]> git.sesse.net Git - ultimatescore/blobdiff - nageru/ultimate.lua
A zillion bugfixes relating to SBS.
[ultimatescore] / nageru / ultimate.lua
index c4fc522826db3f0fa36b763ae51dd0d24b71dab0..a061fb0273ce6a2a2d48b5c0044db1cac1afbee9 100644 (file)
@@ -9,7 +9,9 @@ local transition_dst_signal = 0
 local neutral_colors = {
        {0.5, 0.5, 0.5},  -- Input 0.
        {0.5, 0.5, 0.5},  -- Input 1.
-       {0.5, 0.5, 0.5}   -- Input 2.
+       {0.5, 0.5, 0.5},  -- Input 2.
+       {0.5, 0.5, 0.5},  -- Input 3.
+       {0.5, 0.5, 0.5}   -- Input 4.
 }
 
 local overlay_transition_start = -2.0
@@ -20,19 +22,24 @@ local overlay_enabled = false
 
 local live_signal_num = 0
 local preview_signal_num = 1
+local NUM_CAMERAS = 5  -- Remember to update neutral_colors, too.
 
 -- Valid values for live_signal_num and preview_signal_num.
 local INPUT0_SIGNAL_NUM = 0
 local INPUT1_SIGNAL_NUM = 1
 local INPUT2_SIGNAL_NUM = 2
-local STATIC_SIGNAL_NUM = 3
+local INPUT3_SIGNAL_NUM = 3
+local INPUT4_SIGNAL_NUM = 4
+local SBS_SIGNAL_NUM = NUM_CAMERAS
+local STATIC_SIGNAL_NUM = NUM_CAMERAS + 1
 
 -- Preview-only signal showing the current signal with the overlay.
 -- Not valid for live_signal_num!
-local OVERLAY_SIGNAL_NUM = 4
+local OVERLAY_SIGNAL_NUM = NUM_CAMERAS + 2
 
 -- Valid values for transition_type. (Cuts are done directly, so they need no entry.)
 local NO_TRANSITION = 0
+local ZOOM_TRANSITION = 1
 local FADE_TRANSITION = 2
 
 -- Last width/height/frame rate for each channel, if we have it.
@@ -40,8 +47,14 @@ local FADE_TRANSITION = 2
 -- frame and not per field, since we deinterlace.
 local last_resolution = {}
 
-local caspar_input = VideoInput.new("unix:///tmp/caspar.sock")
-caspar_input:change_rate(2.0)
+local cef_path = Nageru.THEME_PATH:match("(.*)/nageru/")
+local cef_input = HTMLInput.new("file://" .. cef_path .. "/score.html")
+cef_input:execute_javascript_async("play()")
+
+function reload_cef()
+       cef_input:reload()
+       cef_input:execute_javascript_async("play()")
+end
 
 -- Utility function to help creating many similar chains that can differ
 -- in a free set of chosen parameters.
@@ -63,7 +76,7 @@ end
 
 -- An overlay with variable alpha.
 function make_overlay(chain, base)
-       local image = chain:add_video_input(caspar_input, false)
+       local image = chain:add_html_input(cef_input)
        local multiply_effect = chain:add_effect(MultiplyEffect.new())
        local overlay_effect = chain:add_effect(OverlayEffect.new(), base, multiply_effect)
        return {
@@ -122,8 +135,26 @@ function make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, i
        local input0 = make_fade_input(chain, INPUT0_SIGNAL_NUM, input0_live, input0_deint, input0_scale)
        local input1 = make_fade_input(chain, INPUT1_SIGNAL_NUM, input1_live, input1_deint, input1_scale)
 
