problem with CustomBlending

[Dark-Energy]

Function setBlending in WebGLState incrorrectly process customBlending:

if ( blending !== currentBlending || premultipliedAlpha !== currentPremultipledAlpha ) {

	if ( blending === AdditiveBlending ) { 

	} else if ( blending === SubtractiveBlending ) {

	} else if ( blending === MultiplyBlending ) {

	//need check if CustomBlending given

	} else {

		//set normalBlending every time

	}

}

if ( blending === CustomBlending ) {

Three.js version

• Dev
• r85
• ...

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[WestLangley]

I formatted your post for clarity. Can you please make necessary corrections to your post and provide further detail?

[Dark-Energy]

sorry for my poor english, well, i ment this post have enogh details. this code fragment, which need fix. when i give CustomBlending parameter, this code first set NormalBlending, then do some check:
if ( blending === CustomBlending ) {
if ( blendSrc !== currentBlendSrc || blendDst !== currentBlendDst ...
{
this may either enable CustomBlending or not enable because some arbitrary conditions. Then normalBlending will be enabled anyway. In my view, need replace last "else" statement with "else if (blending !== customBlending)" in order prevent this.

[sasha240100]

@Dark-Energy Why not using switch/case syntax?

[WestLangley]

In my view, need replace last "else" statement with "else if (blending !== customBlending)" in order prevent this.

@Dark-Energy So we may better understand, can you please edit your original post and show how you think the code should be written? No code fragments, please.

[Dark-Energy]

how can i explain the code shoud be written with no code fragments?
i have written particle demo with customBlending and discover that my blending mode had been ignored. i began investgation and find that. I add pathed version library in my project.

There are two blocks of if's, first of them check and apply blending mode. It ended with 'else' block which enabled normalblending. State of WebGL is changed. Second if block check and apply custom modes. It checks state of srcColor & srcAlpha function changed and assign new values to local variables. And... this block may run only once, then it reckons states still unchanged. But state of blending may be changed in other places.
I patch the library, replace else in the end of first if block with 'else if'. Now my demo work fine.

[Dark-Energy]

@sasha240100 this way is acceptable.

[WestLangley]

@mrdoob I think the OP is suggesting a one-line change in the WebGLState function setBlending():

} else if ( blending === MultiplyBlending ) {

	if ( premultipliedAlpha ) {

		gl.blendEquationSeparate( gl.FUNC_ADD, gl.FUNC_ADD );
		gl.blendFuncSeparate( gl.ZERO, gl.SRC_COLOR, gl.ZERO, gl.SRC_ALPHA );

	} else {

		gl.blendEquation( gl.FUNC_ADD );
		gl.blendFunc( gl.ZERO, gl.SRC_COLOR );

	}

} else if ( blending !== CustomBlending ) { // <==== PROPOSED CHANGE

	if ( premultipliedAlpha ) {

		gl.blendEquationSeparate( gl.FUNC_ADD, gl.FUNC_ADD );
		gl.blendFuncSeparate( gl.ONE, gl.ONE_MINUS_SRC_ALPHA, gl.ONE, gl.ONE_MINUS_SRC_ALPHA );

	} else {

		gl.blendEquationSeparate( gl.FUNC_ADD, gl.FUNC_ADD );
		gl.blendFuncSeparate( gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.ONE, gl.ONE_MINUS_SRC_ALPHA );

	}

}

With all due respect, that change seems a bit hacky to me. I think the entire code block should not be executed if blending === CustomBlending.

[mrdoob]

@WestLangley sounds hacky indeed.

[WestLangley]

@mrdoob I think something needs to be done. Maybe this one-line change is adequate to prevent the code block from being called when CustomBlending is used.

if ( ( blending !== CustomBlending ) && ( blending !== currentBlending || premultipliedAlpha !== currentPremultipledAlpha ) ) {

[mrdoob]

That looks good.