X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=theme.lua;h=eb5573315e357355c1a21fa59ded979c8c357998;hb=5c560f35dea9f3aa5f13c42f4a0112a4d05f2152;hp=662c1059e8af0372de28280b061358e7011a7a87;hpb=8a6c4382af10caa542f2a0e20a54792cfc51ae28;p=nageru

diff --git a/theme.lua b/theme.lua
index 662c105..eb55733 100644
--- a/theme.lua
+++ b/theme.lua
@@ -6,67 +6,349 @@
 -- Themes are written in Lua, which reflects a simplified form of the Movit API
 -- where all the low-level details (such as texture formats) are handled by the
 -- C++ side and you generally just build chains.
-io.write("hello from lua\n");
 
-local live_signal_num = 0;
-local preview_signal_num = 1;
+-- TODO: Deal with inputs that are different from our native 1280x720 resolution.
+
+local transition_start = -2.0
+local transition_end = -1.0
+local zoom_src = 0.0
+local zoom_dst = 1.0
+local zoom_poi = 0   -- which input to zoom in on
+local fade_src_signal = 0
+local fade_dst_signal = 0
+
+local input0_neutral_color = {0.5, 0.5, 0.5}
+local input1_neutral_color = {0.5, 0.5, 0.5}
+
+local live_signal_num = 0
+local preview_signal_num = 1
+
+-- Valid values for live_signal_num and preview_signal_num.
+local INPUT0_SIGNAL_NUM = 0
+local INPUT1_SIGNAL_NUM = 1
+local SBS_SIGNAL_NUM = 2
+local STATIC_SIGNAL_NUM = 3
+
+-- “fake” signal number that signifies that we are fading from one input
+-- to the next.
+local FADE_SIGNAL_NUM = 4
 
