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 input0_neutral_color = {0.5, 0.5, 0.5}
19 local input1_neutral_color = {0.5, 0.5, 0.5}
21 local live_signal_num = 0
22 local preview_signal_num = 1
24 -- Valid values for live_signal_num and preview_signal_num.
25 local INPUT0_SIGNAL_NUM = 0
26 local INPUT1_SIGNAL_NUM = 1
27 local SBS_SIGNAL_NUM = 2
28 local STATIC_SIGNAL_NUM = 3
30 -- “fake” signal number that signifies that we are fading from one input
32 local FADE_SIGNAL_NUM = 4
34 -- Utility function to help creating many similar chains that can differ
35 -- in a free set of chosen parameters.
36 function make_cartesian_product(parms, callback)
37 return make_cartesian_product_internal(parms, callback, 1, {})
40 function make_cartesian_product_internal(parms, callback, index, args)
41 if index > #parms then
42 return callback(unpack(args))
45 for _, value in ipairs(parms[index]) do
47 ret[value] = make_cartesian_product_internal(parms, callback, index + 1, args)
52 function make_sbs_input(chain, signal, deint, hq)
53 local input = chain:add_live_input(not deint, deint) -- Override bounce only if not deinterlacing.
54 input:connect_signal(signal)
55 local wb_effect = chain:add_effect(WhiteBalanceEffect.new())
57 local resample_effect = nil
58 local resize_effect = nil
60 resample_effect = chain:add_effect(ResampleEffect.new())
62 resize_effect = chain:add_effect(ResizeEffect.new())
65 local padding_effect = chain:add_effect(IntegralPaddingEffect.new())
69 wb_effect = wb_effect,
70 resample_effect = resample_effect,
71 resize_effect = resize_effect,
72 padding_effect = padding_effect
76 -- The main live chain.
77 function make_sbs_chain(input0_deint, input1_deint, hq)
78 local chain = EffectChain.new(16, 9)
80 local input0 = make_sbs_input(chain, INPUT0_SIGNAL_NUM, input0_deint, hq)
81 local input1 = make_sbs_input(chain, INPUT1_SIGNAL_NUM, input1_deint, hq)
83 input0.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0)
84 input1.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 0.0)
86 chain:add_effect(OverlayEffect.new(), input0.padding_effect, input1.padding_effect)
96 -- Make all possible combinations of side-by-side chains.
97 local sbs_chains = make_cartesian_product({
98 {"live", "livedeint"}, -- input0_type
99 {"live", "livedeint"}, -- input1_type
101 }, function(input0_type, input1_type, hq)
102 local input0_deint = (input0_type == "livedeint")
103 local input1_deint = (input1_type == "livedeint")
104 return make_sbs_chain(input0_deint, input1_deint, hq)
107 function make_fade_input(chain, signal, live, deint, scale)
108 local input, wb_effect, resample_effect, last
110 input = chain:add_live_input(false, deint)
111 wb_effect = chain:add_effect(WhiteBalanceEffect.new())
112 input:connect_signal(signal)
115 input = chain:add_effect(ImageInput.new("bg.jpeg"))
119 -- If we cared about this for the non-main inputs, we would have
120 -- checked hq here and invoked ResizeEffect instead.
122 resample_effect = chain:add_effect(ResampleEffect.new())
123 last = resample_effect
128 wb_effect = wb_effect,
129 resample_effect = resample_effect,
134 -- A chain to fade between two inputs, of which either can be a picture
135 -- or a live input. In practice only used live, but we still support the
137 function make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, input1_deint, input1_scale, hq)
138 local chain = EffectChain.new(16, 9)
140 local input0 = make_fade_input(chain, INPUT0_SIGNAL_NUM, input0_live, input0_deint, input0_scale)
141 local input1 = make_fade_input(chain, INPUT1_SIGNAL_NUM, input1_live, input1_deint, input1_scale)
143 local mix_effect = chain:add_effect(MixEffect.new(), input0.last, input1.last)
150 mix_effect = mix_effect
154 -- Chains to fade between two inputs, in various configurations.
