintf(stderr, "Error Reading from %s \n", buf);
+		fclose(f);
+
+		md5_finish(&filemd5state, digest);
+	  return CheckMD5Digest(file, digest, warn);
+	} else { // file not found
+		return false;
+	}
+}
+
+/* Checks, if either the Windows files exist (TRG1R.GRF) or the DOS files (TRG1.GRF)
+ * by comparing the MD5 checksums of the files. _use_dos_palette is set accordingly.
+ * If neither are found, Windows palette is assumed.
+ *
+ * (Note: Also checks sample.cat for corruption) */
+void CheckExternalFiles(void)
+{
+	uint i;
+	// count of files from this version
+	uint dos = 0;
+	uint win = 0;
+
+	for (i = 0; i < 2; i++) if (FileMD5(files_dos.basic[i], true)) dos++;
+	for (i = 0; i < 3; i++) if (FileMD5(files_dos.landscape[i], true)) dos++;
+
+	for (i = 0; i < 2; i++) if (FileMD5(files_win.basic[i], true)) win++;
+	for (i = 0; i < 3; i++) if (FileMD5(files_win.landscape[i], true)) win++;
+
+	if (!FileMD5(sample_cat_win, false) && !FileMD5(sample_cat_dos, false))
+		fprintf(stderr, "Your sample.cat file is corrupted or missing!\n");
+
+	/*
+	 * forced DOS palette via command line -> leave it that way
+	 * all Windows files present -> Windows palette
+	 * all DOS files present -> DOS palette
+	 * no Windows files present and any DOS file present -> DOS palette
+	 * otherwise -> Windows palette
+	 */
+	if (_use_dos_palette) {
+		return;
+	} else if (win == 5) {
+		_use_dos_palette = false;
+	} else if (dos == 5 || (win == 0 && dos > 0)) {
+		_use_dos_palette = true;
+	} else {
+		_use_dos_palette = false;
+	}
+}
+
+static void LoadSpriteTables(void)
+{
+	int load_index = 0;
+	uint i;
+	uint j;
+	const FileList *files; // list of grf files to be loaded. Either Windows files or DOS files
+
+	_loading_stage = 1;
+
+	/*
+	 * TODO:
+	 *   I think we can live entirely without Indexed GRFs, but I have to
+	 *   invest that further. --octo
+	 */
+
+	files = _use_dos_palette? &files_dos : &files_win;
+
+	for (i = 0; files->basic[i].filename != NULL; i++) {
+		load_index += LoadGrfFile(files->basic[i].filename, load_index, i);
+	}
+
+	LoadGrfIndexed("openttd.grf", _openttd_grf_indexes, i++);
+
+	if (_sprite_page_to_load != 0) {
+		LoadGrfIndexed(
+			files->landscape[_sprite_page_to_load - 1].filename,
+			_landscape_spriteindexes[_sprite_page_to_load - 1],
+			i++
+		);
+	}
+
+	LoadGrfIndexed("trkfoundw.grf", _slopes_spriteindexes[_opt.landscape], i++);
+
+	load_index = SPR_AUTORAIL_BASE;
+	load_index += LoadGrfFile("autorail.grf", load_index, i++);
+
+	load_index = SPR_CANALS_BASE;
+	load_index += LoadGrfFile("canalsw.grf", load_index, i++);
+
+	load_index = SPR_OPENTTD_BASE + OPENTTD_SPRITES_COUNT + 1;
+
+
+	/* Load newgrf sprites
+	 * in each loading stage, (try to) open each file specified in the config
+	 * and load information from it. */
+	_custom_sprites_base = load_index;
+	for (_loading_stage = 0; _loading_stage < 2; _loading_stage++) {
+		load_index = _custom_sprites_base;
+		for (j = 0; j != lengthof(_newgrf_files) && _newgrf_files[j]; j++) {
+			if (!FiosCheckFileExists(_newgrf_files[j])) {
+				// TODO: usrerror()
+				error("NewGRF file missing: %s", _newgrf_files[j]);
+			}
+			if (_loading_stage == 0) InitNewGRFFile(_newgrf_files[j], load_index);
+			load_index += LoadNewGrfFile(_newgrf_files[j], load_index, i++);
+			DEBUG(spritecache, 2) ("Currently %i sprites are loaded", load_index);
+		}
+	}
+}
+
+
+void GfxLoadSprites(void)
+{
+	// Need to reload the sprites only if the landscape changed
+	if (_sprite_page_to_load != _opt.landscape) {
+		_sprite_page_to_load = _opt.landscape;
+
+		// Sprite cache
+		DEBUG(spritecache, 1) ("Loading sprite set %d.", _sprite_page_to_load);
+
+		GfxInitSpriteMem();
+		LoadSpriteTables();
+		GfxInitPalettes();
+	}
+}
diff --git a/gfxinit.h b/gfxinit.h
new file mode 100644
index 000000000..f2756e142
--- /dev/null
+++ b/gfxinit.h
@@ -0,0 +1,8 @@
+/* $Id$ */
+
+#ifndef GFXINIT_H
+#define GFXINIT_H
+
+void GfxLoadSprites(void);
+
+#endif
diff --git a/misc_gui.c b/misc_gui.c
index 0b514af32..0b1bcb103 100644
--- a/misc_gui.c
+++ b/misc_gui.c
@@ -4,8 +4,8 @@
 #include "openttd.h"
 #include "debug.h"
 #include "functions.h"
+#include "gfxinit.h"
 #include "saveload.h"
-#include "spritecache.h"
 #include "strings.h"
 #include "table/sprites.h"
 #include "table/strings.h"
diff --git a/newgrf.c b/newgrf.c
index 58483c167..e6efb6bae 100644
--- a/newgrf.c
+++ b/newgrf.c
@@ -30,7 +30,7 @@ extern int _replace_sprites_count[16];
 extern int _replace_sprites_offset[16];
 extern int _traininfo_vehicle_pitch;
 
