Shaders: How to blend shaders that effect SCREEN_UV?

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:bust_in_silhouette: Asked By Ron0Studios

I have a warp shader, it looks like this:

shader_type canvas_item;

uniform vec2 center;
uniform float force : hint_range(0,1, 0.01);
uniform float size : hint_range(0,1,0.01);
uniform float thick : hint_range(0,1,0.01);
uniform float range : hint_range(0,1.0,0.01);

void fragment(){
	vec2 scaledUV = UV;
	float mask = (1.0 - smoothstep(size,size+0.1, length(scaledUV - center)))
	 * smoothstep(size-thick-0.01, size-thick+0.4, length(scaledUV-center));
	vec2 disp = normalize(scaledUV - center) * force * mask;// * clamp(range-size,0.0,100.0);
	if(disp == vec2(0.0,0.0)){
		COLOR = texture(SCREEN_TEXTURE, SCREEN_UV);
	}
	else
		COLOR = texture(SCREEN_TEXTURE, SCREEN_UV-disp);
	//COLOR.rgb = vec3(disp,0.0);
	//COLOR.rgb = vec3(mask * clamp(range-size,0.0,100.0));
}

Basically all it does is warp the SCREEN_UV to create a shockwave effect. I’ve modified it from tutorials on youtube so that it can work as a standalone sfx at any position in the world (by using a regular UV and SCREEN_UV in conjunction)

However, I have been finding it difficult to layer two of these together, such as when two instances of the wave are created close to each other. As you can see, I have tried to solve this with an if-else statement, but it doesn’t really blend the two waves, but rather overrides certain parts to make the effect less jarring.

Is there a way to blend this?

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:bust_in_silhouette: Reply From: Inces

Overrides ? I imagine it would rather create glitched grotesque effect on waves meeting. Still I think You can achieve your goal with backbuffercopy node. You can apply it to whole screen or just child it to a wave instance. It will allow another shader to use information from SCREEN_UV not yet affected by first shockwave. So whenever any shockwave appears on screen, this place should be covered by new instance of backbuffercopy for the time being.