1 -- The theme is what decides what's actually shown on screen, what kind of
2 -- transitions are available (if any), and what kind of inputs there are,
3 -- if any. In general, it drives the entire display logic by creating Movit
4 -- chains, setting their parameters and then deciding which to show when.
6 -- Themes are written in Lua, which reflects a simplified form of the Movit API
7 -- where all the low-level details (such as texture formats) are handled by the
8 -- C++ side and you generally just build chains.
10 local transition_start = -2.0
11 local transition_end = -1.0
14 local zoom_poi = 0 -- which input to zoom in on
15 local fade_src_signal = 0
16 local fade_dst_signal = 0
18 local neutral_colors = {
19 {0.5, 0.5, 0.5}, -- Input 0.
20 {0.5, 0.5, 0.5} -- Input 1.
23 local live_signal_num = 0
24 local preview_signal_num = 1
26 -- Valid values for live_signal_num and preview_signal_num.
27 local INPUT0_SIGNAL_NUM = 0
28 local INPUT1_SIGNAL_NUM = 1
29 local SBS_SIGNAL_NUM = 2
30 local STATIC_SIGNAL_NUM = 3
32 -- “fake” signal number that signifies that we are fading from one input
34 local FADE_SIGNAL_NUM = 4
36 -- Last width/height/frame rate for each channel, if we have it.
37 -- Note that unlike the values we get from Nageru, the resolution is per
38 -- frame and not per field, since we deinterlace.
39 local last_resolution = {}
41 -- Utility function to help creating many similar chains that can differ
42 -- in a free set of chosen parameters.
43 function make_cartesian_product(parms, callback)
44 return make_cartesian_product_internal(parms, callback, 1, {})
47 function make_cartesian_product_internal(parms, callback, index, args)
48 if index > #parms then
49 return callback(unpack(args))
52 for _, value in ipairs(parms[index]) do
54 ret[value] = make_cartesian_product_internal(parms, callback, index + 1, args)
59 function make_sbs_input(chain, signal, deint, hq)
60 local input = chain:add_live_input(not deint, deint) -- Override bounce only if not deinterlacing.
61 input:connect_signal(signal)
63 local resample_effect = nil
64 local resize_effect = nil
66 resample_effect = chain:add_effect(ResampleEffect.new())
68 resize_effect = chain:add_effect(ResizeEffect.new())
70 local wb_effect = chain:add_effect(WhiteBalanceEffect.new())
72 local padding_effect = chain:add_effect(IntegralPaddingEffect.new())
76 wb_effect = wb_effect,
77 resample_effect = resample_effect,
78 resize_effect = resize_effect,
79 padding_effect = padding_effect
83 -- The main live chain.
84 function make_sbs_chain(input0_type, input1_type, hq)
85 local chain = EffectChain.new(16, 9)
87 local input0 = make_sbs_input(chain, INPUT0_SIGNAL_NUM, input0_type == "livedeint", hq)
88 local input1 = make_sbs_input(chain, INPUT1_SIGNAL_NUM, input1_type == "livedeint", hq)
90 input0.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0)
91 input1.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 0.0)
93 chain:add_effect(OverlayEffect.new(), input0.padding_effect, input1.padding_effect)
103 -- Make all possible combinations of side-by-side chains.
104 local sbs_chains = make_cartesian_product({
105 {"live", "livedeint"}, -- input0_type
106 {"live", "livedeint"}, -- input1_type
108 }, function(input0_type, input1_type, hq)
109 return make_sbs_chain(input0_type, input1_type, hq)
112 function make_fade_input(chain, signal, live, deint, scale)
113 local input, wb_effect, resample_effect, last
115 input = chain:add_live_input(false, deint)
116 input:connect_signal(signal)
119 input = chain:add_effect(ImageInput.new("bg.jpeg"))
123 -- If we cared about this for the non-main inputs, we would have
124 -- checked hq here and invoked ResizeEffect instead.
126 resample_effect = chain:add_effect(ResampleEffect.new())
127 last = resample_effect
130 -- Make sure to put the white balance after the scaling (usually more efficient).
