Textures - read and write

[lukeellison]

What is wrong?

Assignment to a texture fails with error gpu-browser.min.js:28 Uncaught Error: Error compiling fragment shader: ERROR: 0:461: 'assign' : l-value required. This should be possible but may not be implemented and would be useful. Regardless the error is cryptic.

Where does it happen?

In Web2GL supported browser running on a mac.

How do we replicate the issue?

const clearKernel = gpu
  .createKernel(function () {
    return 0;
  })
  .setOutput([3, 3])
  .setPipeline(true)
  .setImmutable(true);

const testKernel = gpu
  .createKernel(function (_tex) {
    const x = this.thread.x;
    _tex[x][x] = 1;
    return 0;
  })
  .setOutput([2]);

const tex = clearKernel();
const result = testKernel(tex);
console.log(tex.toArray());
tex.delete();

How important is this (1-5)?

I would say 2 because it currently doesn't break anything but the error and lack of claims that this is not supported is confusing. If it is supposed to be supported it should be higher.

Expected behavior (i.e. solution)

Should not error and should show:

[[1,0,0],
 [0,1,0],
 [0,0,0]]

Other Comments

Another solution would be to have some way of outputting a copied texture that was a different size to the kernel size? I.e different output size to kernel size.

Thank you for your time looking into this.

[regretronics]

i got the same problem even when the textures are not immutable. that feature would be really useful to me, because i'm doing deeply iterative computations (currently, creating new textures for every iteration, which sometimes causes freezing or unpredictable jittering).

[SparkHao]

The array passed as a parameter cannot be modified internally, I don't know why