a few questions about v4.0 render

First: why does it work?

void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 0.0);

I mean alfa value does not work. I have red color with alfa 0.0

Second: why does a Sprite3D’s color mix with parent?

The cat is a child of this red splash.

Sorry, but I can’t help you. I just use Sprite3D with textures, but it probably is a bad idea.

It shouldn’t. Does the cat sprite have transparency? It shouldn’t mix when the red cuboid has a texture or a color.