ovr - nesbox/TIC-80 GitHub Wiki
This function is deprecated as of 1.0. - please use vbank instead. It was added in version 0.6.
The OVR callback is the final step in rendering a frame. It draws on a separate layer and can be used together with BDR to create separate background or foreground layers and other visual effects.
function OVR()
--Draw foreground
endSince OVR() happens after all the scanline callbacks it can be used to draw sprites with a static palette (even if BDR() is otherwise changing the palette on each line). The example below shows this in action.
-- title: Overlap demo
-- author: librorumque
-- desc: OVR() example
-- script: lua
PALETTE_ADDR=0x03FC0
CHANGE_COL=8
SCANLINES=144
x=96
y=24
function BDR(line)
--[[
Gradient background
]]
local color=(0xff*line/SCANLINES)
poke(PALETTE_ADDR+3*CHANGE_COL, color)
end
function OVR()
--[[
This sprite uses the same blue as the
background, but it's not affected by
BDR() palette swap
]]
spr(1,x,y,14,3,0,0,2,2)
end
function TIC()
cls(CHANGE_COL)
print("OVR() example", 85, 3, 12)
print("Press up or down to move the sprite", 22, 10, 12)
if btn(0) then y=y-1 end
if btn(1) then y=y+1 end
end