mirror of
https://github.com/irmen/prog8.git
synced 2024-09-07 03:54:27 +00:00
110 lines
3.6 KiB
Lua
110 lines
3.6 KiB
Lua
%target cx16
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%import gfx2
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%import diskio
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bmp_module {
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sub show_image(uword filenameptr) -> ubyte {
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ubyte load_ok = false
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ubyte[$36] header
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uword size
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uword width
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uword height
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ubyte bpp
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uword offsetx
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uword offsety
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uword palette = memory("palette", 256*4)
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uword total_read = 0
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if diskio.f_open(8, filenameptr) {
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size = diskio.f_read(header, $36)
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if size==$36 {
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total_read = $36
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if header[0]=='b' and header[1]=='m' {
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uword bm_data_offset = mkword(header[11], header[10])
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uword header_size = mkword(header[$f], header[$e])
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width = mkword(header[$13], header[$12])
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height = mkword(header[$17], header[$16])
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bpp = header[$1c]
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uword num_colors = header[$2e]
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if num_colors == 0
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num_colors = 2**bpp
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uword skip_hdr = header_size - 40
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repeat skip_hdr
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void c64.CHRIN()
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total_read += skip_hdr
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size = diskio.f_read(palette, num_colors*4)
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if size==num_colors*4 {
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total_read += size
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repeat bm_data_offset - total_read
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void c64.CHRIN()
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gfx2.clear_screen()
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custompalette.set_bgra(palette, num_colors)
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decode_bitmap()
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load_ok = true
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}
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}
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}
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diskio.f_close()
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}
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return load_ok
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sub start_plot() {
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offsetx = 0
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offsety = 0
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if width < gfx2.width
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offsetx = (gfx2.width - width - 1) / 2
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if height < gfx2.height
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offsety = (gfx2.height - height - 1) / 2
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if width > gfx2.width
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width = gfx2.width
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if height > gfx2.height
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height = gfx2.height
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}
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sub decode_bitmap() {
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start_plot()
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uword bits_width = width * bpp
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ubyte pad_bytes = (((bits_width + 31) >> 5) << 2) - ((bits_width + 7) >> 3) as ubyte
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uword x
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uword y
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ubyte b
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for y in height-1 downto 0 {
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gfx2.position(offsetx, offsety+y)
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when bpp {
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8 -> {
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for x in 0 to width-1
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gfx2.next_pixel(c64.CHRIN())
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}
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4 -> {
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for x in 0 to width-1 step 2 {
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b = c64.CHRIN()
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gfx2.next_pixel(b>>4)
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gfx2.next_pixel(b&15)
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}
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}
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2 -> {
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for x in 0 to width-1 step 4 {
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b = c64.CHRIN()
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gfx2.next_pixel(b>>6)
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gfx2.next_pixel(b>>4 & 3)
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gfx2.next_pixel(b>>2 & 3)
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gfx2.next_pixel(b & 3)
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}
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}
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1 -> {
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for x in 0 to width-1 step 8
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gfx2.set_8_pixels_from_bits(c64.CHRIN(), 1, 0)
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}
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}
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repeat pad_bytes
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void c64.CHRIN()
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}
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}
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}
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}
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