132 wb_effect = chain:add_effect(WhiteBalanceEffect.new())
138 wb_effect = wb_effect,
139 resample_effect = resample_effect,
144 -- A chain to fade between two inputs, of which either can be a picture
145 -- or a live input. In practice only used live, but we still support the
147 function make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, input1_deint, input1_scale, hq)
148 local chain = EffectChain.new(16, 9)
150 local input0 = make_fade_input(chain, INPUT0_SIGNAL_NUM, input0_live, input0_deint, input0_scale)
151 local input1 = make_fade_input(chain, INPUT1_SIGNAL_NUM, input1_live, input1_deint, input1_scale)
153 local mix_effect = chain:add_effect(MixEffect.new(), input0.last, input1.last)
160 mix_effect = mix_effect
164 -- Chains to fade between two inputs, in various configurations.
165 local fade_chains = make_cartesian_product({
166 {"static", "live", "livedeint"}, -- input0_type
167 {true, false}, -- input0_scale
168 {"static", "live", "livedeint"}, -- input1_type
169 {true, false}, -- input1_scale
171 }, function(input0_type, input0_scale, input1_type, input1_scale, hq)
172 local input0_live = (input0_type ~= "static")
173 local input1_live = (input1_type ~= "static")
174 local input0_deint = (input0_type == "livedeint")
175 local input1_deint = (input1_type == "livedeint")
176 return make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, input1_deint, input1_scale, hq)
179 -- A chain to show a single input on screen.
180 function make_simple_chain(input_deint, input_scale, hq)
181 local chain = EffectChain.new(16, 9)
183 local input = chain:add_live_input(false, input_deint)
184 input:connect_signal(0) -- First input card. Can be changed whenever you want.
186 local resample_effect, resize_effect
189 resample_effect = chain:add_effect(ResampleEffect.new())
191 resize_effect = chain:add_effect(ResizeEffect.new())
195 local wb_effect = chain:add_effect(WhiteBalanceEffect.new())
201 wb_effect = wb_effect,
202 resample_effect = resample_effect,
203 resize_effect = resize_effect
207 -- Make all possible combinations of single-input chains.
208 local simple_chains = make_cartesian_product({
209 {"live", "livedeint"}, -- input_type
210 {true, false}, -- input_scale
212 }, function(input_type, input_scale, hq)
213 local input_deint = (input_type == "livedeint")
214 return make_simple_chain(input_deint, input_scale, hq)
217 -- A chain to show a single static picture on screen (HQ version).
218 local static_chain_hq = EffectChain.new(16, 9)
219 local static_chain_hq_input = static_chain_hq:add_effect(ImageInput.new("bg.jpeg"))
220 static_chain_hq:finalize(true)
222 -- A chain to show a single static picture on screen (LQ version).
223 local static_chain_lq = EffectChain.new(16, 9)
224 local static_chain_lq_input = static_chain_lq:add_effect(ImageInput.new("bg.jpeg"))
225 static_chain_lq:finalize(false)
227 -- Used for indexing into the tables of chains.
228 function get_input_type(signals, signal_num)
229 if signal_num == STATIC_SIGNAL_NUM then
231 elseif signals:get_interlaced(signal_num) then
238 function needs_scale(signals, signal_num, width, height)
239 if signal_num == STATIC_SIGNAL_NUM then
240 -- We assume this is already correctly scaled at load time.
243 assert(is_plain_signal(signal_num))
244 return (signals:get_width(signal_num) ~= width or signals:get_height(signal_num) ~= height)
247 function set_scale_parameters_if_needed(chain_or_input, width, height)
248 if chain_or_input.resample_effect then
249 chain_or_input.resample_effect:set_int("width", width)
250 chain_or_input.resample_effect:set_int("height", height)
251 elseif chain_or_input.resize_effect then
252 chain_or_input.resize_effect:set_int("width", width)
253 chain_or_input.resize_effect:set_int("height", height)
258 -- Returns the number of outputs in addition to the live (0) and preview (1).
259 -- Called only once, at the start of the program.
