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.
9 io.write("hello from lua\n");
11 local zoom_start = -2.0;
12 local zoom_end = -1.0;
16 local live_signal_num = 0;
17 local preview_signal_num = 1;
19 -- The main live chain.
20 local main_chain = EffectChain.new(16, 9);
21 local input0 = main_chain:add_live_input();
22 input0:connect_signal(0);
23 local input1 = main_chain:add_live_input();
24 input1:connect_signal(1);
25 local resample_effect = main_chain:add_effect(ResampleEffect.new(), input0);
26 local padding_effect = main_chain:add_effect(IntegralPaddingEffect.new());
27 padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 1.0);
29 local resample2_effect = main_chain:add_effect(ResampleEffect.new(), input1);
30 -- Effect *saturation_effect = main_chain->add_effect(new SaturationEffect());
31 -- CHECK(saturation_effect->set_float("saturation", 0.3f));
32 local wb_effect = main_chain:add_effect(WhiteBalanceEffect.new());
33 wb_effect:set_float("output_color_temperature", 3500.0);
34 local padding2_effect = main_chain:add_effect(IntegralPaddingEffect.new());
36 main_chain:add_effect(OverlayEffect.new(), padding_effect, padding2_effect);
37 main_chain:finalize(true);
39 -- A chain to show a single input on screen.
40 local simple_chain = EffectChain.new(16, 9);
41 local simple_chain_input = simple_chain:add_live_input();
42 simple_chain_input:connect_signal(0); -- First input card. Can be changed whenever you want.
43 simple_chain:finalize(false);
45 -- Returns the number of outputs in addition to the live (0) and preview (1).
46 -- Called only once, at the start of the program.
47 function num_channels()
51 -- Called every frame.
52 function get_transitions()
53 return {"Cut", "Fade", "Zoom!"};
56 function transition_clicked(num, t)
57 -- local temp = live_signal_num;
58 -- live_signal_num = preview_signal_num;
59 -- preview_signal_num = temp;
64 local temp = zoom_src;
69 function channel_clicked(num, t)
70 -- Presumably change the preview here.
71 io.write("STUB: channel_clicked\n");
74 -- Called every frame. Get the chain for displaying at input <num>,
75 -- where 0 is live, 1 is preview, 2 is the first channel to display
76 -- in the bottom bar, and so on up to num_channels()+1. t is the
77 -- current time in seconds. width and height are the dimensions of
78 -- the output, although you can ignore them if you don't need them
79 -- (they're useful if you want to e.g. know what to resample by).
81 -- You should return two objects; the chain itself, and then a
82 -- function (taking no parameters) that is run just before rendering.
83 -- The function needs to call connect_signal on any inputs, so that
84 -- it gets updated video data for the given frame. (You are allowed
85 -- to switch which input your input is getting from between frames,
86 -- but not calling connect_signal results in undefined behavior.)
87 -- If you want to change any parameters in the chain, this is also
90 -- NOTE: The chain returned must be finalized with the Y'CbCr flag
91 -- if and only if num==0.
92 function get_chain(num, t, width, height)
93 if num == 0 then -- Live.
95 if (t < zoom_start) then
96 prepare_sbs_chain(zoom_src, width, height);
97 elseif (t > zoom_end) then
98 prepare_sbs_chain(zoom_dst, width, height);
100 local tt = (t - zoom_start) / (zoom_end - zoom_start);
102 tt = math.sin(tt * 3.14159265358 * 0.5)
103 prepare_sbs_chain(zoom_src + (zoom_dst - zoom_src) * tt, width, height);
106 return main_chain, prepare;
108 if num == 1 then -- Preview.
110 simple_chain_input:connect_signal(preview_signal_num);
112 return simple_chain, prepare;
116 simple_chain_input:connect_signal(0);
118 return simple_chain, prepare;
122 simple_chain_input:connect_signal(1);
124 return simple_chain, prepare;
128 function place_rectangle(resample_effect, padding_effect, x0, y0, x1, y1, screen_width, screen_height)
135 if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
136 resample_effect:set_int("width", 1);
137 resample_effect:set_int("height", 1);
138 resample_effect:set_float("zoom_x", screen_width);
139 resample_effect:set_float("zoom_y", screen_height);
140 padding_effect:set_int("left", screen_width + 100);
141 padding_effect:set_int("top", screen_height + 100);
145 -- Clip. (TODO: Clip on upper/left sides, too.)