 -- The main live chain.
-local main_chain = EffectChain.new(16, 9);
-local input0 = main_chain:add_live_input();
-input0:connect_signal(0);
-local input1 = main_chain:add_live_input();
-input1:connect_signal(1);
-local resample_effect = main_chain:add_effect(ResampleEffect.new(), input0);
-local padding_effect = main_chain:add_effect(IntegralPaddingEffect.new());
-padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0);
-
-local resample2_effect = main_chain:add_effect(ResampleEffect.new(), input1);
--- Effect *saturation_effect = main_chain->add_effect(new SaturationEffect());
--- CHECK(saturation_effect->set_float("saturation", 0.3f));
-local wb_effect = main_chain:add_effect(WhiteBalanceEffect.new());
-wb_effect:set_float("output_color_temperature", 3500.0);
-local padding2_effect = main_chain:add_effect(IntegralPaddingEffect.new());
-
-main_chain:add_effect(OverlayEffect.new(), padding_effect, padding2_effect);
-main_chain:finalize(true);
-
--- A chain to show a single input on screen.
-local simple_chain = EffectChain.new(16, 9);
-local simple_chain_input = simple_chain:add_live_input();
-simple_chain_input:connect_signal(0);  -- First input card. Can be changed whenever you want.
-simple_chain:finalize(false);
+function make_sbs_chain(hq)
+	local chain = EffectChain.new(16, 9)
+	local input0 = chain:add_live_input(true)
+	input0:connect_signal(0)
+	local input0_wb_effect = chain:add_effect(WhiteBalanceEffect.new())
+	local input1 = chain:add_live_input(true)
+	input1:connect_signal(1)
+	local input1_wb_effect = chain:add_effect(WhiteBalanceEffect.new())
+
+	local resample_effect = nil
+	local resize_effect = nil
+	if (hq) then
+		resample_effect = chain:add_effect(ResampleEffect.new(), input0_wb_effect)
+	else
+		resize_effect = chain:add_effect(ResizeEffect.new(), input0_wb_effect)
+	end
+
+	local padding_effect = chain:add_effect(IntegralPaddingEffect.new())
+	padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0)
+
+	local resample2_effect = nil
+	local resize2_effect = nil
+	if (hq) then
+		resample2_effect = chain:add_effect(ResampleEffect.new(), input1_wb_effect)
+	else
+		resize2_effect = chain:add_effect(ResizeEffect.new(), input1_wb_effect)
+	end
+	local padding2_effect = chain:add_effect(IntegralPaddingEffect.new())
+
+	chain:add_effect(OverlayEffect.new(), padding_effect, padding2_effect)
+	chain:finalize(hq)
+
+	return {
+		chain = chain,
+		input0 = {
+			input = input0,
+			wb_effect = input0_wb_effect,
+			resample_effect = resample_effect,
+			resize_effect = resize_effect,
+			padding_effect = padding_effect
+		},
+		input1 = {
+			input = input1,
+			wb_effect = input1_wb_effect,
+			resample_effect = resample2_effect,
+			resize_effect = resize2_effect,
+			padding_effect = padding2_effect
+		}
+	}
+end
+
+local main_chain_hq = make_sbs_chain(true)
+local main_chain_lq = make_sbs_chain(false)
+
+-- A chain to fade between two inputs, of which either can be a picture
+-- or a live input. In practice only used live, but we still support the
+-- hq parameter.
+function make_fade_chain(input0_live, input1_live, hq)
+	local chain = EffectChain.new(16, 9)
+
+	local input0, wb0_effect, input0_last, input1, wb1_effect, input1_last
+
+	if input0_live then
+		input0 = chain:add_live_input(true)
+		wb0_effect = chain:add_effect(WhiteBalanceEffect.new())
+		input0:connect_signal(0)
+		input0_last = wb0_effect
+	else
+		input0 = chain:add_effect(ImageInput.new("bg.jpeg"))
+		input0_last = input0
+	end
+
+	if input1_live then
+		input1 = chain:add_live_input(true)
+		wb1_effect = chain:add_effect(WhiteBalanceEffect.new())
+		input1:connect_signal(1)
+		input1_last = wb1_effect
+	else
+		input1 = chain:add_effect(ImageInput.new("bg.jpeg"))
+		input1_last = input1
+	end
+
+	local mix_effect = chain:add_effect(MixEffect.new(), input0_last, input1_last)
+	chain:finalize(hq)
+
+	return {
+		chain = chain,
+		input0 = {
+			input = input0,
+			wb_effect = wb0_effect
+		},
+		input1 = {
+			input = input1,
+			wb_effect = wb1_effect
+		},
+		mix_effect = mix_effect
+	}
+end
+
+-- Chains to fade between two inputs, in various configurations.
+local fade_chains = {}
+for input0_type, input0_live in pairs({static = false, live = true}) do
+	fade_chains[input0_type] = {}
+	for input1_type, input1_live in pairs({static = false, live = true}) do
+		fade_chains[input0_type][input1_type] = {}
+		for _, hq in pairs({true, false}) do
+			fade_chains[input0_type][input1_type][hq] = make_fade_chain(input0_live, input1_live, hq)
+		end
+	end
+end
+
+-- A chain to show a single input on screen (HQ version).
+local simple_chain_hq = EffectChain.new(16, 9)
+local simple_chain_hq_input = simple_chain_hq:add_live_input(true)
+simple_chain_hq_input:connect_signal(0)  -- First input card. Can be changed whenever you want.
+local simple_chain_hq_wb_effect = simple_chain_hq:add_effect(WhiteBalanceEffect.new())
+simple_chain_hq:finalize(true)
+
+-- A chain to show a single input on screen (LQ version).
+local simple_chain_lq = EffectChain.new(16, 9)
+local simple_chain_lq_input = simple_chain_lq:add_live_input(true)
+simple_chain_lq_input:connect_signal(0)  -- First input card. Can be changed whenever you want.
+local simple_chain_lq_wb_effect = simple_chain_lq:add_effect(WhiteBalanceEffect.new())
+simple_chain_lq:finalize(false)
+
+-- A chain to show a single static picture on screen (HQ version).
+local static_chain_hq = EffectChain.new(16, 9)
+local static_chain_hq_input = static_chain_hq:add_effect(ImageInput.new("bg.jpeg"))
+static_chain_hq:finalize(true)
+
+-- A chain to show a single static picture on screen (LQ version).
+local static_chain_lq = EffectChain.new(16, 9)
+local static_chain_lq_input = static_chain_lq:add_effect(ImageInput.new("bg.jpeg"))
+static_chain_lq:finalize(false)
 