260 function num_channels()
264 function is_plain_signal(num)
265 return num == INPUT0_SIGNAL_NUM or num == INPUT1_SIGNAL_NUM
268 -- Helper function to write e.g. “720p60”. The difference between this
269 -- and get_channel_resolution_raw() is that this one also can say that
270 -- there's no signal.
271 function get_channel_resolution(signal_num)
272 res = last_resolution[signal_num]
273 if (not res) or res.height <= 0 then
276 if not res.has_signal then
277 if res.height == 525 then
278 -- Special mode for the USB3 cards.
281 return get_channel_resolution_raw(res) .. ", no signal"
283 return get_channel_resolution_raw(res)
287 -- Helper function to write e.g. “60” or “59.94”.
288 function get_frame_rate(res)
289 local nom = res.frame_rate_nom
290 local den = res.frame_rate_den
291 if nom % den == 0 then
294 return string.format("%.2f", nom / den)
298 -- Helper function to write e.g. “720p60”.
299 function get_channel_resolution_raw(res)
300 if res.interlaced then
301 return res.height .. "i" .. get_frame_rate(res)
303 return res.height .. "p" .. get_frame_rate(res)
308 -- Returns the name for each additional channel (starting from 2).
309 -- Called at the start of the program, and then each frame for live
310 -- channels in case they change resolution.
311 function channel_name(channel)
312 local signal_num = channel - 2
313 if is_plain_signal(signal_num) then
314 return "Input " .. (signal_num + 1) .. " (" .. get_channel_resolution(signal_num) .. ")"
315 elseif signal_num == SBS_SIGNAL_NUM then
316 return "Side-by-side"
317 elseif signal_num == STATIC_SIGNAL_NUM then
318 return "Static picture"
323 -- Returns, given a channel number, which signal it corresponds to (starting from 0).
324 -- Should return -1 if the channel does not correspond to a simple signal.
325 -- (The information is used for whether right-click on the channel should bring up
326 -- an input selector or not.)
327 -- Called once for each channel, at the start of the program.
328 -- Will never be called for live (0) or preview (1).
329 function channel_signal(channel)
332 elseif channel == 3 then
340 -- Called every frame. Returns the color (if any) to paint around the given
341 -- channel. Returns a CSS color (typically to mark live and preview signals);
342 -- "transparent" is allowed.
343 -- Will never be called for live (0) or preview (1).
344 function channel_color(channel)
345 if channel_involved_in(channel, live_signal_num) then
348 if channel_involved_in(channel, preview_signal_num) then
354 function channel_involved_in(channel, signal_num)
355 if is_plain_signal(signal_num) then
356 return channel == (signal_num + 2)
358 if signal_num == SBS_SIGNAL_NUM then
359 return (channel == 2 or channel == 3)
361 if signal_num == STATIC_SIGNAL_NUM then
362 return (channel == 5)
364 if signal_num == FADE_SIGNAL_NUM then
365 return (channel_involved_in(channel, fade_src_signal) or
366 channel_involved_in(channel, fade_dst_signal))
372 -- Returns if a given channel supports setting white balance (starting from 2).
373 -- Called only once for each channel, at the start of the program.
374 function supports_set_wb(channel)
375 return is_plain_signal(channel - 2)
379 -- Gets called with a new gray point when the white balance is changing.
380 -- The color is in linear light (not sRGB gamma).
381 function set_wb(channel, red, green, blue)
382 if is_plain_signal(channel - 2) then
383 neutral_colors[channel - 2 + 1] = { red, green, blue }
387 function finish_transitions(t)
388 -- If live is SBS but de-facto single, make it so.
389 if live_signal_num == SBS_SIGNAL_NUM and t >= transition_end and zoom_dst == 1.0 then
390 live_signal_num = zoom_poi
393 -- If live is fade but de-facto single, make it so.
394 if live_signal_num == FADE_SIGNAL_NUM and t >= transition_end then
395 live_signal_num = fade_dst_signal
400 -- Called every frame.