+       -- If fading between two live inputs, the overlay is put on top.
+       -- If fading between the static picture and a live input,
+       -- the overlay is put on the live input.
+       local overlay = nil
+       if input0_live and not input1_live then
+               overlay = possibly_make_overlay(has_overlay, chain, input0.last)
+               if overlay then
+                       input0.last = overlay.overlay_effect
+               end
+       elseif input1_live and not input0_live then
+               overlay = possibly_make_overlay(has_overlay, chain, input1.last)
+               if overlay then
+                       input1.last = overlay.overlay_effect
+               end
+       end
+
        local mix_effect = chain:add_effect(MixEffect.new(), input0.last, input1.last)
-       local overlay = possibly_make_overlay(has_overlay, chain, mix_effect)
+       if input0_live and input1_live then
+               overlay = possibly_make_overlay(has_overlay, chain, mix_effect)
+       end
 
        chain:finalize(hq)
 
@@ -152,6 +183,68 @@ local fade_chains = make_cartesian_product({
        return make_fade_chain(input0_live, input0_deint, input0_scale, input1_live, input1_deint, input1_scale, has_overlay, hq)
 end)
 
+function make_sbs_input(chain, signal, deint, has_overlay, hq)
+       local input = chain:add_live_input(not deint, deint)  -- Override bounce only if not deinterlacing.
+       input:connect_signal(signal)
+
+       local overlay = nil
+       if has_overlay then
+               overlay = make_overlay(chain, input)
+       end
+
+       local resample_effect = nil
+       local resize_effect = nil
+       if (hq) then
+               resample_effect = chain:add_effect(ResampleEffect.new())
+       else
+               resize_effect = chain:add_effect(ResizeEffect.new())
+       end
+       local wb_effect = chain:add_effect(WhiteBalanceEffect.new())
+
+       local padding_effect = chain:add_effect(IntegralPaddingEffect.new())
+
+       return {
+               input = input,
+               wb_effect = wb_effect,
+               resample_effect = resample_effect,
+               resize_effect = resize_effect,
+               padding_effect = padding_effect,
+               overlay = overlay
+       }
+end
+
+-- Side-by-side chains.
+function make_sbs_chain(input0_type, input0_overlay, input1_type, hq)
+       local chain = EffectChain.new(16, 9)
+
+       local input0 = make_sbs_input(chain, INPUT0_SIGNAL_NUM, input0_type == "livedeint", input0_overlay, hq)
+       local input1 = make_sbs_input(chain, INPUT4_SIGNAL_NUM, input1_type == "livedeint", false, hq)
+
+       input0.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0)
+       input1.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 0.0)
+
+       chain:add_effect(OverlayEffect.new(), input0.padding_effect, input1.padding_effect)
+       chain:finalize(hq)
+
+       return {
+               chain = chain,
+               input0 = input0,
+               input1 = input1,
+               overlay = input0.overlay  -- May be nil.
+       }
+end
+
+
+-- Make all possible combinations of side-by-side chains.
+local sbs_chains = make_cartesian_product({
+       {"live", "livedeint"},  -- input0_type
+       {true, false},          -- input0_overlay
+       {"live", "livedeint"},  -- input1_type
+       {true, false}           -- hq
+}, function(input0_type, input0_overlay, input1_type, hq)
+       return make_sbs_chain(input0_type, input0_overlay, input1_type, hq)
+end)
+
 -- A chain to show a single input on screen.
 function make_simple_chain(input_deint, input_scale, has_overlay, hq)
        local chain = EffectChain.new(16, 9)
@@ -194,26 +287,23 @@ local simple_chains = make_cartesian_product({
        return make_simple_chain(input_deint, input_scale, has_overlay, hq)
 end)
 
--- A chain to show a single static picture on screen.
+-- A chain to show a single static picture on screen. Never with CasparCG overlay.
 local static_chains = make_cartesian_product({
-       {true, false},           -- has_overlay
        {true, false}            -- hq
-}, function(has_overlay, hq)
+}, function(hq)
        local chain = EffectChain.new(16, 9)
        local chain_input = chain:add_effect(ImageInput.new("tfk_pause.png"))
-       local overlay = possibly_make_overlay(has_overlay, chain, chain_input)
 
        chain:finalize(hq)
        return {
-               chain = chain,
-               overlay = overlay
+               chain = chain
        }
 end)
 
