mirror of
https://github.com/irmen/prog8.git
synced 2024-11-23 07:32:10 +00:00
133 lines
6.5 KiB
Lua
133 lines
6.5 KiB
Lua
%target cx16
|
|
%import gfx2
|
|
%import textio
|
|
%import diskio
|
|
%option no_sysinit
|
|
|
|
; CommanderX16 Image file format. (EXPERIMENTAL/ UNFINISHED)
|
|
; Numbers are encoded in little endian format (lsb first).
|
|
;
|
|
; offset value
|
|
; -----------------
|
|
; HEADER (12 bytes):
|
|
; 0-1 'CI' in petscii , from "CommanderX16 Image".
|
|
; 2 Size of the header data following this byte (always 9, could become more if format changes)
|
|
; 3-4 Width in pixels (must be multiple of 8)
|
|
; 5-6 Height in pixels
|
|
; 7 Bits-per-pixel (1, 2, 4 or 8) (= 2, 4, 16 or 256 colors)
|
|
; this also determines the number of palette entries following later.
|
|
; 8 Settings bits.
|
|
; bit 0 and 1 = compression. 00 = uncompressed
|
|
; 01 = RLE [TODO not yet implemented]
|
|
; 10 = LZSA [TODO not yet implemented]
|
|
; 11 = Exomizer [TODO not yet implemented]
|
|
; bit 2 = palette format. 0 = 4 bits/channel (2 bytes per color, $0R $GB)
|
|
; 1 = 8 bits/channel (3 bytes per color, $RR $GG $BB)
|
|
; 4 bits per channel is what the Vera in the Cx16 supports.
|
|
; bit 3 = bitmap format. 0 = raw bitmap pixels
|
|
; 1 = tile-based image [TODO not yet implemented]
|
|
; bit 4 = hscale (horizontal display resulution) 0 = 320 pixels, 1 = 640 pixels
|
|
; bit 5 = vscale (vertical display resulution) 0 = 240 pixels, 1 = 480 pixels
|
|
; bit 6,7: reserved, set to 0
|
|
; 9-11 Size of the bitmap data following the palette data.
|
|
; This is a 24-bits number, can be 0 ("unknown", in which case just read until the end).
|
|
;
|
|
; PALETTE (always present but size varies):
|
|
; 12-... Color palette. Number of entries = 2 ^ bits-per-pixel. Number of bytes per
|
|
; entry is 2 or 3, depending on the chosen palette format in the setting bits.
|
|
;
|
|
; BITMAPDATA (size varies):
|
|
; After this, the actual image data follows.
|
|
; If the bitmap format is 'raw bitmap pixels', the bimap is simply written as a sequence
|
|
; of bytes making up the image's scan lines. #bytes per scan line = width * bits-per-pixel / 8
|
|
; If it is 'tiles', .... [TODO]
|
|
; If a compression scheme is used, the bitmap data here has to be decompressed first.
|
|
; TODO: with compressed files, store the data in compressed chunks of max 8kb uncompressed?
|
|
; (it is a problem to load let alone decompress a full bitmap at once because there will likely not be enough ram to do that)
|
|
; (doing it in chunks of 8 kb allows for sticking each chunk in one of the banked 8kb ram blocks, or even copy it directly to the screen)
|
|
|
|
ci_module {
|
|
|
|
sub show_image(uword filename) -> ubyte {
|
|
uword buffer = memory("buffer", 620*2) ; enough to store two scanlines of 640 bytes
|
|
ubyte read_success = false
|
|
uword bitmap_load_address = progend()
|
|
; uword max_bitmap_size = $9eff - bitmap_load_address
|
|
|
|
if(diskio.f_open(8, filename)) {
|
|
uword size = diskio.f_read(buffer, 12) ; read the header
|
|
if size==12 {
|
|
if @(buffer+0)=='c' and @(buffer+1)=='i' and @(buffer+2) == 9 {
|
|
uword width = mkword(@(buffer+4), @(buffer+3))
|
|
uword height = mkword(@(buffer+6), @(buffer+5))
|
|
ubyte bpp = @(buffer+7)
|
|
uword num_colors = 2 ** bpp
|
|
ubyte flags = @(buffer+8)
|
|
ubyte compression = flags & %00000011
|
|
ubyte palette_format = (flags & %00000100) >> 2
|
|
ubyte bitmap_format = (flags & %00001000) >> 3
|
|
; ubyte hscale = (flags & %00010000) >> 4
|
|
; ubyte vscale = (flags & %00100000) >> 5
|
|
uword bitmap_size = mkword(@(buffer+10), @(buffer+9))
|
|
uword palette_size = num_colors*2
|
|
if palette_format
|
|
palette_size += num_colors ; 3
|
|
if width > gfx2.width {
|
|
txt.print("image is too wide for the display!\n")
|
|
} else if compression!=0 {
|
|
txt.print("compressed image not yet supported!\n") ; TODO implement the various decompressions
|
|
} else if bitmap_format==1 {
|
|
txt.print("tiled bitmap not yet supported!\n") ; TODO implement tiled image
|
|
} else {
|
|
size = diskio.f_read(buffer, palette_size)
|
|
if size==palette_size {
|
|
if compression {
|
|
txt.print("todo: compressed image support\n")
|
|
} else {
|
|
; uncompressed bitmap data. read it a scanline at a time and display as we go.
|
|
; restrict height to the maximun that can be displayed
|
|
if height > gfx2.height
|
|
height = gfx2.height
|
|
if palette_format
|
|
palette.set_rgb8(buffer, num_colors)
|
|
else
|
|
palette.set_rgb4(buffer, num_colors)
|
|
gfx2.clear_screen()
|
|
gfx2.position(0 ,0)
|
|
uword scanline_size = width * bpp / 8
|
|
ubyte y
|
|
for y in 0 to lsb(height)-1 {
|
|
void diskio.f_read(buffer, scanline_size)
|
|
when bpp {
|
|
8 -> gfx2.next_pixels(buffer, scanline_size)
|
|
4 -> display_scanline_16c(buffer, scanline_size)
|
|
2 -> display_scanline_4c(buffer, scanline_size)
|
|
1 -> display_scanline_2c(buffer, scanline_size)
|
|
}
|
|
}
|
|
read_success = true
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
diskio.f_close()
|
|
}
|
|
|
|
return read_success
|
|
}
|
|
|
|
sub display_scanline_16c(uword dataptr, uword numbytes) {
|
|
; TODO
|
|
}
|
|
|
|
sub display_scanline_4c(uword dataptr, uword numbytes) {
|
|
; TODO
|
|
}
|
|
|
|
sub display_scanline_2c(uword dataptr, uword numbytes) {
|
|
; TODO
|
|
}
|
|
}
|