155 local fade_chains = make_cartesian_product({
156 {"static", "live", "livedeint"}, -- input0_type
157 {true, false}, -- input0_scale
158 {"static", "live", "livedeint"}, -- input1_type
159 {true, false}, -- input1_scale
161 }, function(input0_type, input0_scale, input1_type, input1_scale, hq)
162 local input0_live = (input0_type ~= "static")
163 local input1_live = (input1_type ~= "static")
164 local input0_deint = (input0_type == "livedeint")
165 local input1_deint = (input1_type == "livedeint")
166 return make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, input1_deint, input1_scale, hq)
169 -- A chain to show a single input on screen.
170 function make_simple_chain(input_deint, input_scale, hq)
171 local chain = EffectChain.new(16, 9)
173 local input = chain:add_live_input(false, input_deint)
174 input:connect_signal(0) -- First input card. Can be changed whenever you want.
175 local wb_effect = chain:add_effect(WhiteBalanceEffect.new())
178 local resample_effect, resize_effect
181 resample_effect = chain:add_effect(ResampleEffect.new())
183 resize_effect = chain:add_effect(ResizeEffect.new())
190 wb_effect = wb_effect,
191 resample_effect = resample_effect,
192 resize_effect = resize_effect
196 -- Make all possible combinations of single-input chains.
197 local simple_chains = make_cartesian_product({
198 {"live", "livedeint"}, -- input_type
199 {true, false}, -- input_scale
201 }, function(input_type, input_scale, hq)
202 local input_deint = (input_type == "livedeint")
203 return make_simple_chain(input_deint, input_scale, hq)
206 -- A chain to show a single static picture on screen (HQ version).
207 local static_chain_hq = EffectChain.new(16, 9)
208 local static_chain_hq_input = static_chain_hq:add_effect(ImageInput.new("bg.jpeg"))
209 static_chain_hq:finalize(true)
211 -- A chain to show a single static picture on screen (LQ version).
212 local static_chain_lq = EffectChain.new(16, 9)
213 local static_chain_lq_input = static_chain_lq:add_effect(ImageInput.new("bg.jpeg"))
214 static_chain_lq:finalize(false)
216 -- Used for indexing into the tables of chains.
217 function get_input_type(signals, signal_num)
218 if signal_num == STATIC_SIGNAL_NUM then
220 elseif signals:get_interlaced(signal_num) then
227 function needs_scale(signals, signal_num, width, height)
228 return (signals:get_width(signal_num) ~= width or signals:get_height(signal_num) ~= height)
231 function set_scale_parameters_if_needed(chain_or_input, width, height)
232 if chain_or_input.resample_effect then
233 chain_or_input.resample_effect:set_int("width", width)
234 chain_or_input.resample_effect:set_int("height", height)
235 elseif chain_or_input.resize_effect then
236 chain_or_input.resize_effect:set_int("width", width)
237 chain_or_input.resize_effect:set_int("height", height)
241 -- Returns the number of outputs in addition to the live (0) and preview (1).
242 -- Called only once, at the start of the program.
243 function num_channels()
247 -- Returns the name for each additional channel (starting from 2).
248 -- Called only once for each channel, at the start of the program.
249 function channel_name(channel)
252 elseif channel == 3 then
254 elseif channel == 4 then
255 return "Side-by-side"
256 elseif channel == 5 then
257 return "Static picture"
261 -- Returns if a given channel supports setting white balance (starting from 2).
262 -- Called only once for each channel, at the start of the program.
263 function supports_set_wb(channel)
264 return channel == 2 or channel == 3
267 -- Gets called with a new gray point when the white balance is changing.
268 -- The color is in linear light (not sRGB gamma).
269 function set_wb(channel, red, green, blue)
271 input0_neutral_color = { red, green, blue }
272 elseif channel == 3 then
273 input1_neutral_color = { red, green, blue }
277 function finish_transitions(t)
278 -- If live is SBS but de-facto single, make it so.
279 if live_signal_num == SBS_SIGNAL_NUM and t >= transition_end and zoom_dst == 1.0 then
280 live_signal_num = zoom_poi
283 -- If live is fade but de-facto single, make it so.
