EffectComposer render target does not preserve transparency in GLSL

Questions
1

I am simply trying to ignore (key) the transparent pixels in GLSL. The alpha is never preserved once accessing the texture in GLSL.

setup:


this.renderer = new WebGLRenderer({
    antialias: true,
    alpha: true,
    premultipliedAlpha: false,
    logarithmicDepthBuffer: true,
});
this.renderer.setClearColor(0x000000,0.0);
const cvs = this.renderer.domElement;
cvs.style.backgroundColor = 'transparent';

this.renderTargetComposer = new WebGLRenderTarget(window.innerWidth, window.innerHeight, { format: RGBAFormat });

this.composer = new EffectComposer(this.renderer,this.renderTargetComposer);

this.composer.renderToScreen = false;

update:

this.composer.render();

this.shader.uniforms.tDiffuse.value = this.renderTargetComposer.texture;

glsl:

vec4 baseColorRGBA = texture2D(tDiffuse, vUv);
if( baseColorRGBA.a < 0.01 ){ //never true
    discard;
}