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8bpp sprites

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This commit is contained in:
Matthew Berry 2021-01-07 21:54:18 -08:00
parent cb3280fea6
commit f6fa9f9711
1 changed files with 12 additions and 5 deletions
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15
src/crab/ppu.cr
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@ -175,10 +175,17 @@ class PPU
sprite_x = width - sprite_x - 1 if bit?(sprite.attr1, 12)
x = sprite_x & 7
tile_id = sprite.character_name
tile_id_offset = (sprite_x >> 3) + (sprite_y >> 3) * (@dispcnt.obj_character_vram_mapping ? width >> 3 : 0x20)
palettes = @vram[base + (tile_id + tile_id_offset) * 0x20 + y * 4 + (x >> 1)]
if sprite.color_mode # 8bpp
tile_id += (sprite_x >> 2) + (sprite_y >> 3) * (@dispcnt.obj_character_vram_mapping ? width >> 3 : 0x20)
tile_id &= ~1 unless @dispcnt.obj_character_vram_mapping # bottom bit is ignored in 2D mapping mode
pal_idx = @vram[base + tile_id * 0x20 + y * 8 + x]
else # 4bpp
tile_id += (sprite_x >> 3) + (sprite_y >> 3) * (@dispcnt.obj_character_vram_mapping ? width >> 3 : 0x20)
palettes = @vram[base + tile_id * 0x20 + y * 4 + (x >> 1)]
pal_idx = ((palettes >> ((x & 1) * 4)) & 0xF)
scanline[col] = (sprite.palette_number << 4) + pal_idx + 0x100 if pal_idx > 0
pal_idx += (sprite.palette_number << 4) if pal_idx > 0
end
scanline[col] = pal_idx.to_u16 + 0x100 if pal_idx > 0 # 0x100 vs 0x200 because palette is read as 16 bit
end
end
end
@ -290,7 +297,7 @@ record Sprite, attr0 : UInt16, attr1 : UInt16, attr2 : UInt16, unused_space : UI
bits(attr0, 14..15)
end
def colors
def color_mode
bit?(attr0, 13)
end