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bmx module only supports 320 or 640 image widths for now

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This commit is contained in:
Irmen de Jong 2023-11-28 20:38:52 +01:00
parent ee4da1a757
commit fde136fb7b
3 changed files with 33 additions and 43 deletions
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69
compiler/res/prog8lib/cx16/bmx.p8
View File

@ -1,5 +1,5 @@
; Routines to load and save "BMX" files (commander X16 bitmap format) Version 1.
; Only uncompressed images are supported for now.
; Only uncompressed images, of width 320 or 640, are supported for now.
; BMX Specification: https://cx16forum.com/forum/viewtopic.php?t=6945
%import diskio
@ -23,12 +23,11 @@ bmx {
uword max_height = 0 ; should you want load() to check for this
uword palette_buffer_ptr = 0 ; should you want to load or save the palette into main memory instead of directly into vram
sub load(ubyte drivenumber, str filename, ubyte vbank, uword vaddr, uword screen_width) -> bool {
sub load(ubyte drivenumber, str filename, ubyte vbank, uword vaddr) -> bool {
; Loads a BMX bitmap image and palette into vram. (and Header info into the bmx.* variables)
; Parameters:
; the drive number and filename to load,
; the vram bank and address where the bitmap data should go,
; and the width of the current screen mode (can be 0 if you know no padding is needed).
; and the vram bank and address where the bitmap data should go,
; You can set the max_width and max_height variables first, if you want this routine to check those.
; Note: does not change vera screen mode or colordepth! You have to do that yourself!
; Returns: success status. If false, error_message points to the error message string.
@ -43,12 +42,12 @@ bmx {
error_message = "image too large"
goto load_end
}
if screen_width and width>screen_width {
if max_height and height>max_height {
error_message = "image too large"
goto load_end
}
if max_height and height>max_height {
error_message = "image too large"
if width!=320 and width!=640 {
error_message = "width not 320 or 640" ; TODO: deal with other widths
goto load_end
}
if compression {
@ -56,7 +55,7 @@ bmx {
goto load_end
}
if read_palette() {
if not read_bitmap(vbank, vaddr, screen_width)
if not read_bitmap(vbank, vaddr)
error_message = "bitmap error"
} else
error_message = "palette error"
@ -123,19 +122,23 @@ load_end:
return error_message==0
}
sub save(ubyte drivenumber, str filename, ubyte vbank, uword vaddr, uword screen_width) -> bool {
sub save(ubyte drivenumber, str filename, ubyte vbank, uword vaddr) -> bool {
; Save bitmap and palette data from vram into a BMX file.
; First you must have set all bmx.* variables to the correct values! (like width, height..)
; Parameters:
; drive number and filename to save to,
; vram bank and address of the bitmap data to save,
; and the width of the current screen mode (or 0 if you know no padding is needed).
; vram bank and address of the bitmap data to save.
; Returns: success status. If false, error_message points to the error message string.
; TODO: how to save bitmaps that are not the full visible screen width (non-contiguous scanlines)
if compression {
error_message = "compression not supported"
return false
}
error_message = 0
if width!=320 and width!=640 {
error_message = "width not 320 or 640" ; TODO: deal with other widths
goto save_end
}
ubyte old_drivenumber = diskio.drivenumber
diskio.drivenumber = drivenumber
if diskio.f_open_w(filename) {
@ -145,11 +148,9 @@ load_end:
goto save_end
}
diskio.reset_write_channel()
if screen_width
width = min(width, screen_width)
if write_header() {
if write_palette() {
if not write_bitmap(vbank, vaddr, screen_width)
if not write_bitmap(vbank, vaddr)
error_message = "bitmap error"
} else
error_message = "palette error"
@ -210,18 +211,13 @@ save_end:
return cbm.READST()==0 or cbm.READST()&$40 ; no error or eof?
}
sub read_bitmap(ubyte vbank, uword vaddr, uword screenwidth) -> bool {
sub read_bitmap(ubyte vbank, uword vaddr) -> bool {
; load contiguous bitmap into vram from the currently active input file
; TODO how to deal with bitmaps that are smaller than the screen?
cx16.vaddr(vbank, vaddr, 0, 1)
cx16.r1 = bytes_per_scanline(width)
cx16.r2 = 0
if width<screenwidth
cx16.r2 = bytes_per_scanline(screenwidth-width) ; padding per scanline
repeat height {
read_scanline(cx16.r1)
repeat cx16.r2
cx16.VERA_DATA0 = 0 ; pad out if image width < screen width
}
cx16.r3 = bytes_per_scanline(width)
repeat height
read_scanline(cx16.r3)
return cbm.READST()==0 or cbm.READST()&$40 ; no error or eof?
sub read_scanline(uword size) {
@ -270,21 +266,13 @@ save_end:
return not cbm.READST()
}
sub write_bitmap(ubyte vbank, uword vaddr, uword screenwidth) -> bool {
sub write_bitmap(ubyte vbank, uword vaddr) -> bool {
; save contiguous bitmap from vram to the currently active output file
; TODO how to deal with bitmaps that are smaller than the screen
cx16.vaddr(vbank, vaddr, 0, 1)
cx16.r1 = bytes_per_scanline(width)
cx16.r2 = 0
if width<screenwidth
cx16.r2 = bytes_per_scanline(screenwidth-width) ; padding per scanline
repeat height {
write_scanline(cx16.r1)
repeat cx16.r2 {
%asm {{
lda cx16.VERA_DATA0 ; just read away padding bytes
}}
}
}
cx16.r3 = bytes_per_scanline(width)
repeat height
write_scanline(cx16.r3)
return not cbm.READST()
sub write_scanline(uword size) {
@ -324,7 +312,7 @@ save_end:
height = peekw(&header+8)
palette_entries = header[10]
palette_start = header[11]
; Data start is not needed
; the data offset is not needed: data_offset = peekw(&header+12)
compression = header[14]
border = header[15]
return true
@ -337,7 +325,10 @@ save_end:
; build the internal BMX header structure
; normally you don't have to call this yourself
sys.memset(header, sizeof(header), 0)
uword data_offset = sizeof(header) + palette_entries*2
uword data_offset = 512 ; full palette of 256 entries
if palette_entries
data_offset = palette_entries*$0002
data_offset += sizeof(header)
header[0] = FILEID[0]
header[1] = FILEID[1]
header[2] = FILEID[2]

5
docs/source/libraries.rst
View File

@ -494,12 +494,11 @@ without the need to buffer something in main memory.
Here is the load routine:
``load(ubyte drivenumber, str filename, ubyte vbank, uword vaddr, uword screen_width)``
``load(ubyte drivenumber, str filename, ubyte vbank, uword vaddr)``
Loads a BMX bitmap image and palette into vram. (and Header info into the bmx.* variables)
Parameters:
the drive number and filename to load,
the vram bank and address where the bitmap data should go,
and the width of the current screen mode (can be 0 if you know no padding is needed).
and the vram bank and address where the bitmap data should go.
You can set the ``bmx.max_width`` and ``bmx.max_height`` variables first, if you want this routine to check those.
Returns: success status. If false, ``bmx.error_message`` points to the error message string.

2
examples/cx16/showbmx.p8
View File

@ -40,7 +40,7 @@ main {
cx16.VERA_L0_CONFIG = cx16.VERA_L0_CONFIG & %11111100 | bmx.vera_colordepth
; now load the image
if bmx.load(8, filename, 0, 0, 320) {
if bmx.load(8, filename, 0, 0) {
activate_palette()
void txt.waitkey()
}