Add support for multiple layers.HEADmain

2 files changed, 57 insertions, 35 deletions

diff --git a/src/gfx2d.c b/src/gfx2d.c
index 1c8b06f..eaed2b8 100644
--- a/src/gfx2d.c
+++ b/src/gfx2d.c
@@ -26,6 +26,9 @@
 /// Take the minimum of two values.
 #define min(a, b) ((a) < (b) ? (a) : (b))
 
+/// The 0-tile denotes "no tile". The renderer skips drawing 0-tiles.
+static const Tile NoTile = 0;
+
 typedef struct ivec2 {
   int x, y;
 } ivec2;
@@ -606,6 +609,10 @@ static void draw_tile_ortho(Gfx2d* gfx, Tile tile, int x, int y) {
   assert(x < gfx->map->world_width);
   assert(y < gfx->map->world_height);
 
+  if (tile == NoTile) {
+    return;
+  }
+
   const Ts_Tile* pTile  = ts_tileset_get_tile(gfx->tileset, tile);
   const Pixel*   pixels = ts_tileset_get_tile_pixels(gfx->tileset, tile);
 
@@ -626,6 +633,10 @@ static void draw_tile_iso(Gfx2d* gfx, Tile tile, int iso_x, int iso_y) {
   assert(iso_x < gfx->map->world_width);
   assert(iso_y < gfx->map->world_height);
 
+  if (tile == NoTile) {
+    return;
+  }
+
   const Ts_Tile* pTile  = ts_tileset_get_tile(gfx->tileset, tile);
   const Pixel*   pixels = ts_tileset_get_tile_pixels(gfx->tileset, tile);
 
@@ -677,18 +688,19 @@ static void draw_map_iso(Gfx2d* gfx) {
   assert(gfx);
   assert(gfx->map);
 
-  // TODO: Support for multiple layers.
-  const Tm_Layer* layer = tm_map_get_layer(gfx->map, 0);
-
-  // TODO: Culling.
-  //  Ex: map the screen corners to tile space to cull.
-  //  Ex: walk in screen space and fetch the tile.
-  //  The tile-centric approach might be more cache-friendly since the
-  //  screen-centric approach would juggle multiple tiles throughout the scan.
-  for (int wy = 0; wy < gfx->map->world_height; ++wy) {
-    for (int wx = 0; wx < gfx->map->world_width; ++wx) {
-      const Tile tile = tm_layer_get_tile(gfx->map, layer, wx, wy);
-      draw_tile_iso(gfx, tile, wx, wy);
+  for (uint16_t l = 0; l < gfx->map->num_layers; ++l) {
+    const Tm_Layer* layer = tm_map_get_layer(gfx->map, l);
+
+    // TODO: Culling.
+    //  Ex: map the screen corners to tile space to cull.
+    //  Ex: walk in screen space and fetch the tile.
+    //  The tile-centric approach might be more cache-friendly since the
+    //  screen-centric approach would juggle multiple tiles throughout the scan.
+    for (int wy = 0; wy < gfx->map->world_height; ++wy) {
+      for (int wx = 0; wx < gfx->map->world_width; ++wx) {
+        const Tile tile = tm_layer_get_tile(gfx->map, layer, wx, wy);
+        draw_tile_iso(gfx, tile, wx, wy);
+      }
     }
   }
 }
diff --git a/tools/mkasset.py b/tools/mkasset.py
index a402e3c..1be0573 100644
--- a/tools/mkasset.py
+++ b/tools/mkasset.py
@@ -12,6 +12,7 @@
 #
 import argparse
 import ctypes
+import struct
 import sys
 from enum import IntEnum
 from typing import Generator
@@ -80,7 +81,8 @@ def convert_tsx(input_filepath, output_filepath):
     assert (tileset.tag == "tileset")
 
     # Header.
-    tileset_tile_count = int(tileset.attrib["tilecount"])
+    # +1 for the 0-tile.
+    tileset_tile_count = int(tileset.attrib["tilecount"]) + 1
     tileset_tile_width = int(tileset.attrib["tilewidth"])
     tileset_tile_height = int(tileset.attrib["tileheight"])
 
@@ -88,17 +90,14 @@ def convert_tsx(input_filepath, output_filepath):
     print(f"Tile width:  {tileset_tile_width}")
     print(f"Tile height: {tileset_tile_height}")
 
-    pixels = []  # List of byte arrays
-    pixels_offset = 0
+    pixels = bytearray()
 
     def output_tile(output, tile_width, tile_height, tile_image_bytes):
         # Expecting RGBA pixels.
         assert (len(tile_image_bytes) == (tile_width * tile_height * 4))
 
