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

Created by: 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.

先使用 smooth(8)、P3D 和 createGraphics() 复现 setup()，然后跟踪会在 M1 Mac 上产生报告中 framebuffer 错误的 PGraphics beginDraw() 路径。将其行为与 smooth(4) 进行比较；当检测到或处理了不受支持的 smooth 设置，且不再出现 OpenGL 和 PGraphics 错误时，即表示完成。