 -- A chain to show the overlay and nothing more. LQ only,
 -- since it is not a valid live signal.
 local overlay_chain_lq = EffectChain.new(16, 9)
-local overlay_chain_lq_input = overlay_chain_lq:add_video_input(caspar_input, false)
+local overlay_chain_lq_input = overlay_chain_lq:add_html_input(cef_input)
 overlay_chain_lq:finalize(false)
 
 -- Used for indexing into the tables of chains.
@@ -250,11 +340,11 @@ end
 -- 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 5
+       return NUM_CAMERAS + 3  -- sbs, static picture and overlay
 end
 
 function is_plain_signal(num)
-       return num >= INPUT0_SIGNAL_NUM and num <= INPUT2_SIGNAL_NUM
+       return num >= INPUT0_SIGNAL_NUM and num <= INPUT4_SIGNAL_NUM
 end
 
 -- Helper function to write e.g. “720p60”. The difference between this
@@ -305,12 +395,18 @@ end
 -- channels in case they change resolution.
 function channel_name(channel)
        local signal_num = channel - 2
-       if signal_num == 0 then
+       if signal_num == INPUT0_SIGNAL_NUM then
                return "Main (" .. get_channel_resolution(signal_num) .. ")"
-       elseif signal_num == 1 then
-               return "Goal 1 (" .. get_channel_resolution(signal_num) .. ")"
-       elseif signal_num == 2 then
-               return "Goal 2 (" .. get_channel_resolution(signal_num) .. ")"
+       elseif signal_num == INPUT1_SIGNAL_NUM then
+               return "Secondary (" .. get_channel_resolution(signal_num) .. ")"
+       elseif signal_num == INPUT2_SIGNAL_NUM then
+               return "Goal L (" .. get_channel_resolution(signal_num) .. ")"
+       elseif signal_num == INPUT3_SIGNAL_NUM then
+               return "Goal R (" .. get_channel_resolution(signal_num) .. ")"
+       elseif signal_num == INPUT4_SIGNAL_NUM then
+               return "Commentators (" .. get_channel_resolution(signal_num) .. ")"
+       elseif signal_num == SBS_SIGNAL_NUM then
+               return "Side-by-side"
        elseif signal_num == STATIC_SIGNAL_NUM then
                return "Static picture"
        elseif signal_num == OVERLAY_SIGNAL_NUM then
@@ -326,10 +422,8 @@ end
 -- Called once for each channel, at the start of the program.
 -- Will never be called for live (0) or preview (1).
 function channel_signal(channel)
-       if channel == 2 then
-               return 0
-       elseif channel == 3 then
-               return 1
+       if is_plain_signal(channel - 2) then
+               return channel - 2
        else
                return -1
        end
@@ -362,7 +456,7 @@ function channel_involved_in(channel, signal_num)
                return channel == (signal_num + 2)
        end
        if signal_num == STATIC_SIGNAL_NUM then
-               return (channel == 5)
+               return (channel == NUM_CAMERAS)
        end
        return false
 end
@@ -400,6 +494,15 @@ function in_transition(t)
        return t >= transition_start and t <= transition_end
 end
 
+function is_sbs_participating_signal(signal_num)
+       return signal_num == INPUT0_SIGNAL_NUM or signal_num == INPUT4_SIGNAL_NUM
+end
+
+function simple_signal_has_overlay(signal_num)
+       -- The commentator output has no overlay on it.
+       return signal_num ~= INPUT4_SIGNAL_NUM
+end
+
 -- API ENTRY POINT
 -- Called every frame.
 function get_transitions(t)
@@ -431,6 +534,13 @@ function get_transitions(t)
                return {"Cut", "", "Fade"}
        end
 
