Another ofelia related question...
In the book "Mastering Open Frameworks" is a nice radial slit scan example where they use the deque class for a circular (video) frame buffer:
https://github.com/firmread/ofDemystified/tree/master/05-Video-04-VideoSlitScan/src
"You will note that the buffer of frames is declared here as deque<ofPixels> frames.
Class deque is C++ Standard Template Library container, holding items of any class. In our case, such a class is ofPixels. You can think of frames as a dynamic array, which can change its size during runtime. It provides an indexed access to any item such as frames[i], and most importantly, it efficiently adds and removes items at its ends."

My question is, because I would like to use such a frame buffer (not for a slit scan effect but for a video delay), if and how it is possible to use the deque class with ofelia, or if there is a better (another) way to create such a frame buffer? My naive attempt to implement the example from the book does not work so far (i think because deque is not recognized...).

A totally different question: I wonder if it is possible to use Open Frameworks core or also additional addons with ofelia.

@Jona std::deque (double-ended queue) is an indexed sequence container used to store data types (number, string, classes...etc) in C++. There are many other containers such as std::array, std::vector and std::list in C++. (like [array] and [list] in Pd) These containers work similarly in some way and some are preferred over others depending on cases.

In Lua, there is only one container type: the table. So you should be able to create and use such a frame buffer to store data such as ofPixels class.

For example, a table that holds two ofPixels data would look like this:

local t = {}
t[1] = ofPixels()
t[2] = ofPixels()

You can append/prepend/insert data to the table or remove/modify the element. basically anything that std::deque can do.
It should be fast enough to use unless you use it to store and modify a large number of pixels. storing some frames would be fine.
You will be able to find some tutorials about Lua table from google.

@Cuinjune Hi, and thanks a lot. I did not know that a Lua table can store ofPixels() too.
So it seems not very difficult to create an array (table) filled with frames.
Here I posted a tutorial that helped me to learn the Lua basics (obviously not enough ): https://forum.pdpatchrepo.info/topic/11802/ofelia-openframeworks-lua-learning

@Cuinjune I tried to create a video frame table ("circular video buffer").
It is possible to read (draw) video from the table but somehow only the current frame is stored at every position of the table.
Here is an example patch. "frames" is the frame table. "N" is the table size. At the left is the texture from the table, at the right the original video. Do you know what I do wrong?
I also tried ofPixels instead of ofTexture with the same result.
And I tried to store several images (jpg´s) instead of video to the frame buffer, which does probably work because each image has its own source.

framearray.pd

;
if type(window) ~= "userdata" then;
window = ofWindow();
end;
;
local canvas = pdCanvas(this);
local clock = pdClock(this, "setup");
local videoPlayer = ofVideoPlayer();
local outputList = {};
local frames = {};
local N = 150;
;
function ofelia.bang();
ofWindow.addListener("setup", this);
ofWindow.addListener("update", this);
ofWindow.addListener("draw", this);
ofWindow.addListener("exit", this);
window:setPosition(50, 100);
window:setSize(800 + 40, 600 + 40);
if type(window) ~= "userdata" then;
window = ofWindow();
end;
;
window:create();
if ofWindow.exists then;
clock:delay(0);
end;
end;
;
function ofelia.free();
window:destroy();
ofWindow.removeListener("setup", this);
ofWindow.removeListener("update", this);
ofWindow.removeListener("draw", this);
ofWindow.removeListener("exit", this);
end;
;
function ofelia.setup();
ofSetWindowTitle("Video Player");
ofBackground(0, 0, 0, 255);
end;
;
function ofelia.moviefile(path);
videoPlayer:load(path);
videoPlayer:setLoopState(OF_LOOP_NORMAL);
videoPlayer:setPaused(true);
end;
;
function ofelia.setSpeed(f);
videoPlayer:setSpeed(f / 100);
end;
;
function ofelia.play();
videoPlayer:play();
end;
;
function ofelia.stop();
videoPlayer:setFrame(0);
videoPlayer:setPaused(true);
end;
;
function ofelia.setPaused(f);
if f == 1 then pause = true;
else pause = false;
end;
videoPlayer:setPaused(pause);
end;
;
function ofelia.setFrame(f);
videoPlayer:setFrame(f);
end;
;
function ofelia.setPosition(f);
videoPlayer:setPosition(f);
end;
;
function ofelia.setVolume(f);
videoPlayer:setVolume(f / 100);
end;
;
function ofelia.update();
videoPlayer:update();
if videoPlayer:isFrameNew() then;
table.insert(frames, 1, videoPlayer:getTexture());
if #frames > N then;
table.remove(frames, N + 1);
end;
end;
end;
;
function ofelia.draw();
videoPlayer:draw(420, 20, 400, 600);
if #frames == N then;
frames[ofelia.frame]:draw(20, 20, 400, 600);
end;
outputList[1] = videoPlayer:getPosition();
outputList[2] = videoPlayer:getCurrentFrame();
outputList[3] = videoPlayer:getTotalNumFrames();
return outputList;
end;
;
function ofelia.exit();
videoPlayer:close();
end;
;