146 if x1 > screen_width then
147 srcx1 = (screen_width - x0) / (x1 - x0);
150 if y1 > screen_height then
151 srcy1 = (screen_height - y0) / (y1 - y0);
155 local x_subpixel_offset = x0 - math.floor(x0);
156 local y_subpixel_offset = y0 - math.floor(y0);
158 -- Resampling must be to an integral number of pixels. Round up,
159 -- and then add an extra pixel so we have some leeway for the border.
160 local width = math.ceil(x1 - x0) + 1;
161 local height = math.ceil(y1 - y0) + 1;
162 resample_effect:set_int("width", width);
163 resample_effect:set_int("height", height);
165 -- Correct the discrepancy with zoom. (This will leave a small
166 -- excess edge of pixels and subpixels, which we'll correct for soon.)
167 local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0));
168 local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0));
169 resample_effect:set_float("zoom_x", zoom_x);
170 resample_effect:set_float("zoom_y", zoom_y);
171 resample_effect:set_float("zoom_center_x", 0.0);
172 resample_effect:set_float("zoom_center_y", 0.0);
174 -- Padding must also be to a whole-pixel offset.
175 padding_effect:set_int("left", math.floor(x0));
176 padding_effect:set_int("top", math.floor(y0));
178 -- Correct _that_ discrepancy by subpixel offset in the resampling.
179 resample_effect:set_float("left", -x_subpixel_offset / zoom_x);
180 resample_effect:set_float("top", -y_subpixel_offset / zoom_y);
182 -- Finally, adjust the border so it is exactly where we want it.
183 padding_effect:set_float("border_offset_left", x_subpixel_offset);
184 padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width));
185 padding_effect:set_float("border_offset_top", y_subpixel_offset);
186 padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height));
189 -- This is broken, of course (even for positive numbers), but Lua doesn't give us access to real rounding.
191 return math.floor(x + 0.5)
194 function prepare_sbs_chain(t, screen_width, screen_height)
195 input0:connect_signal(live_signal_num);
196 input1:connect_signal(1);
198 -- First input is positioned (16,48) from top-left.
199 local width0 = round(848 * screen_width/1280.0);
200 local height0 = round(width0 * 9.0 / 16.0);
202 local top0 = 48 * screen_height/720.0;
203 local left0 = 16 * screen_width/1280.0;
204 local bottom0 = top0 + height0;
205 local right0 = left0 + width0;
207 -- Second input is positioned (16,48) from the bottom-right.
208 local width1 = 384 * screen_width/1280.0;
209 local height1 = 216 * screen_height/720.0;
211 local bottom1 = screen_height - 48 * screen_height/720.0;
212 local right1 = screen_width - 16 * screen_width/1280.0;
213 local top1 = bottom1 - height1;
214 local left1 = right1 - width1;
216 -- Interpolate between the fullscreen and side-by-side views.
217 local scale0 = 1.0 + t * (1280.0 / 848.0 - 1.0);
218 local tx0 = 0.0 + t * (-left0 * scale0);
219 local ty0 = 0.0 + t * (-top0 * scale0);
221 top0 = top0 * scale0 + ty0;
222 bottom0 = bottom0 * scale0 + ty0;
223 left0 = left0 * scale0 + tx0;
224 right0 = right0 * scale0 + tx0;
226 top1 = top1 * scale0 + ty0;
227 bottom1 = bottom1 * scale0 + ty0;
228 left1 = left1 * scale0 + tx0;
229 right1 = right1 * scale0 + tx0;
230 place_rectangle(resample_effect, padding_effect, left0, top0, right0, bottom0, screen_width, screen_height);
231 place_rectangle(resample2_effect, padding2_effect, left1, top1, right1, bottom1, screen_width, screen_height);