Detect max `smooth()` setting to avoid OpenGL errors

[cacheflowe]

I don't think this really needs to be addressed, but I wanted to make note of the error, since I didn't find any info elsewhere. I was moving a Java project to Mac from Windows (where this isn't a problem), and it took me a bit to figure out what was causing the error.

On a Silicon Mac (I'm on an M1) with Processing 4.2, setting smooth(8) in setup() has a weird side-effect of breaking PGraphics. I now see in the smooth() documentation that 8 is a valid value, but not on all machines. This makes sense, and probably explains the error, noted below. The problem goes away if I use smooth(4) instead!

The code:

PGraphics pg;

void setup() {
  size(400, 400, P3D);
  smooth(8);

  pg = createGraphics(400, 400, P3D);
  pg.beginDraw();
  pg.fill(0, 255, 0);
  pg.rect(20, 20, 60, 60);
  pg.endDraw();
}

void draw() {
  background(0);
  image(pg, 0, 0);
  ellipse(120, 192, 144, 144);
  ellipse(280, 192, 144, 144);
}

The error:

OpenGL error 1282 at bot beginDraw(): invalid operation
RuntimeException: Cannot validate shader program:
Validation Failed: Current draw framebuffer is invalid.

RuntimeException: Cannot validate shader program:
Validation Failed: Current draw framebuffer is invalid.

If I comment out the drawing on pg, the error changes, and the app doesn't completely crash:

The code:

PGraphics pg;

void setup() {
  size(400, 400, P3D);
  smooth(8);

  pg = createGraphics(400, 400, P3D);
}

void draw() {
  background(0);
  image(pg, 0, 0);
  ellipse(120, 192, 144, 144);
  ellipse(280, 192, 144, 144);
}

The error:

UNSUPPORTED (log once): POSSIBLE ISSUE: unit 0 GLD_TEXTURE_INDEX_2D is unloadable and bound to sampler type (Float) - using zero texture because texture unloadable
OpenGL error 1282 at bot beginDraw(): invalid operation
OpenGL error 1286 at top endDraw(): invalid framebuffer operation
OpenGL error 1286 at bot endDraw(): invalid framebuffer operation
The pixels array is null.

[benfry]

Changing this to an enhancement request in case there's a way we can query GL for the max setting rather than getting these errors. I seem to recall there was not back when this first went in, but that was a long time ago, so maybe it's changed (or I'm mistaken and I just didn't have time to track it down).