401 function get_transitions(t)
402 finish_transitions(t)
404 if live_signal_num == preview_signal_num then
405 -- No transitions possible.
409 if live_signal_num == SBS_SIGNAL_NUM and t >= transition_start and t <= transition_end then
414 if (is_plain_signal(live_signal_num) or live_signal_num == STATIC_SIGNAL_NUM) and
415 (is_plain_signal(preview_signal_num) or preview_signal_num == STATIC_SIGNAL_NUM) then
416 return {"Cut", "", "Fade"}
420 if live_signal_num == SBS_SIGNAL_NUM and is_plain_signal(preview_signal_num) then
421 return {"Cut", "Zoom in"}
422 elseif is_plain_signal(live_signal_num) and preview_signal_num == SBS_SIGNAL_NUM then
423 return {"Cut", "Zoom out"}
430 -- Called when the user clicks a transition button.
431 function transition_clicked(num, t)
434 if live_signal_num == FADE_SIGNAL_NUM then
435 -- Ongoing fade; finish it immediately.
436 finish_transitions(transition_end)
439 local temp = live_signal_num
440 live_signal_num = preview_signal_num
441 preview_signal_num = temp
443 if live_signal_num == SBS_SIGNAL_NUM then
444 -- Just cut to SBS, we need to reset any zooms.
447 transition_start = -2.0
448 transition_end = -1.0
453 finish_transitions(t)
455 if live_signal_num == preview_signal_num then
460 if (is_plain_signal(live_signal_num) and is_plain_signal(preview_signal_num)) then
461 -- We can't zoom between these. Just make a cut.
462 io.write("Cutting from " .. live_signal_num .. " to " .. live_signal_num .. "\n")
463 local temp = live_signal_num
464 live_signal_num = preview_signal_num
465 preview_signal_num = temp
469 if live_signal_num == SBS_SIGNAL_NUM and is_plain_signal(preview_signal_num) then
470 -- Zoom in from SBS to single.
472 transition_end = t + 1.0
475 zoom_poi = preview_signal_num
476 preview_signal_num = SBS_SIGNAL_NUM
477 elseif is_plain_signal(live_signal_num) and preview_signal_num == SBS_SIGNAL_NUM then
478 -- Zoom out from single to SBS.
480 transition_end = t + 1.0
483 preview_signal_num = live_signal_num
484 zoom_poi = live_signal_num
485 live_signal_num = SBS_SIGNAL_NUM
488 finish_transitions(t)
491 if (live_signal_num ~= preview_signal_num) and
492 (is_plain_signal(live_signal_num) or
493 live_signal_num == STATIC_SIGNAL_NUM) and
494 (is_plain_signal(preview_signal_num) or
495 preview_signal_num == STATIC_SIGNAL_NUM) then
497 transition_end = t + 1.0
498 fade_src_signal = live_signal_num
499 fade_dst_signal = preview_signal_num
500 preview_signal_num = live_signal_num
501 live_signal_num = FADE_SIGNAL_NUM
503 -- Fades involving SBS are ignored (we have no chain for it).
509 function channel_clicked(num)
510 preview_signal_num = num
514 -- Called every frame. Get the chain for displaying at input <num>,
515 -- where 0 is live, 1 is preview, 2 is the first channel to display
516 -- in the bottom bar, and so on up to num_channels()+1. t is the
517 -- current time in seconds. width and height are the dimensions of
518 -- the output, although you can ignore them if you don't need them
519 -- (they're useful if you want to e.g. know what to resample by).
521 -- <signals> is basically an exposed InputState, which you can use to
522 -- query for information about the signals at the point of the current
523 -- frame. In particular, you can call get_width() and get_height()
524 -- for any signal number, and use that to e.g. assist in chain selection.
526 -- You should return two objects; the chain itself, and then a
527 -- function (taking no parameters) that is run just before rendering.
528 -- The function needs to call connect_signal on any inputs, so that
529 -- it gets updated video data for the given frame. (You are allowed
530 -- to switch which input your input is getting from between frames,
531 -- but not calling connect_signal results in undefined behavior.)