 -- Returns the number of outputs in addition to the live (0) and preview (1).
 -- Called only once, at the start of the program.
 function num_channels()
-	return 2;
+	return 4
+end
+
+-- Returns the name for each additional channel (starting from 2).
+-- Called only once for each channel, at the start of the program.
+function channel_name(channel)
+	if channel == 2 then
+		return "Input 1"
+	elseif channel == 3 then
+		return "Input 2"
+	elseif channel == 4 then
+		return "Side-by-side"
+	elseif channel == 5 then
+		return "Static picture"
+	end
+end
+
+-- Returns if a given channel supports setting white balance (starting from 2).
+-- Called only once for each channel, at the start of the program.
+function supports_set_wb(channel)
+	return channel == 2 or channel == 3
+end
+
+-- Gets called with a new gray point when the white balance is changing.
+-- The color is in linear light (not sRGB gamma).
+function set_wb(channel, red, green, blue)
+	if channel == 2 then
+		input0_neutral_color = { red, green, blue }
+	elseif channel == 3 then
+		input1_neutral_color = { red, green, blue }
+	end
+end
+
+function finish_transitions(t)
+	-- If live is SBS but de-facto single, make it so.
+	if live_signal_num == SBS_SIGNAL_NUM and t >= transition_end and zoom_dst == 1.0 then
+		live_signal_num = zoom_poi
+	end
+
+	-- If live is fade but de-facto single, make it so.
+	if live_signal_num == FADE_SIGNAL_NUM and t >= transition_end then
+		live_signal_num = fade_dst_signal
+	end
 end
 
 -- Called every frame.
-function get_transitions()
-	return {"Cut", "Fade", "Zoom!"};
+function get_transitions(t)
+	finish_transitions(t)
+
+	if live_signal_num == preview_signal_num then
+		return {}
+	end
+
+	if live_signal_num == SBS_SIGNAL_NUM and t >= transition_start and t <= transition_end then
+		-- Zoom in progress.
+		return {"Cut"}
+	end
+
+	if (live_signal_num == INPUT0_SIGNAL_NUM or
+	    live_signal_num == INPUT1_SIGNAL_NUM or
+	    live_signal_num == STATIC_SIGNAL_NUM) and
+	   (preview_signal_num == INPUT0_SIGNAL_NUM or
+	    preview_signal_num == INPUT1_SIGNAL_NUM or
+	    preview_signal_num == STATIC_SIGNAL_NUM) then
+		return {"Cut", "", "Fade"}
+	end
+
+	-- Various zooms.
+	if live_signal_num == SBS_SIGNAL_NUM and
+	   (preview_signal_num == INPUT0_SIGNAL_NUM or preview_signal_num == INPUT1_SIGNAL_NUM) then
+		return {"Cut", "Zoom in"}
+	elseif (live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM) and
+	       preview_signal_num == SBS_SIGNAL_NUM then
+		return {"Cut", "Zoom out"}
+	end
+
+	return {"Cut"}
 end
 