284 if live_signal_num == FADE_SIGNAL_NUM and t >= transition_end then
285 live_signal_num = fade_dst_signal
289 -- Called every frame.
290 function get_transitions(t)
291 finish_transitions(t)
293 if live_signal_num == preview_signal_num then
297 if live_signal_num == SBS_SIGNAL_NUM and t >= transition_start and t <= transition_end then
302 if (live_signal_num == INPUT0_SIGNAL_NUM or
303 live_signal_num == INPUT1_SIGNAL_NUM or
304 live_signal_num == STATIC_SIGNAL_NUM) and
305 (preview_signal_num == INPUT0_SIGNAL_NUM or
306 preview_signal_num == INPUT1_SIGNAL_NUM or
307 preview_signal_num == STATIC_SIGNAL_NUM) then
308 return {"Cut", "", "Fade"}
312 if live_signal_num == SBS_SIGNAL_NUM and
313 (preview_signal_num == INPUT0_SIGNAL_NUM or preview_signal_num == INPUT1_SIGNAL_NUM) then
314 return {"Cut", "Zoom in"}
315 elseif (live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM) and
316 preview_signal_num == SBS_SIGNAL_NUM then
317 return {"Cut", "Zoom out"}
323 function transition_clicked(num, t)
326 if live_signal_num == FADE_SIGNAL_NUM then
327 -- Ongoing fade; finish it immediately.
328 finish_transitions(transition_end)
331 local temp = live_signal_num
332 live_signal_num = preview_signal_num
333 preview_signal_num = temp
335 if live_signal_num == SBS_SIGNAL_NUM then
336 -- Just cut to SBS, we need to reset any zooms.
339 transition_start = -2.0
340 transition_end = -1.0
345 finish_transitions(t)
347 if live_signal_num == preview_signal_num then
352 if (live_signal_num == INPUT0_SIGNAL_NUM and preview_signal_num == INPUT1_SIGNAL_NUM) or
353 (live_signal_num == INPUT1_SIGNAL_NUM and preview_signal_num == INPUT0_SIGNAL_NUM) then
354 -- We can't zoom between these. Just make a cut.
355 io.write("Cutting from " .. live_signal_num .. " to " .. live_signal_num .. "\n")
356 local temp = live_signal_num
357 live_signal_num = preview_signal_num
358 preview_signal_num = temp
362 if live_signal_num == SBS_SIGNAL_NUM and
363 (preview_signal_num == INPUT0_SIGNAL_NUM or preview_signal_num == INPUT1_SIGNAL_NUM) then
364 -- Zoom in from SBS to single.
366 transition_end = t + 1.0
369 zoom_poi = preview_signal_num
370 preview_signal_num = SBS_SIGNAL_NUM
371 elseif (live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM) and
372 preview_signal_num == SBS_SIGNAL_NUM then
373 -- Zoom out from single to SBS.
375 transition_end = t + 1.0
378 preview_signal_num = live_signal_num
379 zoom_poi = live_signal_num
380 live_signal_num = SBS_SIGNAL_NUM
383 finish_transitions(t)
386 if (live_signal_num ~= preview_signal_num) and
387 (live_signal_num == INPUT0_SIGNAL_NUM or
388 live_signal_num == INPUT1_SIGNAL_NUM or
389 live_signal_num == STATIC_SIGNAL_NUM) and
390 (preview_signal_num == INPUT0_SIGNAL_NUM or
391 preview_signal_num == INPUT1_SIGNAL_NUM or
392 preview_signal_num == STATIC_SIGNAL_NUM) then
394 transition_end = t + 1.0
395 fade_src_signal = live_signal_num
396 fade_dst_signal = preview_signal_num
397 preview_signal_num = live_signal_num
398 live_signal_num = FADE_SIGNAL_NUM
400 -- Fades involving SBS are ignored (we have no chain for it).
