Any way to speed up this simple script?

in Contributed Library Questions • 1 year ago

Hello! I'm pretty much a processing beginner but I've been working on this script that reads the pixels of a video file and draws a rectangle of the same color at a z height dependent on the pixel's brightness value. 2 questions for you processing masters out there: 1.) when drawing rectangles 1x1 pixels it skips frames and gets heavy. How can I make this script more efficient so as not to be so jerky. and 2.) the higher the size of the rectangle being drawn for each pixel, the more the frame of the video file is cut off. How can I rectify this so that I see the whole frame of the video no matter the size of the rectangle (named 'blocksize' in the script). The code has contributed libraries PeasyCam and GSVideo. Thank you in advance!!

import peasy.*;
import codeanticode.gsvideo.*;
PeasyCam cam;
int numPixels;
int blockSize = 1;
GSMovie myMovie;
color myMovieColors[];
void setup() {
size(800, 600, P3D);
frameRate(60);
noStroke();
rectMode(CENTER);
background(0);
myMovie = new GSMovie(this, "facade masked.mov"); // change movie file name here!!
myMovie.loop();
numPixels = width / blockSize;
myMovieColors = new color[numPixels * numPixels];
cam = new PeasyCam(this,width/2,height/2,0,1000);
}
// Read new values from movie
void movieEvent(GSMovie m) {
m.read();
m.loadPixels();
for (int j = 0; j < numPixels; j++) {
for (int i = 0; i < numPixels; i++) {
myMovieColors[j*numPixels + i] = m.get(i, j);
}
}
}
// Display values from movie
void draw() {
background(0);
for (int j = 0; j < numPixels; j++) {
for (int i = 0; i < numPixels; i++) {
pushMatrix();
float z = brightness(myMovieColors[j*numPixels + i]);
translate(i,j,z);
fill(myMovieColors[j*numPixels + i]);
if ( brightness(myMovieColors[j*numPixels + i]) < 220) {
rect(i, j, blockSize, blockSize);
}
popMatrix();
}
}
//saveFrame("facade-####.tif");
}

btw: code is based on Hernando Barragan's Pixelate.

Replies(1)

PhiLho

Re: Any way to speed up this simple script?

1 year ago

I can't comment on the contributed libraries part, if they play any part (but congrats for posting in the right forum!

) but I see a couple of places where you can do small optimizations. I can't guarantee speed gain will be visible...

void movieEvent(GSMovie m) {
m.read();
m.loadPixels();
for (int j = 0; j < numPixels; j++) {
for (int i = 0; i < numPixels; i++) {
myMovieColors[j*numPixels + i] = m.get(i, j);
}
}
}

get() is slow, and if you use it, you don't need loadPixels. But well, use the pixel array, since it is there... Wait, that's a GSMovie. Hmm... OK, a GSMovie is actually an (improved) PImage, so it is usable in the same way.
Actually, you can even go at full speed with something like:

void movieEvent(GSMovie m) {
m.read();
m.loadPixels();
arrayCopy(m.pixels, myMovieColors);
}

(untested!)
Likewise, you can do small improvements in the draw() loop, by avoiding to do unnecessary operations:

for (int j = 0; j < numPixels; j++) {
for (int i = 0; i < numPixels; i++) {
float z = brightness(myMovieColors[j*numPixels + i]);
if (z < 220) { // No need to compute again brightness()!
pushMatrix();
translate(i,j,z);
fill(myMovieColors[j*numPixels + i]);
rect(i, j, blockSize, blockSize);
popMatrix();
}
}
}

Again, not tested, and not sure it is such a gain...

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