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pull out repetitive logic from scanline loops, saving some fps

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Matthew Berry 2021-04-29 23:40:54 -07:00
parent d92d37e875
commit b8c64fa69d
1 changed files with 16 additions and 12 deletions
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28
src/crab/ppu.cr
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@ -141,31 +141,34 @@ class PPU
def render_reg_bg(bg : Int) : Nil
return unless bit?(@dispcnt.value, 8 + bg)
pal_buf = @layer_palettes[bg]
bgcnt = @bgcnt[bg]
bgvofs = @bgvofs[bg]
bghofs = @bghofs[bg]
tw, th = case @bgcnt[bg].screen_size
tw, th = case bgcnt.screen_size
when 0b00 then {0x0FF, 0x0FF} # 32x32
when 0b01 then {0x1FF, 0x0FF} # 64x32
when 0b10 then {0x0FF, 0x1FF} # 32x64
when 0b11 then {0x1FF, 0x1FF} # 64x64
else raise "Impossible bgcnt screen size: #{@bgcnt[bg].screen_size}"
else raise "Impossible bgcnt screen size: #{bgcnt.screen_size}"
end
screen_base = 0x800_u32 * @bgcnt[bg].screen_base_block
character_base = @bgcnt[bg].character_base_block.to_u32 * 0x4000
effective_row = (@vcount.to_u32 + @bgvofs[bg].value) & th
screen_base = 0x800_u32 * bgcnt.screen_base_block
character_base = bgcnt.character_base_block.to_u32 * 0x4000
effective_row = (@vcount.to_u32 + bgvofs.value) & th
ty = effective_row >> 3
240.times do |col|
effective_col = (col + @bghofs[bg].value) & tw
effective_col = (col + bghofs.value) & tw
tx = effective_col >> 3
se_idx = se_index(tx, ty, @bgcnt[bg].screen_size)
se_idx = se_index(tx, ty, bgcnt.screen_size)
screen_entry = @vram[screen_base + se_idx * 2 + 1].to_u16 << 8 | @vram[screen_base + se_idx * 2]
tile_id = bits(screen_entry, 0..9)
y = (effective_row & 7) ^ (7 * (screen_entry >> 11 & 1))
x = (effective_col & 7) ^ (7 * (screen_entry >> 10 & 1))
if @bgcnt[bg].color_mode # 8bpp
if bgcnt.color_mode # 8bpp
pal_idx = @vram[character_base + tile_id * 0x40 + y * 8 + x]
else # 4bpp
palette_bank = bits(screen_entry, 12..15)
@ -181,22 +184,23 @@ class PPU
return unless bit?(@dispcnt.value, 8 + bg)
pal_buf = @layer_palettes[bg]
row = @vcount.to_u32
bgcnt = @bgcnt[bg]
dx, _, dy, _ = @bgaff[bg - 2].map &.num
int_x, int_y = @bgref_int[bg - 2]
size = 16 << @bgcnt[bg].screen_size # tiles, always a square
size = 16 << bgcnt.screen_size # tiles, always a square
size_pixels = size << 3
screen_base = 0x800_u32 * @bgcnt[bg].screen_base_block
character_base = @bgcnt[bg].character_base_block.to_u32 * 0x4000
screen_base = 0x800_u32 * bgcnt.screen_base_block
character_base = bgcnt.character_base_block.to_u32 * 0x4000
240.times do |col|
x = int_x >> 8
y = int_y >> 8
int_x += dx
int_y += dy
if @bgcnt[bg].affine_wrap
if bgcnt.affine_wrap
x %= size_pixels
y %= size_pixels
end