532 -- If you want to change any parameters in the chain, this is also
535 -- NOTE: The chain returned must be finalized with the Y'CbCr flag
536 -- if and only if num==0.
537 function get_chain(num, t, width, height, signals)
538 local input_resolution = {}
539 for signal_num=0,1 do
541 width = signals:get_width(signal_num),
542 height = signals:get_height(signal_num),
543 interlaced = signals:get_interlaced(signal_num),
544 has_signal = signals:get_has_signal(signal_num),
545 frame_rate_nom = signals:get_frame_rate_nom(signal_num),
546 frame_rate_den = signals:get_frame_rate_den(signal_num)
549 if res.interlaced then
550 -- Convert height from frame height to field height.
551 -- (Needed for e.g. place_rectangle.)
552 res.height = res.height * 2
554 -- Show field rate instead of frame rate; really for cosmetics only
555 -- (and actually contrary to EBU recommendations, although in line
556 -- with typical user expectations).
557 res.frame_rate_nom = res.frame_rate_nom * 2
560 input_resolution[signal_num] = res
562 last_resolution = input_resolution
564 if num == 0 then -- Live.
565 if is_plain_signal(live_signal_num) then -- Plain inputs.
566 local input_type = get_input_type(signals, live_signal_num)
567 local input_scale = needs_scale(signals, live_signal_num, width, height)
568 local chain = simple_chains[input_type][input_scale][true]
570 chain.input:connect_signal(live_signal_num)
571 set_scale_parameters_if_needed(chain, width, height)
572 set_neutral_color_from_signal(chain.wb_effect, live_signal_num)
574 return chain.chain, prepare
575 elseif live_signal_num == STATIC_SIGNAL_NUM then -- Static picture.
578 return static_chain_hq, prepare
579 elseif live_signal_num == FADE_SIGNAL_NUM then -- Fade.
580 local input0_type = get_input_type(signals, fade_src_signal)
581 local input0_scale = needs_scale(signals, fade_src_signal, width, height)
582 local input1_type = get_input_type(signals, fade_dst_signal)
583 local input1_scale = needs_scale(signals, fade_dst_signal, width, height)
584 local chain = fade_chains[input0_type][input0_scale][input1_type][input1_scale][true]
586 if input0_type == "live" or input0_type == "livedeint" then
587 chain.input0.input:connect_signal(fade_src_signal)
588 set_neutral_color_from_signal(chain.input0.wb_effect, fade_src_signal)
590 set_scale_parameters_if_needed(chain.input0, width, height)
591 if input1_type == "live" or input1_type == "livedeint" then
592 chain.input1.input:connect_signal(fade_dst_signal)
593 set_neutral_color_from_signal(chain.input1.wb_effect, fade_dst_signal)
595 set_scale_parameters_if_needed(chain.input1, width, height)
596 local tt = calc_fade_progress(t, transition_start, transition_end)
598 chain.mix_effect:set_float("strength_first", 1.0 - tt)
599 chain.mix_effect:set_float("strength_second", tt)
601 return chain.chain, prepare
604 -- SBS code (live_signal_num == SBS_SIGNAL_NUM).
605 local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
606 local input1_type = get_input_type(signals, INPUT1_SIGNAL_NUM)
607 if t > transition_end and zoom_dst == 1.0 then
608 -- Special case: Show only the single image on screen.
609 local input0_scale = needs_scale(signals, fade_src_signal, width, height)
610 local chain = simple_chains[input0_type][input0_scale][true]
612 chain.input:connect_signal(INPUT0_SIGNAL_NUM)
613 set_scale_parameters_if_needed(chain, width, height)
614 set_neutral_color(chain.wb_effect, neutral_colors[1])
616 return chain.chain, prepare
618 local chain = sbs_chains[input0_type][input1_type][true]
620 if t < transition_start then
621 prepare_sbs_chain(chain, zoom_src, width, height, input_resolution)
622 elseif t > transition_end then
623 prepare_sbs_chain(chain, zoom_dst, width, height, input_resolution)
625 local tt = (t - transition_start) / (transition_end - transition_start)
627 tt = math.sin(tt * 3.14159265358 * 0.5)
628 prepare_sbs_chain(chain, zoom_src + (zoom_dst - zoom_src) * tt, width, height, input_resolution)
631 return chain.chain, prepare
633 if num == 1 then -- Preview.