-GRFFile *_cur_grffile;
+static GRFFile *_cur_grffile;
 GRFFile *_first_grffile;
 int _grffile_count;
 static int _cur_spriteid;
diff --git a/openttd.c b/openttd.c
index a7d1ed181..e506f53f6 100644
--- a/openttd.c
+++ b/openttd.c
@@ -16,6 +16,7 @@
 #include "mixer.h"
 #include "spritecache.h"
 #include "gfx.h"
+#include "gfxinit.h"
 #include "gui.h"
 #include "station.h"
 #include "vehicle.h"
diff --git a/openttd.dsp b/openttd.dsp
index 4c653796e..f74d22eae 100644
--- a/openttd.dsp
+++ b/openttd.dsp
@@ -193,6 +193,10 @@ SOURCE=.\gfx.c
 # End Source File
 # Begin Source File
 
+SOURCE=.\gfxinit.c
+# End Source File
+# Begin Source File
+
 SOURCE=.\landscape.c
 # End Source File
 # Begin Source File
@@ -550,6 +554,10 @@ SOURCE=.\gfx.h
 # End Source File
 # Begin Source File
 
+SOURCE=.\gfxinit.h
+# End Source File
+# Begin Source File
+
 SOURCE=.\gui.h
 # End Source File
 # Begin Source File
diff --git a/openttd.vcproj b/openttd.vcproj
index ce8343008..85cdb9bf4 100644
--- a/openttd.vcproj
+++ b/openttd.vcproj
@@ -238,6 +238,9 @@
 				RelativePath="gfx.c">
 			</File>
 			<File
+				RelativePath="gfxinit.c">
+			</File>
+			<File
 				RelativePath="landscape.c">
 			</File>
 			<File
@@ -511,6 +514,9 @@
 				RelativePath="gfx.h">
 			</File>
 			<File
+				RelativePath="gfxinit.h">
+			</File>
+			<File
 				RelativePath="gui.h">
 			</File>
 			<File
diff --git a/spritecache.c b/spritecache.c
index da1b7d43f..aa6b2cf29 100644
--- a/spritecache.c
+++ b/spritecache.c
@@ -4,14 +4,10 @@
 #include "openttd.h"
 #include "debug.h"
 #include "functions.h"
-#include "gfx.h"
 #include "spritecache.h"
 #include "table/sprites.h"
 #include "fileio.h"
 #include "newgrf.h"
-#include "md5.h"
-#include "variables.h"
-#include <ctype.h>
 
 #define SPRITE_CACHE_SIZE 1024*1024
 
@@ -20,15 +16,14 @@
 
 /* These are used in newgrf.c: */
 
-int _skip_sprites = 0;
-int _replace_sprites_count[16];
-int _replace_sprites_offset[16];
+extern int _skip_sprites; // XXX
+extern int _replace_sprites_count[16]; // XXX
+extern int _replace_sprites_offset[16]; // XXX
 
-static const char *_cur_grffile;
-static int _loading_stage;
-static int _skip_specials;
-uint16 _custom_sprites_base;
-static Sprite _cur_sprite;
+extern const char* _cur_grffile; // XXX
+extern int _loading_stage; // XXX
+extern int _skip_specials; // XXX
+static Sprite _cur_sprite; // XXX
 
 
 static void* _sprite_ptr[MAX_SPRITES];
@@ -50,32 +45,6 @@ static uint _sprite_lru_counter;
 static MemBlock *_spritecache_ptr;
 static int _compact_cache_counter;
 
