Add blend parameter

[Pessimistress]

Allow WebGL render pass to explicitly disable blending

Since WebGPU render pass has blending disabled by default this value will be safely ignored?

Change List

• Add blend: false which disables blending in WebGL

[donmccurdy]

Because neither WebGL nor WebGPU enables blending for color and alpha separately from the other, the answers to what is the default value of blendAlphaOperation or what happens with blendColorOperation='add' + blendAlphaOperation='none' are getting a bit complicated. I wonder if we should:

• (A) disallow 'none' for blendAlphaOperation, only use blendColorOperation to enable/disable blending
• (B) add a separate boolean parameter to enable/disable blending

if (parameters.blend === true) {
  const colorEquation = convertBlendOperationToEquation(
    'blendColorOperation',
    parameters.blendColorOperation || 'add'
  );
  // ...
} else {
  // ...
}

I lean toward (b), but not a strong preference.

[ibgreen]

While I initially proposed adding a none option when I was notified of the problem, after reviewing the PR and thinking more about it, I am also thinking that a separate blend enable type parameter seems cleanest.

[ibgreen]

Is there anyway we can avoid this?

[ibgreen]

This auto-enabling seems subtle.

• Is there any reason not to require blend: true to be set and remove the auto-enable?
• If some good backwards compatibility reason then maybe add a comment explaining that so that when we invariably refactor this next time, we don't break things in deck without knowing?

[ibgreen]

@Pessimistress merging, but removed the auto-enabling. we can open a separate PR with those changes if you feel they are important enough.