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l65/samples/vcs_flush.l65
2017-10-06 13:02:12 +02:00

114 lines
3.3 KiB
Plaintext

require'vcs'
mappers['4K']()
local HEADER_LEN = 92
local PICTURE_LEN = 64
local STEP_COUNT = 32
-- FLUSH text as playfield
local logo_img = assert(l65.image("flush.png")) -- analyse the image twice, so load it separately
@@logo_col samepage byte(0x00, 0xd4, 0x72, linecol(logo_img)) end
local pfs = playfield(logo_img)
for i=1,#pfs do
local pf = pfs[i]
section("logo_pf"..(i-1)) samepage byte(0, pf[1], pf[#pf], pf) end
end
local LOGO_HEIGHT = #pfs[1]
-- background
local bg = linecol("flushbg.png")
@@logo_bg_all
samepage
@logo_bg_pre for i=1,8 do dc.b bg[1] end
@logo_bg
for i=1,13 do dc.b bg[1] end
byte(bg)
for i=1,13 do dc.b bg[#bg] end
@logo_bg_post for i=1,8 do dc.b bg[#bg] end
end
-- generate offset tables into logo_pf*
do
local DISP_HEIGHT = PICTURE_LEN
local transfo,bgshift = {},{}
for x=0,STEP_COUNT-1 do
local theta = x/(STEP_COUNT-1) * math.pi/2 - math.pi/4
local s,c = math.sin(theta),math.cos(theta)
local ra,rb,rc,rd = -c, s-c, s+c, c
for y=0,DISP_HEIGHT-1 do
local r = DISP_HEIGHT / LOGO_HEIGHT
local yn = r * (2 * y/(DISP_HEIGHT-1) - 1)
local function f()
local y = (s-yn) / c
return math.min(math.floor((y+1)/2*LOGO_HEIGHT), LOGO_HEIGHT-1) + 3
end
local v
if rd < rc then v = yn>rc and 0 or yn>rb and f(yn) or yn>ra and 2 or 0
else v = yn>rd and 0 or yn>rc and 1 or yn>rb and f(yn) or 0 end
transfo[x*DISP_HEIGHT+DISP_HEIGHT-y] = v
end
bgshift[#bgshift+1] = math.floor(math.sin(math.pi+theta)*LOGO_HEIGHT/4)
end
@@logo_transfo byte(transfo)
@@logo_bgshift byte(bgshift)
end
-- rotation anim
do
local PERIOD = 128
local f = \x((math.sin(x*2*math.pi/PERIOD)+1)/2 * (STEP_COUNT-1))
local rotation = {}
for x=1,PERIOD do
rotation[#rotation+1] = math.floor(math.min(f(x-1), (STEP_COUNT-1)))
end
@@logo_rotation byte(rotation)
end
local bg_ptr = 0x80
local trans_ptr = 0x82
local time = 0x84
local tmp = 0x85
local on_vblank = function()
inc time asl time lsr time
ldy time lda logo_rotation,y sta tmp
ldy tmp lda logo_bgshift,y sta bg_ptr
lda#logo_bg&0xff clc adc bg_ptr sta bg_ptr lda#logo_bg>>8 sta bg_ptr+1
setptr(logo_transfo, trans_ptr)
lda tmp asl asl asl asl asl asl clc adc trans_ptr sta trans_ptr
lda trans_ptr+1 adc#0 sta trans_ptr+1
lda tmp lsr lsr clc adc trans_ptr+1 sta trans_ptr+1
ldy#PICTURE_LEN-1 lda (bg_ptr),y sta COLUBK
end
local kernel = function()
ldy#HEADER_LEN @_header sta WSYNC dey bne _header
samepage @_line
lda (trans_ptr),y tax
lda (bg_ptr),y
sta WSYNC sta COLUBK
lda logo_col,x sta COLUPF
lda logo_pf0,x sta PF0
lda logo_pf1,x sta PF1
lda logo_pf2,x sta PF2
lda logo_pf3,x sta PF0
lda logo_pf4,x sta PF1
lda logo_pf5,x sta PF2
iny cpy#PICTURE_LEN bne _line
end
lda#0 sta WSYNC sta PF0 sta PF1 sta PF2
end
@@main
init()
@_frame
overscan() vblank(on_vblank) screen(kernel) jmp _frame
;
writebin(filename..'.bin')
writesym(filename..'.sym')
print(stats)