 function transition_clicked(num, t)
-	-- Only a cut for now.
-	local temp = live_signal_num;
-	live_signal_num = preview_signal_num;
-	preview_signal_num = temp;
+	if num == 0 then
+		-- Cut.
+		if live_signal_num == FADE_SIGNAL_NUM then
+			-- Ongoing fade; finish it immediately.
+			finish_transitions(transition_end)
+		end
+
+		local temp = live_signal_num
+		live_signal_num = preview_signal_num
+		preview_signal_num = temp
+
+		if live_signal_num == SBS_SIGNAL_NUM then
+			-- Just cut to SBS, we need to reset any zooms.
+			zoom_src = 1.0
+			zoom_dst = 0.0
+			transition_start = -2.0
+			transition_end = -1.0
+		end
+	elseif num == 1 then
+		-- Zoom.
+
+		finish_transitions(t)
+
+		if live_signal_num == preview_signal_num then
+			-- Nothing to do.
+			return
+		end
+
+		if (live_signal_num == INPUT0_SIGNAL_NUM and preview_signal_num == INPUT1_SIGNAL_NUM) or
+		   (live_signal_num == INPUT1_SIGNAL_NUM and preview_signal_num == INPUT0_SIGNAL_NUM) then
+			-- We can't zoom between these. Just make a cut.
+			io.write("Cutting from " .. live_signal_num .. " to " .. live_signal_num .. "\n")
+			local temp = live_signal_num
+			live_signal_num = preview_signal_num
+			preview_signal_num = temp
+			return
+		end
+
+		if live_signal_num == SBS_SIGNAL_NUM and
+		   (preview_signal_num == INPUT0_SIGNAL_NUM or preview_signal_num == INPUT1_SIGNAL_NUM) then
+			-- Zoom in from SBS to single.
+			transition_start = t
+			transition_end = t + 1.0
+			zoom_src = 0.0
+			zoom_dst = 1.0
+			zoom_poi = preview_signal_num
+			preview_signal_num = SBS_SIGNAL_NUM
+		elseif (live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM) and
+		       preview_signal_num == SBS_SIGNAL_NUM then
+			-- Zoom out from single to SBS.
+			transition_start = t
+			transition_end = t + 1.0
+			zoom_src = 1.0
+			zoom_dst = 0.0
+			preview_signal_num = live_signal_num
+			zoom_poi = live_signal_num
+			live_signal_num = SBS_SIGNAL_NUM
+		end
+	elseif num == 2 then
+		finish_transitions(t)
+
+		-- Fade.
+		if (live_signal_num ~= preview_signal_num) and
+		   (live_signal_num == INPUT0_SIGNAL_NUM or
+		    live_signal_num == INPUT1_SIGNAL_NUM or
+		    live_signal_num == STATIC_SIGNAL_NUM) and
+		   (preview_signal_num == INPUT0_SIGNAL_NUM or
+		    preview_signal_num == INPUT1_SIGNAL_NUM or
+		    preview_signal_num == STATIC_SIGNAL_NUM) then
+			transition_start = t
+			transition_end = t + 1.0
+			fade_src_signal = live_signal_num
+			fade_dst_signal = preview_signal_num
+			preview_signal_num = live_signal_num
+			live_signal_num = FADE_SIGNAL_NUM
+		else
+			-- Fades involving SBS are ignored (we have no chain for it).
+		end
+	end
 end
 
-function channel_clicked(num, t)
-	-- Presumably change the preview here.
-	io.write("STUB: channel_clicked\n");
+function channel_clicked(num)
+	preview_signal_num = num
 end
 
