mirror of
https://github.com/irmen/prog8.git
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60 lines
1.6 KiB
Lua
60 lines
1.6 KiB
Lua
%import math
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%import textio
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%import palette
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; use the mouse to move the cursor around the screen
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; it uses the fast direction routine to spotlight your mouse position.
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; you can use the atan2() routine as well for more precision laser beams,
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; but it will use a lot more memory due to the required lookup tables.
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main {
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sub start() {
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const uword WIDTH=320
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const ubyte HEIGHT=240
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uword xx
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ubyte yy
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void cx16.screen_mode(128, false)
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cx16.mouse_config2(1)
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txt.print("move the mouse for the spotlight.")
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; prefill
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for yy in 0 to HEIGHT-1 {
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cx16.FB_cursor_position(0, yy)
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for xx in 0 to WIDTH-1 {
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cx16.FB_set_pixel(math.direction(128, HEIGHT/2, clampx(xx), yy) + 128)
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}
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}
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ubyte previous_direction
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ubyte new_direction
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; dim the screen
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for new_direction in 128 to 128+23
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palette.set_color(new_direction, $024)
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; spotlight
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repeat {
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void cx16.mouse_pos()
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new_direction = math.direction(128, HEIGHT/2, clampx(cx16.r0), cx16.r1L)
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if new_direction != previous_direction {
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sys.waitvsync()
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palette.set_color(new_direction+128, math.rndw())
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palette.set_color(previous_direction+128, $024)
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previous_direction = new_direction
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}
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}
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}
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sub clampx(uword screenx) -> ubyte {
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;; return clamp(screenx, 32, 255+32)-32 as ubyte
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if screenx<32
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return 0
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else if screenx>255+32
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return 255
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return lsb(screenx)-32
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}
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}
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