634 num = preview_signal_num + 2
637 -- Individual preview inputs.
638 if is_plain_signal(num - 2) then
639 local signal_num = num - 2
640 local input_type = get_input_type(signals, signal_num)
641 local input_scale = needs_scale(signals, signal_num, width, height)
642 local chain = simple_chains[input_type][input_scale][false]
644 chain.input:connect_signal(signal_num)
645 set_scale_parameters_if_needed(chain, width, height)
646 set_neutral_color(chain.wb_effect, neutral_colors[signal_num + 1])
648 return chain.chain, prepare
650 if num == SBS_SIGNAL_NUM + 2 then
651 local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
652 local input1_type = get_input_type(signals, INPUT1_SIGNAL_NUM)
653 local chain = sbs_chains[input0_type][input1_type][false]
655 prepare_sbs_chain(chain, 0.0, width, height, input_resolution)
657 return chain.chain, prepare
659 if num == STATIC_SIGNAL_NUM + 2 then
662 return static_chain_lq, prepare
666 function place_rectangle(resample_effect, resize_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height)
672 padding_effect:set_int("width", screen_width)
673 padding_effect:set_int("height", screen_height)
676 if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
677 if resample_effect ~= nil then
678 resample_effect:set_int("width", 1)
679 resample_effect:set_int("height", 1)
680 resample_effect:set_float("zoom_x", screen_width)
681 resample_effect:set_float("zoom_y", screen_height)
683 resize_effect:set_int("width", 1)
684 resize_effect:set_int("height", 1)
686 padding_effect:set_int("left", screen_width + 100)
687 padding_effect:set_int("top", screen_height + 100)
693 srcx0 = -x0 / (x1 - x0)
697 srcy0 = -y0 / (y1 - y0)
700 if x1 > screen_width then
701 srcx1 = (screen_width - x0) / (x1 - x0)
704 if y1 > screen_height then
705 srcy1 = (screen_height - y0) / (y1 - y0)
709 if resample_effect ~= nil then
710 -- High-quality resampling.
711 local x_subpixel_offset = x0 - math.floor(x0)
712 local y_subpixel_offset = y0 - math.floor(y0)
714 -- Resampling must be to an integral number of pixels. Round up,
715 -- and then add an extra pixel so we have some leeway for the border.
716 local width = math.ceil(x1 - x0) + 1
717 local height = math.ceil(y1 - y0) + 1
718 resample_effect:set_int("width", width)
719 resample_effect:set_int("height", height)
721 -- Correct the discrepancy with zoom. (This will leave a small
722 -- excess edge of pixels and subpixels, which we'll correct for soon.)
723 local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0))
724 local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0))
725 resample_effect:set_float("zoom_x", zoom_x)
726 resample_effect:set_float("zoom_y", zoom_y)
727 resample_effect:set_float("zoom_center_x", 0.0)
728 resample_effect:set_float("zoom_center_y", 0.0)
730 -- Padding must also be to a whole-pixel offset.
731 padding_effect:set_int("left", math.floor(x0))
732 padding_effect:set_int("top", math.floor(y0))
734 -- Correct _that_ discrepancy by subpixel offset in the resampling.
735 resample_effect:set_float("left", srcx0 * input_width - x_subpixel_offset / zoom_x)
736 resample_effect:set_float("top", srcy0 * input_height - y_subpixel_offset / zoom_y)
738 -- Finally, adjust the border so it is exactly where we want it.
739 padding_effect:set_float("border_offset_left", x_subpixel_offset)
740 padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width))
741 padding_effect:set_float("border_offset_top", y_subpixel_offset)
742 padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height))
744 -- Lower-quality simple resizing.