 -- Called every frame. Get the chain for displaying at input <num>,
 -- where 0 is live, 1 is preview, 2 is the first channel to display
--- in the bottom bar, and so on up to num_channels()+1. t is the 
+-- in the bottom bar, and so on up to num_channels()+1. t is the
 -- current time in seconds. width and height are the dimensions of
 -- the output, although you can ignore them if you don't need them
 -- (they're useful if you want to e.g. know what to resample by).
 --
+-- <signals> is basically an exposed InputState, which you can use to
+-- query for information about the signals at the point of the current
+-- frame. In particular, you can call get_width() and get_height()
+-- for any signal number, and use that to e.g. assist in chain selection.
+--
 -- You should return two objects; the chain itself, and then a
 -- function (taking no parameters) that is run just before rendering.
 -- The function needs to call connect_signal on any inputs, so that
@@ -78,92 +360,172 @@ end
 --
 -- NOTE: The chain returned must be finalized with the Y'CbCr flag
 -- if and only if num==0.
-function get_chain(num, t, width, height)
+function get_chain(num, t, width, height, signals)
 	if num == 0 then  -- Live.
+		if live_signal_num == INPUT0_SIGNAL_NUM or live_signal_num == INPUT1_SIGNAL_NUM then  -- Plain input.
+			prepare = function()
+				simple_chain_hq_input:connect_signal(live_signal_num)
+				set_neutral_color_from_signal(simple_chain_hq_wb_effect, live_signal_num)
+			end
+			return simple_chain_hq, prepare
+		elseif live_signal_num == STATIC_SIGNAL_NUM then  -- Static picture.
+			prepare = function()
+			end
+			return static_chain_hq, prepare
+		elseif live_signal_num == FADE_SIGNAL_NUM then  -- Fade.
+			local input0_type = (fade_src_signal == STATIC_SIGNAL_NUM) and "static" or "live"
+			local input1_type = (fade_dst_signal == STATIC_SIGNAL_NUM) and "static" or "live"
+			local chain = fade_chains[input0_type][input1_type][true]
+			prepare = function()
+				if input0_type == "live" then
+					chain.input0.input:connect_signal(fade_src_signal)
+					set_neutral_color_from_signal(chain.input0.wb_effect, fade_src_signal)
+				end
+				if input1_type == "live" then
+					chain.input1.input:connect_signal(fade_dst_signal)
+					set_neutral_color_from_signal(chain.input1.wb_effect, fade_dst_signal)
+				end
+				local tt = calc_fade_progress(t, transition_start, transition_end)
+
+				chain.mix_effect:set_float("strength_first", 1.0 - tt)
+				chain.mix_effect:set_float("strength_second", tt)
+			end
+			return chain.chain, prepare
+		end
+
+		-- SBS code (live_signal_num == SBS_SIGNAL_NUM).
+		if t > transition_end and zoom_dst == 1.0 then
+			-- Special case: Show only the single image on screen.
+			prepare = function()
+				simple_chain_hq_input:connect_signal(INPUT0_SIGNAL_NUM)
+				set_neutral_color(simple_chain_hq_wb_effect, input0_neutral_color)
+			end
+			return simple_chain_hq, prepare
+		end
 		prepare = function()
-			prepare_sbs_chain(t, width, height);
+			if t < transition_start then
+				prepare_sbs_chain(main_chain_hq, zoom_src, width, height)
+			elseif t > transition_end then
+				prepare_sbs_chain(main_chain_hq, zoom_dst, width, height)
+			else
+				local tt = (t - transition_start) / (transition_end - transition_start)
+				-- Smooth it a bit.
+				tt = math.sin(tt * 3.14159265358 * 0.5)
+				prepare_sbs_chain(main_chain_hq, zoom_src + (zoom_dst - zoom_src) * tt, width, height)
+			end
 		end
-		return main_chain, prepare;
+		return main_chain_hq.chain, prepare
 	end
 	if num == 1 then  -- Preview.
+		num = preview_signal_num + 2
+	end
+	if num == INPUT0_SIGNAL_NUM + 2 then
 		prepare = function()
-			simple_chain_input:connect_signal(preview_signal_num);
+			simple_chain_lq_input:connect_signal(0)
+			set_neutral_color(simple_chain_lq_wb_effect, input0_neutral_color)
 		end
-		return simple_chain, prepare;
+		return simple_chain_lq, prepare
 	end
-	if num == 2 then
+	if num == INPUT1_SIGNAL_NUM + 2 then
 		prepare = function()
-			simple_chain_input:connect_signal(0);
+			simple_chain_lq_input:connect_signal(1)
+			set_neutral_color(simple_chain_lq_wb_effect, input1_neutral_color)
 		end
-		return simple_chain, prepare;
+		return simple_chain_lq, prepare
 	end
-	if num == 3 then
+	if num == SBS_SIGNAL_NUM + 2 then
 		prepare = function()
-			simple_chain_input:connect_signal(1);
+			prepare_sbs_chain(main_chain_lq, 0.0, width, height)
 		end
-		return simple_chain, prepare;
+		return main_chain_lq.chain, prepare
+	end
+	if num == STATIC_SIGNAL_NUM + 2 then
+		prepare = function()
+		end
+		return static_chain_lq, prepare
 	end
 end
 