-typedef struct MD5File {
-	const char * const filename;     // filename
-	const md5_byte_t hash[16]; // md5 sum of the file
-} MD5File;
-
-typedef struct FileList {
-	const MD5File basic[5];     // grf files that always have to be loaded
-	const MD5File landscape[3]; // landscape specific grf files
-} FileList;
-
-#include "table/files.h"
-#include "table/landscape_sprite.h"
-
-static const SpriteID * const _landscape_spriteindexes[] = {
-	_landscape_spriteindexes_1,
-	_landscape_spriteindexes_2,
-	_landscape_spriteindexes_3,
-};
-
-static const SpriteID * const _slopes_spriteindexes[] = {
-	_slopes_spriteindexes_0,
-	_slopes_spriteindexes_1,
-	_slopes_spriteindexes_2,
-	_slopes_spriteindexes_3,
-};
-
 static void CompactSpriteCache(void);
 
 static bool ReadSpriteHeaderSkipData(int load_index)
@@ -196,7 +165,7 @@ static void* ReadSprite(SpriteID id)
 }
 
 
-static bool LoadNextSprite(int load_index, byte file_index)
+bool LoadNextSprite(int load_index, byte file_index)
 {
 	uint32 file_pos = FioGetPos() | (file_index << 24);
 
@@ -244,107 +213,13 @@ static bool LoadNextSprite(int load_index, byte file_index)
 	return true;
 }
 
-static void SkipSprites(uint count)
+void SkipSprites(uint count)
 {
 	for (; count > 0; --count) {
 		if (!ReadSpriteHeaderSkipData(MAX_SPRITES - 1)) return;
 	}
 }
 
-static int LoadGrfFile(const char *filename, int load_index, int file_index)
-{
-	int load_index_org = load_index;
-
-	FioOpenFile(file_index, filename);
-
-	/* Thou shalt use LoadNewGrfFile() if thou loadeth a GRF file that
-	 * might contain some special sprites. */
-	_skip_specials = 1;
-	_skip_sprites = 0;
-
-	DEBUG(spritecache, 2) ("Reading grf-file ``%s''", filename);
-
-	while (LoadNextSprite(load_index, file_index)) {
-		load_index++;
-		if (load_index >= MAX_SPRITES) {
-			error("Too many sprites. Recompile with higher MAX_SPRITES value or remove some custom GRF files.");
-		}
-	}
-	DEBUG(spritecache, 2) ("Currently %i sprites are loaded", load_index);
-
-	return load_index - load_index_org;
-}
-
-static int LoadNewGrfFile(const char *filename, int load_index, int file_index)
-{
-	int i;
-
-	FioOpenFile(file_index, filename);
-	_cur_grffile = filename;
-	_skip_specials = 0;
-	_skip_sprites = 0;
-
-	DEBUG(spritecache, 2) ("Reading newgrf-file ``%s'' [offset: %u]",
-			filename, load_index);
-
-	/* Skip the first sprite; we don't care about how many sprites this
-	 * does contain; newest TTDPatches and George's longvehicles don't
-	 * neither, apparently. */
-	{
-		int length;
-		byte type;
-
-		length = FioReadWord();
-		type = FioReadByte();
-
-		if (length == 4 && type == 0xFF) {
-			FioReadDword();
-		} else {
-			error("Custom .grf has invalid format.");
-		}
-	}
-
-	for (i = 0; LoadNextSprite(load_index + i, file_index); i++) {
-		if (load_index + i >= MAX_SPRITES)
-			error("Too many sprites (0x%X). Recompile with higher MAX_SPRITES value or remove some custom GRF files.",
-			      load_index + i);
-	}
-
-	/* Clean up. */
-	_skip_sprites = 0;
-	memset(_replace_sprites_count, 0, sizeof(_replace_sprites_count));
-	memset(_replace_sprites_offset, 0, sizeof(_replace_sprites_offset));
-
-	return i;
-}
-
-static void LoadGrfIndexed(const char *filename, const SpriteID *index_tbl, int file_index)
-{
-	int start;
-
-	FioOpenFile(file_index, filename);
-	_skip_specials = 1;
-	_skip_sprites = 0;
-
-	DEBUG(spritecache, 2) ("Reading indexed grf-file ``%s''", filename);
-
-	for (; (start = *index_tbl++) != 0xffff;) {
-		int end = *index_tbl++;
-		if(start == 0xfffe) { // skip sprites (amount in second var)
-			SkipSprites(end);
-		} else { // load sprites and use indexes from start to end
-			do {
-			#ifdef NDEBUG
-				LoadNextSprite(start, file_index);
-			#else
-				bool b = LoadNextSprite(start, file_index);
-				assert(b);
-			#endif
-			} while (++start <= end);
-		}
-	}
-}
-
 
