69 lines
2.0 KiB
GDScript
69 lines
2.0 KiB
GDScript
extends Node
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const LENGTH := 0x500 / 2 # Expanded length 0x500, RLE step produces 0x280 tile mappings
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func decompress_battle_tilemap(buffer: StreamPeerBuffer) -> Array:
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# Decompresses the tilemap for a battle background.
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# Battle BGs use a type of RLE with 2byte repeat and 1byte incremental repeat.
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var mappings := []
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while len(mappings) < LENGTH:
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var byte := buffer.get_u8()
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if byte != 0xFF:
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mappings.append(TileMapping.from_battle_byte(byte))
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else: # Byte begins a repeat code
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var repeat_code := buffer.get_u8()
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var repeat := repeat_code & 0x3F
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byte = buffer.get_u8()
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if repeat_code & 0x80: # Repeat 2 tiles
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var byte2 := buffer.get_u8()
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for i in repeat:
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mappings.append(TileMapping.from_battle_byte(byte))
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mappings.append(TileMapping.from_battle_byte(byte2))
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else: # Incremental repeat
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var inc := buffer.get_u8()
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if repeat_code & 0x40: # Negative increment
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inc = -inc
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for i in repeat:
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mappings.append(TileMapping.from_battle_byte(byte))
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byte += inc
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return mappings
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func apply_battle_tilemap_flips(buffer: StreamPeerBuffer, id: int, tilemap: Array):
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if id==0xFF:
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return
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buffer.seek(0x14C736+(id*2))
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var ptr := 0x140000 + buffer.get_u16()
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buffer.seek(ptr)
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var tile_i := 0
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while tile_i < LENGTH:
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var a := buffer.get_u8()
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if a == 0x00: # Skip N*8 tiles
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tile_i += buffer.get_u8() * 8
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else:
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# Each bit is a tile, 1 means flip horizontally
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for b in range(7, -1, -1):
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tilemap[tile_i].h_flip = bool((a>>b) & 0x01)
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tile_i += 1
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class TileMapping:
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var tile_index: int
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var palette: int
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var priority: bool
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var h_flip: bool
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var v_flip: bool
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static func from_tilemap_word(w: int) -> TileMapping:
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var t := TileMapping.new()
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t.tile_index = w & 0x03FF
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t.palette = (w & 0x1C00) >> 10
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t.priority = bool(w & 0x2000)
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t.h_flip = bool(w & 0x4000)
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t.v_flip = bool(w & 0x8000)
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return t
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static func from_battle_byte(b: int) -> TileMapping:
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var t := TileMapping.new()
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t.tile_index = b | 0x80
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t.palette = 1 + (b >> 7)
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return t
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