-function place_rectangle(resample_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height)
-	local srcx0 = 0.0;
-	local srcx1 = 1.0;
-	local srcy0 = 0.0;
-	local srcy1 = 1.0;
+function place_rectangle(resample_effect, resize_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height)
+	local srcx0 = 0.0
+	local srcx1 = 1.0
+	local srcy0 = 0.0
+	local srcy1 = 1.0
 
 	-- Cull.
 	if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
-		resample_effect:set_int("width", 1);
-		resample_effect:set_int("height", 1);
-		resample_effect:set_float("zoom_x", screen_width);
-		resample_effect:set_float("zoom_y", screen_height);
-		padding_effect:set_int("left", screen_width + 100);
-		padding_effect:set_int("top", screen_height + 100);
-		return;
+		resample_effect:set_int("width", 1)
+		resample_effect:set_int("height", 1)
+		resample_effect:set_float("zoom_x", screen_width)
+		resample_effect:set_float("zoom_y", screen_height)
+		padding_effect:set_int("left", screen_width + 100)
+		padding_effect:set_int("top", screen_height + 100)
+		return
 	end
 
-	-- Clip. (TODO: Clip on upper/left sides, too.)
+	-- Clip.
+	if x0 < 0 then
+		srcx0 = -x0 / (x1 - x0)
+		x0 = 0
+	end
+	if y0 < 0 then
+		srcy0 = -y0 / (y1 - y0)
+		y0 = 0
+	end
 	if x1 > screen_width then
-		srcx1 = (screen_width - x0) / (x1 - x0);
-		x1 = screen_width;
+		srcx1 = (screen_width - x0) / (x1 - x0)
+		x1 = screen_width
 	end
 	if y1 > screen_height then
-		srcy1 = (screen_height - y0) / (y1 - y0);
-		y1 = screen_height;
+		srcy1 = (screen_height - y0) / (y1 - y0)
+		y1 = screen_height
 	end
 
-	local x_subpixel_offset = x0 - math.floor(x0);
-	local y_subpixel_offset = y0 - math.floor(y0);
+	if resample_effect ~= nil then
+		-- High-quality resampling.
+		local x_subpixel_offset = x0 - math.floor(x0)
+		local y_subpixel_offset = y0 - math.floor(y0)
+
+		-- Resampling must be to an integral number of pixels. Round up,
+		-- and then add an extra pixel so we have some leeway for the border.
+		local width = math.ceil(x1 - x0) + 1
+		local height = math.ceil(y1 - y0) + 1
+		resample_effect:set_int("width", width)
+		resample_effect:set_int("height", height)
 
-	-- Resampling must be to an integral number of pixels. Round up,
-	-- and then add an extra pixel so we have some leeway for the border.
-	local width = math.ceil(x1 - x0) + 1;
-	local height = math.ceil(y1 - y0) + 1;
-	resample_effect:set_int("width", width);
-	resample_effect:set_int("height", height);
+		-- Correct the discrepancy with zoom. (This will leave a small
+		-- excess edge of pixels and subpixels, which we'll correct for soon.)
+		local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0))
+		local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0))
+		resample_effect:set_float("zoom_x", zoom_x)
+		resample_effect:set_float("zoom_y", zoom_y)
+		resample_effect:set_float("zoom_center_x", 0.0)
+		resample_effect:set_float("zoom_center_y", 0.0)
 