 #define S_FREE_MASK 1
 
@@ -607,185 +482,8 @@ const void *GetRawSprite(SpriteID sprite)
 	return p;
 }
 
-byte _sprite_page_to_load = 0xFF;
-
-#define OPENTTD_SPRITES_COUNT 100
-static const SpriteID _openttd_grf_indexes[] = {
-	SPR_OPENTTD_BASE + 0, SPR_OPENTTD_BASE + 7, // icons etc
-	134, 134,  // euro symbol medium size
-	582, 582,  // euro symbol large size
-	358, 358,  // euro symbol tiny
-	SPR_OPENTTD_BASE+11, SPR_OPENTTD_BASE+57, // more icons
-	648, 648, // nordic char: æ
-	616, 616, // nordic char: Æ
-	666, 666, // nordic char: ø
-	634, 634, // nordic char: Ø
-	SPR_OPENTTD_BASE+62, SPR_OPENTTD_BASE + OPENTTD_SPRITES_COUNT, // more icons
-	0xffff,
-};
-
-/* FUNCTIONS FOR CHECKING MD5 SUMS OF GRF FILES */
-
-/* Check that the supplied MD5 hash matches that stored for the supplied filename */
-static bool CheckMD5Digest(const MD5File file, md5_byte_t *digest, bool warn)
-{
-	uint i;
-
-	/* Loop through each byte of the file MD5 and the stored MD5... */
-	for (i = 0; i < 16; i++) if (file.hash[i] != digest[i]) break;
-
-		/* If all bytes of the MD5's match (i.e. the MD5's match)... */
-	if (i == 16) {
-		return true;
-	} else {
-		if (warn) fprintf(stderr, "MD5 of %s is ****INCORRECT**** - File Corrupt.\n", file.filename);
-		return false;
-	};
-}
-
-/* Calculate and check the MD5 hash of the supplied filename.
- * returns true if the checksum is correct */
-static bool FileMD5(const MD5File file, bool warn)
-{
-	FILE *f;
-	char buf[MAX_PATH];
-
-	// open file
-	sprintf(buf, "%s%s", _path.data_dir, file.filename);
-	f = fopen(buf, "rb");
-
-#if !defined(WIN32)
-	if (f == NULL) {
-		char *s;
-	// make lower case and check again
-		for (s = buf + strlen(_path.data_dir) - 1; *s != '\0'; s++)
-			*s = tolower(*s);
-		f = fopen(buf, "rb");
-	}
-#endif
-
-	if (f != NULL) {
-		md5_state_t filemd5state;
-		md5_byte_t buffer[1024];
-		md5_byte_t digest[16];
-		size_t len;
-
-		md5_init(&filemd5state);
-		while ((len = fread(buffer, 1, sizeof(buffer), f)) != 0)
-			md5_append(&filemd5state, buffer, len);
-
-		if (ferror(f) && warn) fprintf(stderr, "Error Reading from %s \n", buf);
-		fclose(f);
-
-		md5_finish(&filemd5state, digest);
-	  return CheckMD5Digest(file, digest, warn);
-	} else { // file not found
-		return false;
-	}
-}
-
-/* Checks, if either the Windows files exist (TRG1R.GRF) or the DOS files (TRG1.GRF)
- * by comparing the MD5 checksums of the files. _use_dos_palette is set accordingly.
- * If neither are found, Windows palette is assumed.
- *
- * (Note: Also checks sample.cat for corruption) */
-void CheckExternalFiles(void)
-{
-	uint i;
-	// count of files from this version
-	uint dos = 0;
-	uint win = 0;
-
-	for (i = 0; i < 2; i++) if (FileMD5(files_dos.basic[i], true)) dos++;
-	for (i = 0; i < 3; i++) if (FileMD5(files_dos.landscape[i], true)) dos++;
-
-	for (i = 0; i < 2; i++) if (FileMD5(files_win.basic[i], true)) win++;
-	for (i = 0; i < 3; i++) if (FileMD5(files_win.landscape[i], true)) win++;
-
-	if (!FileMD5(sample_cat_win, false) && !FileMD5(sample_cat_dos, false))
-		fprintf(stderr, "Your sample.cat file is corrupted or missing!\n");
-
-	/*
-	 * forced DOS palette via command line -> leave it that way
-	 * all Windows files present -> Windows palette
-	 * all DOS files present -> DOS palette
-	 * no Windows files present and any DOS file present -> DOS palette
-	 * otherwise -> Windows palette
-	 */
-	if (_use_dos_palette) {
-		return;
-	} else if (win == 5) {
-		_use_dos_palette = false;
-	} else if (dos == 5 || (win == 0 && dos > 0)) {
-		_use_dos_palette = true;
-	} else {
-		_use_dos_palette = false;
-	}
-}
-
-static void LoadSpriteTables(void)
-{
-	int load_index = 0;
-	uint i;
-	uint j;
-	const FileList *files; // list of grf files to be loaded. Either Windows files or DOS files
-
-	_loading_stage = 1;
-
-	/*
-	 * TODO:
-	 *   I think we can live entirely without Indexed GRFs, but I have to
-	 *   invest that further. --octo
-	 */
-
-	files = _use_dos_palette? &files_dos : &files_win;
-
-	for (i = 0; files->basic[i].filename != NULL; i++) {
-		load_index += LoadGrfFile(files->basic[i].filename, load_index, i);
-	}
-
-	LoadGrfIndexed("openttd.grf", _openttd_grf_indexes, i++);
 