+       -- Various zooms.
+       if live_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(preview_signal_num) then
+               return {"Cut", "Zoom in"}
+       elseif is_sbs_participating_signal(live_signal_num) and preview_signal_num == SBS_SIGNAL_NUM then
+               return {"Cut", "Zoom out"}
+       end
+
        return {"Cut"}
 end
 
@@ -505,6 +615,11 @@ function transition_clicked(num, t)
                        swap_preview_live()
                        return
                end
+
+               if (live_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(preview_signal_num)) or
+                  (preview_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(live_signal_num)) then
+                       start_transition(ZOOM_TRANSITION, t, 1.0)
+               end
        elseif num == 2 then
                finish_transitions(t)
 
@@ -547,11 +662,29 @@ function get_fade_chain(signals, t, width, height, input_resolution)
 
                chain.mix_effect:set_float("strength_first", 1.0 - tt)
                chain.mix_effect:set_float("strength_second", tt)
-               prepare_overlay_live(chain, t)
+
+               -- The commentator output has no overlay on it.
+               local extra_alpha_factor = 1.0
+               if not simple_signal_has_overlay(transition_src_signal) and
+                  not simple_signal_has_overlay(transition_dst_signal) then
+                       extra_alpha_factor = 0.0
+               elseif not simple_signal_has_overlay(transition_src_signal) then
+                       extra_alpha_factor = tt
+               elseif not simple_signal_has_overlay(transition_dst_signal) then
+                       extra_alpha_factor = 1.0 - tt
+               end
+               prepare_overlay_live(chain, t, extra_alpha_factor)
        end
        return chain.chain, prepare
 end
 
+-- SBS code (live_signal_num == SBS_SIGNAL_NUM, or in a transition to/from it).
+function get_sbs_chain(signals, t, width, height, input_resolution)
+       local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
+       local input1_type = get_input_type(signals, INPUT4_SIGNAL_NUM)
+       return sbs_chains[input0_type][overlay_enabled][input1_type][true]
+end
+
 -- API ENTRY POINT
 -- 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
@@ -578,7 +711,7 @@ end
 -- if and only if num==0.
 function get_chain(num, t, width, height, signals)
        local input_resolution = {}
-       for signal_num=0,2 do
+       for signal_num=0,(NUM_CAMERAS-1) do
                local res = {
                        width = signals:get_width(signal_num),
                        height = signals:get_height(signal_num),
@@ -607,23 +740,40 @@ function get_chain(num, t, width, height, signals)
        if num == 0 then  -- Live.
                -- See if we're in a transition.
                finish_transitions(t)
-               if transition_type == FADE_TRANSITION then
+               if transition_type == ZOOM_TRANSITION then
+                       -- Transition in or out of SBS.
+                       local chain = get_sbs_chain(signals, t, width, height, input_resolution)
+                       prepare = function()
+                               prepare_sbs_chain(chain, calc_zoom_progress(t), transition_type, transition_src_signal, transition_dst_signal, width, height, input_resolution)
+                               prepare_overlay_live(chain, t, 1.0)
+                       end
+                       return chain.chain, prepare
+               elseif transition_type == NO_TRANSITION and live_signal_num == SBS_SIGNAL_NUM then
+                       -- Static SBS view.
+                       local chain = get_sbs_chain(signals, t, width, height, input_resolution)
+                       prepare = function()
+                               prepare_sbs_chain(chain, 0.0, NO_TRANSITION, 0, SBS_SIGNAL_NUM, width, height, input_resolution)
+                               prepare_overlay_live(chain, t, 1.0)
+                       end
+                       return chain.chain, prepare
+               elseif transition_type == FADE_TRANSITION then
                        return get_fade_chain(signals, t, width, height, input_resolution)
                elseif is_plain_signal(live_signal_num) then
                        local input_type = get_input_type(signals, live_signal_num)
                        local input_scale = needs_scale(signals, live_signal_num, width, height)
-                       local chain = simple_chains[input_type][input_scale][overlay_enabled][true]
+                       local overlay_really_enabled = overlay_enabled and simple_signal_has_overlay(live_signal_num)
+                       local chain = simple_chains[input_type][input_scale][overlay_really_enabled][true]
                        prepare = function()
                                chain.input:connect_signal(live_signal_num)
                                set_scale_parameters_if_needed(chain, width, height)
                                set_neutral_color_from_signal(chain.wb_effect, live_signal_num)
-                               prepare_overlay_live(chain, t)
+                               prepare_overlay_live(chain, t, 1.0)
                        end
                        return chain.chain, prepare
                elseif live_signal_num == STATIC_SIGNAL_NUM then  -- Static picture.
-                       local chain = static_chains[overlay_enabled][true]
+                       local chain = static_chains[true]
                        prepare = function()
-                               prepare_overlay_live(chain, t)
+                               prepare_overlay_live(chain, t, 1.0)  -- FIXME: Should this ever be here?
                        end
                        return chain.chain, prepare
                else
@@ -644,7 +794,7 @@ function get_chain(num, t, width, height, signals)
                        end
                else
                        num = preview_signal_num + 2
-                       show_overlay = overlay_enabled
+                       show_overlay = overlay_enabled and simple_signal_has_overlay(preview_signal_num)
                end
        end
 