-	-- Correct the discrepancy with zoom. (This will leave a small
-	-- excess edge of pixels and subpixels, which we'll correct for soon.)
-	local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0));
-	local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0));
-	resample_effect:set_float("zoom_x", zoom_x);
-	resample_effect:set_float("zoom_y", zoom_y);
-	resample_effect:set_float("zoom_center_x", 0.0);
-	resample_effect:set_float("zoom_center_y", 0.0);
+		-- Padding must also be to a whole-pixel offset.
+		padding_effect:set_int("left", math.floor(x0))
+		padding_effect:set_int("top", math.floor(y0))
 
-	-- Padding must also be to a whole-pixel offset.
-	padding_effect:set_int("left", math.floor(x0));
-	padding_effect:set_int("top", math.floor(y0));
+		-- Correct _that_ discrepancy by subpixel offset in the resampling.
+		resample_effect:set_float("left", srcx0 * input_width - x_subpixel_offset / zoom_x)
+		resample_effect:set_float("top", srcy0 * input_height - y_subpixel_offset / zoom_y)
 
-	-- Correct _that_ discrepancy by subpixel offset in the resampling.
-	resample_effect:set_float("left", -x_subpixel_offset / zoom_x);
-	resample_effect:set_float("top", -y_subpixel_offset / zoom_y);
+		-- Finally, adjust the border so it is exactly where we want it.
+		padding_effect:set_float("border_offset_left", x_subpixel_offset)
+		padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width))
+		padding_effect:set_float("border_offset_top", y_subpixel_offset)
+		padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height))
+	else
+		-- Lower-quality simple resizing.
+		local width = round(x1 - x0)
+		local height = round(y1 - y0)
+		resize_effect:set_int("width", width)
+		resize_effect:set_int("height", height)
 
-	-- Finally, adjust the border so it is exactly where we want it.
-	padding_effect:set_float("border_offset_left", x_subpixel_offset);
-	padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width));
-	padding_effect:set_float("border_offset_top", y_subpixel_offset);
-	padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height));
+		-- Padding must also be to a whole-pixel offset.
+		padding_effect:set_int("left", math.floor(x0))
+		padding_effect:set_int("top", math.floor(y0))
+	end
 end
 
 -- This is broken, of course (even for positive numbers), but Lua doesn't give us access to real rounding.
@@ -171,43 +533,93 @@ function round(x)
 	return math.floor(x + 0.5)
 end
 
-function prepare_sbs_chain(t, screen_width, screen_height)
-	input0:connect_signal(live_signal_num);
-	input1:connect_signal(1);
+function lerp(a, b, t)
+	return a + (b - a) * t
+end
+
+function prepare_sbs_chain(chain, t, screen_width, screen_height)
+	chain.input0.input:connect_signal(0)
+	chain.input1.input:connect_signal(1)
+	set_neutral_color(chain.input0.wb_effect, input0_neutral_color)
+	set_neutral_color(chain.input1.wb_effect, input1_neutral_color)
 
 	-- First input is positioned (16,48) from top-left.
-	local width0 = round(848 * screen_width/1280.0);
-	local height0 = round(width0 * 9.0 / 16.0);
+	local width0 = round(848 * screen_width/1280.0)
+	local height0 = round(width0 * 9.0 / 16.0)
 
-	local top0 = 48 * screen_height/720.0;
-	local left0 = 16 * screen_width/1280.0;
-	local bottom0 = top0 + height0;
-	local right0 = left0 + width0;
+	local top0 = 48 * screen_height/720.0
+	local left0 = 16 * screen_width/1280.0
+	local bottom0 = top0 + height0
+	local right0 = left0 + width0
 
 	-- Second input is positioned (16,48) from the bottom-right.
-	local width1 = 384 * screen_width/1280.0;
-	local height1 = 216 * screen_height/720.0;
+	local width1 = round(384 * screen_width/1280.0)
+	local height1 = round(216 * screen_height/720.0)
 
-	local bottom1 = screen_height - 48 * screen_height/720.0;
-	local right1 = screen_width - 16 * screen_width/1280.0;
-	local top1 = bottom1 - height1;
-	local left1 = right1 - width1;
+	local bottom1 = screen_height - 48 * screen_height/720.0
+	local right1 = screen_width - 16 * screen_width/1280.0
+	local top1 = bottom1 - height1
+	local left1 = right1 - width1
 