@Cuinjune perhaps I found a way to copy textures to a table:
https://forum.openframeworks.cc/t/simply-save-oftexture-from-videograbber/31251

"the only way to copy a texture into another is using an fbo just create an fbo, draw the video into it and get the internal texture with getTexture

you could also use ofImage::setFromPixels(cam.getPixels()) which would be slightly slower but avoids creating an fbo (or many if you want to save several frames"

I think the second method fits better to my case, because I want to save several textures.
But I have problems with the "setFromPixels()" method:
attempt to call a nil value (method 'setFromPixels')

Is it possible that it is a getter function like ofColor::getHsb() that does not work with Ofelia yet?

i am not sure if it is the best solution, but it works now (with setFromPixels) it is a variable framebuffer and the example buffers the last 300 frames from a video.

frameTable300.pd

;
if type(window) ~= "userdata" then;
window = ofWindow();
end;
;
local canvas = pdCanvas(this);
local clock = pdClock(this, "setup");
local videoPlayer = ofVideoPlayer();
local outputList = {};
local frames = {};
local images = {};
local N = 300;
for i = 1, N do;
images[i] = ofImage();
end;
;
function ofelia.new();
ofWindow.addListener("setup", this);
ofWindow.addListener("update", this);
ofWindow.addListener("draw", this);
ofWindow.addListener("exit", this);
window:setPosition(50, 100);
window:setSize(800 + 40, 600 + 40);
if type(window) ~= "userdata" then;
window = ofWindow();
end;
;
window:create();
if ofWindow.exists then;
clock:delay(0);
end;
end;
;
function ofelia.free();
window:destroy();
ofWindow.removeListener("setup", this);
ofWindow.removeListener("update", this);
ofWindow.removeListener("draw", this);
ofWindow.removeListener("exit", this);
end;
;
function ofelia.setup();
ofSetWindowTitle("Video Player");
ofBackground(0, 0, 0, 255);
end;
;
function ofelia.moviefile(path);
videoPlayer:load(path);
videoPlayer:setLoopState(OF_LOOP_NORMAL);
videoPlayer:setPaused(true);
end;
;
function ofelia.setSpeed(f);
videoPlayer:setSpeed(f / 100);
end;
;
function ofelia.play();
videoPlayer:play();
end;
;
function ofelia.stop();
videoPlayer:setFrame(0);
videoPlayer:setPaused(true);
end;
;
function ofelia.setPaused(f);
if f == 1 then pause = true;
else pause = false;
end;
videoPlayer:setPaused(pause);
end;
;
function ofelia.setFrame(f);
videoPlayer:setFrame(f);
end;
;
function ofelia.setPosition(f);
videoPlayer:setPosition(f);
end;
;
function ofelia.setVolume(f);
videoPlayer:setVolume(f / 100);
end;
;
local number = 0;
function ofelia.update();
videoPlayer:update();
if videoPlayer:isFrameNew() then;
number = (number + 1) % N;
print(number + 1);
images[number + 1]:setFromPixels(videoPlayer:getPixels());
table.insert(frames, 1, images[number + 1]);
if #frames > N then;
table.remove(frames);
end;
end;
outputList[1] = videoPlayer:getPosition();
outputList[2] = videoPlayer:getCurrentFrame();
outputList[3] = videoPlayer:getTotalNumFrames();
return outputList;
end;
;
function ofelia.draw();
videoPlayer:draw(420, 20, 400, 600);
if #frames == N then;
frames[ofelia.frame]:draw(20, 20, 400, 600);
end;
end;
;
function ofelia.exit();
videoPlayer:close();
for i = 1, N do;
images[i]:clear();
end;
end;
;