@@ -662,8 +812,17 @@ function get_chain(num, t, width, height, signals)
                end
                return chain.chain, prepare
        end
+       if num == SBS_SIGNAL_NUM + 2 then
+               local input0_type = get_input_type(signals, INPUT0_SIGNAL_NUM)
+               local input1_type = get_input_type(signals, INPUT4_SIGNAL_NUM)
+               local chain = sbs_chains[input0_type][show_overlay][input1_type][false]
+               prepare = function()
+                       prepare_sbs_chain(chain, 0.0, NO_TRANSITION, 0, SBS_SIGNAL_NUM, width, height, input_resolution)
+               end
+               return chain.chain, prepare
+       end
        if num == STATIC_SIGNAL_NUM + 2 then
-               local chain = static_chains[show_overlay][false]
+               local chain = static_chains[false]
                prepare = function()
                        prepare_overlay_static(chain, t)
                end
@@ -682,10 +841,187 @@ function round(x)
        return math.floor(x + 0.5)
 end
 
-function prepare_overlay_live(chain, t)
+function lerp(a, b, t)
+       return a + (b - a) * t
+end
+
+function lerp_pos(a, b, t)
+       return {
+               x0 = lerp(a.x0, b.x0, t),
+               y0 = lerp(a.y0, b.y0, t),
+               x1 = lerp(a.x1, b.x1, t),
+               y1 = lerp(a.y1, b.y1, t)
+       }
+end
+
+function pos_from_top_left(x, y, width, height, screen_width, screen_height)
+       local xs = screen_width / 1280.0
+       local ys = screen_height / 720.0
+       return {
+               x0 = round(xs * x),
+               y0 = round(ys * y),
+               x1 = round(xs * (x + width)),
+               y1 = round(ys * (y + height))
+       }
+end
+
+function prepare_sbs_chain(chain, t, transition_type, src_signal, dst_signal, screen_width, screen_height, input_resolution)
+       chain.input0.input:connect_signal(0)
+       chain.input1.input:connect_signal(4)
+       set_neutral_color(chain.input0.wb_effect, neutral_colors[1])
+       set_neutral_color(chain.input1.wb_effect, neutral_colors[5])
+
+       -- First input is positioned (16,48) from top-left.
+       -- Second input is positioned (16,48) from the bottom-right.
+       local pos0 = pos_from_top_left(16, 48, 848, 477, screen_width, screen_height)
+       local pos1 = pos_from_top_left(1280 - 384 - 16, 720 - 216 - 48, 384, 216, screen_width, screen_height)
+
+       local pos_fs = { x0 = 0, y0 = 0, x1 = screen_width, y1 = screen_height }
+       local affine_param
+       if transition_type == NO_TRANSITION then
+               -- Static SBS view.
+               affine_param = { sx = 1.0, sy = 1.0, tx = 0.0, ty = 0.0 }   -- Identity.
+       else
+               -- Zooming to/from SBS view into or out of a single view.
+               assert(transition_type == ZOOM_TRANSITION)
+               local signal, real_t
+               if src_signal == SBS_SIGNAL_NUM then
+                       signal = dst_signal
+                       real_t = t
+               else
+                       assert(dst_signal == SBS_SIGNAL_NUM)
+                       signal = src_signal
+                       real_t = 1.0 - t
+               end
+
+               if signal == INPUT0_SIGNAL_NUM then
+                       affine_param = find_affine_param(pos0, lerp_pos(pos0, pos_fs, real_t))
