prog8/examples/cx16/showbmx.p8
2023-11-29 21:57:17 +01:00

93 lines
3.6 KiB
Lua

; Viewer program for BMX image files.
; BMX file format: see https://cx16forum.com/forum/viewtopic.php?t=6945
%import textio
%import palette
%import bmx
%option no_sysinit
%zeropage basicsafe
main {
sub start() {
str filename = "?"*40
repeat {
txt.print("\nenter bmx image filename: ")
if txt.input_chars(&filename) {
if bmx.open(8, filename) {
txt.print("\nsize: ")
txt.print_uw(bmx.width)
txt.chrout('*')
txt.print_uw(bmx.height)
txt.print(" bpp: ")
txt.print_uw(bmx.bitsperpixel)
txt.print(" num colors: ")
txt.print_uw(bmx.palette_entries)
txt.nl()
sys.wait(100)
; tell the loader to put the palette into system memory instead
; also make palette black at first, to hide loading (even though it is very fast)
; (you could do a soft fade-in effect with this for instance)
bmx.palette_buffer_ptr = memory("palette", 512, 0)
sys.memset(bmx.palette_buffer_ptr, 512, 0)
palette.set_rgb(bmx.palette_buffer_ptr, 256)
; switch to bitmap screen mode and color depth: 320*240
void cx16.screen_mode($80, false) ; we're lazy and just use a kernal routine to set up the basics
cx16.VERA_L0_CONFIG = cx16.VERA_L0_CONFIG & %11111100 | bmx.vera_colordepth
; now load the image
if bmx.width==320 {
; can use the fast, full-screen load routine
if bmx.continue_load(0, 0) {
if bmx.height<240 {
; fill the remaining bottom part of the screen
cx16.GRAPH_set_colors(bmx.border, bmx.border, 99)
cx16.GRAPH_draw_rect(0, bmx.height, 320, 240-bmx.height, 0, true)
}
activate_palette()
void txt.waitkey()
}
} else {
; clear the screen with the border color
cx16.GRAPH_set_colors(0, 0, bmx.border)
cx16.GRAPH_clear()
; need to use the slower load routine that does padding
; center the image on the screen nicely
uword offset = (320-bmx.width)/2 + (240-bmx.height)/2*320
if bmx.continue_load_stamp(0, offset, 320) {
activate_palette()
void txt.waitkey()
}
}
}
cbm.CINT() ; reset screen
if bmx.error_message {
txt.print("load error:\n")
txt.print(bmx.error_message)
txt.nl()
sys.wait(120)
}
}
}
}
sub activate_palette() {
; copies the pallette data from the memory buffer into vram
cx16.VERA_DC_BORDER = bmx.border
cx16.r1 = bmx.palette_buffer_ptr
cx16.r2L = bmx.palette_start
cx16.r3L = lsb(bmx.palette_entries)
do {
palette.set_color(cx16.r2L, peekw(cx16.r1))
cx16.r1+=2
cx16.r2L++
cx16.r3L--
} until cx16.r3L==0
}
}