745 local width = round(x1 - x0)
746 local height = round(y1 - y0)
747 resize_effect:set_int("width", width)
748 resize_effect:set_int("height", height)
750 -- Padding must also be to a whole-pixel offset.
751 padding_effect:set_int("left", math.floor(x0))
752 padding_effect:set_int("top", math.floor(y0))
756 -- This is broken, of course (even for positive numbers), but Lua doesn't give us access to real rounding.
758 return math.floor(x + 0.5)
761 function lerp(a, b, t)
762 return a + (b - a) * t
765 function lerp_pos(a, b, t)
767 x0 = lerp(a.x0, b.x0, t),
768 y0 = lerp(a.y0, b.y0, t),
769 x1 = lerp(a.x1, b.x1, t),
770 y1 = lerp(a.y1, b.y1, t)
774 function pos_from_top_left(x, y, width, height, screen_width, screen_height)
775 local xs = screen_width / 1280.0
776 local ys = screen_height / 720.0
780 x1 = round(xs * (x + width)),
781 y1 = round(ys * (y + height))
785 function prepare_sbs_chain(chain, t, screen_width, screen_height, input_resolution)
786 chain.input0.input:connect_signal(0)
787 chain.input1.input:connect_signal(1)
788 set_neutral_color(chain.input0.wb_effect, neutral_colors[1])
789 set_neutral_color(chain.input1.wb_effect, neutral_colors[2])
791 -- First input is positioned (16,48) from top-left.
792 -- Second input is positioned (16,48) from the bottom-right.
793 local pos0 = pos_from_top_left(16, 48, 848, 477, screen_width, screen_height)
794 local pos1 = pos_from_top_left(1280 - 384 - 16, 720 - 216 - 48, 384, 216, screen_width, screen_height)
796 local pos_fs = { x0 = 0, y0 = 0, x1 = screen_width, y1 = screen_height }
798 if zoom_poi == INPUT0_SIGNAL_NUM then
799 affine_param = find_affine_param(pos0, lerp_pos(pos0, pos_fs, t))
801 affine_param = find_affine_param(pos1, lerp_pos(pos1, pos_fs, t))
804 -- NOTE: input_resolution is not 1-indexed, unlike usual Lua arrays.
805 place_rectangle_with_affine(chain.input0.resample_effect, chain.input0.resize_effect, chain.input0.padding_effect, pos0, affine_param, screen_width, screen_height, input_resolution[0].width, input_resolution[0].height)
806 place_rectangle_with_affine(chain.input1.resample_effect, chain.input1.resize_effect, chain.input1.padding_effect, pos1, affine_param, screen_width, screen_height, input_resolution[1].width, input_resolution[1].height)
809 -- Find the transformation that changes the first rectangle to the second one.
810 function find_affine_param(a, b)
811 local sx = (b.x1 - b.x0) / (a.x1 - a.x0)
812 local sy = (b.y1 - b.y0) / (a.y1 - a.y0)
816 tx = b.x0 - a.x0 * sx,
817 ty = b.y0 - a.y0 * sy
821 function place_rectangle_with_affine(resample_effect, resize_effect, padding_effect, pos, aff, screen_width, screen_height, input_width, input_height)
822 local x0 = pos.x0 * aff.sx + aff.tx
823 local x1 = pos.x1 * aff.sx + aff.tx
824 local y0 = pos.y0 * aff.sy + aff.ty
825 local y1 = pos.y1 * aff.sy + aff.ty
827 place_rectangle(resample_effect, resize_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height)
830 function set_neutral_color(effect, color)
831 effect:set_vec3("neutral_color", color[1], color[2], color[3])
834 function set_neutral_color_from_signal(effect, signal)
835 if is_plain_signal(signal) then
836 set_neutral_color(effect, neutral_colors[signal - INPUT0_SIGNAL_NUM + 1])
840 function calc_fade_progress(t, transition_start, transition_end)
841 local tt = (t - transition_start) / (transition_end - transition_start)
848 -- Make the fade look maybe a tad more natural, by pumping it
849 -- through a sigmoid function.
851 tt = 1.0 / (1.0 + math.exp(-tt))