GSVideo + GLGraphics: residual frames on Ubuntu?

achang

GSVideo + GLGraphics: residual frames on Ubuntu?

in Contributed Library Questions • 1 year ago

Summary:

It looks like past frames that I render with GLGraphics (regardless of whether I use GSVideo), show up when I run projects that play GSVideo by copying to a GLGraphics texture.

Setup:

Sun Java 1.6.0_26

Ubuntu 11.10

Gnome 3

GSVideo + GLGraphics 1.0.0

Details:

Suppose I first run a project that renders a simple cube rendered in GLGraphics:

import processing.opengl.*;
import codeanticode.glgraphics.*;
void setup() {
size(640, 480, GLConstants.GLGRAPHICS);
}
void draw() {
background(0);
fill(255, 100, 130);
pushMatrix();
translate(130, height/2, 0);
rotateY(1.25);
rotateX(-0.4);
box(100);
popMatrix();
}

This works as normal:

I can also run the GSVideo/Movie (without using GLGraphics) example and it works as normal:

If I close the pink cube and then run the GSVideo/GLGraphics/Movie example, then I get this:

Note that there is no longer any code about a pink cube, but this is what I see every other frame. Every other frame is normal (i.e. black where the pink cube is).

If I close the GSVideo/GLGraphics/Movie example and next run the GLGraphics/Texture/GLBlendModes example, it again appears normal like this:

Now I run GSVideo/GLGraphics/Movie again and I get some lovely post-modernist video art (this time every frame, as far as my eye can tell):

Any suggestions? It is quite the amusing and frustrating bug, I must say. I feel like I ought to be able to force-clean the buffer or something, but the GSVideo javadocs can't tell me if that's possible. In my actual project, the residual problem shows up as past frames of the same movie ghosting over current running frames (you get flashing humans with 12 arms, for example.)

Thanks in advance!

Replies(5)

andres

Re: GSVideo + GLGraphics: residual frames on Ubuntu?

1 year ago

The residual frame issue is often due to buggy opengl drivers (this is why it appears when you use glgraphics and not the java2d renderer). So a suggestion would be to install updated drivers, if possible.

Also, it should only happen when you don't clear the screen with a call to background() at the beginning of draw(). What happens if you add the following code:

void draw()
if (frameCount == 1) {
background(0);
}
...

achang

Re: GSVideo + GLGraphics: residual frames on Ubuntu?

1 year ago

Hi andres!

I suspected it was an opengl driver problem, but I can run the normal opengl examples, as well as normal glgraphics examples (e.g. the GLBlendModes example) without issue, so I am confused.

I just did yet another test: running GSVideo with the normal Processing opengl renderer is fine. It is, however, slow and therefore not ideal.

I have tried clearing background at 1) the beginning of draw, 2) every loop, 3) only if tex.putPixelsIntoTexture() returns true, 4) if tex.putPixelsIntoTexture() returns false -- they all don't solve the problem fully. Clearing background only at the beginning does get rid of the pink cube, but earlier movie frames of the current playing movie leave residue too.

Perhaps I should try with fglrx drivers?

andres

Re: GSVideo + GLGraphics: residual frames on Ubuntu?

1 year ago

Seems that the double buffering is not working properly, and this could be solved by updating the opengl drivers.

If the driver update doesn't fixes the problem, a workaround could be do all the drawing on an offscreen surface:

GLGraphicsOffScreen offscreen;
void setup() {
size(640, 360, GLConstants.GLGRAPHICS);
offscreen = new GLGraphicsOffScreen(this, width, height);
}
void draw() {
offscreen.beginDraw();
...
offscreen.endDraw();
image(offscreen.getTexture(), 0, 0);
}

achang

Re: GSVideo + GLGraphics: residual frames on Ubuntu?

1 year ago

Thanks again andres. Updating fglrx drivers didn't work; the offscreen buffer worked in the end.

In case anyone else encounters this, there seems to be a conflict between the fullscreen api library and the offscreen buffer on ubuntu, not the fault of glgraphics. If I figure out a fix I will post back.

vj.emtv

Re: GSVideo + GLGraphics: residual frames on Ubuntu?

1 year ago

Hi,

I've got the same kind of problem on MacOS 10.6, when switching between two videos (GSVideo).

I'm already using the "drawing on an offscreen surface" method before sending to output, but I get residual frames from the previous video, randomly displaying in the next one, and sometimes even a flicker between frames of the currently playing video.

i've also tried moving around

if (frameCount == 1) {
background(0);
}

but in the end, the flicker effect is still here...

here's my code :

import codeanticode.glgraphics.*; // librairie GLGraphics
import codeanticode.gsvideo.*; // librairie video GLGraphics
import javax.media.opengl.*; // librairie openGL
import processing.opengl.*; // librairie openGL
GSMovie back; // declaration fichiers video
GLGraphicsOffScreen outputCanvas;
GLTexture tex;
GLTexture outTex; // output texture
int outW = 1024; // offscreen buffer width
int outH = 768; // offscreen buffer height
void setup() {
size(1024,768, GLConstants.GLGRAPHICS);
frameRate(25);
tex = new GLTexture(this);
outputCanvas = new GLGraphicsOffScreen(this, outW, outH, true, 4); // 4 ?? A checker...
outTex = new GLTexture(this);
}
void movieEvent(GSMovie back) {
back.read();
}
void draw() {
outputCanvas.beginDraw();
outputCanvas.fill(0, 0);
outputCanvas.noStroke();
outputCanvas.rect(0, 0, width, height);
if (frameCount == 1) {
background(0);
}
if (tex.putPixelsIntoTexture()) {
image(tex, 0, 0);
}
outputCanvas.endDraw();
outTex = outputCanvas.getTexture();
image(outTex, 0, 0);
}
void keyPressed() {
if (key == '1') {
back = new GSMovie(this, "back_video1.mov");
back.setPixelDest(tex);
back.loop();
}
if (key == '2') {
back = new GSMovie(this, "back_video2.mov");
back.setPixelDest(tex);
back.loop();
}
}