public void setCustomBlendFactors(BlendFunc sfactorRGB, BlendFunc dfactorRGB, BlendFunc sfactorAlpha, BlendFunc dfactorAlpha) {
       this.sfactorRGB = sfactorRGB;
       this.dfactorRGB = dfactorRGB;
       this.sfactorAlpha = sfactorAlpha;
       this.dfactorAlpha = dfactorAlpha;
       cachedHashCode = -1;
    }
Sets the blend factors used for the source and destination color.
<p>
These factors will be multiplied with the color values of the input pixel
and the pixel already in the color buffer, before both colors gets combined by the {@link BlendEquation}.
<p>
<b>Note:</b> This gets only used in {@link BlendMode#Custom} mode.
All other blend modes will ignore this setting.

@param sfactorRGB   The source blend factor for RGB components.
@param dfactorRGB   The destination blend factor for RGB components.
@param sfactorAlpha The source blend factor for the alpha component.
@param dfactorAlpha The destination blend factor for the alpha component.
jme3-core/src/main/java/com/jme3/material/RenderState.java