 	-- Interpolate between the fullscreen and side-by-side views.
-	local sub_t = 0.5 + 0.5 * math.cos(t * 1.0);
-	local scale0 = 1.0 + sub_t * (1280.0 / 848.0 - 1.0);
-	local tx0 = 0.0 + sub_t * (-left0 * scale0);
-	local ty0 = 0.0 + sub_t * (-top0 * scale0);
-
-	top0 = top0 * scale0 + ty0;
-	bottom0 = bottom0 * scale0 + ty0;
-	left0 = left0 * scale0 + tx0;
-	right0 = right0 * scale0 + tx0;
-
-	top1 = top1 * scale0 + ty0;
-	bottom1 = bottom1 * scale0 + ty0;
-	left1 = left1 * scale0 + tx0;
-	right1 = right1 * scale0 + tx0;
-	place_rectangle(resample_effect, padding_effect, left0, top0, right0, bottom0, screen_width, screen_height);
-	place_rectangle(resample2_effect, padding2_effect, left1, top1, right1, bottom1, screen_width, screen_height);
+	local scale0, tx0, tx0
+	if zoom_poi == INPUT0_SIGNAL_NUM then
+		local new_left0 = lerp(left0, 0, t)
+		local new_right0 = lerp(right0, screen_width, t)
+		local new_top0 = lerp(top0, 0, t)
+		local new_bottom0 = lerp(bottom0, screen_height, t)
+
+		scale0 = (new_right0 - new_left0) / width0  -- Same vertically and horizonally.
+		tx0 = new_left0 - left0 * scale0
+		ty0 = new_top0 - top0 * scale0
+	else
+		local new_left1 = lerp(left1, 0, t)
+		local new_right1 = lerp(right1, screen_width, t)
+		local new_top1 = lerp(top1, 0, t)
+		local new_bottom1 = lerp(bottom1, screen_height, t)
+
+		scale0 = (new_right1 - new_left1) / width1  -- Same vertically and horizonally.
+		tx0 = new_left1 - left1 * scale0
+		ty0 = new_top1 - top1 * scale0
+	end
+
+	top0 = top0 * scale0 + ty0
+	bottom0 = bottom0 * scale0 + ty0
+	left0 = left0 * scale0 + tx0
+	right0 = right0 * scale0 + tx0
+
+	top1 = top1 * scale0 + ty0
+	bottom1 = bottom1 * scale0 + ty0
+	left1 = left1 * scale0 + tx0
+	right1 = right1 * scale0 + tx0
+	place_rectangle(chain.input0.resample_effect, chain.input0.resize_effect, chain.input0.padding_effect, left0, top0, right0, bottom0, screen_width, screen_height, 1280, 720)
+	place_rectangle(chain.input1.resample_effect, chain.input1.resize_effect, chain.input1.padding_effect, left1, top1, right1, bottom1, screen_width, screen_height, 1280, 720)
+end
+
+function set_neutral_color(effect, color)
+	effect:set_vec3("neutral_color", color[1], color[2], color[3])
+end
+
+function set_neutral_color_from_signal(effect, signal)
+	if signal == INPUT0_SIGNAL_NUM then
+		set_neutral_color(effect, input0_neutral_color)
+	else
+		set_neutral_color(effect, input1_neutral_color)
+	end
+end
+
+function calc_fade_progress(t, transition_start, transition_end)
+	local tt = (t - transition_start) / (transition_end - transition_start)
+	if tt < 0.0 then
+		tt = 0.0
+	elseif tt > 1.0 then
+		tt = 1.0
+	end
+
+	-- Make the fade look maybe a tad more natural, by pumping it
+	-- through a sigmoid function.
+	tt = 10.0 * tt - 5.0
+	tt = 1.0 / (1.0 + math.exp(-tt))
+
+	return tt
 end