-	if (_sprite_page_to_load != 0) {
-		LoadGrfIndexed(
-			files->landscape[_sprite_page_to_load - 1].filename,
-			_landscape_spriteindexes[_sprite_page_to_load - 1],
-			i++
-		);
-	}
-
-	LoadGrfIndexed("trkfoundw.grf", _slopes_spriteindexes[_opt.landscape], i++);
-
-	load_index = SPR_AUTORAIL_BASE;
-	load_index += LoadGrfFile("autorail.grf", load_index, i++);
-
-	load_index = SPR_CANALS_BASE;
-	load_index += LoadGrfFile("canalsw.grf", load_index, i++);
-
-	load_index = SPR_OPENTTD_BASE + OPENTTD_SPRITES_COUNT + 1;
-
-
-	/* Load newgrf sprites
-	 * in each loading stage, (try to) open each file specified in the config
-	 * and load information from it. */
-	_custom_sprites_base = load_index;
-	for (_loading_stage = 0; _loading_stage < 2; _loading_stage++) {
-		load_index = _custom_sprites_base;
-		for (j = 0; j != lengthof(_newgrf_files) && _newgrf_files[j]; j++) {
-			if (!FiosCheckFileExists(_newgrf_files[j])) {
-				// TODO: usrerror()
-				error("NewGRF file missing: %s", _newgrf_files[j]);
-			}
-			if (_loading_stage == 0) InitNewGRFFile(_newgrf_files[j], load_index);
-			load_index += LoadNewGrfFile(_newgrf_files[j], load_index, i++);
-			DEBUG(spritecache, 2) ("Currently %i sprites are loaded", load_index);
-		}
-	}
-
-	_compact_cache_counter = 0;
-}
-
-static void GfxInitSpriteMem(void)
+void GfxInitSpriteMem(void)
 {
 	// initialize sprite cache heap
 	if (_spritecache_ptr == NULL) _spritecache_ptr = malloc(SPRITE_CACHE_SIZE);
@@ -796,20 +494,6 @@ static void GfxInitSpriteMem(void)
 	NextBlock(_spritecache_ptr)->size = 0;
 
 	memset(_sprite_ptr, 0, sizeof(_sprite_ptr));
-}
-
 
-void GfxLoadSprites(void)
-{
-	// Need to reload the sprites only if the landscape changed
-	if (_sprite_page_to_load != _opt.landscape) {
-		_sprite_page_to_load = _opt.landscape;
-
-		// Sprite cache
-		DEBUG(spritecache, 1) ("Loading sprite set %d.", _sprite_page_to_load);
-
-		GfxInitSpriteMem();
-		LoadSpriteTables();
-		GfxInitPalettes();
-	}
+	_compact_cache_counter = 0;
 }
diff --git a/spritecache.h b/spritecache.h
index 9d25f2bc7..c2ff67134 100644
--- a/spritecache.h
+++ b/spritecache.h
@@ -24,7 +24,10 @@ static inline const byte *GetNonSprite(SpriteID sprite)
 	return GetRawSprite(sprite);
 }
 
-void GfxLoadSprites(void);
+void GfxInitSpriteMem(void);
 void IncreaseSpriteLRU(void);
 
+bool LoadNextSprite(int load_index, byte file_index);
+void SkipSprites(uint count);
+
 #endif