405 function channel_clicked(num)
406 preview_signal_num = num
409 -- Called every frame. Get the chain for displaying at input <num>,
410 -- where 0 is live, 1 is preview, 2 is the first channel to display
411 -- in the bottom bar, and so on up to num_channels()+1. t is the
412 -- current time in seconds. width and height are the dimensions of
413 -- the output, although you can ignore them if you don't need them
414 -- (they're useful if you want to e.g. know what to resample by).
416 -- <signals> is basically an exposed InputState, which you can use to
417 -- query for information about the signals at the point of the current
418 -- frame. In particular, you can call get_width() and get_height()
419 -- for any signal number, and use that to e.g. assist in chain selection.
421 -- You should return two objects; the chain itself, and then a
422 -- function (taking no parameters) that is run just before rendering.
423 -- The function needs to call connect_signal on any inputs, so that
424 -- it gets updated video data for the given frame. (You are allowed
425 -- to switch which input your input is getting from between frames,
426 -- but not calling connect_signal results in undefined behavior.)
427 -- If you want to change any parameters in the chain, this is also
430 -- NOTE: The chain returned must be finalized with the Y'CbCr flag
431 -- if and only if num==0.
432 function get_chain(num, t, width, height, signals)
433 if num == 0 then -- Live.
434 if live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM then -- Plain input.
435 local input_type = get_input_type(signals, live_signal_num)
436 local input_scale = needs_scale(signals, live_signal_num, width, height)
437 local chain = simple_chains[input_type][input_scale][true]
439 chain.input:connect_signal(live_signal_num)
440 set_scale_parameters_if_needed(chain, width, height)
441 set_neutral_color_from_signal(chain.wb_effect, live_signal_num)
443 return chain.chain, prepare
444 elseif live_signal_num == STATIC_SIGNAL_NUM then -- Static picture.
447 return static_chain_hq, prepare
448 elseif live_signal_num == FADE_SIGNAL_NUM then -- Fade.
449 local input0_type = get_input_type(signals, fade_src_signal)
450 local input0_scale = needs_scale(signals, fade_src_signal, width, height)
451 local input1_type = get_input_type(signals, fade_dst_signal)
452 local input1_scale = needs_scale(signals, fade_dst_signal, width, height)
453 local chain = fade_chains[input0_type][input0_scale][input1_type][input1_scale][true]
455 if input0_type == "live" then
456 chain.input0.input:connect_signal(fade_src_signal)
457 set_neutral_color_from_signal(chain.input0.wb_effect, fade_src_signal)
459 set_scale_parameters_if_needed(chain.input0, width, height)
460 if input1_type == "live" then
461 chain.input1.input:connect_signal(fade_dst_signal)
462 set_neutral_color_from_signal(chain.input1.wb_effect, fade_dst_signal)
464 set_scale_parameters_if_needed(chain.input1, width, height)
465 local tt = calc_fade_progress(t, transition_start, transition_end)
467 chain.mix_effect:set_float("strength_first", 1.0 - tt)
468 chain.mix_effect:set_float("strength_second", tt)
470 return chain.chain, prepare
473 -- SBS code (live_signal_num == SBS_SIGNAL_NUM).
474 local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
475 local input1_type = get_input_type(signals, INPUT1_SIGNAL_NUM)
476 if t > transition_end and zoom_dst == 1.0 then
477 -- Special case: Show only the single image on screen.
478 local input0_scale = needs_scale(signals, fade_src_signal, width, height)
479 local chain = simple_chains[input0_type][input0_scale][true]
481 chain.input:connect_signal(INPUT0_SIGNAL_NUM)
482 set_scale_parameters_if_needed(chain, width, height)
483 set_neutral_color(chain.wb_effect, input0_neutral_color)
485 return chain.chain, prepare
487 local chain = sbs_chains[input0_type][input1_type][true]
489 if t < transition_start then
490 prepare_sbs_chain(chain, zoom_src, width, height)
491 elseif t > transition_end then
492 prepare_sbs_chain(chain, zoom_dst, width, height)
494 local tt = (t - transition_start) / (transition_end - transition_start)
496 tt = math.sin(tt * 3.14159265358 * 0.5)
497 prepare_sbs_chain(chain, zoom_src + (zoom_dst - zoom_src) * tt, width, height)
500 return chain.chain, prepare
502 if num == 1 then -- Preview.