+               elseif signal == INPUT4_SIGNAL_NUM then
+                       affine_param = find_affine_param(pos1, lerp_pos(pos1, pos_fs, real_t))
+               end
+       end
+
+       -- NOTE: input_resolution is not 1-indexed, unlike usual Lua arrays.
+       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)
+       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)
+end
+
+-- Find the transformation that changes the first rectangle to the second one.
+function find_affine_param(a, b)
+       local sx = (b.x1 - b.x0) / (a.x1 - a.x0)
+       local sy = (b.y1 - b.y0) / (a.y1 - a.y0)
+       return {
+               sx = sx,
+               sy = sy,
+               tx = b.x0 - a.x0 * sx,
+               ty = b.y0 - a.y0 * sy
+       }
+end
+
+function place_rectangle_with_affine(resample_effect, resize_effect, padding_effect, pos, aff, screen_width, screen_height, input_width, input_height)
+       local x0 = pos.x0 * aff.sx + aff.tx
+       local x1 = pos.x1 * aff.sx + aff.tx
+       local y0 = pos.y0 * aff.sy + aff.ty
+       local y1 = pos.y1 * aff.sy + aff.ty
+
+       place_rectangle(resample_effect, resize_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height)
+end
+
+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
+
+       padding_effect:set_int("width", screen_width)
+       padding_effect:set_int("height", screen_height)
+
+       -- Cull.
+       if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
+               if resample_effect ~= nil 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)
+               else
+                       resize_effect:set_int("width", 1)
+                       resize_effect:set_int("height", 1)
+               end
+               padding_effect:set_int("left", screen_width + 100)
+               padding_effect:set_int("top", screen_height + 100)
+               return
+       end
+
+       -- 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
+       end
+       if y1 > screen_height then
+               srcy1 = (screen_height - y0) / (y1 - y0)
+               y1 = screen_height
+       end
+
+       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)
+
+               -- 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))
+
+               -- 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)
+
+               -- 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)
+
+               -- 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
+
+function prepare_overlay_live(chain, t, extra_alpha_factor)
        if chain.overlay then
                local tt = calc_fade_progress(t, overlay_transition_start, overlay_transition_end)
                overlay_alpha = overlay_alpha_src + tt * (overlay_alpha_dst - overlay_alpha_src)
+               overlay_alpha = overlay_alpha * extra_alpha_factor
                --print("overlay_alpha=" .. overlay_alpha .. " [" .. overlay_alpha_src .. "," .. overlay_alpha_dst .. "]@" .. tt)
                if t > overlay_transition_end and overlay_alpha_dst == 0.0 then
                        overlay_enabled = false  -- Takes effect next frame.
@@ -738,3 +1074,7 @@ function calc_fade_progress(t, transition_start, transition_end)
 
        return tt
 end
+
+ThemeMenu.set(
+       { "Reload overlay", reload_cef }
+)