libraryImport video example: can't define movieEvent hook

[jeremydouglass]

I've tried using the importLibrary() function to create a second library example using the Processing Video library ("video"), and specifically its Loop.pde demo sketch.

I was successful -- video plays in a loop in Processing.R -- however I ran into a problem redefining the Video library's movieEvent function hook. My demo sketch works around this problem by dropping the framerate and reading the video each frame no matter what. This creates rough, choppy, low-framerate video. I wonder if there is a way to do this right.

To set up this test sketch, install the Video library in PDE, save the test sketch in Processing.R mode, then copy transit.mov from the video library example into the sketch /data folder.

settings <- function() {
    # Please install the video before you run the example.
    importLibrary("video")
    size(640, 360)
}

setup <- function() {
    frameRate(10) # hack -- drop the framerate to give video more time to load
    # copy transit.mov from video library example into sketch /data folder
    movie = Movie$new(processing, "transit.mov");
    movie$loop()
}

draw <- function() {
    background(0)
    movie$read() # hack -- reads regardless of whether the next frame is ready or not
    image(movie, 0, 0, width, height)
}

## The video library uses the movieEvent() function
## to manage when the movie object reads the next frame.
## However I'm not sure how to redefine this hook
## in R mode. For the original Java video library example, see:
##   /libraries/video/examples/Movie/Loop/Loop.pde

## doesn't work
# movieEvent <- function(m) {
#     m$read()
# }

## also doesn't work
# movieEvent <- function() {
#     movie$read()
# }

## also doesn't work
# Movie$movieEvent <- function(m) {
#     m$read()
# }

## also doesn't work
# Movie$movieEvent <- function() {
#     movie$read()
# }

[gaocegege]

It is a big, I will take a look tomorrow.

[jeremydouglass]

Thanks for taking a look! Keep in mind that any given library test is not high priority -- I'm just looking at importLibrary examples related to #58.

In general, the question of how to redefine a hook function -- which is used in many libraries -- may be related to how to redefine interactive hook functions in the Processing interaction model: #163.

That is much more important that digging into any specific library -- if we can't make a library example work quickly and easily then it should be scheduled for after GSOC.

[gaocegege]

No thanks, it is my job in this summer 😸

Since the hook function is used in many libraries, I think we could put this issue in p1 or p2.

[gaocegege]

It is definitely a bug. functions in rpde is not defined in Processing, we statically find the functions called draw, settings, or setup and override the functions in PApplet with the same name. So the other functions defined in the rpde could not used in Java

[gaocegege]

It is a little difficult, but I will try to solve the problem. We need to implement a compiler similar to java mode.

[gaocegege]

Dup with #170