basic tilemapping

mappers/tilemapper.cpp

@@ -9,11 +9,22 @@
 namespace UwU {
   class TileMapper : public MapperBase<TileMapper> { // not actually tilemapping yet
     public:
-      TileMapper() {}
+      TileMapper() {
+        this->tileMap = new uint16_t[16384]; // the map of tile positions 128x128 8x8 tiles from a 512x512 bitmap space
+      }
+      uint16_t* tileMap;
 
       Coord2 map(uint16_t x0, uint16_t y0, uint16_t x, uint16_t y) {
-        uint16_t u = x -x0;
-        uint16_t v = y -y0;
+        uint16_t u0 = x - x0;
+        uint16_t v0 = y - y0;
+        // returns uv coordinates that point to a specific pixel of a specific tile on a tilesheet buffer
+        uint16_t mapX = (u0 & 0x03f8) >> 3;
+        uint16_t mapY = (v0 & 0x03f8) << 4;
+        uint16_t tileIndex = tileMap[mapY + mapX];
+        uint16_t u = (tileIndex & 0x003f) << 3;
+        u += (u0 & 0x0007);
+        uint16_t v = (tileIndex & 0x0fc0) >> 3;
+        v += (v0 & 0x0007);
         return Coord2(u, v);
      }
   };