Added missing source file, and make the tilemap depend on current layer instead of the sum of layers

git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1860 416bcca6-2ee7-4201-b75f-2eb2f807beb1

src/tiles.h

@@ -0,0 +1,38 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2011 Yves Rizoud
+    Copyright 2011 Adrien Destugues
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+*/
+
+//////////////////////////////////////////////////////////////////////////////
+///@file tiles.h
+/// Functions for tilemap effect
+//////////////////////////////////////////////////////////////////////////////
+
+int compare_tiles(word x1, word y1, word x2, word y2);
+
+/// Create or update a tilemap based on current screen pixels.
+void Tilemap_create(void);
+
+void Tilemap_draw(word x, word y, byte color);
+
+#define TILE_FOR_COORDS(x,y) (((y)-Snap_offset_Y)/Snap_height*Main_tilemap_width+((x)-Snap_offset_X)/Snap_width)
+#define TILE_AT(x,y) (y)*Main_tilemap_width+(x)
+#define TILE_X(t) (((t)%Main_tilemap_width)*Snap_width+Snap_offset_X)
+#define TILE_Y(t) (((t)/Main_tilemap_width)*Snap_height+Snap_offset_Y)
+