-        nonlocal pixels_offset
-        tile_pixels_offset = pixels_offset
-        pixels.append(tile_image_bytes)
-        pixels_offset += len(tile_image_bytes)
+        tile_pixels_offset = len(pixels)
+        pixels.extend(tile_image_bytes)
 
         output.write(ctypes.c_uint16(tile_width))
         output.write(ctypes.c_uint16(tile_height))
@@ -111,6 +110,10 @@ def convert_tsx(input_filepath, output_filepath):
         output.write(ctypes.c_uint16(tileset_tile_height))
         output.write(ctypes.c_uint16(0))  # Pad.
 
+        # Write the 0-tile, which denotes "no tile", at index 0.
+        zero_pixels = bytes(tileset_tile_width * tileset_tile_height * 4)
+        output_tile(output, tileset_tile_width, tileset_tile_height, zero_pixels)
+
         # A tileset made up of multiple images contains various 'tile' children,
         # each with their own 'image':
         #
@@ -174,8 +177,7 @@ def convert_tsx(input_filepath, output_filepath):
                 output_tile(output, tile_width, tile_height, image_bytes)
 
         # Write the pixel data.
-        for bytes in pixels:
-            output.write(bytes)
+        output.write(pixels)
 
 
 def convert_tmx(input_filepath, output_filepath):
@@ -187,8 +189,10 @@ def convert_tmx(input_filepath, output_filepath):
     map_height = int(root.attrib["height"])
     base_tile_width = int(root.attrib["tilewidth"])
     base_tile_height = int(root.attrib["tileheight"])
-    num_layers = 1
     flags = Orientation.Isometric if (root.attrib["orientation"] == "isometric") else Orientation.Orthogonal
+    firstgid = 1
+    layers = []
+    tileset_path = ""
 
     print(f"Map width:   {map_width}")
     print(f"Map height:  {map_height}")
@@ -196,8 +200,6 @@ def convert_tmx(input_filepath, output_filepath):
     print(f"Tile height: {base_tile_height}")
     print(f"Orientation: {flags}")
 
-    tileset_path = None
-
     with open(output_filepath, 'bw') as output:
         for child in root:
             if child.tag == "tileset":
@@ -205,19 +207,12 @@ def convert_tmx(input_filepath, output_filepath):
 
                 tileset = child
                 tileset_path = tileset.attrib["source"]
+                firstgid = int(tileset.attrib["firstgid"])
 
                 print(f"Tile set: {tileset_path}")
 
                 tileset_path = tileset_path.replace("tsx", "ts")
 
-                # Write the header.
-                output.write(to_char_array(tileset_path, MAX_PATH_LENGTH))
-                output.write(ctypes.c_uint16(map_width))
-                output.write(ctypes.c_uint16(map_height))
-                output.write(ctypes.c_uint16(base_tile_width))
-                output.write(ctypes.c_uint16(base_tile_height))
-                output.write(ctypes.c_uint16(num_layers))
-                output.write(ctypes.c_uint16(flags))
             elif child.tag == "layer":
                 layer = child
                 layer_id = int(layer.attrib["id"])
@@ -238,12 +233,27 @@ def convert_tmx(input_filepath, output_filepath):
 
                 csv = data.text.strip()
                 rows = csv.split('\n')
+                tiles = bytearray()
                 for row in rows:
                     tile_ids = [x.strip() for x in row.split(',') if x]
                     for tile_id in tile_ids:
-                        # TODO: We need to handle 'firsgid' in TMX files.
-                        #  For now, assume it's 1 and do -1 to make the tiles 0-based.
-                        output.write(ctypes.c_uint16(int(tile_id) - 1))
+                        # Subtract firstgid and then add 1 to make tiles 1-based.
+                        tile_id = int(tile_id) - firstgid + 1
+                        tiles.extend(struct.pack("=h", tile_id))
+                layers.append(tiles)
+
+        # Write the header.
+        output.write(to_char_array(tileset_path, MAX_PATH_LENGTH))
+        output.write(ctypes.c_uint16(map_width))
+        output.write(ctypes.c_uint16(map_height))
+        output.write(ctypes.c_uint16(base_tile_width))
+        output.write(ctypes.c_uint16(base_tile_height))
+        output.write(ctypes.c_uint16(len(layers)))
+        output.write(ctypes.c_uint16(flags))
+
+        # Write the layers.
+        for layer in layers:
+            output.write(layer)
 
 
 def get_num_cols(image, sprite_width):