503 num = preview_signal_num + 2
506 -- Individual preview inputs.
507 if num == INPUT0_SIGNAL_NUM + 2 then
508 local input_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
509 local input_scale = needs_scale(signals, INPUT0_SIGNAL_NUM, width, height)
510 local chain = simple_chains[input_type][input_scale][false]
512 chain.input:connect_signal(INPUT0_SIGNAL_NUM)
513 set_scale_parameters_if_needed(chain, width, height)
514 set_neutral_color(chain.wb_effect, input0_neutral_color)
516 return chain.chain, prepare
518 if num == INPUT1_SIGNAL_NUM + 2 then
519 local input_type = get_input_type(signals, INPUT1_SIGNAL_NUM)
520 local input_scale = needs_scale(signals, INPUT1_SIGNAL_NUM, width, height)
521 local chain = simple_chains[input_type][input_scale][false]
523 chain.input:connect_signal(INPUT1_SIGNAL_NUM)
524 set_scale_parameters_if_needed(chain, width, height)
525 set_neutral_color(chain.wb_effect, input1_neutral_color)
527 return chain.chain, prepare
529 if num == SBS_SIGNAL_NUM + 2 then
530 local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
531 local input1_type = get_input_type(signals, INPUT1_SIGNAL_NUM)
532 local chain = sbs_chains[input0_type][input1_type][false]
534 prepare_sbs_chain(chain, 0.0, width, height)
536 return chain.chain, prepare
538 if num == STATIC_SIGNAL_NUM + 2 then
541 return static_chain_lq, prepare
545 function place_rectangle(resample_effect, resize_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height)
552 if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
553 resample_effect:set_int("width", 1)
554 resample_effect:set_int("height", 1)
555 resample_effect:set_float("zoom_x", screen_width)
556 resample_effect:set_float("zoom_y", screen_height)
557 padding_effect:set_int("left", screen_width + 100)
558 padding_effect:set_int("top", screen_height + 100)
564 srcx0 = -x0 / (x1 - x0)
568 srcy0 = -y0 / (y1 - y0)
571 if x1 > screen_width then
572 srcx1 = (screen_width - x0) / (x1 - x0)
575 if y1 > screen_height then
576 srcy1 = (screen_height - y0) / (y1 - y0)
580 if resample_effect ~= nil then
581 -- High-quality resampling.
582 local x_subpixel_offset = x0 - math.floor(x0)
583 local y_subpixel_offset = y0 - math.floor(y0)
585 -- Resampling must be to an integral number of pixels. Round up,
586 -- and then add an extra pixel so we have some leeway for the border.
587 local width = math.ceil(x1 - x0) + 1
588 local height = math.ceil(y1 - y0) + 1
589 resample_effect:set_int("width", width)
590 resample_effect:set_int("height", height)
592 -- Correct the discrepancy with zoom. (This will leave a small
593 -- excess edge of pixels and subpixels, which we'll correct for soon.)
594 local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0))
595 local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0))
596 resample_effect:set_float("zoom_x", zoom_x)
597 resample_effect:set_float("zoom_y", zoom_y)
598 resample_effect:set_float("zoom_center_x", 0.0)
599 resample_effect:set_float("zoom_center_y", 0.0)
601 -- Padding must also be to a whole-pixel offset.
602 padding_effect:set_int("left", math.floor(x0))
603 padding_effect:set_int("top", math.floor(y0))
605 -- Correct _that_ discrepancy by subpixel offset in the resampling.
606 resample_effect:set_float("left", srcx0 * input_width - x_subpixel_offset / zoom_x)
607 resample_effect:set_float("top", srcy0 * input_height - y_subpixel_offset / zoom_y)
609 -- Finally, adjust the border so it is exactly where we want it.
610 padding_effect:set_float("border_offset_left", x_subpixel_offset)
611 padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width))
612 padding_effect:set_float("border_offset_top", y_subpixel_offset)
613 padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height))
615 -- Lower-quality simple resizing.
