How to set custom blend func?

mabu · January 27, 2022, 1:28pm

front-to-back alpha blending for example requires GL_ONE_MINUS_DST_ALPHA, GL_ONE - how can this be set with playcanvas?
Also, how can a separate blend func be set for alpha (as can with WebGLRenderingContext.blendFuncSeparate() - Web APIs | MDN) ?

yaustar · January 27, 2022, 2:12pm

I believe you can set this via the graphics device: https://developer.playcanvas.com/en/api/pc.GraphicsDevice.html#setBlendFunction

mabu · January 27, 2022, 2:21pm

won’t this be overwritten by the material though?

yaustar · January 27, 2022, 2:28pm

Ah, I best ask @mvaligursky on this

mvaligursky · January 27, 2022, 2:58pm

I don’t think there’s any public interface for this at the moment.
Under the hood, the material class stores those, so you could carefully set those yourself.

github.com

playcanvas/engine/blob/668a760117e6afadbd76716c69aa959811486342/src/scene/materials/material.js#L117-L125

    
      
          this.blend = false;
          this.blendSrc = BLENDMODE_ONE;
          this.blendDst = BLENDMODE_ZERO;
          this.blendEquation = BLENDEQUATION_ADD;
          
          
this.separateAlphaBlend = false;
          this.blendSrcAlpha = BLENDMODE_ONE;
          this.blendDstAlpha = BLENDMODE_ZERO;
          this.blendAlphaEquation = BLENDEQUATION_ADD;