616 local width = round(x1 - x0)
617 local height = round(y1 - y0)
618 resize_effect:set_int("width", width)
619 resize_effect:set_int("height", height)
621 -- Padding must also be to a whole-pixel offset.
622 padding_effect:set_int("left", math.floor(x0))
623 padding_effect:set_int("top", math.floor(y0))
627 -- This is broken, of course (even for positive numbers), but Lua doesn't give us access to real rounding.
629 return math.floor(x + 0.5)
632 function lerp(a, b, t)
633 return a + (b - a) * t
636 function prepare_sbs_chain(chain, t, screen_width, screen_height)
637 chain.input0.input:connect_signal(0)
638 chain.input1.input:connect_signal(1)
639 set_neutral_color(chain.input0.wb_effect, input0_neutral_color)
640 set_neutral_color(chain.input1.wb_effect, input1_neutral_color)
642 -- First input is positioned (16,48) from top-left.
643 local width0 = round(848 * screen_width/1280.0)
644 local height0 = round(width0 * 9.0 / 16.0)
646 local top0 = 48 * screen_height/720.0
647 local left0 = 16 * screen_width/1280.0
648 local bottom0 = top0 + height0
649 local right0 = left0 + width0
651 -- Second input is positioned (16,48) from the bottom-right.
652 local width1 = round(384 * screen_width/1280.0)
653 local height1 = round(216 * screen_height/720.0)
655 local bottom1 = screen_height - 48 * screen_height/720.0
656 local right1 = screen_width - 16 * screen_width/1280.0
657 local top1 = bottom1 - height1
658 local left1 = right1 - width1
660 -- Interpolate between the fullscreen and side-by-side views.
661 local scale0, tx0, tx0
662 if zoom_poi == INPUT0_SIGNAL_NUM then
663 local new_left0 = lerp(left0, 0, t)
664 local new_right0 = lerp(right0, screen_width, t)
665 local new_top0 = lerp(top0, 0, t)
666 local new_bottom0 = lerp(bottom0, screen_height, t)
668 scale0 = (new_right0 - new_left0) / width0 -- Same vertically and horizonally.
669 tx0 = new_left0 - left0 * scale0
670 ty0 = new_top0 - top0 * scale0
672 local new_left1 = lerp(left1, 0, t)
673 local new_right1 = lerp(right1, screen_width, t)
674 local new_top1 = lerp(top1, 0, t)
675 local new_bottom1 = lerp(bottom1, screen_height, t)
677 scale0 = (new_right1 - new_left1) / width1 -- Same vertically and horizonally.
678 tx0 = new_left1 - left1 * scale0
679 ty0 = new_top1 - top1 * scale0
682 top0 = top0 * scale0 + ty0
683 bottom0 = bottom0 * scale0 + ty0
684 left0 = left0 * scale0 + tx0
685 right0 = right0 * scale0 + tx0
687 top1 = top1 * scale0 + ty0
688 bottom1 = bottom1 * scale0 + ty0
689 left1 = left1 * scale0 + tx0
690 right1 = right1 * scale0 + tx0
691 place_rectangle(chain.input0.resample_effect, chain.input0.resize_effect, chain.input0.padding_effect, left0, top0, right0, bottom0, screen_width, screen_height, 1280, 720)
692 place_rectangle(chain.input1.resample_effect, chain.input1.resize_effect, chain.input1.padding_effect, left1, top1, right1, bottom1, screen_width, screen_height, 1280, 720)
695 function set_neutral_color(effect, color)
696 effect:set_vec3("neutral_color", color[1], color[2], color[3])
699 function set_neutral_color_from_signal(effect, signal)
700 if signal == INPUT0_SIGNAL_NUM then
701 set_neutral_color(effect, input0_neutral_color)
703 set_neutral_color(effect, input1_neutral_color)
707 function calc_fade_progress(t, transition_start, transition_end)
708 local tt = (t - transition_start) / (transition_end - transition_start)
715 -- Make the fade look maybe a tad more natural, by pumping it
716 -- through a sigmoid function.
718 tt = 1.0 / (1.0 + math.exp(-tt))